DOVER, Delaware – The Delaware Department of Agriculture has confirmed the first two cases of West Nile Virus in horses this year. Both horses, a 4-year-old Standardbred gelding and a 7-year-old Standardbred mare, were located in Kent County and were euthanized after showing symptoms of the virus between August 31 and September 1.
West Nile Virus, along with Eastern Equine Encephalitis, is transmitted by mosquitoes, typically during the summer and fall months. The peak transmission period is between mid-August and mid-October. While neither disease can spread directly between horses or from horses to humans, humans are at risk of contracting these viruses through mosquito bites.
Symptoms of West Nile Virus in horses include fever, depression, wobbling, weakness, blindness, and in severe cases, convulsions. Horse owners are advised to contact their veterinarian immediately if they notice any of these symptoms.
The Department of Agriculture is urging horse owners to take steps to protect their animals. Horses should be kept indoors during peak mosquito hours at dawn and dusk, and insect repellents labeled for use on horses can help reduce exposure. In addition, removing standing water around properties and cleaning water troughs every few days will reduce mosquito breeding habitats.
With mosquito season expected to end after the first hard freeze, the Delaware State Veterinarian recommends that horse owners schedule the West Nile Virus and Eastern Equine Encephalitis vaccines for their horses in 2026. These diseases have no specific drug treatments, and Eastern Equine Encephalitis has a fatality rate of 70-90% in horses, while West Nile Virus has a 30% fatality rate.
For more information, Delawareans can contact the Delaware Department of Public Health at 302-744-4990 during regular business hours, or 888-295-5196 after hours. Questions about animal health can be directed to the Delaware Department of Agriculture at 302-698-4500, and mosquito control inquiries can be made to Delaware Mosquito Control at 302-739-9917.
Photo: Delaware.gov