Now that West Nile virus is confirmed in South Valley,
veterinarians are reminding horse owners to protect their animals
from the disease.
Now that West Nile virus is confirmed in South Valley, veterinarians are reminding horse owners to protect their animals from the disease.
Horses can be infected with West Nile virus after receiving a bite from a mosquito that has recently bitten a bird carrying the virus. Humans also can be susceptible to the virus, but horses are the only animals for which a vaccine against the virus exists. The equine vaccine is 95 percent effective.
“We’ve been kind of waiting for (West Nile),” said Bill Seals of Tri-County Veterinary Hospital in Gilroy. “Fortunately, I would say our clients and all other vets in the area have been regularly vaccinating or recommending vaccination for the last two years.
“Those people are prepared, but there are going to be a number of people around with … ‘backyard’ horses and somebody’s going to have a problem. There’s no question it’s going to happen.”
Some clients still are thinking news about West Nile virus is a scare tactic, but Seals says it’s for real. A bird was confirmed to have died in San Jose from West Nile on Wednesday, although no horses in the county have been infected.
The UC Davis Center for Equine Health has set forth some parameters for vaccinating horses now that the virus is in the area, which Seals says he and other local vets are following closely. There are two fully approved West Nile virus vaccines available for horses, both requiring two injections, followed by periodic boosters.
“The horses that have not at this point been vaccinated, it’s important that they do get vaccinated,” Seals said.
UC Davis is recommending that those animals receive a certain brand of the vaccine that provides immunity more quickly. Horses already receiving injections should be re-vaccinated every four months, although the vaccine says it’s good for a year, Seals said.
Douglas Novick, a Santa Clara County veterinarian who treats horses, also is urging all his clients to re-vaccinate before the first horse case is found in the county.
Once the first horse case is found in the area, owners need to give each horse that had not been vaccinated with in eight weeks a booster.
Each West Nile virus vaccine is $30.
To help prevent the spread of mosquitos, Novick encourages all horse owners to regularly empty water troughs where mosquito can breed.
Without the vaccine, horses that come down with West Nile disease have a 30 percent mortality rate, versus a 5.8 percent mortality rate with the vaccine. So far, the virus has been found in 26 horses, all in Southern California.
Once infected, one horse cannot spread the disease to another horse. Both humans and horses are considered dead-ends for the disease because they cannot reproduce enough of the virus to have a mosquito bite them and then spread the virus to another animal or person.
When mosquitos bite birds, the natural host for the disease, they can spread the virus to other birds and animals.
Birds kept for education purposes at the Wildlife Education and Rehabilitation Center in Morgan Hill receive the equestrian vaccination, as well, although Sue Howell, the center’s executive director, says it breaks her heart that all animals cannot be protected.
“We cannot afford to vaccinate all animals, it just really is kind of tearing us apart,” Howell said. “But when you have limited funds, you have to budget appropriately.
“We’ve heard the heartbreaking stories from different people at rehabilitation centers in other states of whole species getting wiped out; I don’t think people in California realize the scope of the affect it’s had on wildlife, especially the bird population.”
Howell said, she expects the center will be inundated with calls, but people will be referred to Vector Control’s West Nile virus hotline.
If an animal is caught in the first stages of the virus, there is a chance it can be saved, but it most often proves fatal, she said.
West Nile virus, although it originates in birds, is a mosquito-borne virus. Residents should eliminate any standing water around their homes to prevent the development of mosquitos and the spread of the virus.
The first human West Nile fatality this year was confirmed Thursday in Orange County.
Staff Writer Cheeto Barrera contributed to this report.
