For the first time in BC, two horses have confirmed cases of the mosquito spreading West Nile virus.
According to the College of Veterinarians of British Columbia two horses in the Cache Creek area have shown clinical signs of the West Nile virus infection.
“Blood tests on both horses show high levels of antibody against the virus indicating active infection.”
Despite the quick spread across most of Canada has been fortunate in the past few years as it has not seen West Nile cases, even though the virus has been active in all the Western Provinces and States.
“Clinical signs of West Nile virus in horses include muscle tremors of the face, chest and body; weakness in the hind legs; fever; depression; and in severe cases, inability to stand,” explains the CVBC. “These symptoms are because the virus attacks the brain and spinal cord nerves.”
Horses who are vaccinated against West Nile are typically safe but sometimes horse owners do not vaccinate due to the costs, unfortunately once the horse is infected it is too late to vaccinate.
The CVBC says that treatment of affected horses can only be supportive as antibiotics are not effective against viral infections.
They note that most horse owners are well aware of the dangerous consequences of West Nile infection and vaccinate annually, but many have decided to take a chance and miss annual booster shots
“Veterinarians strongly recommend that all horses receive an annual booster vaccine to ensure a high level of immunity. Even if the horse has missed a year or two, a booster shot will restore immunity within a few days,” urges the CVBC.
As mosquitoes carry the virus they add that in addition to vaccination, horse owners should take precautions to reduce the mosquito populations around the barn and pasture areas, avoid having horses out when mosquitos are active, and use fly sheets and face masks when horses are turned out.
West Nile is a serious disease and there is no certainty that the horse will survive the acute infection. Horses that do survive may be left with long-term muscle weakness and be unsound for use.