Following confirmation of three new human cases of West Nile virus (WNv) infection, Alberta Health Services (AHS) is again urging Albertans to take precautions to prevent mosquito bites.
Four human cases of WNv infection have been reported in Alberta so far this season, including the province’s first case which was announced Aug. 21.
West Nile virus is a mosquito-borne virus that can cause West Nile Non-Neurological Syndrome (formerly known as West Nile fever). Occasionally it can cause the more serious West Nile Neurological Syndrome.
With increasing numbers of cases, AHS will be releasing updated human West Nile virus case numbers for Alberta on a weekly basis.
A woman in the Calgary zone was diagnosed with the non-neurological syndrome, and officials say the case is travel-related. The infection was likely acquired in eastern Canada. Another woman in the AHS’s Central zone was diagnosed with neurological syndrome, and another non-neurological case, again travel-related, was diagnosed in the northern part of the province.
“By releasing case information, we hope to remind Albertans that West Nile virus is indeed around and that we should all be taking the precautions we always recommend,” says Dr. Gerry Predy, AHS senior medical officer of health. “Our advice to all Albertans remains consistent: wear insect repellent with DEET; wear long-sleeved, light-coloured shirts and pants; wear a hat and consider staying indoors at dawn and dusk when mosquitoes are most active.”
West Nile virus was first isolated in 1937 in the West Nile district of Uganda.
Since then, there have been outbreaks in Egypt, Israel, South Africa and in parts of Europe, Asia and North America.
Officials say there are 44 species of mosquitoes in Alberta and that of these, the Culex tarsalis has been identified as the species most likely to carry and transmit the virus from infected birds to people and horses. The breeding season of the Culex tarsalis runs from mid-June to September. The risk of contracting West Nile virus increases during this period and peaks during August.
Some people who become infected with non-neurological syndrome show no symptoms at all. However, symptoms that could occur can include fever, chills, nausea, vomiting, fatigue, skin rash, swollen glands and headache.
For the small number of individuals who do develop the neurological syndrome, infection can lead to tremors, drowsiness, confusion, swallowing problems, high fever, unconsciousness, paralysis and even death.
For more information, visit www.fightthebite.info or call Health Link Alberta toll-free at 1-866-408-5465 (LINK).