Knowledge of the presence of infectious trematodes or other parasitic organisms dwelling within freshwater crayfish in central Virginia is limited. Related research within Virginia has focused upon trematode infection in Appalachian stream snails, lung helminths in bobcats, and endoparasites in amphibians. Within North America, human infection with trematodes belonging to the Paragonimus kellicotti have been reported, primarily in Mississippi and various Midwestern states. Paragonimus sp. use crayfish as a primary intermediate host after being released from snails as cercariae. Within the freshwater ecosystems of Central Virginia, snails and crayfish could be potential intermediary hosts for observing the presence of trematodes.
The purpose of this study will be to identify the parasitic organism(s) inhabiting the hepatopancreas of crayfish and associated cercariae within snails collected from urban and rural Virginian stream ecosystems. Parasite cyst presence will be quantified and compared in relation to the total length and blotted wet mass (BWM) of individual crayfish. In addition, snails from the study sites will be collected to assess for cercarial presence to support trematode identification. There are three expected outcomes of this study: 1) It is expected that parasites will be found in the hepatopancreas tissue of both the urban and rural stream environments, but that the intensity of cysts presence will be greater in the urban stream. 2) It is expected that hepatopancreas parasite presence will be positively correlated with an increase in crayfish size. 3) It is expected that snails from both stream study sites will carry cercaria. Preliminary examinations of the crayfish hepatopancreas has shown a positive correlation with regards to BWM and cyst density/hepatopancreas/crayfish. After the identification and intensity of parasitic organisms in the streams have been assessed, application will be made to the prevalence of crayfish and snail endoparasites.
