Journal articles: 'Parasite-host relationship'

1

Montenegro, Mario R. "Host Parasite Relationship in Paracoccidioidomycosis." Nippon Ishinkin Gakkai Zasshi 36, no. 3 (1995): 209–13. http://dx.doi.org/10.3314/jjmm.36.209.

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Ambroise-Thomas, Pierre. "Emerging parasite zoonoses: the role of host–parasite relationship." International Journal for Parasitology 30, no. 12-13 (November 2000): 1361–67. http://dx.doi.org/10.1016/s0020-7519(00)00131-4.

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Waldorf, Alayn R. "Host-Parasite Relationship in Opportunistic Mycoses." CRC Critical Reviews in Microbiology 13, no. 2 (January 1986): 133–72. http://dx.doi.org/10.3109/10408418609108737.

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Hasegawa, Hideo. "Phylogeny, host-parasite relationship and zoogeography." Korean Journal of Parasitology 37, no. 4 (1999): 197. http://dx.doi.org/10.3347/kjp.1999.37.4.197.

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Vaughn, Caryn C., and Christopher M. Taylor. "Macroecology of a host-parasite relationship." Ecography 23, no. 1 (February 2000): 11–20. http://dx.doi.org/10.1034/j.1600-0587.2000.230102.x.

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Vaughn, Caryn C., and Christopher M. Taylor. "Macroecology of a host-parasite relationship." Ecography 23, no. 1 (February 2000): 11–20. http://dx.doi.org/10.1111/j.1600-0587.2000.tb00256.x.

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Innes, Elisabeth A., Steve Wright, Paul Bartley, Stephen Maley, Colin Macaldowie, Irma Esteban-Redondo, and David Buxton. "The host–parasite relationship in bovine neosporosis." Veterinary Immunology and Immunopathology 108, no. 1-2 (October 2005): 29–36. http://dx.doi.org/10.1016/j.vetimm.2005.07.004.

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Cheeseman, Kevin, and Jonathan B. Weitzman. "Host-parasite interactions: an intimate epigenetic relationship." Cellular Microbiology 17, no. 8 (July 20, 2015): 1121–32. http://dx.doi.org/10.1111/cmi.12471.

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Mathews, John D. "Streptococcal disease and the host–parasite relationship." International Congress Series 1289 (April 2006): 9–13. http://dx.doi.org/10.1016/j.ics.2005.11.003.

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Mungomba, L. M., D. H. Molyneux, and K. R. Wallbanks. "Host-parasite relationship ofTrypanosoma corvi inOrnithomyia avicularia." Parasitology Research 75, no. 3 (1989): 167–74. http://dx.doi.org/10.1007/bf00931269.

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Tellier, Aurélien, and James K. M. Brown. "The Relationship of Host-Mediated Induced Resistance to Polymorphism in Gene-for-Gene Relationships." Phytopathology® 98, no. 1 (January 2008): 128–36. http://dx.doi.org/10.1094/phyto-98-1-0128.

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Gene-for-gene relationships are a common feature of plant-parasite interactions. Polymorphism at host resistance and parasite avirulence loci is maintained if there is negative, direct frequency-dependent selection on alleles of either gene. More specifically, selection of this kind is generated when the disease is polycyclic with frequent auto-infection. When an incompatible interaction occurs between a resistant host and an avirulent parasite, systemic defenses are triggered, rendering the plant more resistant to a later attack by another parasite. However, induced resistance (IR) incurs a fitness cost to the plant. Here, the effect of IR on polymorphism in gene-for-gene interactions is investigated. First, in an infinite population model in which parasites have two generations per host generation, increasing the fitness cost of IR increases selection for susceptible plants at low disease severity, while increasing the effectiveness of IR against further parasite attacks enhances selection for resistant plants at high disease severity. This reduces the possibility of polymorphism being maintained in host and parasite populations. In finite population models, the number of plants varies over time as a function of the disease burden of the population. Polymorphism in gene-for-gene relationships is then more stable at high disease prevalence and severity if IR reactions are more costly when there is competition for resources between plants.

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Rodríguez, Sara M., and Nelson Valdivia. "Mesoscale spatiotemporal variability in a complex host-parasite system influenced by intermediate host body size." PeerJ 5 (August 17, 2017): e3675. http://dx.doi.org/10.7717/peerj.3675.

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Background Parasites are essential components of natural communities, but the factors that generate skewed distributions of parasite occurrences and abundances across host populations are not well understood. Methods Here, we analyse at a seascape scale the spatiotemporal relationships of parasite exposure and host body-size with the proportion of infected hosts (i.e., prevalence) and aggregation of parasite burden across ca. 150 km of the coast and over 22 months. We predicted that the effects of parasite exposure on prevalence and aggregation are dependent on host body-sizes. We used an indirect host-parasite interaction in which migratory seagulls, sandy-shore molecrabs, and an acanthocephalan worm constitute the definitive hosts, intermediate hosts, and endoparasite, respectively. In such complex systems, increments in the abundance of definitive hosts imply increments in intermediate hosts’ exposure to the parasite’s dispersive stages. Results Linear mixed-effects models showed a significant, albeit highly variable, positive relationship between seagull density and prevalence. This relationship was stronger for small (cephalothorax length >15 mm) than large molecrabs (<15 mm). Independently of seagull density, large molecrabs carried significantly more parasites than small molecrabs. The analysis of the variance-to-mean ratio of per capita parasite burden showed no relationship between seagull density and mean parasite aggregation across host populations. However, the amount of unexplained variability in aggregation was strikingly higher in larger than smaller intermediate hosts. This unexplained variability was driven by a decrease in the mean-variance scaling in heavily infected large molecrabs. Conclusions These results show complex interdependencies between extrinsic and intrinsic population attributes on the structure of host-parasite interactions. We suggest that parasite accumulation—a characteristic of indirect host-parasite interactions—and subsequent increasing mortality rates over ontogeny underpin size-dependent host-parasite dynamics.

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GOIHMAN-YAHR, MAURICIO. "HOST-PARASITE RELATIONSHIP AND AN ALLIANCE FOR PROGRESS." International Journal of Dermatology 33, no. 5 (May 1994): 337–40. http://dx.doi.org/10.1111/j.1365-4362.1994.tb01064.x.

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Agnew, A. M., S. B. Lucas, and M. J. Doenhoff. "The host—parasite relationship ofSchistosoma haematobiumin CBA mice." Parasitology 97, no. 3 (December 1988): 403–24. http://dx.doi.org/10.1017/s0031182000058820.

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SummaryThe host—parasite relationships of two geographical isolates ofSchistosoma haematobiumin CBA mice are described and compared to previous reports on this parasite in other experimental hosts and in man. The mean percentage establishment of worms in mice was 17% and was not affected by the age or sex of the host. Adult worm burdens remained constant over 20 weeks, but were reduced after 18 months of infection. Male and female worms reached mean maximum lengths of 4·78 and 5·9 mm respectively. Egg laying commenced 9·5 weeks after infection and eggs accumulated in the tissues throughout the period of infection. A large increase in the rate of egg accumulation occurred coincidental with the appearance of eggs in the bladder of some mice. Faecal eggs were first observed in some mice at 12·5 weeks and most mice excreted a few eggs by 17 weeks p.i. (post-infection). Eggs were not found in the urine of infected mice. Excreted eggs and eggs isolated from the livers of infected mice hatched, but the resulting miracidia were unable to infect appropriate snail hosts. The development of hepatic granulomas and egg-induced pathology in the bladder of mice is described.

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Evison, Sophie EF. "Chalkbrood: epidemiological perspectives from the host–parasite relationship." Current Opinion in Insect Science 10 (August 2015): 65–70. http://dx.doi.org/10.1016/j.cois.2015.04.015.

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Calvin, Clyde L., and Carol A. Wilson. "Relationship of the Mistletoe Phoradendron Macrophyllum (Viscaceae) to the Wood of its Host." IAWA Journal 16, no. 1 (1995): 33–45. http://dx.doi.org/10.1163/22941932-90001386.

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The importance of direct tracheary element connections between mistletoes and their hosts is controversial. Direct connections have been reported for four genera within the Viscaceae. In the past such connections were considered essential for the movement of water and nutrients from host to parasite. In contrast, recent authors have suggested that the apoplastic continuum provided by the walls of contiguous host and parasite parenchyma cells is the main pathway for the transfer of water and nutrients, with direct connections playing at best a minor role in uptake. Our analysis of the parasite (Phoradendron)/host(Juglans) interface suggests otherwise. Parenchyma predominates at the interface for both host (71%) and parasite (95%). While direct tracheary element connections are less frequent than other types of connections, they occurred in all sinkers analyzed. Further, direct connections were much more abundant in host latewood (3.6%) than in earlywood (1.8%). This, and other evidence indicates that both pathways of transfer are important. We suggest that the apoplastic continuum provided by parasite parenchyma provides for selective uptake of nutrients, whereas direct connections provide for bulk flow between host and parasite.

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Westby, Katie M., Brenden M. Sweetman, Solny A. Adalsteinsson, Elizabeth G. Biro, and Kim A. Medley. "Host food quality and quantity differentially affect Ascogregarina barretti parasite burden, development and within-host competition in the mosquito Aedes triseriatus." Parasitology 146, no. 13 (August 29, 2019): 1665–72. http://dx.doi.org/10.1017/s0031182019000994.

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AbstractHost condition depends in large part on the quality and quantity of available food and heavily influences the outcome of parasite infection. Although parasite fitness traits such as growth rate and size may depend on host condition, whether host food quality or quantity is more important to parasite fitness and within-host interactions is poorly understood. We provided individual mosquito hosts with a standard dose of a gregarine parasite and reared mosquitoes on two food types of different quality and two quantities. We measured host size, total parasite count and area, and average size of parasites within each treatment. Food quality significantly influenced the number of parasites in a host; hosts fed a low-quality diet were infected with more parasites than those provided a high-quality diet. In addition, we found evidence of within-host competition; there was a negative relationship between parasite size and count though this relationship was dependent on host food quality. Host food quantity significantly affected total parasite area and parasite size; lower food quantity resulted in smaller parasites and reduced overall parasite area inside the host. Thus both food quality and quantity have the potential to influence parasite fitness and population dynamics.

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18

Howard, Russell J. "Proceeding of the round-table on host-parasite relationship." Memórias do Instituto Oswaldo Cruz 81, suppl 2 (1986): 93–94. http://dx.doi.org/10.1590/s0074-02761986000600016.

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Arijo, A. G., M. J. Doenhoff, N. M. Soomro, and Z. I. Rajput. "Host-Parasite Relationship of S. Mansoni and B. Glabrata." Pakistan Journal of Biological Sciences 10, no. 24 (December 1, 2007): 4399–405. http://dx.doi.org/10.3923/pjbs.2007.4399.4405.

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Crook, D. W. "Capsular Type and the Pneumococcal Human Host--Parasite Relationship." Clinical Infectious Diseases 42, no. 4 (February 15, 2006): 460–62. http://dx.doi.org/10.1086/499248.

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Siracusano, Alessandra, Federica Delunardo, Antonella Teggi, and Elena Ortona. "Host-Parasite Relationship in Cystic Echinococcosis: An Evolving Story." Clinical and Developmental Immunology 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/639362.

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The larval stage ofEchinococcus granulosuscauses cystic echinococcosis, a neglected infectious disease that constitutes a major public health problem in developing countries. Despite being under constant barrage by the immune system,E. granulosusmodulates antiparasite immune responses and persists in the human hosts with detectable humoral and cellular responses against the parasite.In vitroandin vivoimmunological approaches, together with molecular biology and immunoproteomic technologies, provided us exciting insights into the mechanisms involved in the initiation ofE. granulosusinfection and the consequent induction and regulation of the immune response. Although the last decade has clarified many aspects of host-parasite relationship in human cystic echinococcosis, establishing the full mechanisms that cause the disease requires more studies. Here, we review some of the recent developments and discuss new avenues in this evolving story ofE. granulosusinfection in man.

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Wakelin, Derek. "Immunogenetic and evolutionary influences on the host-parasite relationship." Developmental & Comparative Immunology 16, no. 5 (September 1992): 345–53. http://dx.doi.org/10.1016/0145-305x(92)90037-d.

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Pawelzik, Martina, and Wolfgang Opferkuch. "The influence of antibiotics on the host-parasite relationship." Clinical Immunology Newsletter 7, no. 6 (June 1986): 81–84. http://dx.doi.org/10.1016/0197-1859(86)90042-7.

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INNES, ELISABETH A. "The host-parasite relationship in pregnant cattle infected with Neospora caninum." Parasitology 134, no. 13 (October 25, 2007): 1903–10. http://dx.doi.org/10.1017/s0031182007000194.

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SUMMARYThe protozoan parasite Neospora caninum is an important cause of reproductive disease in cattle worldwide. The dog is a definitive host for the parasite and the oocyst stage, shed in the faeces, is a source of infection for cattle through consumption of contaminated feed or water. In addition, transplacental transmission of N. caninum is a very efficient means of the parasite infecting a new host and this can occur in successive pregnancies and over several generations. Neospora parasites may cause disease during pregnancy resulting in death of the foetus or birth of live congenitally infected calves that may show some neurological clinical signs at birth. The stage of pregnancy at which infection/parasitaemia occurs is an important factor in determining disease severity. Neospora infection in the first trimester of pregnancy may have more severe consequences for the foetus compared with infection occurring in the final trimester. The host-parasite relationship during pregnancy is a fascinating interaction and research in this area will improve understanding of disease pathogenesis and the various consequences of the host immune response, being host-protective, parasite protective and contributing to disease pathology. Pregnancy poses an interesting problem for the immune system of the dam as she is essentially carrying a semi-allogeneic tissue graft (the foetus) without immunological rejection taking place. To facilitate the pregnancy the cytokine environment in the placenta favours the regulatory Th-2-type cytokines, whose role is to counteract the pro-inflammatory Th1-type immune responses. Protective immunity to N. caninum, similar to many other intracellular parasites, involves Th1-type immune responses, which may pose problems for the dam trying to control a Neospora infection during pregnancy.This paper will discuss the host-parasite relationship at different stages of gestation in pregnant cattle and review the implications of this research for our understanding of disease pathogenesis, parasite transmission and host protection.

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CAMPBELL, JENNIFER, BETH KESSLER, CHRISTOPHER MAYACK, and DHRUBA NAUG. "Behavioural fever in infected honeybees: parasitic manipulation or coincidental benefit?" Parasitology 137, no. 10 (May 26, 2010): 1487–91. http://dx.doi.org/10.1017/s0031182010000235.

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SUMMARYInfection by a parasite often induces behavioural changes in the host and these changes may benefit either the host or the parasite. However, whether these changes are active host defence mechanisms or parasitic manipulations or simply incidental byproducts of the infection is not always clear. It has been suggested that understanding the proximate mechanisms of these changes as well as comparative studies could help distinguish these alternatives better. Behavioural fever is a common response to an infection in many animals and we investigated the phenomenon in the novel host-parasite relationship between the honeybee and the temperature-sensitive microsporidian Nosema ceranae. Our results show that infected bees prefer higher temperatures and even though this seems to benefit the pathogen, the proximate mechanism underlying this change is the pathological stress underlying the infection. Especially because it is a new host-parasite relationship, it is best to label the observed behavioural change as a case of incidental benefit although this does not rule out selection acting on it. We discuss the importance of looking at the behavioural outcomes of host-parasite relationships and the importance of studying them at multiple levels for understanding their origin and maintenance.

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McCallum, H. I. "Population effects of parasite survival of host death: experimental studies of the interaction of Ichthyophthirius multifiliis and its fish host." Parasitology 90, no. 3 (June 1985): 529–47. http://dx.doi.org/10.1017/s0031182000055529.

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Current models of the regulation of host populations by parasite infection assume that death of a host results in death of all the parasites contained within or on the host. This assumption acts as a density-dependent constraint on parasite population growth and contributes to the stability of the interaction between host and parasite populations. The protozoan Ichthyophthirius multifiliis, a parasite of freshwater fish, is one of a number of pathogens in which the reproductive capacity of an individual is not entirely destroyed by the death of its host. The effect of host death on the reproductive potential of I. multifiliis was investigated with a series of short-term experiments examining (i) the relationship between parasite burden and host mortality, (ii) parasite survival on the host and (iii) the relationship between parasite age and the number of infective stages released/parasite. Results of a series of experimental epidemics in which host numbers were maintained constant showed large oscillations in parasite numbers. Deterministic models ignoring the age structure of the parasite population were unable to reproduce the behaviour observed in the experimental epidemics. Using the results of the short-term experiments, a difference equation model was developed. This model was able to qualitatively reproduce the observed epidemic behaviour.

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Lafferty, Kevin D. "Biodiversity loss decreases parasite diversity: theory and patterns." Philosophical Transactions of the Royal Society B: Biological Sciences 367, no. 1604 (October 19, 2012): 2814–27. http://dx.doi.org/10.1098/rstb.2012.0110.

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Past models have suggested host–parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.

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Vinson, John E., and Andrew W. Park. "Vector-borne parasite invasion in communities across space and time." Proceedings of the Royal Society B: Biological Sciences 286, no. 1917 (December 18, 2019): 20192614. http://dx.doi.org/10.1098/rspb.2019.2614.

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While vector-borne parasite transmission often operates via generalist-feeding vectors facilitating cross-species transmission in host communities, theory describing the relationship between host species diversity and parasite invasion in these systems is underdeveloped. Host community composition and abundance vary across space and time, generating opportunities for parasite invasion. To explore how host community variation can modify parasite invasion potential, we develop a model for vector-borne parasite transmission dynamics that includes a host community of arbitrary richness and species' abundance. To compare invasion potential across communities, we calculate the community basic reproductive ratio of the parasite. We compare communities comprising a set of host species to their subsets, which allows for flexible scenario building including the introduction of novel host species and species loss. We allow vector abundance to scale with, or be independent of, community size, capturing regulation by feeding opportunities and non-host effects such as limited oviposition sites. Motivated by equivocal data relating host species competency to abundance, we characterize plausible host communities via phenomenological relationships between host species abundance and competency. We identify an underappreciated mechanism whereby changes to communities simultaneously alter average competency and the vector to host ratio and demonstrate that the interaction can profoundly influence invasion potential.

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Flisser, A., B. Espinoza, A. Tovar, A. Plancarte, and D. Correa. "Host-parasite relationship in cysticercosis: Immunologic study in different compartments of the host." Veterinary Parasitology 20, no. 1-3 (March 1986): 95–102. http://dx.doi.org/10.1016/0304-4017(86)90094-4.

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PATTERSON, JESSE E. H., and KATHREEN E. RUCKSTUHL. "Parasite infection and host group size: a meta-analytical review." Parasitology 140, no. 7 (February 21, 2013): 803–13. http://dx.doi.org/10.1017/s0031182012002259.

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SUMMARYMany studies have identified various host behavioural and ecological traits that are associated with parasite infection, including host gregariousness. By use of meta-analyses, we investigated to what degree parasite prevalence, intensity and species richness are correlated with group size in gregarious species. We predicted that larger groups would have more parasites and higher parasite species richness. We analysed a total of 70 correlations on parasite prevalence, intensity and species richness across different host group sizes. Parasite intensity and prevalence both increased positively with group size, as expected. No significant relationships were found between host group size and parasite species richness, suggesting that larger groups do not harbour more rare or novel parasite species than smaller groups. We further predicted that the mobility of the host (mobile, sedentary) and the mode of parasite transmission (direct, indirect, mobile) would be important predictors of the effects of group sizes on parasite infection. It was found that group size was positively correlated with the prevalence and intensity of directly and indirectly transmitted parasites. However, a negative relationship was observed between group size and mobile parasite intensity, with larger groups having lower parasite intensities. Further, intensities of parasites did not increase with group size of mobile hosts, suggesting that host mobility may negate parasite infection risk. The implications for the evolution and maintenance of sociality in host species are discussed, and future research directions are highlighted.

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Thompson, R. C. A., and A. J. Lymbery. "Genetic variability in parasites and host—parasite interactions." Parasitology 112, S1 (March 1996): S7—S22. http://dx.doi.org/10.1017/s0031182000076629.

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SUMMARYWe have examined genetic variability in parasites in the context of ecological interactions with the host. Recent research onEchinococcus, GiardiaandCryptosporidiumhas been used to illustrate: (i) the problems that parasite variability and species recognition pose for understanding the complex and often controversial relationship between parasite and host occurrence; (ii) the need for accurate parasite characterization and the application of appropriate molecular techniques to studies on parasite transmission if fundamental questions about zoonotic relationships and risk factors are to be answered; (iii) our lack of understanding about within-host interactions between genetically heterogeneous parasites at the inter-and intraspecific levels, and the significance of such interactions with respect to evolutionary considerations and the clinical outcome of parasite infections. If advances in molecular biology and mathematical ecology are to be realized, we need to give serious consideration to the development of appropriate species concepts and in vivo systems for testing the predictions and assumptions of theoretical models.

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Báthori, Ferenc, Walter P. Pfliegler, Zoltán Rádai, and András Tartally. "Host age determines parasite load of Laboulbeniales fungi infecting ants: Implications for host-parasite relationship and fungal life history." Mycoscience 59, no. 2 (March 2018): 166–71. http://dx.doi.org/10.1016/j.myc.2017.09.004.

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Cattadori, I. M., B. Boag, O. N. Bjørnstad, S. J. Cornell, and P. J. Hudson. "Peak shift and epidemiology in a seasonal host–nematode system." Proceedings of the Royal Society B: Biological Sciences 272, no. 1568 (June 2, 2005): 1163–69. http://dx.doi.org/10.1098/rspb.2004.3050.

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Insight into the dynamics of parasite–host relationships of higher vertebrates requires an understanding of two important features: the nature of transmission and the development of acquired immunity in the host. A dominant hypothesis proposes that acquired immunity develops with the cumulative exposure to infection, and consequently predicts a negative relationship between peak intensity of infection and host age at this peak. Although previous studies have found evidence to support this hypothesis through between-population comparisons, these results are confounded by spatial effects. In this study, we examined the dynamics of infection of the nematode Trichostrongylus retortaeformis within a natural population of rabbits sampled monthly for 26 years. The rabbit age structure was reconstructed using body mass as a proxy for age, and the host age–parasite intensity relationship was examined for each rabbit cohort born from February to August. The age–intensity curves exhibited a typical concave shape, and a significant negative relationship was found between peak intensity of infection and host age at this peak. Adult females showed a distinct periparturient rise in T. retortaeformis infection, with higher intensities in breeding adult females than adult males and non-breeding females. These findings are consistent with the hypothesis of an acquired immune response of the host to a parasite infection, supporting the principle that acquired immunity can be modelled using the cumulative exposure to infection. These findings also show that seasonality can be an important driver of host–parasite interactions.

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RYNNEL-DAGÖÖ, BRITTA, KARIN LINDBERG, ANDERS SAMULESON, STEN BLOMBERG, and JOACHIM FORSGREN. "The Immunology of The Host-Parasite Relationship In the Nasopharynx." Annals of the New York Academy of Sciences 830, no. 1 Immunologic D (December 1997): 32–48. http://dx.doi.org/10.1111/j.1749-6632.1997.tb51877.x.

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de ROODE, J. C., L. R. GOLD, and S. ALTIZER. "Virulence determinants in a natural butterfly-parasite system." Parasitology 134, no. 5 (May 2006): 657–68. http://dx.doi.org/10.1017/s0031182006002009.

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SUMMARYMuch evolutionary theory assumes that parasite virulence (i.e. parasite-induced host mortality) is determined by within-host parasite reproduction and by the specific parasite genotypes causing infection. However, many other factors could influence the level of virulence experienced by hosts. We studied the protozoan parasite Ophryocystis elektroscirrha in its host, the monarch butterfly, Danaus plexippus. We exposed monarch larvae to wild-isolated parasites and assessed the effects of within-host replication and parasite genotype on host fitness measures, including pre-adult development time and adult weight and longevity. Per capita replication rates of parasites were high, and infection resulted in high parasite loads. Of all host fitness traits, adult longevity showed the clearest relationship with infection status, and decreased continuously with increasing parasite loads. Parasite genotypes differed in their virulence, and these differences were maintained across ecologically relevant variables, including inoculation dose, host sex and host age at infection. Thus, virulence appears to be a robust genetic parasite trait in this system. Although parasite loads and genotypes had strong effects on virulence, inoculation dose, host sex and age at infection were also important. These results have implications for virulence evolution and emphasize the need for a detailed understanding of specific host-parasite systems for addressing theory.

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Goedknegt, M. Anouk, David Shoesmith, A. Sarina Jung, Pieternella C. Luttikhuizen, Jaap van der Meer, Catharina J. M. Philippart, Henk W. van der Veer, and David W. Thieltges. "Trophic relationship between the invasive parasitic copepod Mytilicola orientalis and its native blue mussel (Mytilus edulis) host." Parasitology 145, no. 6 (November 29, 2017): 814–21. http://dx.doi.org/10.1017/s0031182017001779.

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AbstractInvasive parasites can spill over to new hosts in invaded ecosystems with often unpredictable trophic relationships in the newly arising parasite-host interactions. In European seas, the intestinal copepod Mytilicola orientalis was co-introduced with Pacific oysters (Magallana gigas) and spilled over to native blue mussels (Mytilus edulis), with negative impacts on the condition of infected mussels. However, whether the parasite feeds on host tissue and/or stomach contents is yet unknown. To answer this question, we performed a stable isotope analysis in which we included mussel host tissue and the primary food sources of the mussels, microphytobenthos (MPB) and particulate organic matter (POM). The copepods were slightly enriched in δ15N (mean Δ15N ± s.d.; 1·22 ± 0·58‰) and δ13C (Δ13C 0·25 ± 0·32‰) with respect to their host. Stable isotope mixing models using a range of trophic fractionation factors indicated that host tissue was the main food resource with consistent additional contributions of MPB and POM. These results suggest that the trophic relationship of the invasive copepod with its mussel host is parasitic as well as commensalistic. Stable isotope studies such as this one may be a useful tool to unravel trophic relationships in new parasite-host associations in the course of invasions.

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HEMPHILL, A., N. VONLAUFEN, and A. NAGULESWARAN. "Cellular and immunological basis of the host-parasite relationship during infection withNeospora caninum." Parasitology 133, no. 3 (June 6, 2006): 261–78. http://dx.doi.org/10.1017/s0031182006000485.

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Neospora caninumis an apicomplexan parasite that is closely related toToxoplasma gondii, the causative agent of toxoplasmosis in humans and domestic animals. However, in contrast toT. gondii, N. caninumrepresents a major cause of abortion in cattle, pointing towards distinct differences in the biology of these two species. There are 3 distinct key features that represent potential targets for prevention of infection or intervention against disease caused byN. caninum. Firstly, tachyzoites are capable of infecting a large variety of host cellsin vitroandin vivo. Secondly, the parasite exploits its ability to respond to alterations in living conditions by converting into another stage (tachyzoite-to-bradyzoite orvice versa). Thirdly, by analogy withT. gondii, this parasite has evolved mechanisms that modulate its host cells according to its own requirements, and these must, especially in the case of the bradyzoite stage, involve mechanisms that ensure long-term survival of not only the parasite but also of the host cell. In order to elucidate the molecular and cellular bases of these important features ofN. caninum, cell culture-based approaches and laboratory animal models are being exploited. In this review, we will summarize the current achievements related to host cell and parasite cell biology, and will discuss potential applications for prevention of infection and/or disease by reviewing corresponding work performed in murine laboratory infection models and in cattle.

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REGOES, R. R., J. W. HOTTINGER, L. SYGNARSKI, and D. EBERT. "The infection rate of Daphnia magna by Pasteuria ramosa conforms with the mass-action principle." Epidemiology and Infection 131, no. 2 (October 2003): 957–66. http://dx.doi.org/10.1017/s0950268803008793.

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In simple epidemiological models that describe the interaction between hosts with their parasites, the infection process is commonly assumed to be governed by the law of mass action, i.e. it is assumed that the infection rate depends linearly on the densities of the host and the parasite. The mass-action assumption, however, can be problematic if certain aspects of the host–parasite interaction are very pronounced, such as spatial compartmentalization, host immunity which may protect from infection with low doses, or host heterogeneity with regard to susceptibility to infection. As deviations from a mass-action infection rate have consequences for the dynamics of the host–parasite system, it is important to test for the appropriateness of the mass-action assumption in a given host–parasite system. In this paper, we examine the relationship between the infection rate and the parasite inoculum for the water flee Daphnia magna and its bacterial parasite Pasteuria ramosa. We measured the fraction of infected hosts after exposure to 14 different doses of the parasite. We find that the observed relationship between the fraction of infected hosts and the parasite dose is largely consistent with an infection process governed by the mass-action principle. However, we have evidence for a subtle but significant deviation from a simple mass-action infection model, which can be explained either by some antagonistic effects of the parasite spores during the infection process, or by heterogeneity in the hosts' susceptibility with regard to infection.

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HOLAND, HÅKON, HENRIK JENSEN, JARLE TUFTO, BERNT-ERIK SÆTHER, and THOR HARALD RINGSBY. "Temporal and spatial variation in prevalence of the parasite Syngamus trachea in a metapopulation of house sparrows (Passer domesticus)." Parasitology 140, no. 10 (June 21, 2013): 1275–86. http://dx.doi.org/10.1017/s0031182013000735.

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SUMMARYWhen investigating parasite–host dynamics in wild populations, a fundamental parameter to investigate is prevalence. This quantifies the percentage of individuals infected in the population. Investigating how prevalence changes over time and space can reveal interesting aspects in the parasite–host relationship in natural populations. We investigated the dynamic between a common avian parasite (Syngamus trachea) in a host metapopulation of house sparrows (Passer domesticus) on the coast of Helgeland in northern Norway. We found that parasite prevalence varied in both time and space. In addition, the parasite prevalence was found to be different between demographic groups in the local populations. Our results reveal just how complex the dynamic between a host and its parasite may become in a fragmented landscape. Although temperature may be an important factor, the specific mechanisms causing this complexity are not fully understood, but need to be further examined to understand how parasite–host interactions may affect the ecological and evolutionary dynamics and viability of host populations.

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HIGUCHI, Maria de Lourdes. "CHRONIC CHAGASIC CARDIOPATHY: THE PRODUCT OF A TURBULENT HOST-PARASITE RELATIONSHIP." Revista do Instituto de Medicina Tropical de São Paulo 39, no. 1 (January 1997): 53–60. http://dx.doi.org/10.1590/s0036-46651997000100012.

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The pathogenesis of chronic chagasic cardiopathy is still a debated matter. In this review, the main theories raised about it since the first description of the disease in 1909 by Carlos Chagas, are considered. The scarcity of T.cruzi parasites into the myocardium and the apparent lack of correlation between their presence and the occurrence of myocardial inflammatory infiltrate, have originated many theories indicating that chronic Chagas' cardiopathy is an autoimmune disease. Recently however, papers using immunohistochemical technique or PCR have demonstrated a strong association between moderate or severe myocarditis and presence of T.cruzi Ags, indicating a direct participation of the parasite in the genesis of chronic chagasic myocarditis. Different patterns of cytokine production seem to have important role in the outcome of the disease. Participation of the microcirculatory alterations and fibrosis as well as the relationship with the parasite are also emphasized. Finally, the author suggests that the indeterminate form of the disease occurs when the host immunological response against the parasite is more efficient while the chronic cardiopathy occurs in patients with hyperergic and inefficient immune response

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Saad-Fares, A., and C. Combes. "Abundance/host size relationship in a fish trematode community." Journal of Helminthology 66, no. 3 (September 1992): 187–92. http://dx.doi.org/10.1017/s0022149x00014541.

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ABSTRACTThe abundance of six species of trematodes: Aphanurus stossichi, Bacciger israelensis, Diphterostomum israelense, Plagioporus idoneus, Lepocreadium album and L. pegorchis, parasitic in the digestive tract of marine teleostei (Sparidae) collected near Jounieh (east Mediterranean), was analysed as a function of the host-size. In two parasite/host systems, infections were observed from the lowest size classes of the sample, with a clear tendency to an increase of abundance in older fish. In four others, parasites appear only above a rather high threshold class, young individuals never being infected. In the last three parasite/host systems, host invasion may occur early or late, but infection decreases above a well defined size class, old fishes rarely or never being infected. A given trematode species. when parasitizing several host species, shows similar abundance/host size relationships, e.g. P. idoneus in Diplodus vulgaris and Oblada melanura. When more than one species of trematode infects a single host species, curves can be markedly distinct; for instance, L. pegorchis was collected from Pagellus erythrinus below 15 cm. whereas D. israelense parasitized the same fish approximately above the same size. There is no evidence that such a replacement of one trematode by another in the course of host growth is a result of interspecific competition.

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Bibik, Nacheva, and Arkhipov. "MICROMORPHOLOGICAL PECULIARITIES OF RELATIONSHIPS IN THE “PARASIT-HOST” SYSTEM." THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL, no. 20 (May 14, 2019): 108–14. http://dx.doi.org/10.31016/978-5-9902340-8-6.2019.20.108-114.

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Micromorphological, histochemical and pathomorphological features of relationships in the “parasite-host” system before and after exposure to the antitremum (at a dose of 200 mg / kg of LW) and tegalide (at a dose of 30 mg / kg of LW) were studied in a comparative aspect using the example of parasitizing by a Paramphistomum cervi in sheep intestines. The effect of anthelmintics on trematodes is associated with endostation of the parasite, in which certain trophic links are formed between the host and the helminth. The adhesion in the morphofunctional complex “tegument-epithelial tissue of the intestinal villus” at paramphystomy of sheep is considered as an indicator of the maturity of the reciprocal relationship between the parasite and the host. Pathomorphological changes in the mucous membrane of the intestine of sheep with paramphystomy are characterized by the presence of proliferation, hyperplasia and metaplasia, which provide the dynamic stability of the parasite-host system in the endostation of the parasite. Pathomorphological manifestations in the small intestine of sheep with paramphystomy and chemotherapy with tehalide and antithyroid consist of alternative dystrophic and proliferative processes. With the introduction of anthelmintic into the host organism, a violation of the homeokinetic state of each of the biological species that make up this binary system occurs, which leads to destabilization and homeoclase, and then to the death of the system and the development of the disease with clinical manifestations.The micromorphological features of interrelations in the “parasite-host” system, studied with the example of parasitic Paramphistomum cervi in the intestine of spontaneously-infested sheep, before and after the anthelmintic effects of antitermite and tehalid reveal the mechanisms of morphofunctional interrelations in the process of transition of the “parasite-host” from the homeoresistive state to the homeoclasis one and allow you to assess the impact efficiency of anthelmintics with trematodoses.

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Koella, J. C., P. Agnew, and Y. Michalakis. "Coevolutionary interactions between host life histories and parasite life cycles." Parasitology 116, S1 (1998): S47—S55. http://dx.doi.org/10.1017/s0031182000084936.

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SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.

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DOI, HIDEYUKI, and NATALIA I. YURLOVA. "Host-parasite interactions and global climate oscillations." Parasitology 138, no. 8 (May 18, 2011): 1022–28. http://dx.doi.org/10.1017/s0031182011000655.

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SUMMARYIt is suspected that host-parasite interactions are influenced by climatic oscillations such as the North Atlantic Oscillation (NAO). However, the effects of climatic oscillations on host-parasite interactions have never been investigated. A long-term (1982–1999) dataset of the host snail Lymnaea stagnalis and trematode metacercariae infection has been collected for Lake Chany in Western Siberia. Using this dataset, we estimated the impact of the NAO on the population dynamics of hosts and parasites as well as their interactions. The results of general linear models showed that the abundance of dominant parasite species and the total parasite abundance significantly increased with NAO, with the exception of Moliniella anceps. Other climatic and biological factors were relatively weak to explain the abundance. There was no significant relationship between NAO and the population density of host snails. The prevalence of infection was related to the total abundance of parasites, but not to the NAO. Thus, the responses to the NAO differed between the host and parasites, indicating mismatching in host-parasite interactions. Therefore, climatic oscillations, such as the NAO, influence common parasitism.

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Wood, Chelsea L., and Pieter T. J. Johnson. "How Does Space Influence the Relationship Between Host and Parasite Diversity?" Journal of Parasitology 102, no. 5 (October 2016): 485–94. http://dx.doi.org/10.1645/15-920.

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Modha, J., and M. J. Doenhoff. "Schistosoma mansoni host–parasite relationship: interaction of contrapsin with adult worms." Parasitology 109, no. 4 (November 1994): 487–95. http://dx.doi.org/10.1017/s0031182000080744.

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SUMMARYContrapsin, a serine protease inhibitor (serpin) present in mouse serum, was compared with that found in adult Schistosoma mansoni worm homogenates, which although immunologically identical to contrapsin in mouse serum, had a higher molecular weight in Western blotting. Immunolocalization studies demonstrated parasite-associated contrapsin on the surface and interstitial cells of adult male worms. After extraction of these parasites with Triton X-114, contrapsin was found in the aqueous phase of the detergent, suggesting it is unlikely to be an integral membrane protein. Treatment of adult worms with deoxycholate resulted in a change in the electrophoretic behaviour of worm-derived contrapsin. Parallel studies with trypsin suggested this was due to interaction of the serpin with a protease. Using porcine pancreatic trypsin as a model for a putative schistosome protease reacting with contrapsin, we have shown that trypsin, following complex formation with contrapsin, loses immunogenicity. Thus, when contrapsin–trypsin complexes were used as immunogen, the resulting antisera contained antibodies to contrapsin and contrapsin–trypsin complexes only, and none to native trypsin. Thus, epitopes characterizing native trypsin were presumably either masked following complex formation with contrapsin, or their processing and presentation to antigen presenting cells was suppressed, so that an antibody response was not mounted against them. These observations encourage speculation that S. mansoni may be elaborating an immune evasion strategy whereby immunologically sensitive proteases are first complexed with host serpins, which would render them immunogenically inert, and then cleared from the circulation by the host's reticulo-endothelial system. In this way the immune system would be unable to ‘see’ sensitive parasite proteases sufficiently to mount a response against the parasite.

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Sims, T. A., J. Hay, and I. C. Talbot. "Host—parasite relationship in the brains of mice with congenital toxoplasmosis." Journal of Pathology 156, no. 3 (November 1988): 255–61. http://dx.doi.org/10.1002/path.1711560311.

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Piedrafita, D., H. W. Raadsma, R. Prowse, and T. W. Spithill. "Immunology of the host–parasite relationship in fasciolosis (Fasciola hepaticaandFasciola gigantica)." Canadian Journal of Zoology 82, no. 2 (February 1, 2004): 233–50. http://dx.doi.org/10.1139/z03-216.

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The protective resolution of liver fluke (Fasciola hepatica and Fasciola gigantica) infection is a dynamic interplay between the host's effector responses and the parasite's defence and immunomodulatory systems. The evidence suggests that the juvenile or immature parasite is the target of protective host immune responses but the effector mechanisms employed vary between hosts. Moreover, F. hepatica and F. gigantica differ in their susceptibility to these killing mechanisms. In the rat, in vitro killing of juvenile F. hepatica involves an antibody-dependent cell cytotoxicity mediated by nitric oxide produced by activated monocytes and (or) macrophages. However, monocytes and (or) macrophages from Indonesian sheep do not produce nitric oxide yet can effectively kill juvenile F. gigantica in vitro and in vivo by a mechanism that is ineffective against F. hepatica. These data show that disease progression or resolution in fasciolosis is determined both by biochemical differences between Fasciola species and by host-dependent factors. Understanding the genetic basis for these differences is a key question for the future. Fasciola hepatica and F. gigantica actively modulate the host immune response, downregulating type 1 responses during infection. It is important to determine whether such modulation of the immune response by Fasciola spp. directly leads to enhanced parasite survival in the various hosts.

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Kaufmann, S. H. E. "Heat-shock proteins: a missing link in the host-parasite relationship?" Medical Microbiology and Immunology 179, no. 2 (May 1990): 61–66. http://dx.doi.org/10.1007/bf00198526.

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MORALES-MONTOR, J., and C. LARRALDE. "The role of sex steroids in the complex physiology of the host-parasite relationship: the case of the larval cestode of Taenia crassiceps." Parasitology 131, no. 3 (May 23, 2005): 287–94. http://dx.doi.org/10.1017/s0031182005007894.

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Sex steroids play a significant role in regulating the parasite load in experimental intraperitoneal Taenia crassiceps cysticercosis of male and female Balbc/anN mice. Briefly, oestrogens increase parasite loads and androgens decrease them (1) by acting directly on the parasite, favouring or hindering its reproduction, respectively, and (2) by biasing the hosts' immune response towards a parasite-permissive Th2 or a parasite-restrictive Th1 response. The infected male host also undergoes drastic endocrinological and behavioural changes that may impinge upon the course of infection, and the host's mating behaviour and its exposure to predators. In addition, at different times of infection, significant changes occur in the expression of c-fos in the host's hyppocampus, hypothalamus and preoptic area. Thus, the host's brain seems to sense and/or react to intraperitoneal infection. The physiological domains of the network affected by the infection, which classically included the hypothalamus-pituitary-axis and the immune system, must now incorporate the host's sexual hormones and other areas of the brain. The network's complex circuitry and functions may help understand some basic questions of parasitology (i.e. the hosts' sexual dimorphism in parasite infections, host-parasite specificity, heterogeneity in the course and outcome of infections at different stages of parasite and host development). The plurality of elements and the complexity of the network that regulates the host-parasite relationship also point to additional strategies for the treatment and control of infections.

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Journal articles on the topic 'Parasite-host relationship'

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