Gotowa bibliografia na temat „Indoor Residual Spray (IRS)”

Malaria is a worldwide public health problem, in 2017, and an estimated 237 million cases of malaria occurred worldwide compared with 211 million cases in 2010 and 219 million cases in 2015. Several countries used Indoor Residual Spray (IRS) (Bendiocarb 80%) to combat Malaria. The study aimed to evaluate the efficacy of IRS (Bendiocarb 80%) applied in Sennar state, Sudan in which Malaria is endemic. We used Pyrethrum spray collection, Bio efficacy of IRS using Cone methods and Malaria cases reporting to evaluate the efficacy of Indoor Residual Spray. The efficacy of IRS was tested by cone bioassay for four months (August- November 2017) for susceptible strains of Anopheles Mosquitoes. The recorded mortality of the 4 months was 99±1.23, 95±5.14,48±18.37, 23±9.26 respectively and mortality for the field strain of Anopheles mosquito in the study period was 100±0.0; 88.5±7.4; 43.8±20.1; and 0.7±0.8 respectively. The Malaria incidence rates for four months after application of Indoor Residual Spray in Sennar State (September, October, November and December 2017) were (5.18±3.4; 5.0±3.3; 4.31±3.1; and 5.15±3.9 respectively). This study found that there was a reduction in the total number of the collected Anopheles gambiae, female mosquito from 143 to 46, in unfed mosquitoes (UF) from 22 to 0, in fresh feed mosquitoes (FF) from 60 to18, in half gravid mosquitoes (HG) from 0.29 to 18, in gravid mosquitoes (G) from 32 to16, in density/room from 4.1 to 1.3, and in Man Biting Rate (MBR) from 2.5 to 0.7.Data analysed using statistical package for social sciences, version (22), Chi- square test used for the analysis of comparison, probability value of less than 0.05 considered statistically significant. The study concluded that there was a reduction in (Anopheles gambiae) density and Malaria cases after Indoor Residual Spray application in Sennar state, Sudan.

Indoor residual spraying (IRS) is one of the primary vector control interventions for reducing and interrupting malaria transmission. In recent years, however, it has received relatively little attention. Just like it is the case in the 17 villages of the Chipushi area of Mpika district in Muchinga province, Zambia. In community work, among the things that attracted my attention are the non-acceptance and perceived negative attitudes towards acceptance for indoor residual spraying. The purpose of this study was to analyze and establish the factors that contribute to none acceptance for Indoor Residual Spraying (IRS) in the Chipushi area of Mpika, Zambia. None acceptance, in this case, refers to a widespread negative response to having indoor residual spraying performed in people’s homes at the community level. Simple random sampling was used to come up with the study population. And after executing the study through the questionnaire and semi-structured interviews on the 97 respondents, findings revealed that 12 (12.4%) respondents believed that chemicals used in IRS increase mosquitoes and bed bugs instead of controlling them. Other 22 (22.7%) never believed IRS could reduce the incidence of malaria. 18 (18.6%) respondents avoided being in-convenience by the spray operators and health personnel. 10 (10.3%) respondents don’t want to be seen how wrecked their houses are or fear of being embarrassed due to lack of sanity in their homes. Similarly, 17 (17.5%) respondents believed that by the culture, they could not allow strangers to expose their privacy in their homes. Surprisingly 26 (26.8%) respondents never just wanted to participate in spray operations. Keywords: Community, Households, Indoor Residual Spraying, Malaria elimination, Prevention.

Indoor residual spraying of insecticides (IRS) is a key malaria vector control strategy. Whilst human attitude towards IRS is monitored before or shortly after implementation, human activities leading to the modification of insecticide-treated walls post-IRS are not. This could inadvertently reduce the protective effects of IRS. We monitored the extent of modifications to the sprayed indoor wall surfaces by household owners for six months post-IRS campaigns in two districts targeted for malaria elimination in southern Mozambique. In parallel, we assessed building of any additional rooms onto compounds, and mosquito net use. We quantified the contribution of wall modifications, added rooms, prolonged spray campaigns, and product residual efficacies on actual IRS coverage and relative mosquito bite reduction, using a mechanistic approach. Household owners continually modified insecticide-treated walls and added rooms onto compounds. Household surveys in southern Mozambique showed frequent modification of indoor walls (0–17.2% of households modified rooms monthly) and/or added rooms (0–16.2% of households added rooms monthly). Actual IRS coverage reduced from an assumed 97% to just 39% in Matutuine, but only from 96% to 91% in Boane, translating to 43% and 5.8% estimated increases in relative daily mosquito bites per person. Integrating post-IRS knowledge, attitude, and practice (KAP) surveys into programmatic evaluations to capture these modification and construction trends can help improve IRS program efficiency and product assessment.

Indoor residual spraying (IRS) is used to control visceral leishmaniasis (VL) in India, but it is poorly quality assured. Quality assurance was performed in eight VL endemic districts in Bihar State, India, in 2014. Residual dichlorodiphenyltrichloroethane (DDT) was sampled from walls using Bostik tape discs, and DDT concentrations [grams of active ingredient per square meter (g ai/m2)] were determined using HPLC. Pre-IRS surveys were performed in three districts, and post-IRS surveys were performed in eight districts. A 20% threshold above and below the target spray of 1.0 g ai/m2 was defined as “in range.” The entomological assessments were made in four districts in IRS and non-IRS villages. Vector densities were measured: pre-IRS and 1 and 3 mo post-IRS. Insecticide susceptibility to 4% DDT and 0.05% deltamethrin WHO-impregnated papers was determined with wild-caught sand flies. The majority (329 of 360, 91.3%) of pre-IRS samples had residual DDT concentrations of <0.1 g ai/m2. The mean residual concentration of DDT post-IRS was 0.37 g ai/m2; 84.9% of walls were undersprayed, 7.4% were sprayed in range, and 7.6% were oversprayed. The abundance of sand flies in IRS and non-IRS villages was significantly different at 1 mo post-IRS only. Sand flies were highly resistant to DDT but susceptible to deltamethrin. The Stockholm Convention, ratified by India in 2006, calls for the complete phasing out of DDT as soon as practical, with limited use in the interim where no viable IRS alternatives exist. Given the poor quality of the DDT-based IRS, ready availability of pyrethroids, and susceptibility profile of Indian sand flies, the continued use of DDT in this IRS program is questionable.

Abstract: BACKGROUND: The World Health Organization recommends indoor residual spray (IRS) including dichlorodiphenyltrichloroethane (DDT), as a malaria vector control measure. OBJECTIVE: The objective was to assess the knowledge and practice of IRS with DDT in rural area of the West Tripura district. METHODOLOGY: A community based cross-sectional study was conducted in rural area of West Tripura District during the period of June to July 2019. Two hundred adult participants were interviewed from randomly selected families using multistage simple random sampling technique using a predesigned, pretested interview schedule. Data were analyzed using Microsoft excel 2007 and the Epi-info version 6.0 (CDC, Atlanta, Georgia, USA). RESULTS: More than 43% of the families knew that DDT spray was for malaria prevention and control measures. Reasons for not allowing DDT spray were due to stains of houses (35.13%), bad odors (3.5%), unpreparedness (3.5%), uninformed (3%), and 7% other reasons. CONCLUSIONS: Practice on indoor residual spray (DDT) was below the level of coverage required for mass effect recommended by the World Health Organization. However, the population had a good knowledge of the diseases spread by the mosquitoes.

Indoor residual spraying (IRS) has changed little since its introduction in the 1940s. Manual spraying is still prone to variation in insecticide dose. To improve the application of IRS in experimental hut trials, an automated track sprayer was developed, which regulates the speed of application and the distance of the nozzle from the wall, two key sources of variation. The automated track sprayer was compared to manual spraying, firstly using fluorescein solution in controlled indoor settings, and secondly in experimental huts in Tanzania using several IRS products. Manual spraying produced greater variation with both fluorescein and insecticide applications. Both manual and automated spray methods under-dosed the actual dose sprayed compared to the target dose. Overall, the track sprayer treats surfaces more consistently, offering a potential improvement over manual spraying for experimental hut evaluation of new IRS formulations.

Indoor residual spraying (IRS) has changed little since its introduction in the 1940s. Manual spraying is still prone to variation in insecticide dose. To improve the application of IRS in experimental hut trials, an automated track sprayer was developed, which regulates the speed of application and the distance of the nozzle from the wall, two key sources of variation. The automated track sprayer was compared to manual spraying, firstly using fluorescein solution in controlled indoor settings, and secondly in experimental huts in Tanzania using several IRS products. Manual spraying produced greater variation with both fluorescein and insecticide applications. Both manual and automated spray methods under-dosed the actual dose sprayed compared to the target dose. Overall, the track sprayer treats surfaces more consistently, offering a potential improvement over manual spraying for experimental hut evaluation of new IRS formulations.

IntroductionIndoor residual spraying (IRS) and insecticide-treated bed nets (ITNs) are cornerstone malaria prevention methods in Madagascar. This retrospective observational study uses routine data to evaluate the impacts of IRS overall, sustained IRS exposure over multiple years and level of spray coverage (structures sprayed/found) in nine districts where non-pyrethroid IRS was deployed to complement standard pyrethroid ITNs from 2017 to 2020.MethodsMultilevel negative-binomial generalised linear models were fit to estimate the effects of IRS exposure overall, consecutive years of IRS exposure and spray coverage level on monthly all-ages population-adjusted malaria cases confirmed by rapid diagnostic test at the health facility level. The study period extended from July 2016 to June 2021. Facilities with missing data and non-geolocated communes were excluded. Facilities in IRS districts were matched with control facilities by propensity score analysis. Models were controlled for ITN survivorship, mass drug administration coverage, precipitation, enhanced vegetation index, seasonal effects and district. Predicted cases under a counterfactualno IRSscenario and number of cases averted by IRS were estimated using the fitted models.ResultsExposure to IRS overall reduced case incidence by an estimated 30.3% from 165.8 cases per 1000 population (95% CI=139.7 to 196.7) under a counterfactual no IRS scenario, to 114.3 (95% CI=96.5 to 135.3) over 12 months post-IRS campaign in nine districts. A third year of IRS reduced malaria cases 30.9% more than a first year (incidence rate ratio (IRR)=0.578, 95% CI=0.578 to 0.825, p<0.001) and 26.7% more than a second year (IRR=0.733, 95% CI=0.611 to 0.878, p=0.001). There was no significant difference between the first and second year (p>0.05). Coverage of 86%–90% was associated with a 19.7% reduction in incidence (IRR=0.803, 95% CI=0.690 to 0.934, p=0.005) compared with coverage ≤85%, although these results were not robust to sensitivity analysis.ConclusionThis study demonstrates that non-pyrethroid IRS appears to substantially reduce malaria incidence in Madagascar and that sustained implementation of IRS over three years confers additional benefits.

Background: Indoor Residual Spray (IRS) with insecticide (DDT) is one of the most important component of integrated vector management for malaria prevention. Though, NVBDCP targets at least 80% coverage at high risk malaria zone by effective protective measures (eg. IRS) by 2017, but the real coverage is however limited, due to low community acceptance and several other factors. Objectives were to assess the IRS coverage in two blocks of Tripura and to study the factors influencing IRS acceptance.Methods: A cross sectional study was conducted among 600 households of all 30 sub centres of two blocks of Sepahijala district of Tripura 2015 to 2017 using LQAS technique. Head of the families were interviewed to collect information regarding IRS. Data analysis was done in SPSS 20.0. Statistical analysis used Chi square test was applied to assess the association between different variables. P-value (<0.05) was considered as statistically significant.Results: IRS coverage and acceptance were 61.7% and 75.05% respectively. The factors influencing IRS acceptance were Age of the Head of the family p 0.015, Religion p 0.011, Education p 0.04, Occupation p 0.018, type of Community p.0.000, House type p 0.000, By LQAS analysis, 9 out of 30 lots were accepted for having target coverage of IRS (80%).Conclusions: IRS coverage was lower than the NVBDCP target of 80 % coverage. Sound programmatic management strategy along with IEC, BCC is needed to scale up the coverage.

Indoor residual spray (IRS) of insecticides and insecticide-treated bednets (ITNs) are the two most important malaria vector control tools in the tropical world. Application of both tools in the same locations is being implemented for malaria control in endemic and epidemic Africa. The two tools are assumed to have synergistic benefits in reducing malaria transmission because they both act at multiple stages of the transmission cycle. However, this assumption has not been rigorously examined, empirically or theoretically. Using mathematical modelling, we obtained the conditions for which a combination strategy can be expected to improve upon single control tools. Specifically, spraying of dichlorodiphenyltrichloroethane (DDT) in all houses where residents are not using ITNs can reduce transmission of malaria ( R 0 ) by up to 10 times more than the reduction achieved through ITNs alone. Importantly, however, we also show how antagonism between control tools can arise via interference of their modes of action. Repellent IRS reduces the likelihood that ITNs are contacted within sprayed houses and ITNs reduce the rate at which blood-fed mosquitoes rest on sprayed walls. For example, 80 per cent coverage of ITNs and DDT used together at the household level resulted in an R 0 of 11.1 when compared with an R 0 of 0.1 achieved with 80 per cent ITN coverage without DDT. While this undesired effect can be avoided using low-repellence pyrethroid chemicals for IRS, the extent of the potential benefits is also attenuated. We discuss the impact that this result will likely have on future efforts in malaria control combination strategy.

Since the start of Roll Back Malaria (RBM) in 1998 funding for malaria control has increased dramatically, resulting in the current peak of $2.5billion spent on global malaria control annually. Vector control has been a major source of expenditure, with the focus in sub-Saharan Africa being free Long-Lasting Insecticidal Net (LLIN) distribution and Indoor Residual Spraying (IRS). Use of pyrethroid insecticides in agriculture and rapid scaling up of pyrethroid LLINs and IRS for malaria vector control has led to the development and spread of pyrethroid resistance in Anopheles gambiae malaria vectors. In community use, the level of insecticide resistance at which malaria control is compromised remains uncertain, but experimental hut trials in Benin, an area of high frequency pyrethroid resistance, showed that holed pyrethroid Insecticide Treated Nets (ITNs) failed to protect sleepers from being bitten and no longer had a mass killing effect on malaria vectors. If LLINs and IRS are to remain effective it is essential that new public health insecticides are developed to address the growing problem of resistance. All insecticides that are currently recommended by the World Health Organization Pesticide Evaluation Scheme (WHOPES) for LLIN or IRS belong to just four classes of chemistry that act on nerve and muscle targets; namely pyrethroid, organophosphate (OP), carbamate, and organochlorine (DDT). The Global Plan for Insecticide Resistance Management (GPIRM) states that in areas of pyrethroid resistance or high LLIN coverage, alternative insecticide classes should be used for IRS in a rotation. Rotation of insecticides is very difficult to implement due to a lack of new public health insecticides. The Stockholm Convention on Persistent Organic Pollutants (POPs) came into effect in 2004, yet the use of DDT (classified as a POP) for malaria control has been allowed to continue under exemption since then due to a perceived absence of equally effective and efficient alternatives. Alternative classes of insecticide for IRS such as pirimiphos-methyl (OP) and bendiocarb (carbamate) have a relatively short residual duration of action (2-6 months according to WHOPES). In areas of year-round transmission, multiple spray cycles are required resulting in significantly higher costs for malaria control programs and user fatigue. For continued cost-effectiveness of IRS programs it is important to develop new longer-lasting formulations of currently available insecticides, while also developing insecticides with new modes of action. Pyrethroids are the only insecticides that are currently recommended by WHOPES for LLIN. Therefore, it is essential to develop and evaluate new insecticides for LLIN before effectiveness of pyrethroid LLIN is compromised. 6 This thesis consisted of a sequence of tests to evaluate the efficacy of several new formulations of WHOPES recommended insecticides and novel insecticides both in the laboratory and against wild mosquitoes entering experimental huts. Specifically these studies have shown that:  Addition of eave baffles in experimental huts succeeded in reducing the potential for mosquito escape and is preferable to the assumption of doubling veranda catch to allow for unrecorded escapes (research paper 2).  A Capsule Suspension (CS) formulation of pirmiphos-methyl used for IRS showed a significant improvement in terms of longevity on mud, concrete and plywood when compared with the previously recommended Emulsifiable Concentrate (EC) formulation in laboratory and experimental hut bioassays (research paper 3).  A new formulation of deltamethrin with polymeric binder (SC-PE) for IRS showed only a slight improvement over the existing Water Dispersible Granules (WG) formulation in bioassays, but both formulations equalled DDT in experimental huts and should provide annual mosquito control. Deltamethrin SC-PE or WG should only be considered for use by malaria control programs where there is low pyrethroid LLIN coverage (research paper 4).  In experimental hut trials, chlorfenapyr (pyrrole) IRS was equivalent to alphacypermethrin against pyrethroid susceptible An. arabiensis but superior against pyrethroid-resistant Cx. quinquefasciatus. The unique non-neurological mode of action shows no cross-resistance to existing resistance mechanisms and should be successful for control of pyrethroid resistant mosquitoes (research paper 5).  In experimental hut trials, chlorfenapyr ITNs produced relatively high mortality rates of pyrethroid susceptible An. arabiensis but due to low irritability there was only a small reduction in blood-feeding (research paper 8). Mortality rates were similar to those produced by deltamethrin ITN.  Unlike neurotoxic insecticides, such as pyrethroids and carbamates, chlorfenapyr owes its toxicity to the disruption of molecular pathways which enable cellular respiration to occur. Conventional 3 minute contact bioassay based on WHOPES guidelines is suitable for pyrethroids but does not predict field performance of 7 chlorfenapyr, which is metabolic in nature and sensitive to temperature and the phase of the insect’s circadian activity rhythm (research paper 9).  Combining chlorfenapyr with a more excito-repellent pyrethroid on mosquito nets produced higher levels of blood-feeding inhibition than chlorfenapyr alone, in tunnel tests with both pyrethroid susceptible and resistant strains of Cx. quinquefasciatus (research paper 10).  Restricting insecticide to particular surfaces of the nets (top only or sides only) indicated that An. arabiensis contacts both the top and sides of a mosquito net during host-seeking behaviour. These results support the rationale behind the ‘2-in-1’ mosquito net, in which the top of the net is treated with a non-pyrethroid insecticide and the sides with pyrethroid (research paper 11).

Background Malaria remains a serious epidemic threat in the Lowveld region of Mpumalanga Province. In order to appropriately target interventions to achieve substantial reductions in malaria morbidity and mortality, there is a need to assess the impact of current control interventions such as indoor residual spraying (IRS) for vector control. This study aimed to assess long-term changes in the burden of malaria in Mpumalanga Province during the past eight years (2001-2009) and whether IRS and climate variability had an effect on these changes. Methods All malaria cases and deaths notified to the Malaria Control Programme, Department of Health was reviewed for the period 2001 to 2009. Data were retrieved from the provincial Integrated Malaria Information System (IMIS) database. Climate and population data were obtained from the South Africa Weather Service and Statistics South Africa, respectively. Descriptive statistics were computed to determine any temporal changes in malaria morbidity and mortality. Autoregressive integrated moving average (ARIMA) models were developed to assess the effect of climatic factors on malaria. Results Within the eight-year period of the study, a total of 35,191 cases and 164 deaths-attributed to malaria were notified in Mpumalanga Province. There was a significant decrease in the incidence of malaria in Mpumalanga Province from 385 in 2001/02 to 50 cases per 100,000 population in 2008/09 (P < 0.005). The overall incidence and case fatality rates were 134 cases per 100,000 and 0.54%, respectively. Malaria incidence and case fatality rate by gender showed significant differences, higher in males than in L.M. Ngomane University of Pretoria, 2012 iv females (166.9 versus 106.4; P < 0.001; CFR 0.41% versus 0.55%). The incidence of malaria increased from age 5-14 years (70), reaching a peak at age 25-34 years (190), declining thereafter (50 in those >65 years). Mortality due to malaria was higher in those >65 years, the mean CFR reaching a 2.1% peak. Almost half (47.8%) of the notified cases originated from Mozambique and Mpumalanga Province itself constituted 50.1%. The distribution of malaria varied across the districts, highest in Ehlanzeni district (96.5%), lowest in Nkangala (<1%) and Gert Sibande (<1%). A notable decline in malaria case notification was observed following the increased IRS coverage from 2006/07 to 2008/09 malaria seasons. A distinct seasonal transmission pattern was found to be significantly related to changes in rainfall patterns (P = 0.007). Conclusion Decades of continuous IRS with insecticides have proved to be successful in reducing the burden of malaria morbidity and mortality in Mpumalanga Province between 2001 and 2009. A decline of above 50% in malaria morbidity and mortality was observed following expanded IRS coverage. These results highlight the need to continue with IRS together with other control strategies until interruption in local malaria transmission is completely achieved and alternative vector control strategies implemented. Efforts need to be directed towards the control of imported cases, interruption of local transmission and focus on research into sustainable and cost-effective combination of control interventions.<br>Dissertation (MSc)--University of Pretoria, 2012.<br>School of Health Systems and Public Health (SHSPH)<br>Unrestricted

Introduction: Over the past few years, the capacity of the government of Mozambique to sustain the cost of payment of salaries to operationalize the Indoor Residual Spray (IRS), a widely recommended tool to control and prevent malaria, is facing numerous challenges. This is due to recent restrictions of the Official Development Assistance (ODA), an external aid scheme and the main source of financing of the Mozambican government budget. Objective: The objective of this study was to estimate the cost of IRS operationalization activities in Matutuine and Namaacha districts health directorates, in Maputo Province, Mozambique. Methods: A cost analysis using an approach from the provider’s perspective was conducted in two district health directorates in the Maputo province, Matutuine and Namaacha. The institutions were purposely selected since in 2014 in both districts the expenditure on salaries to operationalize IRS was funded by the government budget. Cost information was collected retrospectively and both economic and financial costs were calculated. Uncertainty of results was tested using “one-way” deterministic sensitivity analysis. Results: The average total annual economic cost was 117,351.34 US$. The average economic cost per households sprayed totalled 16.35 US$. On average the economic costs per person protected is 4.09 US$ in total. In the financial analysis, the average total annual financial costs totalled 69,174.83 US$. The average financial cost per household sprayed and per person protected were 9.84 US$ and 2.46 US$ respectively. Vehicles, personnel salaries and consumables were the major substantial cost components. Conclusion: Setting aside the ODA restriction and focusing on the aim of implementing IRS within the existing resources, the study makessuggestions for improving efficiency by focusing on areas with a higher need and pays attention to cost drivers in order to reduce the costs.

Malgré les efforts national et international pour contrôler le paludisme, de nombreux pays d’Afrique Sub-saharienne restent à risque d’infection, de morbidité et de décès liés au paludisme. L’objectif de cette thèse est d’évaluer l’efficacité « théorique » et l’efficacité « réelle » des outils de la lutte anti-vectorielle (LAV) en utilisant des indicateurs parasitologiques et cliniques. Pour évaluer l’efficacité « théorique » d’une mesure de LAV (étude expérimentale), il faut effectuer un essai contrôlé randomisé à unité de randomisation collective. L’évaluation de l’efficacité « réelle » des outils de LAV est possible grâce à l’utilisation d’un essai contrôlé randomisé à condition que le groupe témoin soit couvert au minimum par les moustiquaires imprégnées d’insecticide à longue durée d’action (MILD) de référence ou les outils de LAV déjà en utilisation dans la population d’étude. Mais, elle nécessite d’énormes moyens techniques, logistiques et financiers. Les résultats de cet essai ont permis de noter que ni la couverture universelle en MILD, ni les combinaisons de MILD+Pulvérisation intra-domiciliaire (PID) ou de MILD+bâches imprégnées d’insecticides n’ont pas apporté une protection supplémentaire contre l’infection et l’accès palustre non compliqué (APNC) par rapport à la MILD en couverture sélective. L’évaluation de l’efficacité réelle des outils de LAV en post-distribution requiert un type d’étude épidémiologique plus souple dans la faisabilité. Face aux contraintes éthiques et financières de l’étude longitudinale, nous avons validé l’utilisation d’une étude cas-témoin à cet effet. Elle a été réalisée en premier chez les enfants de 0-5 ans puis appliquée à toute la population. Les résultats obtenus indiquent que l’efficacité des MILD est variable d’une région à l’autre. En zone rurale, les MILD ont conféré sur l’APNC une efficacité de 40-50 % en ouverture sélective en MILD chez les enfants de zéro à cinq ans. Une réduction de 49 % des APNC a été notée dans toute la population si les MILD (en couverture universelle) sont associées à la PID. En zone urbaine, les MILD en couverture universelle n’ont pas permis de réduire le nombre d’APNC dans toute la population. Elles ont cependant permis une réduction de 50 % des infections palustres dans un seul quartier de la zone d’étude. Les limites de cette étude cas-témoin peuvent être intrinsèques aux mesures de lutte (défaut de couverture, résistance des vecteurs aux insecticides etc.). La mesure de l’exposition peut également être soumise à des biais. Plusieurs facteurs interférant avec la réussite de la LAV ont été évoqués. Le premier facteur défavorable à l’efficacité de la MILD est son défaut d’utilisation. De même, la description de la pièce où se joue la LAV montre que l’espace disponible pour que tous les acteurs puissent jouer convenablement leur rôle (MILD, PID, Homme et vecteur) est assez restreint. Cet espace est souvent mal éclairé. De même la présence des flammes libres participe à la dégradation de l’intégrité physique des MILD. La présence de trous sur les moustiquaires indique une perte de leur efficacité car à partir d’un certain indice &gt; 100, les individus sont fortement exposés aux piqûres de vecteurs. En plus, An. funestus, un des principaux vecteurs assurant la transmission dans les zones d’études concernées peut piquer au-delà de 6 h du matin et assure une bonne partie de la transmission à l’extérieur des habitations. Enfin, les moustiquaires peuvent également créer des dommages corporels à partir d’incendie auxquelles elles participent de part leur caractère inflammable. A l’étape actuelle de la lutte contre le paludisme, il est nécessaire de trouver de meilleurs outils pour améliorer la qualité de la prévention par la LAV. La recherche opérationnelle nous semble en outre primordiale dans la mesure où les outils de LAV utilisés à large échelle ont déjà fourni de bons résultats d’efficacité au laboratoire<br>Despite national and international efforts, malaria remains a major public health in many countries. Health systems are hindered by the lack of information on the actual burden of malaria and the effectiveness of vector control tools. Vector-control measures are a component of integrated malaria control strategies. The objective of our thesis was to evaluate the efficacy and the effectiveness of malaria vector control tools using parasitological and clinical criteria.With a block randomized control trial, we investigated whether the combination of long-lasting insecticidal mosquito nets (LNs) with indoor residual spraying (IRS) or Carbamate-treated Plastic Sheeting (CTPS) conferred better protection against malaria vectors than did LNs alone. The clinical incidence density of malaria was not reduced in the children from the "Universal LN" group (incidence density rate (0.95, 95% CI 0.67–1.36, p=0.79), nor in those from the "Target LN + IRS" group (1.32, 0.90–1.93, p=0.15) or from the "Universal LN + CTPS group (1.05, 0.75–1.48, p=0.77) compared with the reference group "Target LN". The same trend was observed with the prevalence and parasite density of asymptomatic infections. The evaluation of the effectiveness of vector control tools is possible but requires enormous technical, logistic and financial resources. The evaluation of the effectiveness of malaria vector control tools after distribution requires a more flexible epidemiological study. Considering the ethical and financial constraints of the longitudinal study, we validated the use of a case-control study to this purpose. It was conducted primarily among children aged 0-5 years old and then applied to the entire population. Results were spatial dependant when taking into account age and compliance to chemoprophylaxis as confusion factors, use of other vector control tools, sex, and economic status, school level of the mother or the head of the house. In the rural area, the use of LNs provided significant level of protection (40-50%) against clinical cases among children aged 0-5 years old. This significant protection was obtained among all population only if the LNs were associated to IRS. In the urban area, the use of LN was not provided protection against clinical cases but reduce 50% of the risk of Plasmodium falciparum infection in one neighbourhood. The limits of this case-control study may be intrinsic to control measures (lake of coverage, vector resistance to insecticides etc.). The exposure of vector control tools measures may also be subject to bias. Several factors interfering with the success of malaria control were discussed. The first negative factor to the effectiveness of vector control tools was the "no use of LNs". Then follows the immediate environment where the fight against vectors took place. The description of the room where played vector control fighting shows that the space available for all the actors (LNs, IRS, humans and vectors) to play their role properly is quite limited. This space is often poorly enlightened. Similarly the presence of open flames is involved in the degradation of the physical integrity of LNs. The presence of holes on the bed-nets indicates a loss of effectiveness because from a hole index above 100, individuals are highly exposed to the bites of vectors. In addition, An. funestus, one of the main vectors of malaria transmission in the study area, bitted after 6:00 am and provides much of the transmission in outdoor. Finally, the nets can also create personal injury as fire. At the end our work, we conclude that the innovative vector control tools are required to improve malaria vector control. But, operational research seems now essential as the vector control tools used on a large scale have provided good efficacy results in the laboratory. The challenge then is to obtain comparable results in real condition of use and look for effectiveness barriers

The insecticide dichloro-diphenyl-trichloroethane (DDT) is widely used in indoor residual spraying (IRS) for malaria control owing to its longer residual efficacy compared to other World Health Organization (WHO) alternatives. It was envisaged that by investigating mechanisms of degradation of these alternative insecticides, a better understanding would be obtained on strategies of stabilising them and rendering their efficacy comparable with or better than DDT, hence providing less controversial and more acceptable and effective alternative insecticide formulations to DDT. This study sought to investigate the reasons behind the reported longer lasting behaviour of DDT by exposing all the WHO approved insecticides to high temperature, high humidity and ultra-violet light. Interactions between the insecticides and some mineral powders in the presence of an aqueous medium were also tested. Simple insecticidal paints were made using slurries of these mineral powders whilst some insecticides were dispersed into a conventional acrylic paint binder. These formulations were then spray painted on neat and manure coated mud plaques, representative of the material typically used in rural mud houses, at twice the upper limit of the WHO recommended dosage range. DDT was applied directly onto mud plaques at four times the WHO recommended concentration and on manure plaques at twice WHO recommended concentration. All plaques were subjected to accelerated ageing conditions of 40 °C and a relative humidity of 90%. In the accelerated ageing tests, Fourier transform infra-red (FTIR) interferograms showed that pyrethroids were the most stable insecticides compared to carbamates and DDT. High temperature oxidation, ultra violet light and humidity were ruled out as the cause of failure of the alternative insecticides. Gas chromatography (GC) interferograms showed that phosphogypsum stabilised the insecticides the most against alkaline degradation. Bioassay testing showed that the period of efficacy of these formulations was comparable to that of DDT sprayed at 4 times the upper limit of the WHO recommended dosage range. Bioassay testing also showed that these insecticidal “paint” formulations stabilised the insecticides on cattle manure coated surfaces as compared to DDT sprayed directly on similar surfaces. Bioassay experiments indicated that incorporating insecticides into a conventional paint binder or adsorbing them onto phosphogypsum provided effective life spans, under accelerated ageing conditions, comparable to or exceeding that of DDT directly applied to typical soil substrates. Best results were obtained with propoxur in standard acrylic emulsion paint. Similarly, insecticides adsorbed on phosphogypsum and sprayed on cattle manure coated surfaces provided superior lifespans compared with DDT sprayed directly on a similar surface. Copyright<br>Dissertation (MEng)--University of Pretoria, 2012.<br>Chemical Engineering<br>unrestricted

Student Number : 0110574V - MPh research report - School of Public Health - Faculty of Health Sciences<br>Pesticide poisoning poses a health risk to individuals throughout the world although the reported global and local risk are not consistent in the literature. Mpumalanga Province has areas of epidemic malaria. Spray teams, applying local insecticides to indoor surfaces operate just prior to the rainy season (October to May) to control malaria. The purpose of this cross sectional study was to compare prescribed safe handling and application practices of Mpumalanga malaria spray operators mixing and applying insecticides versus actual practices in the field. All members of the spray operating teams were included in the study. A tick list and questionnaire was utilized to observe field practices and enquire about reasons for non-compliance. Only 28% of all operators complied with prescribed safety practices and differences in compliance between mixing (38%) and application (36%) were marginal. Gloves, face shields and dust masks were not utilized as recommended and contributed to the highest levels of non-compliance. Compliance was found to be dependent on gender, age, years of experience, education level and employment status. The low compliance rate necessitates further investigation of the malaria programme occupational safety management system. All stakeholders need to be aware of the consequences of pesticide poisoning and collaborate in efforts to work towards prevention rather than cure.

Malaria is known to be endemic throughout Zambia and continues to be a major public health problem. Eighty three percent (83 %) of Zambian population is reported to be living in malaria high risk areas and the remaining 17 percent is reported living in malaria low risk areas. Zambia has a 16 percent malaria national prevalence. Malaria peak transmission periods are usually during the rainy season ? from November to April and the main transmitting vectors are anopheles species; funestus, gambiae and arabiensis. Plasmodium falciparum is the main transmitting parasite accounting for about 98 percent of all malaria infections in the country. Other species of plasmodium that can be found in Zambia are ovale and malariae. The main intervention measures used in the prevention and control of malaria in Zambia are; Indoor Residual spray (IRS), mass distribution of insecticide treated mosquito nets (ITNs) and Intermittent Prevention Treatment (IPT). The main aim of this thesis is to analyze the efficiency and effectiveness of the the current intervention measures used to prevent and control malaria in Zambia. I approached this issue from time the ?roll back malaria ? project was intiated in 1998 up to 2011. With help of the changes introduced to the health sector under the sector wide approach reforms in 1995, the public health approach in the fight against malaria was even much widened. The second aim of my thesis is to offer acceptable alternative interventions that can used in the prevention and control of malaria. In this qualitative type of research, I chose to use secondary analyzation of data as my research method. I obtained much of the information from studying health literature, journals, laws and other online publications, which I found to be relevant to the topic at hand. I also consulted with the Zambian ministry of health through provincial health offices as well as via district health offices. A series of three open research questions was used as a guide to obtaining the much needed data. However, the results revealed that the current intervention measures used in the prevention and control of malaria are efficient and effective. In 2009, Zambia recorded a 66 percent reduction in deaths due to malaria. This success recorded clearly surpasses the target set by the ?roll back malaria? 2006 which was aimed at reducing mortality due to malaria by 50 percent by year 2010. However, parasitemia results still show great variation in prevalence between urban areas and rural. This inequality is also evident in the access to health care as well. There is much need to scale up on intervention measures if a Zambia without malaria is to be achieved. This work can as used as a public health tool in the prevention of malaria in Zambia and also as a road map to future research concerning malaria and public health.

Insecticide resistance is a major threat to vector control programmes as insecticides still remain the most effective method to control the vector-borne diseases. For effective management of insecticide resistance, a knowledge of the insecticides used along with their mode of action is a prerequisite to optimize their use. Nowadays, different detection methods, viz., phenotypic, genotypic and proteomic assays are used for assessment of insecticide resistance in vectors. An understanding of the phenotypic and genotypic variations present in the vectors help in implementation of these techniques to evaluate the usefulness of insecticides in an area and to determine the efficacy of an ongoing vector control programmes. The understanding of different factors involved in emergence of insecticide resistance and the alternative solutions to control this problem by the use of rotational, mixture of insecticides and use of piperonyl butoxide to increase the efficacy of indoor residual spray and insecticide treated bed nets are some of the steps taken to tackle the problem of insecticide resistance in vectors.

Malaria remains one of the most important and deadliest diseases in many countries in Africa, in the Americas, in South-East Asia, in the Eastern Mediterranean and in the Western Pacific regions, with high morbidity and mortality, despite important successes for the control of this disease borne by the vector Anopheles mosquitoes. Malaria elimination relies on different strategies including early diagnosis, improved drug therapies and better health infrastructure, and mainly the use of long-lasting insecticidal nets (LLINs) and indoor residual sprayings (IRS) of insecticide. In Cameroon, a country composed of several ethnic groups, malaria transmission is endemic in some regions, while it is seasonal in others; children and pregnant women are most vulnerable. Progress has been made towards malaria control, considering these specificities, and led to a reduction in both morbidity and mortality, but these accomplishments are under threat, mainly due to the development of resistance to insecticides among mosquitoes, targeting the 4 commonly used insecticide classes. To continue our route towards malaria control and elimination, it is urgent to have more knowledge about resistance mechanisms, in the objective of elaborating new strategies with the involvement of the community; these strategies should take into consideration socio-ecological factors such as the young age of the population, low literacy rate especially among women, population’s beliefs, traditions, and customs. Forest ecosystems with abundant rains, humidity and hot temperature, lower access to water for populations living in rural areas, and poverty level are other factors to consider when elaborating malaria control approaches.