April 30, 2003

 

West Nile Virus is Here to Stay and Vaccinating Your Horses is Crucial

"From observations made in areas that have been affected by West Nile virus, it looks pretty certain that West Nile is going to be endemic to North Dakota. To horse owners, this means that vaccinating against it will have to become part of our usual vaccination protocols, much like vaccinating against Eastern and Western encephalitis," states Charlie Stoltenow, an NDSU Extension Service veterinarian. "This vaccine is a killed vaccine, which means that two doses are required for it to be effective."

"According to anecdotal evidence, very, very few horses vaccinated twice have contracted the disease and died," says Stoltenow. "We have lost horses to the virus that had one dose, but there is a good chance that these horses may have already been incubating the disease. So I definitely recommend two doses. For horses that were vaccinated last year I recommend that they get a booster this year."

"Most cases of West Nile that we see are in August, September, or October," Stoltenow says. "We want these animals in good immune status by then. The first dose or booster dose should be given now, at the beginning of the mosquito season. The second dose should be given three weeks later. An additional two weeks are needed for the animal’s immune system to be fully protective. So from start to finish, it takes about five weeks for your horse to be fully protected."

The current West Nile virus vaccine is only available through a veterinarian. It won't be available at livestock supply stores like other vaccines, Stoltenow says. "Pharmaceutical companies are looking at developing vaccines that address all horse-related vaccines in one."

Due to the fact that the disease is caused by a virus, some resistance will be passed on from mares to foals in the colostrum. "I wouldn't rely on that immunity to protect our horses," Stoltenow says. "Whether you look at the issue from a risk management or cost analysis angle, the fact is that vaccinating is the way to go. These horses have significant sentimental and economic value to their owners."

"It's important to remember that West Nile virus is here to stay. People should also take preventive steps to ensure their safety," Stoltenow adds. "Once mosquito season begins, repellant, long sleeves, hats and common sense will go a long way in helping to protect all of us."

###

Source: Charles Stoltenow, (701) 231-7522, charles.stoltenow@ndsu.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu 

Click here to download an Audio clip to accompany this story. ( 563 Kb wav file )
Click here to download an Audio clip to accompany this story. ( 722 Kb wav file )