نتایج جستجو برای: intermediate host
تعداد نتایج: 339629 فیلتر نتایج به سال:
The ability to culture parasites outside their host (i.e. in vitro) is essential for several aspects of parasitological research. Here, a culture medium for marine trematode parthenitae was optimized using Philophthalmus sp. rediae from the intermediate snail host, Zeacumantus subcarinatus. The medium was optimized by sequentially testing the suitability of different levels of osmolality, diffe...
A key feature of the vertebrate adaptive immune system is acquired immune memory, whereby hosts launch a faster and heightened response when challenged by previously encountered pathogens, preventing full infection. Here, we use a mathematical model to explore the role of ecological and epidemiological processes in shaping selection for costly acquired immune memory. Applying the framework of a...
The importance and prevalence of phylogenetic tracking between hosts and dependent organisms caused by co-evolution and shifting between closely related host species have been debated for decades. Most studies of phylogenetic tracking among phytophagous insects and their host plants have been limited to insects feeding on a narrow range of host species. However, narrow host ranges can confound ...
Theoretical models predict that genetic relatedness affects the competition within and between parasite clonal groups sharing a common host. Here, we studied natural and experimental multiple infections of the trematode Coitocaecum parvum in its intermediate host. We focused on the effects of clonality on the life-history strategy of parasites competing for resources. Coitocaecum parvum can eit...
The discontinuous distribution of Schistosoma mansoni in the Caribbean islands results from accidents of history, geography, and the migration of both infected people and intermediate host snails. The spread of infection requires the presence of infected people, a susceptible snail host, poor sanitation, and human dependence upon snail-infested water. The various Caribbean countries differ in t...
Various processes can generate associations between the larvae of different helminth species in their fish intermediate or paratenic host. We investigated the pairwise associations among larval helminth species in eight different fish populations, using two different coefficients of associations, in order to determine in what situations they are strongest. All helminth species included use the ...
Besides conspicuous changes in behaviour, manipulative parasites may also induce subtle physiological effects in the host that may also be favourable to the parasite. In particular, parasites may be able to influence the re-allocation of resources in their own favour. We studied the association between the presence of the acanthocephalan parasite, Pomphorhynchus laevis, and inter-individual var...
The trematode Microphallus sp. alters the behavior of its snail intermediate host, Potamopyrgus antipodarum, in ways that seem to increase transmission to its final host, e.g., waterfowl, and decrease the probability of being eaten by other predators, e.g., fish. The parasite seems to cause the snail to move from the top to the bottom of rocks at about 0900 hr. Waterfowl feed predominantly befo...
The Parasite Fasciola hepatica, the common liver fluke, is the most likely cause of liver fluke disease in domestic ruminants in the United States. The fluke life cycle requires a snail intermediate host to complete transmission to a new ruminant host. The parasite is most often found in Florida, along the Gulf Coast, in the Pacific Northwest, in portions of the Rocky Mountains, and Hawaii. Oth...
The prevalence of larval stages of Dicrocoeliidae in the land snail, Chondrus tournefortianus (Férussac, 1821), found in Kastamonu, Turkey, was investigated and some of its morphological and histological features were determined. The snail samples were collected in spring and autumn. C. tournefortianus has been reported for the first time as being an intermediate host in the life cycle of Dicro...
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