West Nile Virus (WNV) is a viral disease found in humans, birds, horses and other animals. WNV is a viral disease that belongs to the group of viruses called flaviviruses and is spread by mosquitoes About West Nile | West Nile Virus | CDC. WNV is the most common disease transmitted by mosquitoes. Mosquitoes acquire the virus by a blood meal from an infected bird and the mosquito then spreads it to other birds, animals and humans. Birds are the main hosts of WNV with both humans and horses as dead-end hosts, meaning neither humans nor horses can spread it. It was first discovered in the New York City area in 1999 and has since spread throughout the country West Nile Virus | Washington State Department of Health. Symptoms of the disease range from fever to neurological and can also manifest as encephalitis and meningitis. There are no treatments for WNV except for supportive pain medications when needed, fluids and rest. Many people will not have any symptoms therefore many cases go undocumented. Symptoms, if present, can last from a few days to months, neurologic issues may never go away. Diagnosis is made through history and blood tests. It is believed those individuals infected will have a lifelong immunity to the disease. In 2023 there were 2,628 WNV cases in the United States, of which 1,891 people were hospitalized and 194 people died Historic Data (1999-2024) | West Nile Virus | CDC.     

Between 1999-2023 there were 215 cases of WNV in the state of Kentucky, compared to California (8007) and Colorado (6698) CDFA - AHFSS - Animal Health Branch - Equine West Nile Virus. Between 2012 and 2024 there have been 70 positive equine cases in Kentucky, compared to California where between 2003 and 2018, 1,284 horses had been diagnosed with 540 deaths (data courtesy of University of Kentucky Veterinary Diagnostic Laboratory). Although Kentucky has much lower numbers of horse owners a horses should be aware of the risk of WNV. The symptoms in horses, like humans, can range from no symptoms at all; to fever and in severe cases neurologic issues will occur (referred to West Nile Encephalitis). A vaccine is available for horses and is recommended as part of their annual vaccinations. Mosquito control for both humans and animals is considered the best way to protect against WNV, removing standing water, making sure containers are clean and using repellents, plus staying inside during the peak periods mosquitos are out, which is dawn and dusk.