April 29, 2011

In the Spotlight: Recent Disease Investigation from USGS National Wildlife Health Center

From the Latest USGS National Wildlife Health Center Quarterly Wildlife Mortality Report - October 2010 to December 2010

Trematodiasis in Bowstring Lake (Minnesota)

Lesser Scaup
Photo Copyright Camden Hackworth /
Idaho Fish and Game
For the third consecutive year, Bowstring Lake [mapped] experienced avian mortalities in October and November due to intestinal trematode infections with Sphaeridiotrema globulus [fact sheet]and Cyathocoytle bushinesis [image]. Avian mortality due to intestinal trematodes was first detected at Bowstring Lake in 2008 and has been seen every year since.

In this 2010 mortality event, an estimated 1200 birds died; primarily lesser scaup and American coots. Avian mortality due to intestinal trematodes has been observed at nearby Lake Winnibigoshish [mapped] since 2005. Snail surveys conducted in the summer of 2008 at Lake Winnibigoshish found the invasive host snail, Bithynia tentaculata.

American Coots
Photo Credit: Terry Hartley,
Alabama Conservation and Natural Resources
Parasite infection rate for snails was between 0-93% with the highest prevalence occurring near shore. All 3 trematodes, S. globulus, C. bushinesis, and Legyonimus polyoon were detected and in some instances, a single snail was infected by more than 1 species of metacercariae, the intermediate life stage of the parasites.


Source: USGS National Wildlife Health Center, Quarterly Mortality Reports






More Resources

Michigan Dept of Natural Resources 
University of Minnesota
United States Geological Survey

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