Ridgefield Animal Hopsital

919 Percy Brown Road
Thibodaux, LA 70301



 Remember - not all encephalitis vaccines are complete.   Always vaccinate your horse with a vaccine that includes Eastern Equine Encephalitis ( EEE ) and West Nile Virus.  Vaccinating for West Nile only will leave your horse exposed to EEE, which actually kills more horses every year: 

West Nile Virus (WNV) causes encephalitis in birds, horses and humans.  The virus is transmitted from infected birds by mosquitoes.  Humans and horses appear to be especially susceptible.  Studies done by the U.S. Department of Agriculture show that infected horses will not transmit WNV to other horses or to people.  This means an infected horse is not a hazard to other horses or people, but that the disease is present in the bird populations in the area and therefore the people and horses in that area are at risk.  

Symptoms of disease caused by WNV may include the following:

    * Flu-like signs (fever and depression)
    * Skin twitching, especially around the muzzle.
    * Hypersensitivity to touch and sound
    * Driving or pushing forward without control, "head pressing"
    * Incoordination

Because permanent neurological problems and death can occur, early recognition and initiation of treatment is important.  No specific treatment protocol exists however most cases will resolve with supportive therapy and anti-inflammatory medications. Hospitalization at a referral institution is often required and can cost upwards of $2000 per week depending on the horse's needs. 

Efforts to prevent disease in horses caused by WNV is through the use of the West Nile Vaccine and through actions that will reduce exposure to mosquitoes.  The vaccine is safe and appears to be effective. AAEP vaccination guidelines recommend vaccinating twice a year in Louisiana and the Gulf Coast.  It is very important to realize that the other encephalitis strains, especially Eastern Equine Encephalitis, need to be vaccinated for as well since the fatality rate for EEE is actually much higher than West Nile.  Combination products are available and suggested to make it easy to cover your horse for both of these serious and potentially deadly diseases.  These should be used every 6 months as opposed to the common "annual" label usage, as our mosquito season and exposure to migratory birds exposes us to the virus for a longer period than other parts of the country.

Limiting mosquito exposure does not replace vaccinating, but can be helpful to your horse and, more importantly, to you!  The most effective way to limit the mosquito population is to destroy the mosquito larval habitat.  This is done by reducing the amount of standing water.  Water troughs should be cleaned at least once a week.  Keeping weeds trimmed and lawn mowed help eliminate areas where mosquitoes rest.  Directly protecting horses and people from mosquito bites is more difficult.  Fly and mosquito repellents may be helpful.  Products containing pyrethrins are considered safe for horses.  Spray stalls, aisle walls and other areas such as under shade trees where horses congregate.  Fans can also be used to discourage mosquitoes from residing in your barn as they cannot fly against even moderate wind currents.  Fly systems can be purchased to release pyrethrins at timed intervals in your barn and on your premisis, which can help with both flies and mosquitos.