A viral disease affecting thousands of deer across Wisconsin has been detected in dairy cattle in Waukesha County, according to the Wisconsin Department of Agriculture, Trade and Consumer Protection. State officials confirmed that the affected samples came from non-lactating dairy cattle, marking an appearance of Epizootic Hemorrhagic Disease in livestock populations.
Understanding Epizootic Hemorrhagic Disease Transmission
Epizootic Hemorrhagic Disease is a non-contagious viral infection transmitted by flies, sometimes called midges, that are most active during late summer and early fall. According to the Cornell University Wildlife Health Lab, the pathogen does not infect humans and generally causes mild or unapparent infections in domestic cattle and small ruminants. State agricultural officials confirmed that humans face no health risks from insect bites, direct exposure, or the consumption of meat and milk from infected cattle or deer.
Unlike deer, cattle rarely show clinical signs of the virus, according to state documentation. When symptoms do appear in cattle, they can include fever, weight loss, lameness, and sores on the mouth, legs, or teats. State agricultural regulators noted that there is no specific treatment for the virus, and these documented cases confirm that the pathogen is actively circulating in the local environment.
Wisconsin previously recorded a single case of the virus in cattle in 2013, making this recent detection an uncommon occurrence for the state’s domestic livestock sector.
Ongoing Outbreak Across Wisconsin Deer Populations
While the virus remains sporadic in cattle, the Wisconsin Department of Natural Resources reported an active outbreak across multiple counties’ deer herds. Washington County leads the state with over 1,200 recorded cases, while Waukesha County has documented approximately 400 cases. Additional suspected and confirmed cases appear in Dodge, Fond du Lac, Milwaukee, Ozaukee, and Jefferson counties, with Milwaukee County reporting roughly 10 estimated cases.
State wildlife officials explain that Wisconsin sits on the far northern edge of the geographic range for the midges that carry the virus, resulting in sporadic rather than annual widespread outbreaks. Infected deer typically exhibit weakness and foaming around the mouth and nose. To seek relief from high fevers, sick animals frequently lie in cool water, where carcasses are often discovered.
The wildlife agency stated that the virus does not survive inside animal carcasses, but discourages citizens from handling dead wildlife due to other potential disease risks. Natural transmission cycles typically decline following the first hard freeze, which reduces active midge populations.
Biosecurity and Reporting Guidelines for Livestock Producers
State agricultural officials advise livestock and farm-raised deer producers to monitor herds closely for signs of illness. Anyone observing animals displaying symptoms should consult a local veterinarian to secure a positive identification. Under state guidelines, suspected or confirmed cases of the virus must be reported to the agricultural department within 10 days.
To minimize transmission risks, producers should maintain rigorous parasite control measures and avoid overcrowding in holding areas.
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