The collaborative multi-year study explores ruffed grouse West Nile virus exposure and infection in the western Great Lakes region. The study also aims to identify future research needs in Wisconsin, including a potential survival study investigating sources of mortality.
Although the DNR did not distribute new testing kits in 2020 due to the ongoing COVID-19 pandemic, Wisconsin hunters with leftover kits from previous years' sampling efforts submitted 36 birds for testing.
As in humans, ruffed grouse can develop antibodies as an immune response to viruses they encounter. Blood test results from birds collected in 2020 showed that 20% had antibodies consistent with exposure to West Nile. Of these samples, 11% had confirmed exposure to the virus, and 9% had likely exposure to West Nile or a closely related virus. Only one of the 36 samples submitted also had detectable portions of the virus present in the heart.
"We are grateful to the passionate grouse hunters of Wisconsin who took the time to submit samples from their harvested birds," said Alaina Gerrits, DNR Assistant Upland Game Bird Ecologist. "Without their support, this study would not be possible."
Hunters who submitted samples and provided contact information will receive test results via email as soon as possible, regardless of whether the results were negative or positive. The ruffed grouse harvested in Wisconsin during the 2020 hunting season were sent to the Southeastern Cooperative Wildlife Disease Study in Athens, Georgia, to be analyzed. Partners in Michigan and Minnesota decided not to participate in 2020 due to the logistical challenges of COVID-19.