Second horse being tested for West Nile virus

A second dead horse in Rainy River District is being tested for the West Nile virus, Dr. Chris Cannon of the Nor-West Animal Clinic here confirmed Tuesday night.
“We got the results back [Tuesday] and it’s not rabies, so we’ll have to test for the West Nile virus now,” he noted.
The testing comes on the heels of a horse near Rainy River that was confirmed positive with the West Nile virus last month.
While the only other reported positive case of an infected horse in the area so far this year was in Littlefork, Mn. in August, Dr. Cannon said he’s been busy administering vaccines against the virus, which can be transmitted to horses and other animals by mosquitoes after they’ve extracted blood from infected birds like jays and crows.
“I’ve given 50 doses so far,” he said, adding that would mean about 25 horses have received it since July.
The shots are administered two-four weeks apart, and none of the horses have had adverse reactions to the vaccine.
But Dr. Cannon said vaccinations are expected to pick up again in the spring since horses given shots now face little threat from mosquitoes this late in the year.
“The thing is with vaccinating now, I would still recommend boosters in the spring. I expect vaccinations to start in April,” he remarked.
The shots should immunize the horses for about eight months.
And looking down the road, Dr. Cannon doesn’t expect the West Nile virus to go away anytime soon.
“The way the mosquito-borne encephalitis virus tends to go, a new strain shows up in the population and there’s a high incidence of mortality. It’s a cycle,” he remarked.
“And then it will decline for a number of years and show itself again.”
But as the mosquito season winds down, it appears that incidences of infection have remained low among horses overall in the region this year.
“I hear there’s been a few horses that have been tested for it. Not because it was suspected the horses died of the virus, but because the owners were being cautious,” noted Dr. Sue Legge of Kakabeka Equine Services in Kakabeka Falls.
Dr. Legge also said she’s given “quite a few” West Nile virus vaccinations to horses in the Thunder Bay area since news of the virus cropped up in the media.
Dr. Legge, who has done extensive research on the disease, said the cases of the virus showing up in humans or horses are rare because the disease is meant to be transmitted between birds and mosquitoes—anything else is a “missed target.”
“Some horses can be bitten by an infected mosquito and nothing happens. Others can show a visible reaction, and others may die from the virus,” she remarked.
These signs include a slow paralysis which sees the horse reluctant to move or walking stiffly to an eventual immobility.
But despite not seeing the disease take hold in horses in the region yet, Dr. Legge still is concerned about what will happen in years to come.
“There’s been a lot of incidents of the virus, not necessarily with horses, around us. It’s certainly been virulent,” she said. “I’ve never seen a disease spread like this, being reported in so many States.
“When people call me about it, I would never say, ‘Don’t be concerned.’ They should be aware of the virus,” she added.
Al Mathers, environmental health officer with the Northwestern Health Unit in Kenora, said given two dead crows—one in Kenora and the second most recently in Dryden—have tested positive for the West Nile virus, cases of infected horses could well follow.
“It wouldn’t be a great surprise to hear if it did,” he said. “Mosquitoes feed on animals, including humans.
“And there’s been cases of the virus reported here [in birds], and in Minnesota and Manitoba,” he added, noting the health unit doesn’t deal with horses and so it’s possible it might not hear about the virus striking horses.
Mathers also noted it’s highly unlikely to see the mosquito season carry on this year, and that the risk of further transmission of the virus is “slim.”
“If there are any adult mosquitoes out there with the virus right now, they would be looking for overwintering, not feeding,” he remarked.