What is West Nile virus?
West Nilevirus (WNV), a mosquito-borne virus, was detected for the first time in the United States in August 1999. When a mosquito bites a bird carrying the West Nile virus, the mosquito then becomes infected. This infected mosquito can then feeds on horses thereby infecting them with WNV. The virus can cause encephalitis, which is characterized by inflammation of the brain and spinal cord. Early signs may include one or more of the following: weakness (hind end, front end, or both, characterized by falling to their knees or difficulty in remaining standing), ataxia (in coordination), muscle twitching or tremors, altered mental state (somnolent or aggressive, circling, or stall-walking), hypersensitivity to touch or sound, cataplexy or narcolepsy, seizures, blindness, cranial nerve deficits (facial paralysis, tongue weakness, difficulty swallowing), recumbence, and fever. West Nile virus in horses becomes dangerous once the virus infects the brain. This can lead to brain inflammation and thereafter interfere with the normal function of the animal’s central nervous system. Once the horse’s central nervous system is seriously affected, possible death can ensue.
How do you prevent the West Nile Virus?
Vaccines are generally effective and recommended to prevent West Nile encephalitis. Horse owners should consult their veterinarians regarding its use. The vaccine shots are no value if they aren't given prior to exposure to the disease. If the horse develops WNV it is too late for the shot.
The vaccines require two doses, administered three to six weeks apart, and full protection doesn't develop until four to six weeks after the second dose.
Sometimes a third does is recommended. Boosters are recommended, but recommendations vary and depend upon mosquito infestation where you live so consult your vet.
It can take from 7 to 12 weeks for the horse to develop maximum resistance to infection.
West NileInnovator + EWT. For vaccination of healthy horses as an aid in the prevention of viremia caused by West Nile virus, and as an aid in the prevention of equine encephalomyelitis due to Eastern and Western viruses, and tetanus. Efficacy of the West Nile fraction was demonstrated in horses that received two doses of the vaccine and were challenged one year post-vaccination with West Nile Virus. The vaccine protected 95% of the vaccinates against infection, while 82% of the controls were viremic.
West Nile Innovator + VEWT For vaccination of healthy horses as an aid in the prevention of viremia caused by West Nile virus, and as an aid in the prevention of equine encephalomyelitis due to Eastern, Western and Venezuelan viruses, and tetanus.
Equine West Nile Virus contains a lyophilized recombinant canarypox vectored West Nile Virus vaccine plus a sterile liquid diluent. A canarypox vector has been modified using recombinant technology to express the desired antigens capable of stimulating a protective immune response to West Nile Virus. After inoculation, the vector does not multiply in the horse, but does express the protective proteins. As a consequence, these components induce an immune status against West Nile Virus.
Safety and immunogenicity of this vaccine have been demonstrated by vaccination and challenge tests in susceptible horses.
RECOMBITEK (WNV) is recommended for the vaccination of healthy horses as an aid in the prevention of viremia due to West Nile Virus infection.