Generalized estuarine trematode life cycle. |
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The Ecology of Infectious Diseases (EID) Program is jointly funded by the National Institutes of Health and the National Science Foundation.
Predictive models for the emergence and transmission of disease will require discovery of basic ecological and biological mechanisms. This task is particularly challenging for parasites with complex life cycles. We seek to reveal how anthropogenic changes, particularly those related to biodiversity loss and habitat transformation, influence communities of parasites with complex life cycles. The types of changes most likely to affect parasite communities are alterations in host communities resulting from climate change (range shifts, habitat formation, and destruction) and environmental degradation (introduced species, habitat fragmentation, pollution, overharvesting). In turn, because parasites, particularly those transmitted through predation events (i.e. trophically-transmitted parasites) have the potential to organize their host communities, changes to parasite communities could profoundly alter natural systems. The dynamics of trophically-transmitted parasites are also of considerable practical importance as these parasites cause many human, veterinary and wildlife diseases (e.g. disease caused by lung flukes, hydatid-tapeworms, pork-tapeworms, etc.).
We are especially interested in the potential for complex feedback dynamics initiated by anthropogenic change or:
As a model system, we study salt marshes along the West Coast of North America. These habitats include an abundant and diverse community of trematode parasites with complex life-cycle embedded in rich food webs. We shall investigate the following specific hypotheses that are amenable to testing in this model system and that have broad applicability to other ecosystems and medically important diseases.
I. Anthropogenic change affects parasite communities: (A) loss of biodiversity affects parasite communities by altering the density of hosts, (B) pollution increases susceptibility of hosts or is toxic to parasites, (C) introduced species affect parasites communities by (i) displacing native hosts and (ii) introducing new parasites and (D) climate change affects parasites communities by (i) shifting host ranges and (ii) habitat transformation.
II. Such changes to parasite communities indirectly affect ecosystems: (A) parasites alter the flow of energy through a food web by converting host tissue into parasite tissue and (B) parasite-increased trophic transmission alters predator-prey dynamics by making infected prey easier to capture.
III. Anthropogenic change results in feedback between hosts and parasites.
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