MADISON, Wis. – The Wisconsin Department of Natural Resources (DNR) has received the 2019 test results from the second year of the ruffed grouse West Nile virus (WNV) surveillance project.
Results from the blood samples collected from harvested ruffed grouse in 2019 indicate that 20% of the Wisconsin submitted samples had antibodies consistent with WNV exposure. Of these samples, 9% showed confirmed WNV and 11% showed likely exposure. None of the 188 samples had evidence of the virus present in their hearts.
“These findings indicate that while ruffed grouse are being exposed to WNV, there are birds that are surviving and clearing the virus from their bodies,” said Alaina Gerrits, Wisconsin DNR Assistant Upland Game Ecologist.
This collaborative multi-year study aims to provide biologists with more information about WNV exposure and infection in ruffed grouse in the western Great Lakes region. Ruffed grouse harvested in Michigan, Minnesota and Wisconsin during the 2019 hunting season were sent to the Southeastern Cooperative Wildlife Disease Study in Athens, Georgia, to be analyzed.
“We are grateful to the passionate grouse hunters of Wisconsin who took the time to submit samples from their harvested birds. Without their support, this study would not be possible,” said Gerrits.
Hunter-submitted samples underwent two types of testing to help determine if the birds were exposed to WNV. First, a test to look for traces of viral genetic material in heart tissue. And second, a blood test to determine if the grouse had developed an immune response from exposure to the virus. Similar to humans, ruffed grouse can develop antibodies as an immune response to viruses they encounter. When the body fights off WNV, these antibodies can be found in the blood.
In fall 2019, Wisconsin hunters assisted in the collection and submission of 188 of the 752 samples submitted