Though the Centers for Disease Control reported last week that more than 40 people have died across the country this year from West Nile virus, many horse owners can breath a little easier—the equine vaccines available are effective, according to veterinarians.
"All of my clients have been vaccinated for years now," Dr. Larry Kelly . "(Horse owners) are crazy if they don't."
According to the American Association of Equine Practitioners, about one-third of horses who exhibit clinical signs of WNV infection, which is transmitted by mosquitos, will die or be euthanized. Of the horses who survive, about 40 percent will still exhibit residual effects—such as gait and behavioral abnormalities—six months after they were diagnosed.
"(WNV) is a neurologic problem, and it's most difficult … to turn a horse around from the disease," Kelly said.
Symptoms of WNV in horses include fever, weakness, wobbles, seizures, falling down or even behavioral or mood changes, Kelly said.
The vaccines, which have been around for about a decade, require a two-shot series when first administered, then an an annual booster shot, according to veterinarian Dr. Ruth Sobeck.
Because it takes about six weeks for a horse to develop full immunity after being vaccinated, Kelly recommended horse owners vaccinate early.
"It doesn't do the horse any service (for the owner) to read in the newspaper that West Nile is here and then get (their horse) vaccinated," said Kelly. Horse owners should "think well ahead of what they want to do (and) … have these horses super-vaccinated by the time the disease is rolling through."
In California this year, nine horses were positively diagnosed as infected with WNV, according to the California Department of Food and Agriculture. Two of the horses—including an unvaccinated yearling colt in Galt—were euthanized. One other case has been found in a horse in Sacramento County this year, and three humans have been found to be infected, according to the Sacramento-Yolo Mosquito and Vector Control District. All the horses infected have been in the Central Valley, where West Nile Virus cases has been particularly abundant this year.
, after it found infected mosquitoes. This is in a different area from a fogging in the two cities at the beginning of August.