The spatial and temporal distribution of Bithynia Tentaculata and three parasite species implicated in waterfowl mortality in the Upper Mississippi River National Wildlife and Fish Refuge

Abstract

The Upper Mississippi River National Wildlife and Fish Refuge (UMRNW&FR) is a 418 km long refuge that lies within the Mississippi Flyway. Over 40% of the nation's waterbirds use the Mississippi Flyway to navigate to and from their reeding grounds in the spring and fall. Since 2002, large waterbird mortality events caused by the parasitic trematodes, Cyathocotyle bushiensis (Digenea: Cyathocotylidae) and Sphaeridiotrema spp. (Digenea: Psilostomidae), have been occurring within the Refuge's boundaries. The parasites use the prosobranch snail, Bithynia tentaculata as first and second intermediate hosts. Although B. tentaculata and its parasites have caused seasonal waterbird mortality events, little is known about the spatial or temporal distributions of these snails and their trematodes in the UMRNW&FR. The onjectives of this study were to quantitatively sample both B. tentaculata densities and parasites intensities in waterbird stopover areas across space and time, and to map disease risk with the use of Geographic Information System (GIS). Snails with primary and secondary infections were found to vary in infection prevalence and intensity across 2 navigation pools of the UMRN&FR.