West Nile Virus

West Nile virus is a disease spread by mosquito. Mosquitoes carry the highest amounts of virus in the early fall, which is why the rate of the disease increases in late August to early September. The risk of disease decreases as the weather becomes colder and mosquitoes die off.

Infection with West Nile Virus does not always lead to signs of illness in people or animals. Horses appear to be a species that is susceptible to infection with the virus. In horses that do become clinically ill, the virus infects the central nervous system and may cause symptoms of encephalitis. Clinical signs of encephalitis in horses may include a general loss of appetite and depression, in addition to any combination of the following signs:

·         Fever

·         weakness of hind limbs

·         paralysis of hind limbs

·         impaired vision

·         weakness

·          head pressing

·         aimless wandering

·         convulsions (seizures)

·         inability to swallow

·         walking in circles

·         hyperexcitability

·         coma

Vaccines are now available to protect against the West Nile Virus, Eastern, Western and Venezuelan equine encephalitis. Available vaccines on the market are:

·         PreveNile West Nile

·         Recombitek

·         West Nile Innovator

·         West Nile Innovator + EWT

·         West Nile Innovator + VEWT

·         Recombitek rWNV EWT

PreveNile, Recombitek, and West Nile Innovator is for vaccination of healthy horses to prevent Viremia, and as an aid in the prevention of diseases and encephalitis caused by West Nile virus infection. West Nile Innovator + EWT and Recombitek rWNV EWT protects horses from the West Nile Virus and aids in the prevention of viremia caused by West Nile; equine encephalitis due to Eastern, Western viruses; and tetanus. West Nile Innovator + VEWT protects from the same thing as the EWT only this vaccine goes an extra step protecting against the Venezuelan equine encephalitis.

Vaccination of horses is not a guarantee of protection against infection, and does not offer any protection for other animals or people. The best method of prevention of infection with West Nile Virus for people and animals is to reduce the risk of exposure to the mosquitoes that may carry the virus. Reducing the risk involves eliminating mosquito breeding sites to reduce the number of hatching mosquitoes, and to reduce exposure to adult mosquitoes. Mosquitoes breed in stagnant water, so reduction of breeding sites involves eliminating stagnant water sources.