Warnings on West Nile Virus

Written by Dr. Christina Vittoria

Dear readers: I know that I recently wrote an article about West Nile virus, but I need to write it again. We have had several neurological horses in our area in recent months. One of them has proved positive for the disease and several others have not been confirmed by the diagnosis. This disease, which was so prevalent in 2002, has gone unnoticed over the past decade.

This is usually the case when the majority of the population has been vaccinated against a disease. Whether it is measles in humans or West Nile in the horse, once there are fewer cases of the disease, people become lax in their belief that the vaccine is necessary. The disease is still hidden in the background and we are starting to see it develop again and again. Horses from the unvaccinated nave will attack the virus after being bitten by infected mosquitoes.

This year, many infected mosquitoes have been reported in Berks County and surrounding areas. Combine that with the ridiculously wet summer we've had and you get a perfect storm for the West Nile virus to kill unvaccinated horses. The floods have resulted in many areas of stagnant water and a breeding ground for mosquitoes.

No cases of human infection with West Nile virus have been confirmed in Berks County this year, but this disease has existed in Pennsylvania since 2000. It seemed to worsen in 2002 with the 39, infection of several horses each week. It was hard to see so many people crying when their horses had to fall asleep. Often, these horses were less than ten years old. Veterinarians are afraid to see this trend happen again. Many of our horses are vaccinated and this alone should help reduce the number of unfortunate horses infected.

Infected horses show signs of facial contractions, personality changes, nervous behavior, neurological symptoms, stumbling, paralysis and inability to stand up. The state of decubitus is the worst point of this disease. Horses that can not get up often end up being euthanized. The horse is a dead-end for this disease and they can not pass it on to other horses. The mosquito must bite an infected bird and then transmit it to the horse or to the man.

The West Nile virus vaccine has been deemed safe and is one of the main vaccines we use in horses. Horses should only be vaccinated with their first vaccine and recalled within three to four weeks. After that, once a year, the vaccination is enough.

Check your bird baths and any areas that water can accumulate on your property. You will have to remove any stagnant water so that the mosquitoes can not reproduce. You do not want to be known to be the first human case of West Nile in Berks County this year.

Christina Vittoria, MD, practices equine medicine, small ruminants and pets at the Willow Creek Veterinary Services. The comments provided here are for educational purposes only. Readers should consult their veterinarian before taking any action. Do you have a question for Dr. Vittoria? Send it to [email protected]. Please put ASK THE VET in the subject line.