Major rainfall brings West Nile virus warning to Alberta
Heavy June rains triggered mosquito season early and brought a species usually rare in the province.
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Alberta's recent heavy rainfall has kicked off mosquito season in the province, heightening the risk of West Nile virus infection.
Primary Care Alberta issued guidance Tuesday recommending residents cover as much skin as possible when outdoors using long-sleeved shirts, hats, and light colours. The province recommends Health Canada-approved insect repellents containing DEET or Icaridin.
DEET should not be used on babies under six months old, only once daily for children between six months and two years old, and up to three times daily for children over two years of age.
Edmonton received more than 200 millimetres of rain in June, which created conditions for culex pipiens — a mosquito type not commonly seen in Alberta. This species is associated with West Nile virus and was implicated in the deaths of two grey owls at the Calgary Zoo in 2025.
Most people bitten by a mosquito carrying the virus won't develop symptoms. About one in five develops West Nile non-neurological syndrome, with symptoms including fever, chills, nausea, vomiting, fatigue, skin rash, swollen glands, and headache. Symptoms can appear up to 14 days after a bite. A more serious West Nile neurological syndrome can also occur.
Albertans can learn more at www.fightthebite.info or by calling Health Link at 811.
