OSOYOOS TIMES-September 16, 2009

By Paul Everest – Osoyoos Times

An Osoyoos-area horse is one of the first horses in the province to test positive for West Nile virus.
And a second local horse may also be infected.
Tara Sackett, who operates Osoyoos’s South Valley Veterinary Hospital with her husband, Dr. Henry Kleinhofmeyer, said blood work from a female horse, whose owner lives in a rural area between Osoyoos and Oliver, came back positive for the virus on Sept. 10.
Blood work from a second mare, from a different owner who lives in the same area, was expected from a U.S. laboratory early this week and it’s likely that test will also be positive, Sackett said.
The horse that has tested positive had mild symptoms of the virus and has nearly recovered, she said, while the second horse’s symptoms were more severe.
Both animals are expected to survive.
Sackett said her clinic alerted Interior Health, the Canadian Food Inspection Agency, the British Columbia Veterinary Medical Association (BCVMA) and local doctors about the positive test.
The horses are younger animals, she added, and the owner of the horse that has tested positive for the virus called the hospital on Aug. 27.
The owner said the horse was experiencing symptoms such as tremors, Sackett said.
The second horse’s owner contacted the hospital on Sept. 4.
Sackett said blood work from the animals was sent to a laboratory in Iowa.
The owners of the horses were given pain medication to administer to the animals.
They were also told to keep the horses separate from other horses and not to travel with them.
Although horses infected with the virus are not contagious, blood from an infected horse could be transmitted to another horse by a mosquito and it’s best to keep infected animals away from non-infected horses to minimize the risk of transmission, Sackett said.
The virus was found for the first time in B.C. last month in mosquito pools in the South Okanagan.
So far, two humans, both from the same household in Kelowna, have tested positive for the virus.
Dr. John Twidale, chair of the BCVMA’s Equine Committee, said the Osoyoos case, along with a horse in Langley that tested positive for the virus on Sept. 10, are the first ever incidents of the virus in horses in British Columbia.
According to a media release issued by the province, “none of these animals have travelled outside the province.”
British Columbia has been a “holdout” area for the virus, Twidale said, adding that since cases have popped up in Alberta and Washington state, the virus has been expected here for at least three years.
Twidale said symptoms of the virus in horses include sleepiness, depression, staggering and muscle twitching.
Advanced symptoms can include neurological problems, blindness and encephalitis.
Twidale recommends that horse owners throughout the province vaccinate their horses.
He added that by the time signs of the virus are seen, it’s too late to vaccinate.
The vaccine costs between $30 and $40, Twidale said, and there is no shortage of the vaccine in Canada.
“Horses that have never been vaccinated against West Nile should receive two doses of vaccine two to four weeks apart, and horses that have been previously vaccinated should receive a single booster dose each year,” Twidale said in a statement on the BCVMA’s website. “There is also a new vaccine which only requires a single dose for protection, given annually.”
Since the virus has only recently arrived in B.C., Twidale said there are a number of horses that have not been vaccinated and that could make the first year of West Nile’s appearance in the province the worst.
The virus “always starts up” in the late summer and fall, goes dormant in the winter when mosquitoes die or hibernate, and reactivates in the spring, he said.
Twidale added that the virus cannot be transmitted from horse to human.
Dr. John Brocklebank, the BCVMA’s deputy registrar, said horse owners in B.C. need to start talking to their local veterinarians about the West Nile virus vaccination and about the risks of moving horses on and off of their properties.
He said signs of the virus will appear within five to 15 days after infection and horse owners should keep an eye out for early symptoms including loss of appetite, fatigue and fever.
The BCVMA is encouraging its members to report cases and suspected cases of the virus so that the association can get the word out to veterinarians throughout the province.
Notices will be put up on the BCVMA’s website about cases and suspected cases of the virus.
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