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Journal articles on the topic 'Live parasites'
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Harwood, David. "Parasites in the goat." Livestock 19, no. 6 (November 2, 2014): 360–67. http://dx.doi.org/10.12968/live.2014.19.6.360.
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Combes, C., and S. Morand. "Do parasites live in extreme environments? Constructing hostile niches and living in them." Parasitology 119, S1 (December 1999): S107—S110. http://dx.doi.org/10.1017/s0031182000084663.
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SUMMARYWe develop the hypothesis that parasites do not invade extreme environments, i.e. hostile hosts, but rather ‘create’ them. We argue that parasites may have driven the evolution of the constitutive and adaptive immune system. This leads to several implications. First, parasites respond to ‘genes to kill’ by ‘genes to survive’ and this triggers an indefinite selection of measures and counter-measures. Second, these revolutionary arms races may lead to local adaptation, in which parasite populations perform better on local hosts. Third, the evolution of the immune system, whose responses are predictable, may allow parasites to specialize, to evade and even to manipulate. Finally we show that the correlations between the increase in the antibody repertoire, the expansion of MHC loci and parasite pressures support our hypothesis that both host complexity and parasite pressures can be invoked to explain the diversity of antibodies, T-receptors and MHC molecules.
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Buckner, Frederick S., Aaron J. Wilson, and Wesley C. Van Voorhis. "Detection of Live Trypanosoma cruzi in Tissues of Infected Mice by Using Histochemical Stain for β-Galactosidase." Infection and Immunity 67, no. 1 (January 1, 1999): 403–9. http://dx.doi.org/10.1128/iai.67.1.403-409.1999.
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ABSTRACT The pathogenesis of tissue damage in chronic Trypanosoma cruzi infection has been a subject of long-standing debate. Conventional staining methods reveal a paucity of parasites in tissues from chronically infected individuals, which has led to the theory that the pathologic findings may be primarily autoimmune in origin. Immunostaining for T. cruzi antigens or in situ PCR methods show evidence for parasite components in chronic tissues; however, these methods do not address whether the stained material represents parasite debris or live organisms. An improved method for detecting intact T. cruzi in tissues was developed by making a genetically engineered strain that expresses Escherichia coli β-galactosidase. The expression of this enzyme allows the detection of T. cruzi in tissues by using the histochemical stain 5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside (X-Gal). The technique was used to monitor tissue parasitism and its relation to pathologic findings in the mouse model of Chagas’ disease. Parasites were easily visible as bright blue structures in skeletal muscle, heart, bladder, peripheral nerve, liver, spleen, adrenal gland, brain, and adipose tissue in acutely infected mice. The number of viable parasites diminished >100-fold when tissues from 3-week-infected mice were compared with those from 10-month-infected mice. However, even at the lower level, parasites were clearly recognizable in sections of skeletal muscle and bladder at the 10-month time point. Inflammation remained robust in skeletal muscle, bladder, and sciatic nerve despite the near disappearance of parasites, suggesting three possibilities: exuberant host reactions to the few remaining parasites, autoimmune inflammation, or reactions to retained parasite antigens in the tissues.
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Rénia, Laurent, Anne Charlotte Grüner, Marjorie Mauduit, and Georges Snounou. "Vaccination against malaria with live parasites." Expert Review of Vaccines 5, no. 4 (August 2006): 473–81. http://dx.doi.org/10.1586/14760584.5.4.473.
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Tabbara, Khaled S., Nathan C. Peters, Farhat Afrin, Susana Mendez, Sylvie Bertholet, Yasmine Belkaid, and David L. Sacks. "Conditions Influencing the Efficacy of Vaccination with Live Organisms against Leishmania major Infection." Infection and Immunity 73, no. 8 (August 2005): 4714–22. http://dx.doi.org/10.1128/iai.73.8.4714-4722.2005.
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ABSTRACT Numerous experimental vaccines have been developed with the goal of generating long-term cell-mediated immunity to the obligate intracellular parasite Leishmania major, yet inoculation with live, wild-type L. major remains the only successful vaccine in humans. We examined the expression of immunity at the site of secondary, low-dose challenge in the ear dermis to determine the kinetics of parasite clearance and the early events associated with the protection conferred by vaccination with live L. major organisms in C57BL/6 mice. Particular attention was given to the route of vaccination. We observed that the rapidity, strength, and durability of the memory response following subcutaneous vaccination with live parasites in the footpad are even greater than previously appreciated. Antigen-specific gamma interferon (IFN-γ)-producing T cells infiltrate the secondary site by 1.5 weeks, and viable parasites are cleared as early as 2.5 weeks following rechallenge, followed by a rapid drop in IFN-γ+ CD4+ cell numbers in the site. In comparison, intradermal vaccination with live parasites in the ear generates immunity that is delayed in effector cell recruitment to the rechallenge site and in the clearance of parasites from the site. This compromised immunity was associated with a rapid recruitment of interleukin-10 (IL-10)-producing CD4+ T cells to the rechallenge site. Treatment with anti-IL-10-receptor or anti-CD25 antibody enhanced early parasite clearance in ear-vaccinated mice, indicating that chronic infection in the skin generates a population of regulatory cells capable of influencing the level of resistance to reinfection. A delicate balance of effector and regulatory T cells may be required to optimize the potency and durability of vaccines against Leishmaniasis and other intracellular pathogens.
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Omeji, S., S. G. Solomon, and E. S. Idoga. "A Comparative Study of the Common Protozoan Parasites ofClarias gariepinusfrom the Wild and Cultured Environments in Benue State, Nigeria." Journal of Parasitology Research 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/916489.
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A total of one hundred and twentyClarias gariepinuscomprising 30 dead and 30 live fishes were examined for protozoan parasites infestation, sixty each from the wild and a pond (cultured environment) over a period of six months.Ichthyophthirius multifiliiswas the most common protozoan parasites found inC. gariepinusfrom the wild (River Benue) and cultured (pond) environments. These protozoan parasites constitute 37.08% of the total parasites encountered for fishes in the pond and 42.51% of fishes in the wild. Among the body parts of the sampled fishes from the pond, the gills had the highest parasite load (38.86%). Also, the gills had the highest parasite load (40.54%) among the body parts of the fishes sampled from the wild. Fishes not infested with any protozoan parasites from the pond constituted 36.70% of the total fish sampled. On the other hand, fishes not infested with any protozoan parasites from the wild constituted 31.65% of the total fish sampled. Female fishes had more protozoan parasites than the male fishes. Bigger fishes of total length (25–48 cm) had more parasite load than the smaller ones (19–24 cm). Also, fishes between 150–750 g had more parasite load than the smaller ones of less than 150 g. Protozoan parasite load of fish from the cultured environment (pond) did not differ significantly (P<0.05) from those from River Benue (wild).
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Bhattacharya, Parna, Ranadhir Dey, Pradeep K. Dagur, Michael Kruhlak, Nevien Ismail, Alain Debrabant, Amritanshu B. Joshi, et al. "Genetically Modified Live Attenuated Leishmania donovani Parasites Induce Innate Immunity through Classical Activation of Macrophages That Direct the Th1 Response in Mice." Infection and Immunity 83, no. 10 (July 13, 2015): 3800–3815. http://dx.doi.org/10.1128/iai.00184-15.
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Visceral leishmaniasis (VL) causes significant mortality and there is no effective vaccine. Previously, we have shown that genetically modifiedLeishmania donovaniparasites, here described as live attenuated parasites, induce a host protective adaptive immune response in various animal models. In this study, we demonstrate an innate immune response upon infection with live attenuated parasites in macrophages from BALB/c mice bothin vitroandin vivo. In vitroinfection of macrophages with live attenuated parasites (compared to that with wild-type [WT]L. donovaniparasites) induced significantly higher production of proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin-12 [IL-12], gamma interferon [IFN-γ], and IL-6), chemokines (monocyte chemoattractant protein 1/CCL-2, macrophage inflammatory protein 1α/CCL-3, and IP-10), reactive oxygen species (ROS), and nitric oxide, while concomitantly reducing anti-inflammatory cytokine IL-10 and arginase-1 activities, suggesting a dominant classically activated/M1 macrophage response. The classically activated response in turn helps in presenting antigen to T cells, as observed with robust CD4+T cell activationin vitro. Similarly, parasitized splenic macrophages from live attenuated parasite-infected mice also demonstrated induction of an M1 macrophage phenotype, indicated by upregulation of IL-1β, TNF-α, IL-12, and inducible nitric oxide synthase 2 and downregulation of genes associated with the M2 phenotype, i.e., the IL-10, YM1, Arg-1, and MRC-1 genes, compared to WTL. donovani-infected mice. Furthermore, anex vivoantigen presentation assay showed macrophages from live attenuated parasite-infected mice induced higher IFN-γ and IL-2 but significantly less IL-10 production by ovalbumin-specific CD4+T cells, resulting in proliferation of Th1 cells. These data suggest that infection with live attenuated parasites promotes a state of classical activation (M1 dominant) in macrophages that leads to the generation of protective Th1 responses in BALB/c mice.
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Chamidah, Dina. "Jenis-jenis Benalu dengan Tanaman Inang Pada Ruang Terbuka Hijau Kota Surabaya." Ibriez : Jurnal Kependidikan Dasar Islam Berbasis Sains 2, no. 2 (December 29, 2017): 215–24. http://dx.doi.org/10.21154/ibriez.v2i2.38.
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Green Open Space serves as a container for human life, both individually and in groups, as well as other creature containers to live and thrive in a sustainable manner. The beauty and value of the benefits of plants in the Green Open Space are often disturbed by the presence of parasites. The presence of parasites often indicates the occurrence of disturbance or damage to host plants that paraded. Benalu has been widely known by the community, but has never received attention in handling it. There has been little research on crop damage or loss caused by parasites. The purpose of this research is to know the presence or absence of parasite in green open space of Surabaya city and to know identification of dominance of parasite with the host plant in green open space of Surabaya city. Observation on the type of parasite with its host in the green open space of Surabaya City, East Java had been conducted in some spots, yield : Center Surabaya area, North Surabaya area, East Surabaya area, South Surabaya area, West Surabaya area. The observation methodology is by cruising (cruise method) by visiting the place where much overgrown vegetation plants at each point there are 500 vegetation plants which allows to be a parent host. The results of the observation obtained 3 types of parasites, 1 type of parasite of the tribe Crypteroniaceae which was parasite 39 species of host plants i.e. Henslowia frutescens .Champ. and 2 types of parasites of the tribe Loranthaceae, i.e. Loranthus Sp and Macrosolen cochinchinensis (Lour.) van Tiegh.
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Jarra, William, and Georges Snounou. "Only Viable Parasites Are Detected by PCR following Clearance of Rodent Malarial Infections by Drug Treatment or Immune Responses." Infection and Immunity 66, no. 8 (August 1, 1998): 3783–87. http://dx.doi.org/10.1128/iai.66.8.3783-3787.1998.
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ABSTRACT Detection and analysis of pathogens by PCR plays an important role in infectious disease research. The value of these studies would be diminished if nuclear material from dead parasites were found to remain in circulation for extended periods and thus result in positive amplification. This possibility was tested in experimental rodent malaria infections. Blood samples were obtained from infected mice during and following drug or immune clearance of Plasmodium chabaudi chabaudi parasitemias. Detection of parasite DNA by a sensitive Plasmodium-specific PCR amplification assay was associated with the presence of viable parasites, as detected by subinoculation. No parasite DNA could be detected by PCR 48 h after the injection of killed parasites into mice. Nuclear material from parasites removed by drug or immune responses is rapidly cleared from the circulation and does not contribute significantly to amplification. Thus, results from PCR analysis of malaria-infected blood accurately reflect the presence of live parasites.
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Waterfall, Martin, Antony Black, and Eleanor Riley. "γδ+ T Cells Preferentially Respond to Live Rather than Killed Malaria Parasites." Infection and Immunity 66, no. 5 (May 1, 1998): 2393–98. http://dx.doi.org/10.1128/iai.66.5.2393-2398.1998.
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ABSTRACT We have compared the in vitro responses of peripheral blood T cells from malaria-unexposed donors to live Plasmodium falciparumschizonts, freeze-thawed schizont extracts (P. falciparumschizont extracts [PfSE]), and parasite culture supernatants. We show that the cells responding to PfSE and parasite culture supernatants are predominantly CD4+ TCRαβ+ while in the presence of live schizonts there is an additional activation of TCRγδ+ cells. Activation of TCRγδ+cells in response to PfSE was seen only when irradiated autologous feeder cells or recombinant interleukin-2 (IL-2) was added to the cultures. Live schizonts but not PfSE induced significant IL-2 production in vitro in the first 5 days after stimulation, suggesting that induction of early IL-2 by live parasites may contribute to the marked activation of the TCRγδ+ population.
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INNES, E. A., and A. N. VERMEULEN. "Vaccination as a control strategy against the coccidial parasitesEimeria,ToxoplasmaandNeospora." Parasitology 133, S2 (October 2006): S145—S168. http://dx.doi.org/10.1017/s0031182006001855.
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The protozoan parasitesEimeriaspp.Toxoplasma gondiiandNeospora caninumare significant causes of disease in livestock worldwide andT. gondiiis also an important human pathogen. Drugs have been used with varying success to help control aspects of these diseases and commercial vaccines are available for all three groups of parasites. However, there are issues with increasing development of resistance to many of the anti-coccidial drugs used to help control avian eimeriosis and public concerns about the use of drugs in food animals. In addition there are no drugs available that can act against the tissue cyst stage of eitherT. gondiiorN. caninumand thus cure animals or people of infection. All three groups of parasites multiply within the cells of their host species and therefore cell mediated immune mechanisms are thought to be an important component of host protective immunity. Successful vaccination strategies for bothEimeriaandToxoplasmahave relied on using a live vaccination approach using attenuated parasites which allows correct processing and presentation of antigen to the host immune system to stimulate appropriate cell mediated immune responses. However, live vaccines can have problems with safety, short shelf-life and large-scale production; therefore there is continued interest in devising new vaccines using defined recombinant antigens. The major challenges in devising novel vaccines are to select relevant antigens and then present them to the immune system in an appropriate manner to enable the induction of protective immune responses. With all three groups of parasites, vaccine preparations comprising antigens from the different life cycle stages may also be advantageous. In the case ofEimeriaparasites there are also problems with strain-specific immunity therefore a cocktail of antigens from different parasite strains may be required. Improving our knowledge of the different parasite transmission routes, host-parasite relationships, disease pathogenesis and determining the various roles of the host immune response being at times host-protective, parasite protective and in causing immunopathology will help to tailor a vaccination strategy against a particular disease target. This paper discusses current vaccination strategies to help combat infections withEimeria,ToxoplasmaandNeosporaand recent research looking towards developing new vaccine targets and approaches.
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BARTLEY, P. M., S. WRIGHT, F. CHIANINI, D. BUXTON, and E. A. INNES. "Inoculation of Balb/c mice with live attenuated tachyzoites protects against a lethal challenge ofNeospora caninum." Parasitology 135, no. 1 (September 4, 2007): 13–21. http://dx.doi.org/10.1017/s0031182007003526.
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SUMMARYNeospora caninumtachyzoites attenuated through passage in tissue culture were tested for their ability to induce protective immunity against a lethal challenge dose of parasites. Balb/c mice were each inoculated with either 1×106live virulent tachyzoites (Group 1) or 1×106live attenuated tachyzoites (Group 2), while (Group 3) received a control inoculum. All mice were each challenged 28 days later with 5×106virulent parasites. Histopathological lesions in the brains including necrosis and microgliosis were observed following post-mortem on day 28 post-challenge (p.c.) in 71% of Group 1 and 56% of Group 2. Immunohistochemistry (IHC) of these lesions showed tachyzoites andNeosporaantigens to be associated with moderate brain lesions in 17% of Group 1, while in 11% of Group 2N. caninumtissue cysts were detected, but these were not associated with lesions, Parasite DNA was detected by PCR in the brains of 86% of mice in Group 1 and 56% of mice in Group 2. Following challenge the mice in Group 3 showed high morbidity and 100% mortality within 17 days p.c. Positive IHC forN. caninumwas seen in 88% of the Group 3 mice and parasite DNA was detected in all brain samples. This study shows that it is possible to protect against a lethal challenge ofN. caninumthrough inoculation with attenuated or virulent tachyzoites. However, more severe pathology developed in mice initially inoculated with virulent parasites following a secondary challenge, compared to mice initially inoculated with attenuated parasites.
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Woods, Gregory M., A. Bruce Lyons, and Silvana S. Bettiol. "A Devil of a Transmissible Cancer." Tropical Medicine and Infectious Disease 5, no. 2 (April 1, 2020): 50. http://dx.doi.org/10.3390/tropicalmed5020050.
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Devil facial tumor disease (DFTD) encompasses two independent transmissible cancers that have killed the majority of Tasmanian devils. The cancer cells are derived from Schwann cells and are spread between devils during biting, a common behavior during the mating season. The Centers for Disease Control and Prevention (CDC) defines a parasite as “An organism that lives on or in a host organism and gets its food from, or at, the expense of its host.” Most cancers, including DFTD, live within a host organism and derive resources from its host, and consequently have parasitic-like features. Devil facial tumor disease is a transmissible cancer and, therefore, DFTD shares one additional feature common to most parasites. Through direct contact between devils, DFTD has spread throughout the devil population. However, unlike many parasites, the DFTD cancer cells have a simple lifecycle and do not have either independent, vector-borne, or quiescent phases. To facilitate a description of devil facial tumor disease, this review uses life cycles of parasites as an analogy.
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Al-Anouti, Fatme, Stanislas Tomavo, Stephen Parmley, and Sirinart Ananvoranich. "The Expression of Lactate Dehydrogenase Is Important for the Cell Cycle ofToxoplasma gondii." Journal of Biological Chemistry 279, no. 50 (September 30, 2004): 52300–52311. http://dx.doi.org/10.1074/jbc.m409175200.
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InToxoplasma gondii, lactate dehydrogenase is encoded by two independent and developmentally regulated genesLDH1andLDH2. These genes and their products have been implicated in the control of a metabolic flux during parasite differentiation. To investigate the significance ofLDH1andLDH2in this process, we generated stable transgenic parasite lines in which the expression of these two expressed isoforms of lactate dehydrogenase was knocked down in a stage-specific manner. TheseLDHknockdown parasites exhibited variable growth rates in either the tachyzoite or the bradyzoite stage, as compared with the parental parasites. Their differentiation processes were impaired when the parasites were grown underin vitroconditions.In vivostudies in a murine model system revealed that tachyzoites of these parasite lines were unable to form significant numbers of tissue cysts and to establish a chronic infection. Most importantly, all mice that were initially infected with tachyzoites of either of the fourLDHknockdown lines survived a subsequent challenge with tachyzoites of the parental parasites (104), a dose that usually causes 100% mortality, suggesting that live vaccination of mice with theLDHknockdown tachyzoites can confer protection againstT. gondii. Thus, we conclude thatLDHexpression is essential for parasite differentiation. The knockdown ofLDH1andLDH2expression gave rise to virulence-attenuated parasites that were unable to exhibit a significant brain cyst burden in a murine model of chronic infection.
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Nee, S., and J. Maynard Smith. "The evolutionary biology of molecular parasites." Parasitology 100, S1 (June 1990): S5—S18. http://dx.doi.org/10.1017/s0031182000072978.
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A parasite can be considered to be the device of a nucleic acid which allows it to exploit the gene products of other nucleic acid–the host organisms. In this view, all parasites are ‘molecular parasites’. But it is interesting to restrict our attention to nucleic acids which do not encode organisms, as these live in a purely molecular world which lacks emergent features such as fangs and ovipositors. Viruses and transposons are molecular parasites in this sense. Most viral nucleic acids do code for some proteins, such as replicases and the protein shell in which they travel between their cellular oases. Some, however, do not even have a shell and code for nothing at all–these are the ‘viroids’ (Reisner & Gross, 1985), the smallest parasites in the world.
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Soto, Manuel, Laura Ramírez, José Carlos Solana, Emma C. L. Cook, Elena Hernández-García, José María Requena, and Salvador Iborra. "Inoculation of the Leishmania infantum HSP70-II Null Mutant Induces Long-Term Protection against L. amazonensis Infection in BALB/c Mice." Microorganisms 9, no. 2 (February 12, 2021): 363. http://dx.doi.org/10.3390/microorganisms9020363.
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Leishmania amazonensis parasites are etiological agents of cutaneous leishmaniasis in the New World. BALB/c mice are highly susceptible to L. amazonensis challenge due to their inability to mount parasite-dependent IFN-γ-mediated responses. Here, we analyzed the capacity of a single administration of the LiΔHSP70-II genetically-modified attenuated L. infantum line in preventing cutaneous leishmaniasis in mice challenged with L. amazonensis virulent parasites. In previous studies, this live attenuated vaccine has demonstrated to induce long-protection against murine leishmaniasis due to Old World Leishmania species. Vaccinated mice showed a reduction in the disease evolution due to L. amazonensis challenge, namely reduction in cutaneous lesions and parasite burdens. In contrast to control animals, after the challenge, protected mice showed anti-Leishmania IgG2a circulating antibodies accompanied to the induction of Leishmania-driven specific IFN-γ systemic response. An analysis performed in the lymph node draining the site of infection revealed an increase of the parasite-specific IFN-ϒ production by CD4+ and CD8+ T cells and a decrease in the secretion of IL-10 against leishmanial antigens. Since the immunity caused by the inoculation of this live vaccine generates protection against different forms of murine leishmaniasis, we postulate LiΔHSP70-II as a candidate for the development of human vaccines.
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Rénia, L. "Protective immunity against malaria liver stage after vaccination with live parasites." Parasite 15, no. 3 (September 2008): 379–83. http://dx.doi.org/10.1051/parasite/2008153379.
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Phelps, Eric D., Kristin R. Sweeney, and Ira J. Blader. "Toxoplasma gondii Rhoptry Discharge Correlates with Activation of the Early Growth Response 2 Host Cell Transcription Factor." Infection and Immunity 76, no. 10 (August 4, 2008): 4703–12. http://dx.doi.org/10.1128/iai.01447-07.
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ABSTRACT Toxoplasma gondii is a ubiquitous apicomplexan parasite that can cause severe disease in fetuses and immune-compromised patients. Rhoptries, micronemes, and dense granules, which are secretory organelles unique to Toxoplasma and other apicomplexan parasites, play critical roles in parasite growth and virulence. To understand how these organelles modulate infected host cells, we sought to identify host cell transcription factors triggered by their release. Early growth response 2 (EGR2) is a host cell transcription factor that is rapidly upregulated and activated in Toxoplasma-infected cells but not in cells infected with the closely related apicomplexan parasite Neospora caninum. EGR2 upregulation occurred only when live parasites were in direct contact with the host cell and not from exposure to cell extracts that contain dense granule or micronemal proteins. When microneme-mediated attachment was blocked by pretreating parasites with a calcium chelator, EGR2 expression was significantly reduced. In contrast, when host cells were infected with parasites in the presence of cytochalasin D, which allows rhoptry secretion but prevents parasite invasion, EGR2 was activated. Finally, we demonstrate that Toxoplasma activation of host p38 mitogen-activated protein kinase is necessary but not sufficient for EGR2 activation. Collectively, these data indicate that EGR2 is specifically upregulated by a parasite-derived secreted factor that is most likely a resident rhoptry protein.
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MASEK, K. S., P. ZHU, B. D. FREEDMAN, and C. A. HUNTER. "Toxoplasma gondii induces changes in intracellular calcium in macrophages." Parasitology 134, no. 14 (September 4, 2007): 1973–79. http://dx.doi.org/10.1017/s0031182007003447.
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SUMMARYToxoplasma gondii is an obligate intracellular parasite that interacts with calcium storage organelles and induces calcium-dependent signalling in macrophages. This study was performed to determine whether Toxoplasma induces changes in intracellular calcium in these cells. Ratiometric imaging of live, Fura-2 loaded macrophages challenged with T. gondii revealed robust elevations in intracellular calcium. These elevations were late in onset, beginning 15–20 min after addition of parasites and occurred in up to 20% of macrophages in an imaging field. Further characterization of these events revealed that they follow from challenge with live T. gondii, but not heat-killed parasites or soluble Toxoplasma antigen (STAg). Parasite-induced calcium elevations derived from extracellular sources, and were independent of host recognition factors MyD88 and CCR5. These findings indicate that Toxoplasma gondii alters calcium homeostasis in macrophages and this activity is independent of known pathways involved in the innate recognition of this organism.
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Römisch, Karin. "Diversion at the ER: How Plasmodium falciparum exports proteins into host erythrocytes." F1000Research 1 (December 7, 2012): 12. http://dx.doi.org/10.12688/f1000research.1-12.v2.
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Malaria is caused by parasites which live in host erythrocytes and remodel these cells to provide optimally for the parasites’ needs by exporting effector proteins into the host cells. Eight years ago the discovery of a host cell targeting sequence present in both soluble and transmembrane P. falciparum exported proteins generated a starting point for investigating the mechanism of parasite protein transport into infected erythrocytes. Since then many confusing facts about this targeting signal have emerged. In this paper, I try to make sense of them.
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STROHBUSCH, M., N. MÜLLER, A. HEMPHILL, G. GREIF, and B. GOTTSTEIN. "NcGRA2as a molecular target to assess the parasiticidal activity of toltrazuril againstNeospora caninum." Parasitology 135, no. 9 (June 13, 2008): 1065–73. http://dx.doi.org/10.1017/s0031182008004599.
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SUMMARYThe treatment ofNeospora caninuminfection in the bovine host is still at an experimental stage. In contrast to thein vivosituation, a wide range of compounds have been intensively investigated in cell-culture-based assays. Tools to demonstrate efficacy of treatment have remained conventional including morphological and cell biological criteria. In this work, we present a molecular assay that allows the distinction between live and dead parasites. Live parasites can be detected by measuring the mRNA level of specific genes, making use of the specific mRNA available in live cells. TheNcGra2gene ofN. caninum, which is known to be expressed in both tachyzoites and bradyzoites, was used to establish a quantitative real-time RT-PCR, for monitoring parasite viability. Validation of the systemin vitrowas achieved usingNeospora-infected cells that had been treated for 2–20 days with 30 μg/ml toltrazuril.NcGRA2-RT-real time PCR demonstrated that a 10-day toltrazuril-treatment exerted parasitostatic activity, as assessed by the presence ofNcGRA2-transcripts, whereas after a 14-day treatment period noNcGRA2-transcripts were detected, showing that the parasites were no longer viable. Concurrently, extended culture for a period of 4 weeks in the absence of the drug following the 14-day toltrazuril treatment did not lead to further parasite proliferation, confirming the parasiticidal effect of the treatment. This assay has the potential to be widely used in the development of novel drugs againstN. caninum, with a view to distinguishing between parasiticidal and parasitostatic efficacy of given compounds.
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Veerappan, Annamalai, Jerome H. Siegel, Jiri Podany, Romulo Prudente, and Alvin Gelb. "Fasciola hepatica pancreatitis: endoscopic extraction of live parasites." Gastrointestinal Endoscopy 37, no. 4 (July 1991): 473–75. http://dx.doi.org/10.1016/s0016-5107(91)70784-0.
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Heil, Martin. "Manipulators live better, but are they always parasites?" Trends in Plant Science 20, no. 9 (September 2015): 538–40. http://dx.doi.org/10.1016/j.tplants.2015.08.001.
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Zhao, Zhe, Hui Lin Ding, and Liang Jun Wu. "Research on Parasitic Infections in Raw Seafood Industry." Applied Mechanics and Materials 707 (December 2014): 180–83. http://dx.doi.org/10.4028/www.scientific.net/amm.707.180.
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Seafood products has a long history and the teachings ‘Raw crabs and shrimp live’ spread among people. This study carrys out an investigation into parasitic infections of raw seafood of Qinhuangdao through sampling, smearing, UV examination and statistical methods. The experimental datas we get tell that there is various kinds of parasite lar-vae in body of shrimp frequently and metacercariae in crabs. The seafood likeoster and clam aren't without parasites also. Experiments show that the lung fl-uke metacercaria could live about 48 hours in Salt solution with concentration-f 10%, 43 hours in 15% liquor and 28 hours in 14 degrees of yellow wine. Itis obvious that these parasites could not killed through salt leaching and temul-entia. Due to domestic waters pollution is serious, so don't eat raw food.
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Torres-Chablé, Oswaldo Margarito, Ricardo Alfonso García-Herrera, Melchor Hernández-Hernández, Jorge Alonso Peralta-Torres, Nadia Florencia Ojeda-Robertos, Bradley John Blitvich, Carlos Marcial Baak-Baak, Julián Everardo García-Rejón, and Carlos Ignacio Machain-Wiliams. "Prevalence of gastrointestinal parasites in domestic dogs in Tabasco, southeastern Mexico." Revista Brasileira de Parasitologia Veterinária 24, no. 4 (December 4, 2015): 432–37. http://dx.doi.org/10.1590/s1984-29612015077.
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Abstract The overall goal of this study was to estimate the prevalence of gastrointestinal (GI) parasites in dogs in the city of Villahermosa in Tabasco, Mexico. The study population consisted of 302 owned dogs that had limited access to public areas. A fecal sample was collected from each animal and examined for GI parasites by conventional macroscopic analysis and centrifugal flotation. Fecal samples from 80 (26.5%) dogs contained GI parasites. Of these, 58 (19.2%) were positive for helminths and 22 (7.3%) were positive for protozoan parasites. At least seven parasitic species were identified. The most common parasite was Ancylostoma caninum which was detected in 48 (15.9%) dogs. Other parasites detected on multiple occasions were Cystoisospora spp. (n = 19), Toxocara canis (n = 7) and Giardia spp. (n = 3). Three additional parasites, Dipylidium caninum, Trichuris vulpis and Uncinaria spp., were each detected in a single dog. No mixed parasitic infections were identified. In summary, we report a moderately high prevalence of GI parasites in owned dogs in Villahermosa, Tabasco. Several parasitic species identified in this study are recognized zoonotic pathogens which illustrates the important need to routinely monitor and treat dogs that live in close proximity to humans for parasitic infections.
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Gascoigne, Emily, and Ben Dustan. "Health planning for goats." Livestock 24, no. 6 (November 2, 2019): 305–10. http://dx.doi.org/10.12968/live.2019.24.6.305.
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There is evidence that goat numbers are increasing in the UK in both pet and commercial settings and with that a demand for health planning and veterinary surgeons who are familiar with and comfortable advising keepers. In this article we consider the main challenges for keepers of herds of all sizes including routine procedures, parasites, lameness and some of the obstacles for veterinary surgeons such as the lack of licensed medicines and limited evidence-based medicine breadth.
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Abshire, James R., Christopher J. Rowlands, Suresh M. Ganesan, Peter T. C. So, and Jacquin C. Niles. "Quantification of labile heme in live malaria parasites using a genetically encoded biosensor." Proceedings of the National Academy of Sciences 114, no. 11 (February 27, 2017): E2068—E2076. http://dx.doi.org/10.1073/pnas.1615195114.
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Heme is ubiquitous, yet relatively little is known about the maintenance of labile pools of this cofactor, which likely ensures its timely bioavailability for proper cellular function. Quantitative analysis of labile heme is of fundamental importance to understanding how nature preserves access to the diverse chemistry heme enables, while minimizing cellular damage caused by its redox activity. Here, we have developed and characterized a protein-based sensor that undergoes fluorescence quenching upon heme binding. By genetically encoding this sensor in the human malarial parasite, Plasmodium falciparum, we have quantified cytosolic labile heme levels in intact, blood-stage parasites. Our findings indicate that a labile heme pool (∼1.6 µM) is stably maintained throughout parasite development within red blood cells, even during a period coincident with extensive hemoglobin degradation by the parasite. We also find that the heme-binding antimalarial drug chloroquine specifically increases labile cytosolic heme, indicative of dysregulation of this homeostatic pool that may be a relevant component of the antimalarial activity of this compound class. We propose that use of this technology under various environmental perturbations in P. falciparum can yield quantitative insights into fundamental heme biology.
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Hart, Benjamin L., and Lynette A. Hart. "How mammals stay healthy in nature: the evolution of behaviours to avoid parasites and pathogens." Philosophical Transactions of the Royal Society B: Biological Sciences 373, no. 1751 (June 4, 2018): 20170205. http://dx.doi.org/10.1098/rstb.2017.0205.
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Mammals live and thrive in environments presenting ongoing threats from parasites in the form of biting flies, ticks and intestinal worms and from pathogens as wound contaminants and agents of infectious disease. Several strategies have evolved that enable animals to deal with parasites and pathogens, including eliminating away from the sleeping–resting areas, use of an array of grooming techniques, use of saliva in licking, and consuming medicinal plant-based compounds. These strategies all are species-specific and reflect the particular environment that the animal inhabits. This article is part of the Theo Murphy meeting issue ‘Evolution of pathogen and parasite avoidance behaviours’.
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OURA, C. A. L., R. BISHOP, B. B. ASIIMWE, P. SPOONER, G. W. LUBEGA, and A. TAIT. "Theileria parva live vaccination: parasite transmission, persistence and heterologous challenge in the field." Parasitology 134, no. 9 (March 13, 2007): 1205–13. http://dx.doi.org/10.1017/s0031182007002557.
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SUMMARYThe ‘Muguga cocktail’ live vaccine, delivered by an infection and treatment protocol, has been widely deployed in Eastern, Central and Southern Africa to protect cattle against East Coast fever, caused by Theileria parva. The vaccine contains 3 component stocks (Muguga, Serengeti-transformed and Kiambu 5). In a previous study, parasites from vaccinated and unvaccinated animals were genotyped with a panel of micro- and minisatellite markers (Oura et al.2004a) and it was shown that only the Kiambu 5 stock establishes a long-term carrier state but there was no evidence for the transmission of this stock. Also parasite genotypes different from the 3 component vaccine stocks were identified in vaccinated animals. We now report a follow-up study on the same farm, some 4 years after the initial vaccination, aimed at establishing the source of the novel parasite genotypes identified in vaccinated cattle, determining the longevity of the carrier state established by the Kiambu 5 vaccine stock and re-examining whether vaccine transmission can occur over a longer time-scale. To do this, samples were taken from vaccinated and unvaccinated cattle and the parasites were genotyped with a series of micro- and minisatellite markers. The data indicate that the vaccine stabilates contain at least 6 parasite genotypes, the Kiambu 5 stock can be detected in many but not all vaccinated cattle for up to 4 years and can be transmitted to unvaccinated cattle which share grazing and that some of the vaccinated animals become infected with local genotypes without causing overt disease.
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Stoldt, Marah, Linda Klein, Sara Beros, Falk Butter, Evelien Jongepier, Barbara Feldmeyer, and Susanne Foitzik. "Parasite Presence Induces Gene Expression Changes in an Ant Host Related to Immunity and Longevity." Genes 12, no. 1 (January 13, 2021): 95. http://dx.doi.org/10.3390/genes12010095.
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Most species are either parasites or exploited by parasites, making parasite–host interactions a driver of evolution. Parasites with complex life cycles often evolve strategies to facilitate transmission to the definitive host by manipulating their intermediate host. Such manipulations could explain phenotypic changes in the ant Temnothorax nylanderi, the intermediate host of the cestode Anomotaenia brevis. In addition to behavioral and morphological alterations, infected workers exhibit prolonged lifespans, comparable to that of queens, which live up to two decades. We used transcriptomic data from cestodes and ants of different castes and infection status to investigate the molecular underpinnings of phenotypic alterations in infected workers and explored whether the extended lifespan of queens and infected workers has a common molecular basis. Infected workers and queens commonly upregulated only six genes, one of them with a known anti-aging function. Both groups overexpressed immune genes, although not the same ones. Our findings suggest that the lifespan extension of infected workers is not achieved via the expression of queen-specific genes. The analysis of the cestodes’ transcriptome revealed dominant expression of genes of the mitochondrial respiratory transport chain, which indicates an active metabolism and shedding light on the physiology of the parasite in its cysticercoid stage.
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Morrill, A., J. J. Mlynarek, and M. R. Forbes. "Explaining covariation between endo- and ecto-parasites in spreadwing damselflies (Zygoptera: Lestidae)." Canadian Journal of Zoology 91, no. 10 (October 2013): 761–65. http://dx.doi.org/10.1139/cjz-2013-0096.
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Host individuals and populations are commonly infected by more than one type of parasite, yet studies examining parasite effects on host fitness often limit observations or experiments to only a single parasite taxon or to a narrow subset of potential parasite taxa. Addressing covariation between parasite taxa is important for determining the potential for misattributing effects caused by one parasite species to another parasite species, and also for testing more broadly whether host attributes relate to exposure or susceptibility to infection. In this study, parasitism by ectoparasitic water mites (Arrenuridae) and endoparasitic gregarines (Eugregarinidae) of two spreadwing damselfly species, Lestes disjunctus Selys, 1862 and Lestes forcipatus Rambur, 1842, was measured and analyzed for covariance. No significant correlations between the intensities of the two types of infecting parasites were found when both live and resisted mites were considered. However, significant negative correlations between live mites and gregarines were consistently found in L. forcipatus host samples, but never in L. disjunctus samples. These results show some species-specific patterns of covariation between mite and gregarine infections in damselflies. We propose potential underlying causes for this correlation related to parasite–host ecology and to changes in host behaviour resulting from water mite infection of L. forcipatus.
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Mauduit, Marjorie, Rita Tewari, Nadya Depinay, Michèle Kayibanda, Eliette Lallemand, Jean-Marc Chavatte, Georges Snounou, Laurent Rénia, and Anne Charlotte Grüner. "Minimal Role for the Circumsporozoite Protein in the Induction of Sterile Immunity by Vaccination with Live Rodent Malaria Sporozoites." Infection and Immunity 78, no. 5 (March 1, 2010): 2182–88. http://dx.doi.org/10.1128/iai.01415-09.
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ABSTRACT Immunization with live Plasmodium sporozoites under chloroquine prophylaxis (Spz plus CQ) induces sterile immunity against sporozoite challenge in rodents and, more importantly, in humans. Full protection is obtained with substantially fewer parasites than with the classic immunization with radiation-attenuated sporozoites. The sterile protection observed comprised a massive reduction in the hepatic parasite load and an additional effect at the blood stage level. Differences in the immune responses induced by the two protocols occur but are as yet little characterized. We have previously demonstrated that in mice immunized with irradiated sporozoites, immune responses against the circumsporozoite protein (CSP), the major component of the sporozoite's surface and the leading malaria vaccine candidate, were not essential for sterile protection. Here, we have employed transgenic P lasmodium berghei parasites in which the endogenous CSP was replaced by that of P lasmodium yoelii, another rodent malaria species, to assess the role of CSP in the sterile protection induced by the Spz-plus-CQ protocol. The data demonstrated that this role was minor because sterile immunity was obtained irrespective of the origin of CSP expressed by the parasites in this model of protection. The immunity was obtained through a single transient exposure of the host to the immunizing parasites (preerythrocytic and erythrocytic), a dose much smaller than that required for immunization with radiation-attenuated sporozoites.
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Selvapandiyan, Angamuthu, Ranadhir Dey, Sreenivas Gannavaram, Ines Lakhal-Naouar, Robert Duncan, Poonam Salotra, and Hira L. Nakhasi. "Immunity to Visceral Leishmaniasis Using Genetically Defined Live-Attenuated Parasites." Journal of Tropical Medicine 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/631460.
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Leishmaniasis is a protozoan parasitic disease endemic to the tropical and subtropical regions of the world, with three major clinical forms, self-healing cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and visceral leishmaniasis (VL). Drug treatments are expensive and often result in the development of drug resistance. No vaccine is available against leishmaniasis. SubunitLeishmaniavaccine immunization in animal models has shown some efficacy but little or none in humans. However, individuals who recover from natural infection are protected from reinfection and develop life-long protection, suggesting that infection may be a prerequisite for immunological memory. Thus, genetically altered live-attenuated parasites with controlled infectivity could achieve such memory. In this paper, we discuss development and characteristics of genetically altered, live-attenuatedLeishmania donovaniparasites and their possible use as vaccine candidates against VL. In addition, we discuss the challenges and other considerations in the use of live-attenuated parasites.
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Magoulas, Charalampos. "Democracy, Polis and Parasite in Communication." Studies in Linguistics and Literature 5, no. 1 (December 18, 2020): p1. http://dx.doi.org/10.22158/sll.v5n1p1.
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Communication, as a social activity existing in and comprising almost any human action, cannot take place but as a mediated performance, given that it consists in the triadic relation between transmitter, message and receiver. Its goal is always the transmission of a message with the highest possible coherence and, at the same time, its simultaneous comprehension with the less possible deterioration of its original meaning. A basic assumption is that a potential difficulty in everyday communication is due for the most part to the existence of one or more parasites, which could be detected either in external factors or in the message itself. The question is whether a parasite could live in the signifier of a word and thus determine or alter its signified during an act of communication. This paper aims at exploring Serres’ view on parasite and attempting to identify its existence and function within the signifier of words we use in everyday life. To that end the terms of “democracy” and “polis” will be used as examples of hosts of parasites.
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Dorin-Semblat, Dominique, Audrey Sicard, Caroline Doerig, Lisa Ranford-Cartwright, and Christian Doerig. "Disruption of the PfPK7 Gene Impairs Schizogony and Sporogony in the Human Malaria Parasite Plasmodium falciparum." Eukaryotic Cell 7, no. 2 (December 14, 2007): 279–85. http://dx.doi.org/10.1128/ec.00245-07.
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ABSTRACT PfPK7 is an orphan protein kinase of Plasmodium falciparum with maximal homology to MEK3/6 and to fungal protein kinase A proteins in its C-terminal and N-terminal regions, respectively. We showed previously that recombinant PfPK7 is active on various substrates but is unable to phosphorylate the Plasmodium falciparum mitogen-activated protein kinase homologues, suggesting that it is not a MEK functional homologue. Using a reverse genetics approach to investigate the function of this enzyme in live parasites, we now show that PfPK7 − parasite clones display phenotypes at two stages of their life cycle: first, a decrease in the rate of asexual growth in erythrocytes associated with a lower number of daughter merozoites generated per schizont, and second, a dramatic reduction in the ability to produce oocysts in the mosquito vector. A normal asexual growth rate and the ability to produce oocysts are restored if a functional copy of the PfPK7 gene is reintroduced into the PfPK7 − parasites. Hence, PfPK7 is involved in a pathway that regulates parasite proliferation and development.
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Gray, J., R. Langley, P. Brophy, and P. Gannon. "Vaccination against bovine babesiosis with drug-controlled live parasites." Veterinary Record 125, no. 14 (September 30, 1989): 369–72. http://dx.doi.org/10.1136/vr.125.14.369.
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LUONG, LIEN T., TAYLOR BROPHY, EMILY STOLZ, and SOLOMON J. CHAN. "State-dependent parasitism by a facultative parasite of fruit flies." Parasitology 144, no. 11 (June 23, 2017): 1468–75. http://dx.doi.org/10.1017/s0031182017000890.
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SUMMARYParasites can evolve phenotypically plastic strategies for transmission such that a single genotype can give rise to a range of phenotypes depending on the environmental condition. State-dependent plasticity in particular can arise from individual differences in the parasite's internal state or the condition of the host. Facultative parasites serve as ideal model systems for investigating state-dependent plasticity because individuals can exhibit two life history strategies (free-living or parasitic) depending on the environment. Here, we experimentally show that the ectoparasitic mite Macrocheles subbadius is more likely to parasitize a fruit fly host if the female mite is mated; furthermore, the propensity to infect increased with the level of starvation experienced by the mite. Host condition also played an important role; hosts infected with moderate mite loads were more likely to gain additional infections in pairwise choice tests than uninfected flies. We also found that mites preferentially infected flies subjected to mechanical injury over uninjured flies. These results suggest that a facultative parasite's propensity to infect a host (i.e. switch from a free-living strategy) depends on both the parasite's internal state and host condition. Parasites often live in highly variable and changing environments, an infection strategy that is plastic is likely to be adaptive.
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Petersen, J. J., and B. M. Pawson. "Discrimination by the Pupal Parasite Spalangia cameroni (Hymenoptera: Pteromalidae) Between Live and Freeze Killed House Fly (Diptera: Muscidae) Pupae." Journal of Entomological Science 28, no. 1 (January 1, 1993): 120–25. http://dx.doi.org/10.18474/0749-8004-28.1.120.
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Live house fly pupae were suitable as hosts for Spalangia cameroni Perkins at all age classes tested. However, no parasite emergence occurred from house fly pupae freeze-killed when 12 h old and very limited emergence occurred for pupae freeze-killed when 132 h old. Furthermore, significantly more parasites emerged from hosts that were alive when parasitized when compared with freeze-killed hosts parasitized under similar conditions. In choice experiments, S. cameroni exhibited a strong preference for live hosts over freeze-killed hosts at all parasite-to-host ratios. It does not appear that freeze-killed hosts will be useful as a survey tool or as a method for field propagation of S. cameroni as they are for other species of pteromalids.
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BURET, A. G., K. MITCHELL, D. G. MUENCH, and K. G. E. SCOTT. "Giardia lamblia disrupts tight junctional ZO-1 and increases permeability in non-transformed human small intestinal epithelial monolayers: effects of epidermal growth factor." Parasitology 125, no. 1 (July 2002): 11–19. http://dx.doi.org/10.1017/s0031182002001853.
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In order to improve our understanding of the host cell–parasite interactions in giardiasis, this study assessed the effects of Giardia lamblia on epithelial permeability and tight junctional ZO-1, determined whether epidermal growth factor (EGF) may affect Giardia-induced epithelial injury, and evaluated if EGF modulates epithelial colonization by live G. lamblia trophozoites. Permeability was assessed in assays of trans-epithelial fluxes of FITC-dextran, and ZO-1 integrity was characterized by confocal laser immunofluorescence microscopy in confluent epithelial cell monolayers. G. lamblia significantly increased paracellular permeability and disrupted tight-junctional ZO-1 of a novel non-transformed human small intestinal epithelial cell line (SCBN). Pre-treatment with EGF prevented the development of these abnormalities and significantly inhibited attachment of live trophozoites to the enterocytes, independently of a direct microbiocidal action. These findings demonstrate that G. lamblia may cause intestinal pathophysiology by disrupting tight junctional ZO-1 and increasing epithelial permeability. Apical administration of EGF prevents these abnormalities, and reduces epithelial colonization by the live parasites.
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Papadopoulou, Barbara, Martin Olivier, and Marc Ouellette. "Recent Progress in Vaccine Development againstLeishmaniaSpecies Infections." Canadian Journal of Infectious Diseases 10, suppl c (1999): 9C—15C. http://dx.doi.org/10.1155/1999/168108.
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The understanding of the immunobiology of infections caused by the protozoan parasite leishmania is now extensive and has pinpointed the importance of T cell-mediated immunity. Several vaccination strategies using either killed parasites, subunit vaccines, DNA vaccines or live attenuated strains have been used successfully with and without adjuvants to induce cellular immunity and protect against leishmania infections. The most recent progress in leishmania vaccine development is described.
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Wetzel, D. M., S. Håkansson, K. Hu, D. Roos, and L. D. Sibley. "Actin Filament Polymerization Regulates Gliding Motility by Apicomplexan Parasites." Molecular Biology of the Cell 14, no. 2 (February 2003): 396–406. http://dx.doi.org/10.1091/mbc.e02-08-0458.
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Host cell entry by Toxoplasma gondii depends critically on actin filaments in the parasite, yet paradoxically, its actin is almost exclusively monomeric. In contrast to the absence of stable filaments in conventional samples, rapid-freeze electron microscopy revealed that actin filaments were formed beneath the plasma membrane of gliding parasites. To investigate the role of actin filaments in motility, we treated parasites with the filament-stabilizing drug jasplakinolide (JAS) and monitored the distribution of actin in live and fixed cells using yellow fluorescent protein (YFP)-actin. JAS treatment caused YFP-actin to redistribute to the apical and posterior ends, where filaments formed a spiral pattern subtending the plasma membrane. Although previous studies have suggested that JAS induces rigor, videomicroscopy demonstrated that JAS treatment increased the rate of parasite gliding by approximately threefold, indicating that filaments are rate limiting for motility. However, JAS also frequently reversed the normal direction of motility, disrupting forward migration and cell entry. Consistent with this alteration, subcortical filaments in JAS-treated parasites occurred in tangled plaques as opposed to the straight, roughly parallel orientation observed in control cells. These studies reveal that precisely controlled polymerization of actin filaments imparts the correct timing, duration, and directionality of gliding motility in the Apicomplexa.
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Barbero, F., D. Patricelli, M. Witek, E. Balletto, L. P. Casacci, M. Sala, and S. Bonelli. "MyrmicaAnts and Their Butterfly Parasites with Special Focus on the Acoustic Communication." Psyche: A Journal of Entomology 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/725237.
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About 10,000 arthropod species live as ants' social parasites and have evolved a number of mechanisms allowing them to penetrate and survive inside the ant nests.Myrmicacolonies, in particular, are exploited by numerous social parasites, and the presence of their overwintering brood, as well as of their polygyny, contributes to make them more vulnerable to infestation. Butterflies of the genusMaculineaare among the most investigatedMyrmicainquilines. These lycaenids are known for their very complex biological cycles.Maculineaspecies are obligated parasites that depend on a particular food plant and on a specificMyrmicaspecies for their survival.Maculinealarvae are adopted byMyrmicaants, which are induced to take them into their nests by chemical mimicry. Then the parasite spends the following 11–23 months inside the ants' nest. Mimicking the acoustic emission of the queen ants,Maculineaparasites not only manage to become integrated, but attain highest rank within the colony. Here we review the biology ofMaculinea/Myrmicasystem with a special focus on some recent breakthrough concerning their acoustical patterns.
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MORIN-ADELINE, VICTORIA, and JAN ŠLAPETA. "The past, present and future of fluorescent protein tags in anaerobic protozoan parasites." Parasitology 143, no. 3 (December 14, 2015): 260–75. http://dx.doi.org/10.1017/s0031182015001663.
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SUMMARYThe world health organization currently recognizes diarrhoeal diseases as a significant cause of death in children globally. Protozoan parasites such asGiardiaandEntamoebathat thrive in the oxygen-deprived environment of the human gut are common etiological agents of diarrhoea. In the urogenital tract of humans, the anaerobic protozoan parasiteTrichomonas vaginalisis notorious as the most common non-viral, sexually transmitted pathogen. Even with high medical impact, our understanding of anaerobic parasite physiology is scarce and as a result, treatment choices are limited. Fluorescent proteins (FPs) are invaluable tools as genetically encoded protein tags for advancing knowledge of cellular function. These FP tags emit fluorescent colours and once attached to a protein of interest, allow tracking of parasite proteins in the dynamic cellular space. Application of green FPs-like FPs in anaerobic protozoans is hindered by their oxygen dependency. In this review, we examine aspects of anaerobic parasite biology that clash with physio-chemical properties of FPs and limit their use as live-parasite protein tags. We expose novel FPs, such as miniSOG that do not require oxygen for signal production. The potential use of novel FPs has the opportunity to leverage the anaerobe parasitologist toolkit to that of aerobe parasitologist.
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Dailey, D. C., C. Te-Hung, and J. F. Alderete. "Characterization ofTrichomonas vaginalishaemolysis." Parasitology 101, no. 2 (October 1990): 171–75. http://dx.doi.org/10.1017/s0031182000063204.
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The haemolytic activity of liveTrichomonas vaginalisorganisms was investigated. Optimal haemolysis of human erythrocytes was observed at a parasite to erythrocyte ratio of 1:5 during a 2 h incubation period. No haemolytic activity was detected in concentrated culture supernatants after overnight growth of trichomonads or when parasites were separated from erythrocytes by a 3 μm filter, suggesting a contact-dependent mechanism for haemolysis. The haemolytic activity was temperature-dependent and maximal haemolysis occurred at 37 °C. Treatment of trichomonads with metronidazole reduced levels of haemolysis by > 50%. Maximal haemolysis occurred at the pH range of the vagina during trichomoniasis.N-μ-tosyl-L-lysyl-chloromethyl ketone and iodoacetamide, inhibitors of trichomonad cysteine proteinases, reduced the haemolytic activity of live parasites.
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Clarêncio, Jorge, Camila I. de Oliveira, Glória Bomfim, Margarida M. Pompeu, Maria Jania Teixeira, Theolis C. Barbosa, Sebastião Souza-Neto, et al. "Characterization of the T-Cell Receptor Vβ Repertoire in the Human Immune Response against Leishmania Parasites." Infection and Immunity 74, no. 8 (August 2006): 4757–65. http://dx.doi.org/10.1128/iai.00265-06.
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ABSTRACT In order to explore a possible presence of hyperreactive T-cell clones in human cutaneous leishmaniasis (CL), we have investigated, by flow cytometry, the expression of Vβ chains of T-cell receptors (TCRs) in the following types of cells: (i) peripheral blood mononuclear cells (PBMCs) from CL patients, which were then compared to those from normal volunteers; (ii) unstimulated and soluble Leishmania antigen-stimulated draining lymph node cells from CL patients; (iii) PBMCs from volunteers before versus after Leishmania immunization; and (iv) PBMCs from healthy volunteers that were primed in vitro with live Leishmania parasites. Our results show a modulation in the TCR Vβ repertoire during CL and after antigen stimulation of patients' cells. Vaccination, however, leads to a broad expansion of different Vβ TCRs. We also observed an association between TCR Vβ12 expression, T-cell activation, and gamma interferon production upon in vitro priming with Leishmania. Collectively, these results both indicate that infection with live parasites or exposure to parasite antigen can modulate the TCR Vβ repertoire and suggest that TCR Vβ12 may be implicated in the response to Leishmania.
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Kuhnen, VV, ME Graipel, and CJC Pinto. "Differences in richness and composition of gastrointestinal parasites of small rodents (Cricetidae, Rodentia) in a continental and insular area of the Atlantic Forest in Santa Catarina state, Brazil." Brazilian Journal of Biology 72, no. 3 (August 2012): 563–67. http://dx.doi.org/10.1590/s1519-69842012000300019.
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The first and only study on gastrointestinal parasites of wild rodents in the Island of Santa Catarina was done in 1987. The aim of this study was to identify intestinal parasites from wild rodents in Santo Amaro da Imperatriz and Santa Catariana Island, and to compare the richness and composition of the gastrointestinal parasite community of both areas. Rodents were captured with live traps, and feces were screened using the sedimentation method and optical microscopy. The following species of rodents were captured in the two areas: Akodon montensis, Euryoryzomys russatus, Oligoryzomys nigripes and Nectomys squamipes. In Santo Amaro da Impetratriz, prevalent parasites were: A. montensis (51%), E. russatus (62%), O. nigripes (53%) and N. squamipes (20%). From the Island of Santa Catarina the rodent prevalence rates were: A. montensis (43%), E. russatus (59%), O. nigripes (30%) and N. squamipes (33%) and the collected parasites were: Hymenolepis sp., Longistriata sp., Strongyloides sp., Hassalstrongylus sp., Syphacia sp., Trichomonas sp., Ancylostomidae, Trichuridae, Oxyuridae and Eucoccidiorida. The species richness (10.6 ± 0.7) of the endoparasite comunity in the area located on the continent was higher (p < 0.01) and different (p = 0.001) from that of the area located on the island (6.9 ± 0.5).
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Faulkes, Zen. "Filtering out parasites: sand crabs (Lepidopa benedicti) are infected by more parasites than sympatric mole crabs (Emerita benedicti)." PeerJ 5 (September 22, 2017): e3852. http://dx.doi.org/10.7717/peerj.3852.
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Two digging decapod crustaceans, the sand crab speciesLepidopa benedictiand the mole crab speciesEmerita benedicti, both live in the swash zone of fine sand beaches. They were examined for two parasites that infect decapod crustaceans in the region, an unidentified nematode previously shown to infectL. benedicti, and cestode tapeworm larvae,Polypocephalussp., previously shown to infect shrimp (Litopenaeus setiferus).Lepidopa benedictiwere almost always infected with both parasite species, whileE. benedictiwere rarely infected with either parasite species. This difference in infection pattern suggests that tapeworms are ingested during sediment feeding inL. benedicti, whichE. benedictiavoid by filter feeding. LargerL. benedictihad morePolypocephalussp. larvae. The thoracic ganglia, which make up the largest proportion of neural tissue, contained the largest numbers ofPolypocephalussp. larvae. Intensity ofPolypocephalussp. infection was not correlated with how longL. benedictiremained above sand in behavioural tests, suggesting thatPolypocephalussp. do not manipulate the sand crabs in a way that facilitates trophic transmission of the parasite.Litopenaeus setiferusmay be a primary host forPolypocephalussp., andL. benedictmay be a secondary, auxiliary host.
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Waap, H., J. Gomes, and T. Nunes. "Parasite communities in stray cat populations from Lisbon, Portugal." Journal of Helminthology 88, no. 4 (May 30, 2013): 389–95. http://dx.doi.org/10.1017/s0022149x1300031x.
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AbstractStray cats live in high-density colonies in urban areas and pose a health hazard to household cats and humans. In Portugal, information on the parasitic fauna of stray cats is limited and relies mostly on results from faecal analysis. The present survey aimed to determine the prevalence, diversity and intensity of parasites in stray cats from the urban area of Lisbon by means of parasitological necropsy. Internal organs were collected from 162 cats captured in different areas of the city and systematically subjected to parasitological dissection. Helminths were identified by macro- and microscopic examination and protozoa by faecal floatation and sedimentation techniques. The overall prevalence of parasites was 90.7% (95% confidence interval (CI): 85.3–94.6%). A total of 12 parasite species was recorded:Cystoisospora felis(14.2%),Cystoisospora rivolta(46.3%),Sarcocystissp. (1.2%),Ancylostoma tubaeforme(19.1%),Toxocara cati(38.3%),Ollulanus tricuspis(30.9%),Aelurostrongylus abstrusus(12.4%), Eucoleus aerophilus(0.6%),Taenia taeniaeformis(3.1%),Dipylidium caninum(53.1%),Joyeuxiella pasqualei(15.4%) andDiplopylidium nölleri(3.7%). Overall mean species richness was 2.36 ± 1.52. Helminth mean intensity was highest forO. tricuspis(285.8), followed byD. caninum(42.4),J. pasqualei(14.4),A. tubaeforme(8.1) andT. cati(5.9). The prevalence and variety of parasites found in our sampling are substantially higher than the numbers previously reported in Portugal. Some of the parasites, includingT. catiandA. tubaeforme,are zoonotic, which emphasizes the need for parasite control strategies based on demographic containment of stray cat populations in urban areas to promote public health protection.
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Råberg, Lars. "How to Live with the Enemy: Understanding Tolerance to Parasites." PLoS Biology 12, no. 11 (November 4, 2014): e1001989. http://dx.doi.org/10.1371/journal.pbio.1001989.
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Forbes, Andrew. "Refugia: what are they and how can they be managed?" Livestock 24, no. 3 (May 2, 2019): 144–48. http://dx.doi.org/10.12968/live.2019.24.3.144.
Full textAbstract:
The word refugia appears commonly in the veterinary literature in relation to anthelmintic resistance, however it has its origins in ecology and crop protection. In the context of veterinary therapeutics, the reduction in exposure of target parasites, essentially through fewer treatments, can have bystander benefits too for non-target organisms, thus reducing the potential for environmental impact. Large refugia are intrinsic features of some livestock systems, for example extensive beef suckler farms, where treatments are typically infrequent, however on lowland sheep farms for instance, parasiticide treatments are typically more frequent and may involve both lambs and ewes, so management may need to be changed, for example through targeted selective treatment (TST), in order to enhance the refugia. Precision livestock farming and pen-side diagnostics can facilitate and extend the adoption of TST and other methods of refugia management.