Search results for "Immunodepression"
showing 4 items of 4 documents
Variation and covariation in infectivity, virulence and immunodepression in the host-parasite association Gammarus pulex-Pomphorhynchus laevis.
2009
Parasites often manipulate host immunity for their own benefit, either by exacerbating or suppressing the immune response and this may directly affect the expression of parasite virulence. However, genetic variation in immunodepression, which is a prerequisite to its evolution, and the relationship between immunodepression and virulence, have rarely been studied. Here, we investigated the variation among sibships of the acanthocephalan parasite, Pomphorhynchus laevis , in infecting and in immunodepressing its amphipod host, Gammarus pulex . We also assessed the covariation between infectivity, parasite-induced immune depression and host mortality (parasite virulence). We found that infecti…
Parasite virulence when the infection reduces the host immune response.
2010
Parasite infections often induce a reduction in host immune response either because of a direct manipulation of the immune system by the parasite or because of energy depletion. Although infection-induced immunodepression can favour the establishment of the parasite within the host, a too severe immunodepression may increase the risk of infection with opportunistic pathogens, stopping the period over which the parasite can be transmitted to other hosts. Here, we explore how the risk of contracting opportunistic diseases affects the survival of the amphipod Gammarus pulex infected by the acanthocephalan Pomphorhynchus laevis . Previous work with this system has shown that upon infection, G.…
Density-dependent effects on parasite growth and parasite-induced host immunodepression in the larval helminth Pomphorhynchus laevis.
2011
SUMMARYLarval helminths exploit the physiology of their intermediate hosts: first, as a resource for energy and space and second by altering the immune system activity to ensure their survival. Whereas the growth pattern under parasite competition has been investigated, the effect of multiple infections on the level of parasite-induced immunodepression in a trophically transmitted helminth has been neglected. In this study, amphipodsGammarus pulexwere infected in the laboratory by the acanthocephalanPomphorhynchus laevisto investigate how parasite density in the intermediate host affected (i) cystacanth growth and (ii) the level of parasite-induced alterations of the host immune defences, t…
Des lésions cutanées diffuses
2015
International audience