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1
Andriessen, Rob, Janneke Snetselaar, Remco A. Suer, Anne J. Osinga, Johan Deschietere, Issa N. Lyimo, Ladslaus L. Mnyone, et al. "Electrostatic coating enhances bioavailability of insecticides and breaks pyrethroid resistance in mosquitoes." Proceedings of the National Academy of Sciences 112, no. 39 (August 31, 2015): 12081–86. http://dx.doi.org/10.1073/pnas.1510801112.
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Insecticide resistance poses a significant and increasing threat to the control of malaria and other mosquito-borne diseases. We present a novel method of insecticide application based on netting treated with an electrostatic coating that binds insecticidal particles through polarity. Electrostatic netting can hold small amounts of insecticides effectively and results in enhanced bioavailability upon contact by the insect. Six pyrethroid-resistant Anopheles mosquito strains from across Africa were exposed to similar concentrations of deltamethrin on electrostatic netting or a standard long-lasting deltamethrin-coated bednet (PermaNet 2.0). Standard WHO exposure bioassays showed that electrostatic netting induced significantly higher mortality rates than the PermaNet, thereby effectively breaking mosquito resistance. Electrostatic netting also induced high mortality in resistant mosquito strains when a 15-fold lower dose of deltamethrin was applied and when the exposure time was reduced to only 5 s. Because different types of particles adhere to electrostatic netting, it is also possible to apply nonpyrethroid insecticides. Three insecticide classes were effective against strains of Aedes and Culex mosquitoes, demonstrating that electrostatic netting can be used to deploy a wide range of active insecticides against all major groups of disease-transmitting mosquitoes. Promising applications include the use of electrostatic coating on walls or eave curtains and in trapping/contamination devices. We conclude that application of electrostatically adhered particles boosts the efficacy of WHO-recommended insecticides even against resistant mosquitoes. This innovative technique has potential to support the use of unconventional insecticide classes or combinations thereof, potentially offering a significant step forward in managing insecticide resistance in vector-control operations.
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Gourley, Stephen A., Rongsong Liu, and Jianhong Wu. "Slowing the evolution of insecticide resistance in mosquitoes: a mathematical model." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 467, no. 2132 (January 19, 2011): 2127–48. http://dx.doi.org/10.1098/rspa.2010.0413.
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A big problem in malaria control is the rapidity with which mosquitoes can develop resistance to insecticides. The possibility of creating evolution-proof insecticides is therefore of considerable interest. Biologists have suggested that effective malaria control, with only weak selection for insecticide resistance, could be achieved if insecticides target only old mosquitoes that have already laid most of their eggs. The strategy aims to exploit the fact that most malarial mosquitoes do not live long enough to transmit the disease. We derive, analyse and compare two mathematical models, one for an insecticide that kills on exposure, and the other for an insecticide that targets only older mosquitoes. Both models predict that insecticide-resistant mosquitoes will become dominant over time but, very importantly, this occurs on a very much slower time scale when the insecticide only affects older mosquitoes. We present analytical results on linear and global stability of the non-trivial equilibrium in which only the resistant mosquito strain is present, together with a theorem comparing the rates of convergence for the two models. Numerical simulations show that the effect of targeting only old mosquitoes on the evolution of resistance is dramatic.
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N’Dri, Bédjou P., Kathrin Heitz-Tokpa, Mouhamadou Chouaïbou, Giovanna Raso, Amoin J. Koffi, Jean T. Coulibaly, Richard B. Yapi, Pie Müller, and Jürg Utzinger. "Use of Insecticides in Agriculture and the Prevention of Vector-Borne Diseases: Population Knowledge, Attitudes, Practices and Beliefs in Elibou, South Côte d’Ivoire." Tropical Medicine and Infectious Disease 5, no. 1 (March 1, 2020): 36. http://dx.doi.org/10.3390/tropicalmed5010036.
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People’s knowledge, attitudes, practices and beliefs (KAPB) pertaining to malaria are generally well described. However, little is known about population knowledge and awareness of insecticide resistance in malaria vectors. The aim of this study was to investigate KAPB related to insecticide resistance in malaria vectors due to the use of insecticides in agriculture and the prevention against mosquitoes. In mid-2017, we carried out a cross-sectional survey in Elibou, South Côte d’Ivoire, employing a mixed methods approach. Quantitative data were obtained with a questionnaire addressed to household heads. Interviews were conducted with key opinion leaders, including village chiefs, traditional healers, heads of health centres and pesticide sellers. Focus group discussions were conducted with youth and elders. A total of 203 individuals participated in the questionnaire survey (132 males, 65%). We found that people had good knowledge about malaria and mosquitoes transmitting the disease, while they felt that preventing measures were ineffective. Pesticides were intensively used by farmers, mainly during the rainy season. Among the pesticides used, insecticides and herbicides were most commonly used. While there was poor knowledge about resistance, the interviewees stated that insecticides were not killing the mosquitoes anymore. The main reason given was that insecticides were diluted by the manufacturers as a marketing strategy to sell larger quantities. More than a third of the farmers used agricultural pesticides for domestic purposes to kill weeds or mosquitoes. We observed a misuse of pesticides among farmers, explained by the lack of specific training. In the community, long-lasting insecticidal nets were the most common preventive measure against malaria, followed by mosquito coils and insecticide sprays. The interviewees felt that the most effective way of dealing with insecticide resistance was to combine at least two preventive measures. In conclusion, population attitudes and practices related to insecticides used in agriculture and the prevention against mosquitoes could lead to resistance in malaria vectors, while people’s knowledge about insecticide resistance was limited. There is a need to raise awareness in communities about the presence of resistance in malaria vectors and to involve them in resistance management.
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David, Jean-Philippe, Hanafy Mahmoud Ismail, Alexia Chandor-Proust, and Mark John Ingraham Paine. "Role of cytochrome P450s in insecticide resistance: impact on the control of mosquito-borne diseases and use of insecticides on Earth." Philosophical Transactions of the Royal Society B: Biological Sciences 368, no. 1612 (February 19, 2013): 20120429. http://dx.doi.org/10.1098/rstb.2012.0429.
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The fight against diseases spread by mosquitoes and other insects has enormous environmental, economic and social consequences. Chemical insecticides remain the first line of defence but the control of diseases, especially malaria and dengue fever, is being increasingly undermined by insecticide resistance. Mosquitoes have a large repertoire of P450s (over 100 genes). By pinpointing the key enzymes associated with insecticide resistance we can begin to develop new tools to aid the implementation of control interventions and reduce their environmental impact on Earth. Recent technological advances are helping us to build a functional profile of the P450 determinants of insecticide metabolic resistance in mosquitoes. Alongside, the cross-responses of mosquito P450s to insecticides and pollutants are also being investigated. Such research will provide the means to produce diagnostic tools for early detection of P450s linked to resistance. It will also enable the design of new insecticides with optimized efficacy in different environments.
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Luan, Kun, Andre J. West, Marian G. McCord, Emiel A. DenHartog, Quan Shi, Isa Bettermann, Jiayin Li, et al. "Mosquito-Textile Physics: A Mathematical Roadmap to Insecticide-Free, Bite-Proof Clothing for Everyday Life." Insects 12, no. 7 (July 13, 2021): 636. http://dx.doi.org/10.3390/insects12070636.
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Garments treated with chemical insecticides are commonly used to prevent mosquito bites. Resistance to insecticides, however, is threatening the efficacy of this technology, and people are increasingly concerned about the potential health impacts of wearing insecticide-treated clothing. Here, we report a mathematical model for fabric barriers that resist bites from Aedes aegypti mosquitoes based on textile physical structure and no insecticides. The model was derived from mosquito morphometrics and analysis of mosquito biting behavior. Woven filter fabrics, precision polypropylene plates, and knitted fabrics were used for model validation. Then, based on the model predictions, prototype knitted textiles and garments were developed that prevented mosquito biting, and comfort testing showed the garments to possess superior thermophysiological properties. Our fabrics provided a three-times greater bite resistance than the insecticide-treated cloth. Our predictive model can be used to develop additional textiles in the future for garments that are highly bite resistant to mosquitoes.
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Hareem Sajjad and Neelam Arif. "Biological Control of Mosquito Vectors." Scientific Inquiry and Review 3, no. 1 (January 31, 2019): 25–32. http://dx.doi.org/10.32350/sir.31.03.
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The main purpose of this review paper is to study different biological control methods for controlling mosquito vectors. Mosquitoes act as vector for many harmful diseases including malaria, dengue fever, yellow fever, filarial, encephalitis, chikungunya, dengue and poly arthritis. The use of chemical insecticides for controlling mosquitoes is limited because they develop resistance against these insecticides. So, efforts have been made to control the mosquito vectors by eco-friendly techniques. At present, biocontrol agents are used to control the mosquito species with the aim to reduce the impact and cost of insecticide based strategies. These biocontrol agents involve the use of natural enemies including bacteria, fungi, larvivorous fish, protozoans and nematodes. These agents target mosquitoes at different stages of their life cycle. In this paper, we focus on several bio-controlling methods used to reduce the population of mosquito vectors.
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Yanuar, Firda, and Willem Sugiharto. "Efikasi Insektisida Gokilath-S50EC (d,d-transsifenotrin 50 g/l) terhadap Nyamuk Aedes aegypti dengan Metode Pengabutan (Thermal Fogging)." ASPIRATOR - Journal of Vector-borne Disease Studies 10, no. 2 (December 10, 2018): 73–82. http://dx.doi.org/10.22435/asp.v10i2.187.
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Dengue vector control is still relying on fogging using insecticides with solar solvents. This causes pollution due to the odors generated and residues left in the environment. It is necessary to look for alternative insecticides that no longer use solar as a solvent but use water such as Gokilath-S50EC. In this experiment, we tested the effectiveness of Gokilath-S50EC (d,d-trans-syphenotrin 50 g/l) with the aim to see the insecticidal efficacy of Aedes aegypti known as DHF vector. The sample test mosquito used is Ae. aegypti which comes from Pangandaran Lokalitbangkes as many as 25 females. Test mosquitoes were exposed to insecticides for 3-5 seconds with a method of fogging. The experimental results showed that mosquitoes tested fainting in the first 30 seconds after exposure to insecticides. The same results were shown when the solvent was added polyethylene-glycol (PEG). This time trial also measured droplet diameters at 1.0 mm and 1.2 mm nozzle with or without PEG. The test results showed that PEG increased the percentage of droplets of ≥ 50 µm in air and made the insecticide reach even further. Gokilath-S50EC insecticides are effective in killing Ae. aegypti by using water solvents, the addition of PEG will increase the reach of insecticides but not affect the effectiveness of insecticides.
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Weedall, Gareth D., Leon M. J. Mugenzi, Benjamin D. Menze, Magellan Tchouakui, Sulaiman S. Ibrahim, Nathalie Amvongo-Adjia, Helen Irving, et al. "A cytochrome P450 allele confers pyrethroid resistance on a major African malaria vector, reducing insecticide-treated bednet efficacy." Science Translational Medicine 11, no. 484 (March 20, 2019): eaat7386. http://dx.doi.org/10.1126/scitranslmed.aat7386.
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Metabolic resistance to insecticides such as pyrethroids in mosquito vectors threatens control of malaria in Africa. Unless it is managed, recent gains in reducing malaria transmission could be lost. To improve monitoring and assess the impact of insecticide resistance on malaria control interventions, we elucidated the molecular basis of pyrethroid resistance in the major African malaria vector, Anopheles funestus. We showed that a single cytochrome P450 allele (CYP6P9a_R) in A. funestus reduced the efficacy of insecticide-treated bednets for preventing transmission of malaria in southern Africa. Expression of key insecticide resistance genes was detected in populations of this mosquito vector throughout Africa but varied according to the region. Signatures of selection and adaptive evolutionary traits including structural polymorphisms and cis-regulatory transcription factor binding sites were detected with evidence of selection due to the scale-up of insecticide-treated bednet use. A cis-regulatory polymorphism driving the overexpression of the major resistance gene CYP6P9a allowed us to design a DNA-based assay for cytochrome P450–mediated resistance to pyrethroid insecticides. Using this assay, we tracked the spread of pyrethroid resistance and found that it was almost fixed in mosquitoes from southern Africa but was absent from mosquitoes collected elsewhere in Africa. Furthermore, a field study in experimental huts in Cameroon demonstrated that mosquitoes carrying the resistance CYP6P9a_R allele survived and succeeded in blood feeding more often than did mosquitoes that lacked this allele. Our findings highlight the need to introduce a new generation of insecticide-treated bednets for malaria control that do not rely on pyrethroid insecticides.
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Balabanidou, Vasileia, Mary Kefi, Michalis Aivaliotis, Venetia Koidou, Juan R. Girotti, Sergio J. Mijailovsky, M. Patricia Juárez, et al. "Mosquitoes cloak their legs to resist insecticides." Proceedings of the Royal Society B: Biological Sciences 286, no. 1907 (July 17, 2019): 20191091. http://dx.doi.org/10.1098/rspb.2019.1091.
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Malaria incidence has halved since the year 2000, with 80% of the reduction attributable to the use of insecticides. However, insecticide resistance is now widespread, is rapidly increasing in spectrum and intensity across Africa, and may be contributing to the increase of malaria incidence in 2018. The role of detoxification enzymes and target site mutations has been documented in the major malaria vector Anopheles gambiae ; however, the emergence of striking resistant phenotypes suggests the occurrence of additional mechanisms. By comparing legs, the most relevant insect tissue for insecticide uptake, we show that resistant mosquitoes largely remodel their leg cuticles via enhanced deposition of cuticular proteins and chitin, corroborating a leg-thickening phenotype. Moreover, we show that resistant female mosquitoes seal their leg cuticles with higher total and different relative amounts of cuticular hydrocarbons, compared with susceptible ones. The structural and functional alterations in Anopheles female mosquito legs are associated with a reduced uptake of insecticides, substantially contributing to the resistance phenotype.
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Sadia, Christabelle G., France-Paraudie A. Kouadio, Behi K. Fodjo, Sebastien K. Oyou, Adepo-Gourene A. Beatrice, Benjamin G. Koudou, and Chouaïbou S. Mouhamadou. "Short-term metabolic resistance inductive effect of different agrochemical groups on Anopheles gambiae mosquitoes." Wellcome Open Research 6 (June 11, 2021): 147. http://dx.doi.org/10.12688/wellcomeopenres.16876.1.
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Background: In order to assess the impact of the different groups of agricultural pesticides used in Côte d'Ivoire on the increase of mosquitoes resistance to insecticides, the expression profiles of 7 P450 cytochromes and one GSTE2 of Anopheles gambiae involved in mosquito resistance to insecticides were studied. The goal of this study was to determine the effect of short exposure of mosquito larvae to different groups of agricultural pesticides on mosquito resistance. Methods: Three groups of pesticides were selected: (i) agricultural insecticide solutions, (ii) none-insecticide pesticide solutions (a mixture of herbicides and fungicides), and (iii) a mixture of the first two. A fourth non-pesticide solution was used as a control. Four groups of each stage 2 larvae (strain Kisumu, male and female) were exposed to 20% concentrated solution for 24 hours. Susceptibility tests for dichlorodiphenyltrichloroethane (DDT) and Deltamethrin were carried out on adults aged 2-5 days. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was performed to quantify the expression of eight metabolic genes involved in mosquito resistance to insecticides. Results: Susceptibility to DDT showed a similar increase in the time required to knock down 50% of mosquitoes (kdt50) in l colonies exposed to insecticides and none-insecticides compared to the control colony. As for deltamethrin, kdt50 was higher in the colonies exposed to insecticides and the pesticide mixture compared to the colony exposed to none-insecticides. Of all the genes studied in all colonies, except for CYP6P1 induced only in the colony consisting of the pesticide mixture, no genes were induced. Conclusions: This study confirmed that induction is influenced by the duration, the concentration of the solution and the type of xenobiotic used as an inducer. The overexpression of CYP6P1 confirmed the inductive effect that a short exposure of mosquito larvae to agricultural pesticides could have.
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Chandor-Proust, Alexia, Jaclyn Bibby, Myriam Régent-Kloeckner, Jessica Roux, Emilie Guittard-Crilat, Rodolphe Poupardin, Muhammad Asam Riaz, et al. "The central role of mosquito cytochrome P450 CYP6Zs in insecticide detoxification revealed by functional expression and structural modelling." Biochemical Journal 455, no. 1 (September 13, 2013): 75–85. http://dx.doi.org/10.1042/bj20130577.
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The key role of mosquito cytochrome P450 monooxygenases from the CYP6Z subfamily in the resistance of mosquitoes to insecticides was revealed. By using functional expression and in silico modelling, the capacity of CYP6Zs to degrade insecticide metabolites produced by esterase-mediated hydrolysis was demonstrated.
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Aryaprema, Vindhya S. "SEMI-FIELD EVALUATION OF ULTRA-LOW VOLUME (ULV) GROUND SPRAY OF AQUALUER ® 20-20 AGAINST IRRADIATED AEDES AEGYPTI." Journal of the Florida Mosquito Control Association 68, no. 1 (June 10, 2021): 63–69. http://dx.doi.org/10.32473/jfmca.v68i1.129101.
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Sterile insect technique (SIT) using irradiated mosquitoes is an effective control method capable of being assimilated into integrated vector management (IVM) programs. Chemical control of mosquitoes using ultra-low volume (ULV) spray applications of pyrethroid and organophosphate insecticides is already an essential component of IVM programs. Prior to their release in nature, irradiation of mosquitoes for SIT use can significantly impact the mosquito’s biology, specifically its host-seeking and feeding behavior. Little is known about how radiation exposure might impact a mosquito’s susceptibility to pyrethroid insecticides. The present study was carried out to evaluate the influence of Aqualuer ® 20-20 ULV applications on irradiated Aedes aegypti. Caged mosquito trials indicated that both male and female irradiated Ae. aegypti were as susceptible as their non-irradiated counterparts of the same population to Aqualuer 20-20 ULV application, with the highest mean percent mortalities achieved at the first 24h post-treatment period at both 30.5 m and 61 m downwind of the spray application path.
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Githinji, Edward K., Lucy W. Irungu, Paul N. Ndegwa, Maxwell G. Machani, Richard O. Amito, Brigid J. Kemei, Paul N. Murima, et al. "Impact of Insecticide Resistance on P. falciparum Vectors’ Biting, Feeding, and Resting Behaviour in Selected Clusters in Teso North and South Subcounties in Busia County, Western Kenya." Journal of Parasitology Research 2020 (April 8, 2020): 1–11. http://dx.doi.org/10.1155/2020/9423682.
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Introduction. Behavioural resistance to insecticides restrains the efficacy of vector control tools against mosquito-transmitted diseases. The current study is aimed at determining the impact of insecticide resistance on major malaria vectors’ biting, feeding, and resting behaviour in areas with and areas without insecticide resistance in Teso North and Teso South, Busia County, Western Kenya. Methods. Mosquito larvae were sampled using a dipper, reared into 3-5-day-old female mosquitoes [4944] which were exposed to 0.75% permethrin and 0.05% deltamethrin using World Health Organization tube assay method. Blood meal, species identification, and kdr Eastgene PCRs were also performed on adult mosquitoes sampled using mosquito collection methods [3448]. Biting, feeding, resting, and exiting behaviours of field-collected mosquitoes from five selected clusters were analysed. Results. The lowest Kdr genotypic frequency (SS) proportion was found in female Anophelines collected in Kengatunyi at 58% while Rwatama had the highest genotypic frequency at 93%, thus susceptible and resistant clusters, respectively. The peak hour for mosquito seeking a human bite was between 0300 and 0400 hrs in the resistant cluster and 0400-0500 hrs in the susceptible cluster. The heterozygous mosquitoes maintained the known 2100-2200 hrs peak hour. There was a higher proportion of homozygous susceptible vectors (86.4%) seeking humans indoor than outdoor bitters (78.3%). Mosquito blood meals of human origin were 60% and 87% in susceptible Kengatunyi and resistant Rwatama cluster, respectively. There was significant difference between homozygous-resistant vectors feeding on human blood compared to homozygous susceptible mosquitoes (p≤0.05). The proportion of bovine blood was highest in the susceptible cluster. A higher proportion of homozygous-resistant anophelines were feeding and resting indoors. No heterozygous mosquito was found resting indoor while 4.2% of the mosquitoes were caught while exiting the house through the window. Discussion. A shift in resistant Anopheles gambiae sl highest peak hour of aggressiveness from 2100-2200 hrs to 0300-0400 hrs is a key change in its biting pattern. Due to the development of resistance, mosquitoes no longer have to compete against the time the human host enters into the formerly lethal chemical and or physical barrier in the form of long-lasting insecticide-treated net. No heterozygous LS mosquito rested indoors possibly due to disadvantages of heterozygosity which could have increased their fitness costs as well as energy costs in the presence of the insecticidal agents in the treated nets. Conclusions and recommendations. Out of bed biting by female mosquitoes and partial susceptibility may contribute to residual malaria transmission. Insecticide-resistant vectors have become more endophagic and anthropophillic. Hence, insecticidal nets, zooprophylaxis, and novel repellents are still useful chemical, biological, and physical barriers against human blood questing female mosquitoes. Further studies should be done on genetic changes in mosquitoes and their effects on changing mosquito behaviour.
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Knecht, Heidi, Stephanie Richards, Jo Balanay, and Avian White. "Impact of Mosquito Age and Insecticide Exposure on Susceptibility of Aedes albopictus (Diptera: Culicidae) to Infection with Zika Virus." Pathogens 7, no. 3 (August 12, 2018): 67. http://dx.doi.org/10.3390/pathogens7030067.
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Zika virus (ZIKV) is primarily transmitted to humans by Aedes aegypti and Ae. albopictus. Vector–virus interactions influencing vector competence vary and depend on biological and environmental factors. A mosquito’s chronological age may impact its immune response against virus infection. Insecticides, source reduction, and/or public education are currently the best defense against mosquitoes that transmit ZIKV. This study assessed the effects of a mosquito’s chronological age at time of infection on its response to ZIKV infection. We exposed young (6–7 d post-emergence) and old (11–12 d post-emergence) Ae. albopictus to a sublethal dose of bifenthrin prior to oral exposure to blood meals containing ZIKV (7-day incubation period). Old mosquitoes experienced a significantly (p < 0.01) higher rate of mortality than young mosquitoes. Significantly higher ZIKV body titers (p < 0.01) were observed in the old control group compared to the young control group. Significantly higher (p < 0.01) ZIKV dissemination rates and leg titers (p < 0.01) were observed in old bifenthrin-exposed mosquitoes compared to old control mosquitoes or young bifenthrin-exposed or control mosquitoes. Hence, bifenthrin exposure may increase the potential for virus transmission; however, the degree of these impacts varies with mosquito age. Impacts of insecticides should be considered in risk assessments of potential vector populations.
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Abdurrakhman, Abdurrakhman. "Uji Resistensi Lambdacyhalothrin Terhadap Nyamuk Aedes Aegypti di Wilayah Pelabuhan Laut." JURNAL KESEHATAN LINGKUNGAN: Jurnal dan Aplikasi Teknik Kesehatan Lingkungan 16, no. 1 (November 21, 2019): 689. http://dx.doi.org/10.31964/jkl.v16i1.156.
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Abstract: Resistance Test of Lambdacyhalothrin on Aedes Aegypti Mosquito In Port Area. Dengue fever is caused by dengue virus which is transmitted to human blood circulation through the bite of the Aedes aegypti mosquito which is transmitted in almost all parts of Indonesia. Aedes vector control is very intense, especially in the use of insecticides and community empowerment in vector habitat environmental management. Factors using improper insecticides can lead to resistance. This study aims to identify insecticide resistant levels of aedes aegypti mosquitoes in the Semayang Port area. This study was an observational study. The research was carried out by taking samples of mosquitoes from the Prapatan sub-district RT 14 Semayang Port working area, Balikpapan Class II KKP. The population of this study is Ae. adult aegypti from pre-mature breeding obtained from a field that inherits the parent's resisitency. The sample of this study was 20 Ae mosquitoes. Adult aegypti each treatment. Mosquitoes for the test material in this study came from larvae obtained from the RT 14 wilker village of Semayang Port where the area is a buffer zone in Semayang which is routinely controlled. The test data was obtained by observing the mortality of test and control mosquitoes after being exposed to 0.05% lambdacyhalothrin for 30 minutes. Of the 20 mosquitoes tested, the number of mosquitoes fell in minutes 1, 5, 10, 20, 30, 1 hour and 24 hours. Aedes aegypti mosquito originating from RT 14 Prapatan Subdistrict, Balikpapan tolerant to lambdacyhalothrin 0.05%.
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Salinas, Wendy S., Teresa P. Feria-Arroyo, and Christopher J. Vitek. "Temperatures Influence Susceptibility to Insecticides in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Mosquitoes." Pathogens 10, no. 8 (August 6, 2021): 992. http://dx.doi.org/10.3390/pathogens10080992.
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Aedes aegypti and Aedes albopictus (Diptera: Culicidae) are vectors for several arboviruses, including dengue, Zika virus and chikungunya virus. The primary method of controlling these diseases is controlling the vector population, often with insecticides. Insecticide resistance may impact the success of these efforts. We tested the effect of variable temperature exposures on susceptibility to insecticides by exposing adult A.aegypti and A. albopictus to different temperatures and tested their susceptibility to insecticides. We hypothesized that adults maintained at high temperatures would show increased susceptibility to insecticides relative to lower temperatures. Colony mosquitoes were hatched, reared to adulthood and then maintained in three temperature regimes that reflect average seasonal temperatures in the Rio Grande Valley, TX. Susceptibility to permethrin and deltamethrin was assessed using the CDC bottle bioassay method. Overall Aedes albopictus had higher susceptibility to all insecticides than Aedes aegypti. Mosquitoes kept at different temperatures exhibited differential susceptibility to insecticides. Low temperature exposed mosquitoes had decreased susceptibility while high temperature conditions resulted in increased mortality. Our results suggest public health officials must consider temperature effects when controlling mosquitoes with insecticides.
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Park, Seo Hye, Hojong Jun, Seong Kyu Ahn, Jinyoung Lee, Sung-Lim Yu, Sung Keun Lee, Jung-Mi Kang, et al. "Monitoring Insecticide Resistance and Target Site Mutations of L1014 Kdr And G119 Ace Alleles in Five Mosquito Populations in Korea." Korean Journal of Parasitology 58, no. 5 (October 22, 2020): 543–50. http://dx.doi.org/10.3347/kjp.2020.58.5.543.
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Mosquitoes are globally distributed and important vectors for the transmission of many human diseases. Mosquito control is a difficult task and the cost of preventing mosquito-borne diseases is much lower than that for curing the associated diseases. Thus, chemical control remains the most effective tool for mosquito. Due to the long-term intensive use of insecticides to control mosquito vectors, resistance to most chemical insecticides has been reported. This study aimed to investigate the relationship between insecticide resistance and target site mutation of L1014 kdr and G119 ace alleles in 5 species/species group of mosquitoes (Aedes vexans, Ae. albopictus, Anopheles spp., Culex pipiens complex, and Cx. tritaeniorhynchus) obtained from 6 collection sites. For Anopheles spp., the proportion of mosquitoes with mutated alleles in L1014 was 88.4%, homozygous resistant genotypes were observed in 46.7%, and heterozygous resistant genotypes were observed in 41.8%. For the Cx. pipiens complex and Cx. tritaeniorhynchus species, homozygous resistant genotypes were found in 25.9% and 9.8%, respectively. However, target site mutation of L1014 in the Ae. vexans nipponii and Ae. albopictus species was not observed. Anopheles spp., Cx. pipiens complex, and Cx. tritaeniorhynchus mosquitoes were resistant to deltamethrin and chlorpyriphos, whereas Ae. vexans nipponii and Ae. albopictus were clearly susceptible. We also found a correlation between the resistance phenotype and the presence of the L1014 kdr and G119 ace mutations only in the Anopheles spp. population. In this study, we suggest that insecticide resistance poses a growing threat and resistance management must be integrated into all mosquito control programs.
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Yang, Fan, Samuel Schildhauer, Sarah A. Billeter, Melissa Hardstone Yoshimizu, Robert Payne, Mary Joyce Pakingan, Marco E. Metzger, et al. "Insecticide Resistance Status of Aedes aegypti (Diptera: Culicidae) in California by Biochemical Assays." Journal of Medical Entomology 57, no. 4 (March 11, 2020): 1176–83. http://dx.doi.org/10.1093/jme/tjaa031.
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Abstract Insecticide resistance in Aedes aegypti mosquitoes poses a major threat to public health worldwide. There are two primary biological mechanisms that can lead to insecticide resistance, target site and metabolic resistance, both of which confer resistance to specific classes of insecticides. Due to the limited number of chemical compounds available for mosquito control, it is important to determine current enzymatic profiles among mosquito populations. This study assessed resistance profiles for three metabolic pathways, α-esterases, β-esterases, and mixed-function oxidases (MFOs), as well as insensitivity of the acetylcholinesterase (iAChE) enzyme in the presence of propoxur, among Ae. aegypti from the Central Valley and southern California. All field-collected Ae. aegypti demonstrated elevated MFOs and iAChE activity, indicating potential development of pyrethroid and organophosphate resistance, respectively. Although regional variations were found among α-esterase and β-esterase activity, levels were generally elevated, further suggesting additional mechanisms for developing organophosphate resistance. Furthermore, mosquito samples from southern California exhibited a higher expression level to all three metabolic enzymes and iAChE activity in comparison to mosquitoes from the central region. These results could help guide future mosquito control efforts, directing the effective use of insecticides while limiting the spread of resistance.
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Viana, Mafalda, Angela Hughes, Jason Matthiopoulos, Hilary Ranson, and Heather M. Ferguson. "Delayed mortality effects cut the malaria transmission potential of insecticide-resistant mosquitoes." Proceedings of the National Academy of Sciences 113, no. 32 (July 11, 2016): 8975–80. http://dx.doi.org/10.1073/pnas.1603431113.
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Malaria transmission has been substantially reduced across Africa through the distribution of long-lasting insecticidal nets (LLINs). However, the emergence of insecticide resistance within mosquito vectors risks jeopardizing the future efficacy of this control strategy. The severity of this threat is uncertain because the consequences of resistance for mosquito fitness are poorly understood: while resistant mosquitoes are no longer immediately killed upon contact with LLINs, their transmission potential may be curtailed because of longer-term fitness costs that persist beyond the first 24 h after exposure. Here, we used a Bayesian state-space model to quantify the immediate (within 24 h of exposure) and delayed (>24 h after exposure) impact of insecticides on daily survival and malaria transmission potential of moderately and highly resistant laboratory populations of the major African malaria vector Anopheles gambiae. Contact with LLINs reduced the immediate survival of moderately and highly resistant An. gambiae strains by 60–100% and 3–61%, respectively, and delayed mortality impacts occurring beyond the first 24 h after exposure further reduced their overall life spans by nearly one-half. In total, insecticide exposure was predicted to reduce the lifetime malaria transmission potential of insecticide-resistant vectors by two-thirds, with delayed effects accounting for at least one-half of this reduction. The existence of substantial, previously unreported, delayed mortality effects within highly resistant malaria vectors following exposure to insecticides does not diminish the threat of growing resistance, but posits an explanation for the apparent paradox of continued LLIN effectiveness in the presence of high insecticide resistance.
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Fodjo, Behi K., Benjamin G. Koudou, Emmanuel Tia, Jasmina Saric, Prisca B. N’dri, Marius G. Zoh, Christabelle S. Gba, Alida Kropf, Nestor B. Kesse, and Mouhamadou S. Chouaïbou. "Insecticides Resistance Status of An. gambiae in Areas of Varying Agrochemical Use in Côte D’Ivoire." BioMed Research International 2018 (October 8, 2018): 1–9. http://dx.doi.org/10.1155/2018/2874160.
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Background. Insecticide resistance monitoring of the malaria vectors to different classes of insecticides is necessary for resistance management. Malaria vector control management approaches are essentially based on IRS and LLINs. However, insecticide resistance is caused by several sources of selection and in case the selection pressure is from agricultural practices, then measures need to be taken to avoid a failure of the control methods put in place. The current study was undertaken to monitor the susceptibility of vectors to different classes of insecticides in areas of varying agrochemical use patterns. Methods. A survey to determine the agricultural chemical use pattern was undertaken in ten localities across Côte d’Ivoire. In addition, WHO susceptibility tests were carried out on adults Anopheles gambiae s.l. mosquitoes emerging from collected larvae from the sites surveyed. Four insecticides from each class of the four classes of insecticides were evaluated using the standard susceptibility test methods. Furthermore, the target site mutations involved in resistance mechanisms were identified following the Taqman assay protocols and mosquito species were identified using SINE-PCR. Results. The mortalities of all the An. gambiae s.l populations were similar regardless of the pesticide use pattern. The vectors were resistant to DDT, deltamethrin, and bendiocarb in all localities. In contrast, mosquitoes showed high susceptibility to malathion. High frequency of the Kdr-West gene allele was observed (70-100%). A single Kdr-East mutation was identified in a mosquito that harboured both Ace-1 and Kdr-West genes. Conclusion. Cultivated marshlands representing good habitats for mosquito development may deeply contribute to the selection of resistance genes given the intensive use of agrochemical for crop protection. In view of these, special attention must be given to them to mitigate mosquito resistance to insecticides.
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Agbor, Okemena V., Taiwo E. Idowu, Kayode I. Fagbohun, Amos T. Oyeniyi, Romoke T. Jimoh, and Adetoro O. Otubanjo. "Molecular Identification and Insecticide Resistance Status of Culex mosquitoes collected from blocked drainages in Lagos State, Nigeria." Pan African Journal of Life Sciences 4, no. 1 (April 1, 2020): 1–6. http://dx.doi.org/10.36108/pajols/0202/40(0110).
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Background: Culex mosquitoes are important vectors of several human pathogens causing infections such as lymphatic filariasis and several viruses. Poor and blocked drainage system can lead to impediment in water flow, leading to the artificial creation of larval habitats for Culex mosquitoes. Culex mosquitoes has the ability to breed in organically polluted water bodies and exhibit high resistance to insecticides. Therefore, this study assessed the species and insecticides susceptibility status of Culex breeding in blocked drainages in Lagos State. Methods: Culex mosquito larvae were collected from blocked drainages in three Local Government Areas (LGAs) of Lagos State, Nigeria, using standard WHO technique. The physicochemical parameters of the larval habitats were also recorded. Collected mosquito larvae were raised to adult, 2-3 days old. Glucose fed adults female mosquitoes were exposed to permethrin (0.75%) and DDT (4.0%) WHO insecticide test papers. Morphological identification was carried out using standard keys and molecular identification of Culex pipiens sub-species and kdr genotyping was carried out using PCR Results: High level of resistance was recorded with mortality r ate after 24 hour s for DDT ranging from 20% to 32% while permethrin ranges from 14% to 36%. The pH of the all the Culex mosquito larva habitats ranges from 7.38±0.11 to 7.62±0.29, while TDS ranges from 592.6±79.1 to 655±68.1. A total of 1113 Culex pipiens mosquitoes that were identify morphologically, some were selected for molecular identification using PCR assays, out of which 96.2% were identified as Culex p. quinquefasciatus while 3.7% were unidentified. Knockdown mutation (L1014F) was not detected in DDT and pyrethroids resistant Cx. quinquefasciatus in this study. Conclusion: Unplanned ur banization, inadequate w ater su pply and inefficient solid w aste and sewage management practices can result in the creation artificial larval habitats for Culex mosquitoes leading to potential outbreak of Culex mosquito borne diseases. The resistance to DDT and permethrin insecticides in Cx. quinquefasciatus in Lagos State may represent a threat towards the efficacy of ITNs and other forms of vector control such as indoor residual spraying in the future.
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Azizi, Salum, Janneke Snetselaar, Alexandra Wright, Johnson Matowo, Boniface Shirima, Robert Kaaya, Rashid Athumani, Filemoni Tenu, Natacha Protopopoff, and Matthew Kirby. "Colonization and Authentication of the Pyrethroid-Resistant Anopheles gambiae s.s. Muleba-Kis Strain; an Important Test System for Laboratory Screening of New Insecticides." Insects 12, no. 8 (August 8, 2021): 710. http://dx.doi.org/10.3390/insects12080710.
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Background: The emergence and spread of insecticide resistance in malaria vectors to major classes of insecticides call for urgent innovation and application of insecticides with novel modes of action. When evaluating new insecticides for public health, potential candidates need to be screened against both susceptible and resistant mosquitoes to determine efficacy and to identify potential cross-resistance to insecticides currently used for mosquito control. The challenges and lessons learned from establishing, maintaining, and authenticating the pyrethroid-resistant An. gambiae s.s. Muleba-Kis strain at the KCMUCo-PAMVERC Test Facility are described in this paper. Methods: Male mosquitoes from the F1 generation of wild-pyrethroid resistant mosquitoes were cross-bred with susceptible female An. gambiae s.s. Kisumu laboratory strain followed by larval selection using a pyrethroid insecticide solution. Periodic screening for phenotypic and genotypic resistance was done. WHO susceptibility tests and bottle bioassays were used to assess the phenotypic resistance, while Taqman™ assays were used to screen for known target-site resistance alleles (kdr and ace-1). Additionally, the strains were periodically assessed for quality control by monitoring adult weight and wing length. Results: By out-crossing the wild mosquitoes with an established lab strain, a successful resistant insectary colony was established. Intermittent selection pressure using alphacypermethrin has maintained high kdr mutation (leucine-serine) frequencies in the selected colony. There was consistency in the wing length and weight measurements from the year 2016 to 2020, with the exception that one out of four years was significantly different. Mean annual wing length varied between 0.0142–0.0028 mm compared to values obtained in 2016, except in 2019 where it varied by 0.0901 mm. Weight only varied by approximately 0.001 g across four years, except in 2017 where it differed by 0.005 g. Routine phenotypic characterization on Muleba-Kis against pyrethroids using the WHO susceptibility test indicated high susceptibility when type I pyrethroids were used compared to type II pyrethroids. Dynamics on susceptibility status also depended on the lapse time when the selection was last done. Conclusions: This study described the procedure for introducing, colonizing, and maintaining a resistant An. gambiae s.s. strain in the laboratory with leucine to serine substitution kdr allele which reflects the features of the wild-resistant population in East Africa. Challenges in colonizing a wild-resistant mosquito strain were overcome by out-crossing between mosquito strains of desired traits followed by intermittent insecticide selection at the larval stage to select for the resistant phenotype.
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Fuseini, Godwin, Raul Ncogo Nguema, Wonder P. Phiri, Olivier Tresor Donfack, Carlos Cortes, Michael E. Von Fricken, Jacob I. Meyers, et al. "Increased Biting Rate of Insecticide-Resistant Culex Mosquitoes and Community Adherence to IRS for Malaria Control in Urban Malabo, Bioko Island, Equatorial Guinea." Journal of Medical Entomology 56, no. 4 (March 18, 2019): 1071–77. http://dx.doi.org/10.1093/jme/tjz025.
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Abstract Sustaining high levels of indoor residual spraying (IRS) coverage (≥85%) for community protection against malaria remains a challenge for IRS campaigns. We examined biting rates and insecticide resistance in Culex species and Anopheles gambiae s.l., and their potential effect on community adherence to IRS. The average IRS coverage in urban Malabo between 2015 and 2017 remained at 80%. Culex biting rate increased 6.0-fold (P < 0.001) between 2014 and 2017, reaching 8.08 bites per person per night, whereas that of An. gambiae s.l. remained steady at around 0.68. Although An. gambiae s.l. was susceptible to carbamates and organophosphates insecticides, Culex spp. were phenotypically resistant to all four main classes of WHO-recommended IRS insecticides. Similarly, the residual activity of the organophosphate insecticide used since 2017, ACTELLIC 300CS, was 8 mo for An. gambiae s.l., but was almost absent against Culex for 2 mo post-spray. A survey conducted in 2018 within urban Malabo indicated that 77.0% of respondents related IRS as means of protection against mosquito bites, but only 3.2% knew that only Anopheles mosquitoes transmit malaria. Therefore, the increasing biting rates of culicines in urban Malabo, and their resistance to all IRS insecticides, is raising concern that a growing number of people may refuse to participate in IRS as result of its perceived failure in controlling mosquitoes. Although this is not yet the case on Bioko Island, communication strategies need refining to sensitize communities about the effectiveness of IRS in controlling malaria vectors in the midst of insecticide resistance in nonmalaria vector mosquitoes.
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NGONGHALA, CALISTUS N., JOSEPHINE WAIRIMU, JESSE ADAMSKI, and HARDIK DESAI. "IMPACT OF ADAPTIVE MOSQUITO BEHAVIOR AND INSECTICIDE-TREATED NETS ON MALARIA PREVALENCE." Journal of Biological Systems 28, no. 02 (June 2020): 515–42. http://dx.doi.org/10.1142/s0218339020400100.
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Malaria prevalence in sub-Saharan Africa remains high. Kenya for example, records about 3.5 million new cases and 11 thousand deaths each year.1 Most of these cases and deaths are among children under five. The main control method in malaria endemic regions has been through the use of insecticide-treated nets (ITNs). Although this approach has been fairly successful, the gains are threatened by mosquito-resistance to pyrethroids (insecticides on nets), physical and chemical degradation of ITNs that reduce their efficacy, inconsistent and improper use by humans, etc. We present a model to investigate the effects of ITN use and mosquito-resistance and adaptation to pyrethroids used to treat bed nets on malaria prevalence and control in malaria endemic regions. The model captures the development and loss of resistance to insecticides, the effects of ITN use on malaria control in a setting where proper and consistent use is not guaranteed, as well as differentiated biting of human hosts by resistant and sensitive mosquitoes. Important thresholds, including the basic reproduction number [Formula: see text], and two parameter groupings that are important for disease control and for establishing the existence of endemic equilibria to the model are calculated. Furthermore, a global sensitivity analysis is carried out to identify important parameters such as insecticide treated bed-net coverage, ITN, the maximum biting rate of resistant mosquitoes, etc., that drive the system and that can be targeted for disease control. Threshold levels of ITN coverage and ITN efficacy required for containing the disease are identified and shown to depend on the type of insecticide-resistance. For example, when mosquito-resistance to insecticides is not permanent and is acquired only through recruitment and the efficacy of ITNs is [Formula: see text], about [Formula: see text] net coverage is required to contain malaria. However, for the same ITN efficacy, i.e., [Formula: see text], approximately [Formula: see text] net coverage is required to contain the disease when resistance to insecticides is permanent and is acquired through recruitment and mutation in mosquitoes. The model exhibits a backward bifurcation, which implies that simply reducing [Formula: see text] slightly below unity might not be enough to contain the disease. We conclude that appropriate measures to reduce or eliminate mosquito-resistance to insecticides, ensure that more people in endemic areas own and use ITNs properly, and that the efficacy of these nets remain high most of the time, as well as educating populations in malaria endemic areas on how to keep mosquito densities low and minimize mosquito bites are important for containing malaria.
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Almet, Julianty, Diana A. Wuri, Antin Y. N. Widi, and Edwin K. Ndawa Lu. "STATUS RESISTENSI NYAMUK Anopheles sp.TERHADAP INSEKTISIDA MALATHION DI KOTA KUPANG." JURNAL KAJIAN VETERINER 6, no. 2 (June 11, 2019): 69–77. http://dx.doi.org/10.35508/jkv.v6i2.851.
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The aim of this study is to investigate the insectidace resistance of Anopheles sp. to malathion 0.8% in Kota Lama and Maulafa districts. This study used the sample approximately 650 of Anopheles sp. The collected mosquitoes are inserted into the maintenance cage to identify and ensure that the mosquito is truly Anopheles sp. The test was done by using impregnanted paper malathion 0.8% .Amount of 25 mosquitoes were caught using an aspirator and put into a collector tube which had been coated with 0.8% impregnated paper malathion , while other 25 mosquitoes were put into a green tube and had no insecticide paper. The test results were obtained by counting the knocked down mosquitoes every 15 minutes during 2 hours of insecticide exposure and continued for 24 hours of holding time. The test was repeated for 3 times. The results showed that Anopheles sp. in Kota Lama and Maulafa districts, were resistant to Malathion insecticides 0.8% with the percentage of death mosquitoes (Kota Lama: 4,35-28% ; Maulafa: 8-12,5%)(< 90%). So it has a high level of resistance.
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Dheasabel, Gita, and Muhammad Azinar. "Kemampuan Ekstrak Buah Pare terhadap Kematian Nyamuk Aedes aegypti." HIGEIA (Journal of Public Health Research and Development) 2, no. 2 (April 30, 2018): 331–41. http://dx.doi.org/10.15294/higeia.v2i2.20866.
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The mosquito of Aedes aegypti is the vector of the dengue virus can transmit the disease through bites DBD. The popular control in a society is by using chemical insecticides. The use of chemical insecticides can lead to continuous resistance of mosquitoes. The efforts to reduce the negative impact of chemical insecticides can be controlled with an insecticides plant. This control can be done by using materials that came from plant, one of them namely bitter melon (Momordica charantia L). The purpose of this research is to analyze the kill power of bitter melon extracts against the mosquito of Aedes aegypti. This type of research is pure experiment with the design of the post test only control group design with five variants of extract concentration of 13%, 19%, 27%, 40%, and 59% with five repetitions. A kruskal wallis test result showed a difference in thye average number of deaths the mosquito of Aedes agypti in various concentration of bitter melon extract, indicated by the value of significance p=0,001 (p<0,05). The probit analysis obtained LC50 at 24,41% concentration and LC90 at 70,54% concentratin. The summary of this research, namely bitter melon extracts has the effect of insecticide against the mosquito of Aedes aegypti.
Keywords: Aedes aegypti, insecticide, bitter melon
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Agusto, Folashade B. "Optimal Control and Temperature Variations of Malaria Transmission Dynamics." Complexity 2020 (November 28, 2020): 1–32. http://dx.doi.org/10.1155/2020/5056432.
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Malaria is a Plasmodium parasitic disease transmitted by infected female Anopheles mosquitoes. Climatic factors, such as temperature, humidity, rainfall, and wind, have significant effects on the incidence of most vector-borne diseases, including malaria. The mosquito behavior, life cycle, and overall fitness are affected by these climatic factors. This paper presents the results obtained from investigating the optimal control strategies for malaria in the presence of temperature variation using a temperature-dependent malaria model. The study further identified the temperature ranges in four different geographical regions of sub-Saharan Africa, suitable for mosquitoes. The optimal control strategies in the temperature suitable ranges suggest, on average, a high usage of both larvicides and adulticides followed by a moderate usage of personal protection such as bednet. The average optimal bednet usage mimics the solution profile of the mosquitoes as the mosquitoes respond to changes in temperature. Following the results from the optimal control, this study also investigates using a temperature-dependent model with insecticide-sensitive and insecticide-resistant mosquitoes the impact of insecticide-resistant mosquitoes on disease burden when temperature varies. The results obtained indicate that optimal bednet usage on average is higher when insecticide-resistant mosquitoes are present. Besides, the average bednet usage increases as temperature increases to the optimal temperature suitable for mosquitoes, and it decreases after that, a pattern similar to earlier results involving insecticide-sensitive mosquitoes. Thus, personal protection, particularly the use of bednets, should be encouraged not only at low temperatures but particularly at high temperatures when individuals avoid the use of bednets. Furthermore, control and reduction of malaria may be possible even when mosquitoes develop resistance to insecticides.
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Akoton, Romaric, Genevieve M. Tchigossou, Innocent Djègbè, Akadiri Yessoufou, Michael Seun Atoyebi, Eric Tossou, Francis Zeukeng, et al. "Experimental huts trial of the efficacy of pyrethroids/piperonyl butoxide (PBO) net treatments for controlling multi-resistant populations of Anopheles funestus s.s. in Kpomè, Southern Benin." Wellcome Open Research 3 (June 13, 2018): 71. http://dx.doi.org/10.12688/wellcomeopenres.14589.1.
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Background: Insecticides resistance in Anopheles mosquitoes limits Long-Lasting Insecticidal Nets (LLIN) used for malaria control in Africa, especially Benin. This study aimed to evaluate the bio-efficacy of current LLINs in an area where An. funestus s.l. and An. gambiae have developed multi-resistance to insecticides, and to assess in experimental huts the performance of a mixed combination of pyrethroids and piperonyl butoxide (PBO) treated nets on these resistant mosquitoes. Methods: The study was conducted at Kpomè, Southern Benin. The bio-efficacy of LLINs against An. funestus and An. gambiae was assessed using the World Health Organization (WHO) cone and tunnel tests. A released/recapture experiment following WHO procedures was conducted to compare the efficacy of conventional LLINs treated with pyrethroids only and LLINs with combinations of pyrethroids and PBO. Prior to huts trials, we confirmed the level of insecticide and PBO residues in tested nets using high performance liquid chromatography (HPLC). Results: Conventional LLINs (Type 2 and Type 4) have the lowest effect against local multi-resistant An. funestus s.s. and An. coluzzii populations from Kpomè. Conversely, when LLINs containing mixtures of pyrethroids and PBO (Type 1 and Type 3) were introduced in trial huts, we recorded a greater effect against the two mosquito populations (P < 0.0001). Tunnel test with An. funestus s.s. revealed mortalities of over 80% with this new generation of LLINs (Type 1 and Type 3),while conventional LLINs produced 65.53 ± 8.33% mortalities for Type 2 and 71.25 ±7.92% mortalities for Type 4. Similarly, mortalities ranging from 77 to 87% were recorded with the local populations of An. coluzzii. Conclusion: This study suggests the reduced efficacy of conventional LLINs (Pyrethroids alone) currently distributed in Benin communities where Anopheles populations have developed multi-insecticide resistance. The new generation nets (pyrethroids+PBO) proved to be more effective on multi-resistant populations of mosquitoes.
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Ranathunge, Tharaka, Lahiru Udayanga, Sumudu Sarasija, Samudra Karunathilaka, Shavindhya Nawarathne, Haruthra Rathnarajah, Fathima Fazla Dulficar, Fathima Nafla Shafi, Ranil S. Dassanayake, and Y. I. Nilmini Silva Gunawardene. "Voltage-Gated Sodium Channel (Vgsc) Mutation-Based Pyrethroid Resistance in Aedes aegypti Populations of Three Endemic Dengue Risk Areas of Sri Lanka." BioMed Research International 2021 (May 22, 2021): 1–10. http://dx.doi.org/10.1155/2021/8874092.
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Background. Pyrethroid insecticides are widely used in many countries for chemical-based control of Ae. aegypti. Regardless of their efficacy, the constant use of insecticides has induced insecticide resistance mechanisms, such as knockdown resistance (kdr) in mosquitoes. Sri Lankan Vector Controlling Entities (VCE) have been using a variety of pyrethroid insecticides as the primary approach for dengue control. However, development of any resistance among the Aedes mosquitoes has been limitedly studied in the country. Therefore, the current study was conducted to evaluate the prevalence of F1534C, V1016G, and S989P mutations among Ae. aegypti mosquito populations in three dengue endemic high-risk regions of Sri Lanka. Methodology. Immature (both pupae and larvae) stages of Ae. aegypti mosquitoes were collected from Colombo, Gampaha, and Kandy districts of Sri Lanka from February 2018 to December 2019. Polymerase Chain Reaction- (PCR-) based assay for molecular genotyping of mutations was performed to identify the prevalence of kdr mutations in collected Ae. aegypti populations, separately. The frequencies of the resistant and susceptible kdr alleles were determined by using the Hardy–Weinberg equilibrium. Results. The Ae. aegypti populations from Colombo, Gampaha, and Kandy districts showed 46%, 42%, and 22% of F1534C mutation allele frequencies, along with 15%, 12%, and 6% of V1016G mutation allele frequencies, respectively. The mutation allele frequencies of S989 in Colombo, Gampaha, and Kandy districts were 9.5%, 8.5%, and 4.5%, respectively. The wild-type (PP) genotype remained predominant within all the three districts, whereas the homogenous (QQ) mutation genotype occurred only in minority. The abundance of Q allele frequency in Ae. aegypti mosquitoes was relatively higher for all the three mutations in Colombo. Conclusions. The findings clearly indicate that long-term insecticide applications and multiple use of pyrethroids have led to the acquisition of kdr mutations, leading to the development of insecticide resistance among local Ae. aegypti populations, especially in the Colombo and Gampaha districts. Therefore, evaluation of the prevalence levels of these kdr mutations highlights the necessity for shifting towards novel vector control strategies.
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Shrivastava, Amit Kumar, Laxmi Shrestha, Shraddha Prakash, and Roshan Kumar Mehta. "Transgenic Mosquitoes Fight against Malaria: A Review." Journal of Universal College of Medical Sciences 7, no. 1 (July 2, 2019): 59–65. http://dx.doi.org/10.3126/jucms.v7i1.24695.
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Malaria control with transgenic mosquitoes will be challenging; however, recent advances suggest that it may be a possibility in the foreseeable future. Progress towards discovering refractory genes for rodent malaria and gene drive systems for Drosophila provide hope that similar advances may be made for human malaria in mosquito vector species. That said, the African malaria burden has proved exceptionally difficult to diminish by all means tried thus far; and it is unlikely that transgenic mosquitoes will provide an all-in-one solution. Transgenic mosquitoes should be considered within the context of an integrated vector management strategy which should also include insecticide-treated bed-nets, indoor residual spraying with insecticides and treatment of infected individuals with antimalarial drugs. Integrated strategies will be a necessity for any successful african malaria control program and transgenic mosquitoes should be considered as a potential ingredient in the future goal of continent-wide disease control.
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Yang, Jingxiang, Bryan Erriah, Chunhua T. Hu, Ethan Reiter, Xiaolong Zhu, Vilmalí López-Mejías, Isis Paola Carmona-Sepúlveda, Michael D. Ward, and Bart Kahr. "A deltamethrin crystal polymorph for more effective malaria control." Proceedings of the National Academy of Sciences 117, no. 43 (October 12, 2020): 26633–38. http://dx.doi.org/10.1073/pnas.2013390117.
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Pyrethroid contact insecticides are mainstays of malaria control, but their efficacies are declining due to widespread insecticide resistance in Anopheles mosquito populations, a major public health challenge. Several strategies have been proposed to overcome this challenge, including insecticides with new modes of action. New insecticides, however, can be expensive to implement in low-income countries. Here, we report a simple and inexpensive method to improve the efficacy of deltamethrin, the most active and most commonly used pyrethroid, by more than 10 times against Anopheles mosquitoes. Upon heating for only a few minutes, the commercially available deltamethrin crystals, form I, melt and crystallize upon cooling into a polymorph, form II, which is much faster acting against fruit flies and mosquitoes. Epidemiological modeling suggests that the use of form II in indoor residual spraying in place of form I would significantly suppress malaria transmission, even in the presence of high levels of resistance. The simple preparation of form II, coupled with its kinetic stability and markedly higher efficacy, argues that form II can provide a powerful, timely, and affordable malaria control solution for low-income countries that are losing protection in the face of worldwide pyrethroid resistance.
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Alout, Haoues, Innocent Djègbè, Fabrice Chandre, Luc Salako Djogbénou, Roch Kounbobr Dabiré, Vincent Corbel, and Anna Cohuet. "Insecticide exposure impacts vector–parasite interactions in insecticide-resistant malaria vectors." Proceedings of the Royal Society B: Biological Sciences 281, no. 1786 (July 7, 2014): 20140389. http://dx.doi.org/10.1098/rspb.2014.0389.
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Currently, there is a strong trend towards increasing insecticide-based vector control coverage in malaria endemic countries. The ecological consequence of insecticide applications has been mainly studied regarding the selection of resistance mechanisms; however, little is known about their impact on vector competence in mosquitoes responsible for malaria transmission. As they have limited toxicity to mosquitoes owing to the selection of resistance mechanisms, insecticides may also interact with pathogens developing in mosquitoes. In this study, we explored the impact of insecticide exposure on Plasmodium falciparum development in insecticide-resistant colonies of Anopheles gambiae s.s. , homozygous for the ace-1 G119S mutation (Acerkis) or the kdr L1014F mutation (Kdrkis). Exposure to bendiocarb insecticide reduced the prevalence and intensity of P. falciparum oocysts developing in the infected midgut of the Acerkis strain, whereas exposure to dichlorodiphenyltrichloroethane reduced only the prevalence of P. falciparum infection in the Kdrkis strain. Thus, insecticide resistance leads to a selective pressure of insecticides on Plasmodium parasites, providing, to our knowledge, the first evidence of genotype by environment interactions on vector competence in a natural Anopheles–Plasmodium combination . Insecticide applications would affect the transmission of malaria in spite of resistance and would reduce to some degree the impact of insecticide resistance on malaria control interventions.
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Marcombe, Sebastien, Phoutmany Thammavong, Phonesavanh Luangamath, Somsanith Chonephetsarath, Nothasin Phommavanh, Khaitong Lakeomany, Somphat Nilaxay, et al. "Malaria and Dengue Mosquito Vectors from Lao PDR Show a Lack of the rdl Mutant Allele Responsible for Cyclodiene Insecticide Resistance." Journal of Medical Entomology 57, no. 3 (December 6, 2019): 815–23. http://dx.doi.org/10.1093/jme/tjz227.
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Abstract The gamma-aminobutyric acid (GABA) receptor, RDL, plays important roles in neuronal signaling and is the target of highly effective insecticides. A mutation in RDL, commonly A296S, underlies resistance to several insecticides such as cyclodienes. Even though the use of cyclodienes has been banned, the occurrence of mutations substituting A296 is notably high in mosquitoes from several countries. Here, we report a survey investigating the prevalence of the Rdl mutant allele in mosquitoes from Laos, a country where mosquito-borne diseases such as malaria and dengue fever are health concerns. Anopheles and Aedes mosquitoes were collected from 12 provinces in Laos. Adult bioassays on Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Aedes albopictus (Skuse) (Diptera: Culicidae) showed that all the populations tested were susceptible to dieldrin (4%) following WHO protocols. Exon 7 from a total of 791 mosquitoes was sequenced to identify the amino acid encoded for at 296 of RDL. Only one of these mosquitoes, Anopheles maculatus rampae Harbach and Somboon (Diptera: Culicidae) from Attapeu, carried the mutant allele being heterozygous for A296S. We therefore found a general lack of the Rdl mutant allele indicating that mosquitoes from Laos are not exposed to insecticides that act on the GABA receptor compared to mosquitoes in several other countries. Identifying the prevalence of the Rdl mutation may help inform the potential use of alternative insecticides that act on the GABA receptor should there be a need to replace pyrethroids in order to prevent/manage resistance.
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Cataldo, Natalie P., C. Suzanne Lea, Timothy Kelley, and Stephanie L. Richards. "Assessment of Resistance to Organophosphates and Pyrethroids in Aedes aegypti (Diptera: Culicidae): Do Synergists Affect Mortality?" Journal of Medical Entomology 57, no. 6 (June 2, 2020): 1992–96. http://dx.doi.org/10.1093/jme/tjaa101.
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Abstract Aedes aegypti (L.) is the primary vector of Zika, dengue, yellow fever, and chikungunya viruses. Insecticides used in mosquito control can help prevent the spread of vector-borne diseases. However, it is essential to determine insecticide resistance (IR) status before control measures are undertaken. Only the most effective insecticides should be used to avoid ineffective control and/or promotion of IR. Pyrethroids and organophosphates are the most commonly used insecticides for mosquito control. Here, the efficacy of two active ingredients (AIs; permethrin [pyrethroid], chlorpyrifos [organophosphate]), two formulated products (FPs; Biomist [AI: permethrin]) and (Mosquitomist [AI: chlorpyrifos]), and three synergists (piperonyl butoxide, diethyl maleate, S-S-S-tributyl phosphorotrithioate) was evaluated in two Ae. aegypti colonies (pyrethroid resistant and susceptible). Mosquitomist was most effective against the pyrethroid-resistant colony (100% mortality at diagnostic time). Pre-exposure to synergists did not increase the efficacy of AIs against the pyrethroid-resistant colony. Further research is needed to discover how synergists may affect the efficacy of insecticides when used on pyrethroid-resistant mosquitoes.
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Sun, X. H., N. Xu, Y. Xu, D. Zhou, Y. Sun, W. J. Wang, L. Ma, C. L. Zhu, and B. Shen. "A novel miRNA, miR-13664, targetsCpCYP314A1to regulate deltamethrin resistance inCulex pipiens pallens." Parasitology 146, no. 2 (July 3, 2018): 197–205. http://dx.doi.org/10.1017/s0031182018001002.
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AbstractExtensive insecticide use has led to the resistance of mosquitoes to these insecticides, posing a major barrier to mosquito control. Previous Solexa high-throughput sequencing ofCulex pipiens pallensin the laboratory has revealed that the abundance of a novel microRNA (miRNA), miR-13664, was higher in a deltamethrin-sensitive (DS) strain than a deltamethrin-resistant (DR) strain. Real-time quantitative PCR revealed that the miR-13664 transcript level was lower in the DR strain than in the DS strain. MiR-13664 oversupply in the DR strain increased the susceptibility of these mosquitoes to deltamethrin, whereas inhibition of miR-13664 made the DS strain more resistant to deltamethrin. Results of bioinformatic analysis, quantitative reverse-transcriptase polymerase chain reaction, luciferase assay and miR mimic/inhibitor microinjection revealedCpCYP314A1to be a target of miR-13664. In addition, downregulation ofCpCYP314A1expression in the DR strain reduced the resistance of mosquitoes to deltamethrin. Taken together, our results indicate that miR-13664 could regulate deltamethrin resistance by interacting withCpCYP314A1, providing new insights into mosquito resistance mechanisms.
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Riyadi, Slamet, and Tri Baskoro Tunggul Satoto. "Hubungan Perilaku Penggunaan Insektisida dengan Status Kerentanan Nyamuk Aedes aegypti di Daerah Endemis Kabupaten Purbalingga." Berita Kedokteran Masyarakat 33, no. 10 (October 1, 2017): 459. http://dx.doi.org/10.22146/bkm.25941.
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Purpose: This study aimed to identify the correlation between behavior towards insecticide use and susceptibility status of Aedes aegypti mosquito and to identify the level of mosquito susceptibility from an endemic area in Purbalingga.Methods: This research used a cross-sectional design and was conducted from January 2017 until April 2017 in four endemic villages of Purbalingga. 40 respondents were involved in the research. Samples from each village were taken using purposive sampling. Ovitraps were installed and interviews were conducted using questionnaires for selected households. Mosquito susceptibility status was described based on the results of WHO’s standardized bioassay test.Results: The results of susceptibility test indicated that Aedes aegypti from three endemic villages (Purbalingga Lor, Penaruban, Sempor Lor) were resistant, while mosquitoes from Kembaran Kulon Village were tolerant to cypermethrin 0.05%. Variables correlated with susceptibility status of Aedes aegypti mosquito were respondent's negative attitude (PR = 0.55; 0.37 - 0.80) and behavior towards insecticide use (PR = 1.24; 1.05 - 1.47).Conclusions: Misuse of insecticides increased susceptibility status of Aedes aegypti mosquito and becomes the main risk factor for resistance. It is necessary to rotate the insecticide use for programs and households through different modes of action and to provide public health education about insecticide use, selection of active ingredients, dosage, mode of application and periodic replacement of insecticides.
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Udoidung, N. I., K. N. Opara, P. D. Okodi, N. D. Ekpo, and I. Atting. "Susceptibility of Anopheles gambiae complex to carbamates and organophosphate insecticides in Uyo, Akwa Ibom State, Nigeria." Nigerian Journal of Parasitology 41, no. 1 (June 25, 2020): 114–18. http://dx.doi.org/10.4314/njpar.v41i1.18.
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Rapid emergence in insecticide resistance among malaria vector populations to commonly used public health insecticides poses a challenge to current malaria vector control strategies and interventions in sub- Saharan Africa. This study was conducted to determine the susceptibility status of female An.gambiae s.l to Propoxur (0.01%) and bendiocarb (0.1%) (carbamate) and pirimiphosmethyl (0.25%) (organophosphate) insecticides in Uyo Metropolis, Akwa Ibom State, Nigeria. The larvae of An. gambiae s.l were collected from natural water bodies and other potential breeding sites from different sites in Uyo Metropolis. Insecticide susceptibility bioassays were performed according to the World Health Organization standard operating procedures on 2-3 days old, sugar-fed but none blood fed female Anopheles mosquitoes. Post exposure mortality after 24 hours and knockdown values for KDT50 and KDT95 were calculated. Knock-down at 1 hour insecticide exposure ranged from 94 % to 100 %. Mortality after 24 hours post exposure was 100% for all insecticides except Propoxur which was 98 %. There was high variability in KDT50 and KDT95 values (in minutes) with propoxur (4.337 and 15.620), Bendiocarb (9.523 and 20.996) and pirimiphosmethyl (39.908 and 61.722) respectively. Adopting the WHO criteria, the mosquitoes were not resistant to any of the insecticides tested. The results therefore showed that vector control campaigns employing the use of any of these insecticides in the study area would not be compromised. However, there is need for continued monitoring to ensure early detection of resistance.
Keywords: Anopheles gambiae; insecticide susceptibility; Uyo; Akwa Ibom State; Nigeria.
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Wang, Yan, Chunlai Cui, Guandong Wang, Yifei Li, and Sibao Wang. "Insects defend against fungal infection by employing microRNAs to silence virulence-related genes." Proceedings of the National Academy of Sciences 118, no. 19 (May 3, 2021): e2023802118. http://dx.doi.org/10.1073/pnas.2023802118.
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Chemical insecticides remain the main strategy to combat mosquito-borne diseases, but the growing threat of insecticide resistance prompts the urgent need to develop alternative, ecofriendly, and sustainable vector control tools. Entomopathogenic fungi can overcome insecticide resistance and represent promising biocontrol tools for the control of mosquitoes. However, insects have evolved robust defense mechanisms against infection. Better understanding of mosquito defenses against fungal infection is critical for improvement of fungal efficacy. Here, we show that as the pathogenic fungus Beauveria bassiana penetrates into the host hemocoel, mosquitoes increase expression of the let-7 and miR-100 microRNAs (miRNAs). Both miRNAs translocate into fungal hyphae to specifically silence the virulence-related genes sec2p and C6TF, encoding a Rab guanine nucleotide exchange factor and a Zn(II)2Cys6 transcription factor, respectively. Inversely, expression of a let-7 sponge (anti–let-7) or a miR-100 sponge (anti–miR-100) in the fungus efficiently sequesters the corresponding translocated host miRNA. Notably, B. bassiana strains expressing anti–let-7 and anti–miR-100 are markedly more virulent to mosquitoes. Our findings reveal an insect defense strategy that employs miRNAs to induce cross-kingdom silencing of pathogen virulence-related genes, conferring resistance to infection.
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Endersby, N. M., and A. A. Hoffmann. "Effect of Wolbachia on insecticide susceptibility in lines of Aedes aegypti." Bulletin of Entomological Research 103, no. 3 (November 13, 2012): 269–77. http://dx.doi.org/10.1017/s0007485312000673.
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AbstractTwo stable infections of Wolbachia pipientis, wMelPop and wMel, now established in Aedes aegypti, are being used in a biocontrol program to suppress the transmission of dengue. Any effects of Wolbachia infection on insecticide resistance of mosquitoes may undermine the success of this program. Bioassays of Ae. aegypti were conducted to test for differences in response to insecticides between Wolbachia infected (wMelPop, wMel) and uninfected lines. Insecticides screened were bifenthrin, the pyrethroid commonly used for adult knockdown, as well as larvicides: Bacillus thuringiensis var. israelensis, the organophosphate, temephos and the insect growth regulator, s-methoprene. While differences in response between lines were detected for some insecticides, no obvious or consistent effects related to presence of Wolbachia infection were observed. Spreading Wolbachia infections are, therefore, unlikely to affect the efficacy of traditional chemical control of mosquito outbreaks.
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Lama, P. S., J. D. C. Tongjura, R. J. Ombugadu, and A. B. Yako. "Susceptibility of Anopheles Mosquitoes to Deltamethrin and Bendiocarb Insecticides in Nasarawa Local Government Area, Nasarawa State Nigeria." European Journal of Biology and Biotechnology 2, no. 3 (June 12, 2021): 75–78. http://dx.doi.org/10.24018/ejbio.2021.2.3.202.
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Anopheles mosquito’s resistance to insecticides has been one of the major challenges in eradicating malaria. This study was carried out to determine the susceptibility status of Anopheles mosquitoes to Deltamethrin and Bendiocarb in some communities of Nasarawa Local Government Area of Nasarawa State for four months. The research was carried out at the insectary laboratory of Nasarawa State University Keffi. Center for Disease Control (CDC) bioassay bottle and WHO impregnated papers were used to test the susceptibility of Anopheles mosquitoes. The result shows that Anopheles mosquitoes exposed to Bendiocarb and Deltamethrin using CDC bioassay bottles were susceptible at 15mins, there was no mortality recorded from the control at 30 minutes of exposure. Anopheles mosquitoes exposed to WHO impregnated paper of Bendiocarb and Deltamethrin were susceptible at 60 minutes, mortality was recorded at 24h post exposure time from the control. χ2analysis of Bendiocarb and Deltamethrin insecticides exposed to CDC bioassay bottles was statistically insignificant p>0.05, while χ2 analysis of Bendiocarb and Deltamethrin exposed to WHO impregnated papers was also insignificant p>0.05. These results indicated susceptibility of Anopheles mosquitoes to Bendiocarb and Deltamethrin for the two methods of susceptibility test. The use of these synthetic insecticides in the control of malaria should be encouraged and made available.
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Meredith, Hannah R., Luis Furuya-Kanamori, and Laith Yakob. "Optimising systemic insecticide use to improve malaria control." BMJ Global Health 4, no. 6 (November 2019): e001776. http://dx.doi.org/10.1136/bmjgh-2019-001776.
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BackgroundLong-lasting insecticidal nets and indoor residual sprays have significantly reduced the burden of malaria. However, several hurdles remain before elimination can be achieved: mosquito vectors have developed resistance to public health insecticides, including pyrethroids, and have altered their biting behaviour to avoid these indoor control tools. Systemic insecticides, drugs applied directly to blood hosts to kill mosquitoes that take a blood meal, offer a promising vector control option. To date, most studies focus on repurposing ivermectin, a drug used extensively to treat river blindness. There is concern that overdependence on a single drug will inevitably repeat past experiences with the rapid spread of pyrethroid resistance in malaria vectors. Diversifying the arsenal of systemic insecticides used for mass drug administration would improve this strategy’s sustainability.MethodsHere, a review was conducted to identify systemic insecticide candidates and consolidate their pharmacokinetic/pharmacodynamic properties. The impact of alternative integrated vector control options and different dosing regimens on malaria transmission reduction are illustrated through mathematical model simulation.ResultsThe review identified drugs from four classes commonly used in livestock and companion animals: avermectins, milbemycins, isoxazolines and spinosyns. Simulations predicted that isoxazolines and spinosyns are promising candidates for mass drug administration, as they were predicted to need less frequent application than avermectins and milbemycins to maintain mosquitocidal blood concentrations.ConclusionsThese findings will provide a guide for investigating and applying different systemic insecticides to achieve more effective and sustainable control of malaria transmission.
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Dery, Dominic B., Guillaume K. Ketoh, Joseph Chabi, George Apetogbo, Isabelle A. Glitho, Thierry Baldet, and Jean-Marc Hougard. "Efficacy of a Mosaic Long-Lasting Insecticide Net, PermaNet 3.0, against Wild Populations of Culex quinquefasciatus in Experimental Huts in Togo." ISRN Infectious Diseases 2013 (December 5, 2013): 1–8. http://dx.doi.org/10.5402/2013/209654.
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PermaNet 3.0 was evaluated against Culex quinquefasciatus in experimental huts in Lomé. Endpoints were deterrence, exophily, blood feeding inhibition, and mortality. Insecticide susceptibility of Culex quinquefasciatus was assessed with permethrin (1%), DDT (4%), bendiocarb (0.1%), deltamethrin (0.5%, 0.05%), carbosulfan (0.4%), and chlorpyrifos methyl (0.4%). Total of 1,223 Cx. quinquefasciatus females were collected. PermaNet 3.0 unwashed deterred 16.84% Culex mosquitoes. After 20 washes, it deterred 5.79% mosquitoes compared to 6.84% deterrence by unwashed PermaNet 2.0. PermaNet 3.0 induced mosquitoes to exit huts 50.48% and inhibited blood feeding 70.97% in unwashed state. After 20 washes, the net induced 42.91% mosquitoes to exit and inhibited 67.06% mosquitoes from blood feeding. PermaNet 3.0 gave 76% personal protection at zero wash and 69% protection after 20 washes. The net retained 7.1% insecticidal effect in the unwashed state and after 20 washes 6.5%. Cx. quinquefasciatus was resistant to tested insecticides (6%–50% mortality). PermaNet 3.0 is a good control tool against mosquitoes. However, Cx. quinquefasciatus is less affected by PermaNet 3.0. The evaluation depicts the success of vector control innovations using pyrethroids and nonpyrethroids in combination on nets. Additional studies with Culex species are recommended to know whether the difference in blood feeding is interspecific (difference in vector behaviour) and not due to intertrial variability.
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Sene, Ndeye Marie, Konstantinos Mavridis, El Hadji Ndiaye, Cheikh Tidiane Diagne, Alioune Gaye, El Hadji Malick Ngom, Yamar Ba, et al. "Insecticide resistance status and mechanisms in Aedes aegypti populations from Senegal." PLOS Neglected Tropical Diseases 15, no. 5 (May 10, 2021): e0009393. http://dx.doi.org/10.1371/journal.pntd.0009393.
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Aedes aegypti is the main epidemic vector of arboviruses in Africa. In Senegal, control activities are mainly limited to mitigation of epidemics, with limited information available for Ae. aegypti populations. A better understanding of the current Ae. aegypti susceptibility status to various insecticides and relevant resistance mechanisms involved is needed for the implementation of effective vector control strategies. The present study focuses on the detection of insecticide resistance and reveals the related mechanisms in Ae. aegypti populations from Senegal. Bioassays were performed on Ae. aegypti adults from nine Senegalese localities (Matam, Louga, Barkedji, Ziguinchor, Mbour, Fatick, Dakar, Kédougou and Touba). Mosquitoes were exposed to four classes of insecticides using the standard WHO protocols. Resistance mechanisms were investigated by genotyping for pyrethroid target site resistance mutations (V1016G, V1016I, F1534C and S989P) and measuring gene expression levels of key detoxification genes (CYP6BB2, CYP9J26, CYP9J28, CYP9J32, CYP9M6, CCEae3a and GSTD4). All collected populations were resistant to DDT and carbamates except for the ones in Matam (Northern region). Resistance to permethrin was uniformly detected in mosquitoes from all areas. Except for Barkédji and Touba, all populations were characterized by a susceptibility to 0.75% Permethrin. Susceptibility to type II pyrethroids was detected only in the Southern regions (Kédougou and Ziguinchor). All mosquito populations were susceptible to 5% Malathion, but only Kédougou and Matam mosquitoes were susceptible to 0.8% Malathion. All populations were resistant to 0.05% Pirimiphos-methyl, whereas those from Louga, Mbour and Barkédji, also exhibited resistance to 1% Fenitrothion. None of the known target site pyrethroid resistance mutations was present in the mosquito samples included in the genotyping analysis (performed in > 1500 samples). In contrast, a remarkably high (20-70-fold) overexpression of major detoxification genes wasobserved, suggesting that insecticide resistance is mostly mediated through metabolic mechanisms. These data provide important evidence to support dengue vector control in Senegal.
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Utami, Nastiti, and Ari Dwi Cahyani. "Pencegahan Penyakit Demam Berdarah Dengue (DBD) dengan Pembuatan Bio Spray Pengusir Nyamuk di Kelurahan Taman Sari, Ampenan, NTB." Jurnal Surya Masyarakat 3, no. 1 (November 22, 2020): 55. http://dx.doi.org/10.26714/jsm.3.1.2020.55-61.
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Dengue hemorrhagic fever (DHF) in West Nusa Tenggara in 2017 has an incidence rate per 100,000 population of 26.86 above the national rate of 22.55% and a Case Fatality Rate of 0.15%. Prevention of mosquitoes with insecticides is the main choice for people to avoid mosquito bites. Insecticide products circulating in the community include combustion, electricity, spray, burn, and lotion. The chemicals contained in mosquito repellent insecticides include organochlorines, organophosphates, carbamates, pyrethroids, and DEET. The synthetic active ingredients pose a threat to human health. This underlies the implementation of Community Service Program from Undergraduate Programm in Pharmacy STIKES Nasional for the development of safer insecticide products use natural potentials such as lemongrass, cloves, and lime leaves. The method used is to provide education about dengue disease, the Aedes Aegypti mosquito, and a workshop by making bio spray. The results show that there is an increase in the knowledge of the people of Taman Sari, Ampenan, West Nusa Tenggara about the efforts to prevent DHF, as indicated by an increase in all correct post-test answers, In addition, the results of evaluations of overall community service satisfaction programs are very interesting.
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Arévalo-Cortés, Andrea, Ana M. Mejia-Jaramillo, Yurany Granada, Heather Coatsworth, Carl Lowenberger, and Omar Triana-Chavez. "The Midgut Microbiota of Colombian Aedes aegypti Populations with Different Levels of Resistance to the Insecticide Lambda-cyhalothrin." Insects 11, no. 9 (September 1, 2020): 584. http://dx.doi.org/10.3390/insects11090584.
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Insecticide resistance in Aedes aegypti populations is a problem that hinders vector control and dengue prevention programs. In this study, we determined the susceptibility of Ae. aegypti populations from six Colombian regions to the pyrethroid lambda-cyhalothrin and evaluated the presence of the V1016I mutation in the sodium channel gene, which has been broadly involved in the resistance to this insecticide. The diversity of the gut microbiota of these mosquito populations was also analyzed. Only mosquitoes from Bello were susceptible to lambda-cyhalothrin and presented a lower allelic frequency of the V1016I mutation. Remarkably, there was not an important change in allelic frequencies among populations with different resistance ratios, indicating that other factors or mechanisms contributed to the resistant phenotype. Treatment of mosquitoes with antibiotics led us to hypothesize that the intestinal microbiota could contribute to the resistance to lambda-cyhalothrin. Beta diversity analysis showed significant differences in the species of bacteria present between susceptible and resistant populations. We identified 14 OTUs of bacteria that were unique in resistant mosquitoes. We propose that kdr mutations are important in the development of resistance to lambda-cyhalothrin at low insecticide concentrations but insect symbionts could play an essential role in the metabolization of pyrethroid insecticides at higher concentrations, contributing to the resistant phenotype in Ae. aegypti.
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Skovmand, Ole. "Insecticidal Bednets for the Fight Against Malaria – Present Time and Near Future." Open Biology Journal 3, no. 1 (September 8, 2010): 92–96. http://dx.doi.org/10.2174/18741967010030100092.
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Malaria is to-day a tropical disease that especially has major impact in Subsahelian Africa. The current largescale campaign against malaria focuses on better first line use of medication and prevention: (1) the combined use of an Artimisin derivative and one of several synthetic anti-malarials; and (2) the use of insecticidal bednets for transmission prevention, since the disease is transmitted between humans by female mosquitoes. The change from nets that were to be treated and often re-treated to factory pre-treated nets about 7 years ago, made the change from a promising research tool to a major campaign tool. However, once the first line problem of fast disappearance of insecticide treatment was solved, other problems appeared such as physical net durability and low use rate of bednets among people that do not see only the advantages of the nets, but also experience the inconvenience of their use in the daily life. Finally, resistance to insecticides is appearing, probably originating from agricultural use of the same insecticides, but now amplified by the extensive use of insecticides for malaria control. A call for use of common sense and diversified use of insecticides is concluded.
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Idowu, Taiwo E., Tolulope A. Oyeniyi, Tolulope O. Omodara, Olubunmi A. Otunbanjo, and Samson T. A. wolola. "Low Knockdown Resistance Frequency In Anopheles Gambiae Complex Resistant To Some Who-Approved Insecticides In Selected Areas Of Lagos State, South-West, Nigeria." Pan African Journal of Life Sciences 2, no. 1 (June 1, 2019): 99–104. http://dx.doi.org/10.36108/pajols/9102/20(0170).
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Background: Decline in malaria prevalence is usually attributed to the efficient vector control strategies implemented in such endemic areas. The spread of insecticide resistance in Anopheles mosquitoes is a major drawback to the gains in malaria vector control. Here we assessed the susceptibility status of Anopheles gambiae s.l. to some selected WHO-approved insecticides and frequency of knockdown resistance gene in two Local Government Areas of Lagos State, Nigeria. Methods: Three to five days old adult female mosquitoes were exposed to deltamethrin, permethrin and bendocarb. Knockdown time was recorded every ten minutes and % mortality taken at 24hr post exposure. KDT50 and KDT95 were determined using probit regression analysis. The resistant mosquitoes were used for species identification by Polymerase Chain Reaction (PCR) assays and characterized for the knockdown resistance (kdr) mutation by allele-specific PCR (AS-PCR). Results: The results of twenty-four hour post exposure mortality rate showed that mosquitoes sampled at differ-ent locations were resistant to permethrin (39% mortality for Lagos Mainland L.G.A.; 45% for Kosofe L.G.A.), del-tamethrin (51% for Lagos Mainland L.G.A; 68% for Kosofe L.G.A), but susceptible to bendiocarb (100% for Lagos Mainland L.G.A.; 99% for Kosofe L.G.A.). The KDT50 varied from 34 minutes in bendiocarb for both LGAs to 190 minutes in deltamethrin for Kosofe and 119 minutes in permethrin for Lagos Mainland. In all insecticides tested for both LGAs, KDT95 was greater than 60 minutes. Only the 1014F kdr mutation was detected. The overall kdr frequen-cy was low (1.79%). There was no significant association between the presence of the 1014F kdr allele and ability of Anopheles mosquitoes to survive exposure to the tested insecticides (P > 0.05). Conclusion: This level of resistance to WHO approved insecticides is a threat to control programs and can have significant operational impact, if action is not taken.
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Black, William C., Trey K. Snell, Karla Saavedra-Rodriguez, Rebekah C. Kading, and Corey L. Campbell. "From Global to Local—New Insights into Features of Pyrethroid Detoxification in Vector Mosquitoes." Insects 12, no. 4 (March 24, 2021): 276. http://dx.doi.org/10.3390/insects12040276.
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The threat of mosquito-borne diseases continues to be a problem for public health in subtropical and tropical regions of the world; in response, there has been increased use of adulticidal insecticides, such as pyrethroids, in human habitation areas over the last thirty years. As a result, the prevalence of pyrethroid-resistant genetic markers in natural mosquito populations has increased at an alarming rate. This review details recent advances in the understanding of specific mechanisms associated with pyrethroid resistance, with emphasis on features of insecticide detoxification and the interdependence of multiple cellular pathways. Together, these advances add important context to the understanding of the processes that are selected in resistant mosquitoes. Specifically, before pyrethroids bind to their targets on motoneurons, they must first permeate the outer cuticle and diffuse to inner tissues. Resistant mosquitoes have evolved detoxification mechanisms that rely on cytochrome P450s (CYP), esterases, carboxyesterases, and other oxidation/reduction (redox) components to effectively detoxify pyrethroids to nontoxic breakdown products that are then excreted. Enhanced resistance mechanisms have evolved to include alteration of gene copy number, transcriptional and post-transcriptional regulation of gene expression, as well as changes to cellular signaling mechanisms. Here, we outline the variety of ways in which detoxification has been selected in various mosquito populations, as well as key gene categories involved. Pathways associated with potential new genes of interest are proposed. Consideration of multiple cellular pathways could provide opportunities for development of new insecticides.
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Hamid, P. H., V. I. Ninditya, J. Prastowo, A. Haryanto, A. Taubert, and C. Hermosilla. "Current Status of Aedes aegypti Insecticide Resistance Development from Banjarmasin, Kalimantan, Indonesia." BioMed Research International 2018 (December 20, 2018): 1–7. http://dx.doi.org/10.1155/2018/1735358.
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Aedes aegypti represents the principal vector of many arthropod-borne diseases in tropical areas worldwide. Since mosquito control strategies are mainly based on use of insecticides, resistance development can be expected to occur in frequently exposed Ae. aegypti populations. Surveillance on resistance development as well as testing of insecticide susceptibility is therefore mandatory and needs further attention by national/international public health authorities. In accordance, we here conducted a study on Ae. aegypti resistance development towards several often used insecticides, i.e., malathion, deltamethrin, permethrin, λ-cyhalothrin, bendiocarb, and cyfluthrin, in the periurban area of Banjarmasin city, Kalimantan, Indonesia. Our results clearly showed resistance development of Ae. aegypti populations against tested insecticides. Mortalities of Ae. aegypti were less than 90% with the highest resistance observed against 0.75% permethrin. Collected mosquitoes from Banjarmasin also presented high level of resistance development to 0.1% bendiocarb. Molecular analysis of voltage-gated sodium channel (Vgsc) gene showed significant association of V1016G gene point mutation in resistance Ae. aegypti phenotypes against 0.75% permethrin. However, F1534C gene point mutation did not correlate to Ae. aegypti insecticide resistance to 0.75% permethrin. Irrespective of periurban areas in Kalimantan considered as less densed island of Indonesia, Ae. aegypti-derived resistance to different routinely applied insecticides occurred. Our findings evidence that Ae. aegypti insecticide resistance is most likely spreading into less populated areas and thus needs further surveillance in order to delay Ae. aegypti resistance development.
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Lee, Han-Jung, Michael Longnecker, Travis L. Calkins, Andrew D. Renfro, Chris L. Fredregill, Mustapha Debboun, and Patricia V. Pietrantonio. "Detection of the Nav channel kdr-like mutation and modeling of factors affecting survivorship of Culex quinquefasciatus mosquitoes from six areas of Harris County (Houston), Texas, after permethrin field-cage tests." PLOS Neglected Tropical Diseases 14, no. 11 (November 19, 2020): e0008860. http://dx.doi.org/10.1371/journal.pntd.0008860.
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Culex quinquefasciatus is one of the most important mosquito vectors of arboviruses. Currently, the fastest approach to control disease transmission is the application of synthetic adulticide insecticides. However, in highly populated urban centers the development of insecticide resistance in mosquito populations could impair insecticide efficacy and therefore, disease control. To assess the effect of resistance on vector control, females of Cx. quinquefasciatus collected from six mosquito control operational areas in Harris County, Texas, were treated in field cage tests at three different distances with the pyrethroid Permanone® 31–66 applied at the operational rate. Females were analyzed by sequencing and/or diagnostic PCR using de novo designed primers for detecting the kdr-like mutation in the voltage-gated sodium channel (L982F; TTA to TTT) (house fly kdr canonical mutation L1014F). Females from the Cx. quinquefasciatus susceptible Sebring strain and those from the six operational areas placed at 30.4 m from the treatment source were killed in the tests, while 14% of field-collected mosquitoes survived at 60.8 m, and 35% at 91.2 m from the source. The diagnostic PCR had a with 97.5% accuracy to detect the kdr-like mutation. Pyrethroid resistant mosquitoes carrying the L982F mutation were broadly distributed in Harris County at high frequency. Among mosquitoes analyzed (n = 1,028), the kdr-kdr genotype was prevalent (81.2%), the kdr-s genotype was 18%, and s-s mosquitoes were less than 1% (n = 8). A logistic regression model estimated an equal probability of survival for the genotypes kdr-kdr and kdr-s in all areas analyzed. Altogether, our results point to a high-risk situation for the pyrethroid-based arboviral disease control in Harris County.