Last week, West Nile Virus was detected in a Tuscola County horse, the seventh case of the illness in a domestic animal this year.
State Veterinarian Nora Wineland released a statement following the detection in a 12-year-old Quarter Horse mare, sharing that the mare became ill around October 15, suffering from a loss of coordination and weakness, progressing to being down with an inability to rise. Subsequent testing revealed the mare was positive for the virus.
While the horse was vaccinated against the disease in the past, the mare had not been vaccinated in over a year. The horse was humanely euthanized due to the severity of its disease.
Despite the cooler temperatures being experienced around the state, the mosquitoes that carry WNV and other mosquito-borne diseases will remain alive and active until there has been at least one hard freeze where the temperatures fall below 28 degrees Fahrenheit. Until this occurs, it is important to continue taking precautions to keep mosquitoes away from animals.
West Nile Virus (WNV) is a viral disease transmitted through the bite of an infected mosquito. While the disease typically affects horses, humans, and birds, it can sometimes cause illness in other animals. The disease is not spread by horse-to-horse or horse-to-human contact.
Cases of WNV are typically seen in the late summer through early fall each year in Michigan. Placing livestock in a barn under fans during peak mosquito activity (from dusk to dawn), eliminating standing water on one’s property, using an insect repellant on animals that is approved for the species, and contacting a veterinarian to vaccinate horses against WNV and other mosquito-borne diseases are all vital measures to take in order to keep animals healthy.
Also, please contact a veterinarian if a horse shows signs of illness: mild fever and stumbling, which can progress to being down and struggling to stand.
As of October 25, 2024, WNV was also detected in 88 wild birds and 150 mosquito pools throughout Michigan. There were 29 cases of the disease reported in humans as well. For more information about WNV, please visit michigan.gov/emergingdiseases.
