Interior Health is reporting that two dead ravens, found in Kimberley, and submitted as part of routine surveillance, have tested positive for West Nile virus. The provincial Animal Health Centre lab confirmed the findings this week.
This is the first evidence of the virus in the province this year.
Interior Health says there have been no human cases reported, no positive mosquito pools identified, and no positives identified by Canadian Blood Services through their screening program.
The risk of infection from handling birds is very low, IH says; however, you should not use your bare hands to handle wild birds (dead or alive). If you need to move a dead bird precautions should be taken. Unusual clusters of dead birds can be reported to the BC Interagency Wild Bird Mortality Investigation at 1-866-431-BIRD (2473).
What is West Nile Virus?
West Nile virus is a disease usually spread between birds by mosquitoes. Some mosquitoes in Canada can spread West Nile virus to humans through mosquito bites.
Mosquitoes can also transmit West Nile virus to horses and occasionally to other animals. Horse owners are advised to contact their veterinarians for information about equine vaccines for West Nile virus.
The risk of getting West Nile virus is highest in the warmer months of the summer, usually from the end of July through August. The risk of becoming seriously ill is low for most people; however, people over the age of 50 and those with compromised immune systems are more at risk.
How can I protect myself?
There are things everyone can do to reduce the risk of West Nile virus infection. Any activity that prevents mosquitoes from biting or breeding can help to reduce the risk.
Prevent mosquito breeding around your home. Anything that can hold water can be a mosquito breeding area. Identify and remove potential breeding areas on your property – empty saucers under flowerpots; change water in bird baths twice a week; unclog rain gutters; drain tarps, tires, and other debris where rain water may collect; and install a pump in ornamental ponds or stock them with fish. Stagnant backyard pools can be a big source of mosquitoes and should be maintained regularly to prevent mosquito growth.
Install screens on windows. Screens will help prevent mosquitoes from coming indoors.
Avoid outdoor activities at dusk and dawn. This is the time of day mosquitoes that can carry the virus are most active.
Wear protective clothing. If you are in an area with many mosquitoes, wear loose fitting, light coloured clothing, full-length pants, and a long-sleeved shirt.
Use mosquito repellent. Apply mosquito repellent to areas of exposed skin. Check the product label for instructions on proper use. Repellents containing DEET are safe for those over six months of age when used according to the directions on the label. DEET-free products (such as those containing icardin, p-menthane-3, 8-diol /lemon-eucalyptus oil, or soybean oil) are also available, but may not provide as long-lasting protection.
2016 was the first year positive WNV indicators were detected in the Kootenays (specifically the south Kootenays), with nine equine WNV cases and two WNV infected crows. The other 2016 equine case occurred in the Fraser Valley. A Kootenays equine case and the Fraser Valley case had arrived from Alberta and the US, respectively so WNV infection of these horses outside of BC cannot be ruled out. Prior to 2016, all positive results in all species had been located in the Okanagan, with the exception of one horse located in the Fraser Valley. Although variable across the province and from year to year, typically June to September is the risk period for WNV infection. Positive indicators have been detected in B.C. in the months of August and September.
Detection of WNV in crows and other corvids (ravens, crows, magpies, jays), which are very sensitive to the infection, is often used as an early warning of its presence in mosquitoes.
Horses with WNV can exhibit a range of signs such as stumbling, confusion, listlessness, head pressing, lack of appetite, inability to stand, seizures and weakness. In severe cases (about 30%), horses that develop clinical signs will die or be euthanized. Although there is no specific treatment for the diseases, there are vaccines to prevent WNV in horses. Horse owners should consult with their veterinarian about WNV vaccination including timing of vaccination, routinely drain standing water around homes and barns to reduce mosquito breeding sites, and use insecticides according to the label when needed.
WNV is a B.C. provincially notifiable disease. The Public Health Veterinarian at the Animal Health Centre, on behalf of the province’s Chief Veterinarian, collects information on horses with WNV and shares this information with the BCCDC. As a federal immediately notifiable disease, laboratories suspecting or diagnosing a horse with WNV are required to contact the Canadian Food Inspection Agency (CFIA).