Leyogonimus polyoon is a common killer of moorhens and coots in Eastern Europe, especially the Danube River area. The parasite resides in snails, which are an important food source for moorhens and coots alike. Once inside a bird's body, the parasite causes intestinal damage and a slow death. Cole does not know which of the many varieties of snail in Shawano Lake carries the parasite. Also unknown is how easily the parasite can spread.
Many coots migrate to Florida and other Southern states for the winter.
The coot migration may enable the parasite to spread to other regions of the country. So far, wildlife managers in the area have not reported any other events similar to the die-off in Shawano Lake. Cole has only found the new parasite in coot carcasses. She does not know if other snail-eating birds are at risk. They may not be susceptible to the parasite, or they may not feed on the infected snail species.