Ten human cases of West Nile virus infection were reported in Alberta this year, including one West Nile virus-related death in the south zone of Alberta Health Services (AHS).
“Sadly, as we’ve seen in Alberta this year, West Nile virus infection can cause severe illness and even death,” said Dr. Gerry Predy, senior medical officer of health.
Of the 10 human cases of West Nile virus (WNv) infection reported in Alberta this season, seven cases were reported in south zone, including the single WNv-related death. The Calgary, central and north zones of AHS each reported one case. To protect patient confidentiality, AHS will not be releasing any additional case-specific information about any of Alberta’s human West Nile virus infections other than what is provided below.
As of Sept. 29th, the Public Health Agency of Canada had reported 386 clinical cases of WNv infection in Canada; 102 cases of WNv infection were reported in Canada in 2011.
After being bitten by a mosquito carrying West Nile virus, humans can develop West Nile Non-Neurological Syndrome (formerly known as West Nile fever) and, occasionally, the more serious West Nile Neurological Syndrome.
Individuals who develop non-neurological syndrome may experience fever, chills, nausea, vomiting, fatigue, skin rash, swollen glands and headache. The small number of individuals who do develop neurological syndrome may experience tremors, drowsiness, confusion, swallowing problems, high fever, unconsciousness, paralysis and even death.
Although precautions that reduce risk of mosquito-borne illness, including West Nile virus, are not necessary during the winter months in Alberta, these illnesses can still be a risk in warmer climates, long after Alberta’s typical season ends.
“By providing this reminder at the end of Alberta’s season, I hope all Albertans are encouraged to take the precautions that can prevent illness, not only here in Alberta every summer, but also year-round when travelling,” said Dr. Predy.
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.
For more information on West Nile virus, including the important preventative precautions, Albertans can visit www.fightthebite.info or call Health Link Alberta, 24 hours a day, seven days a week, toll-free at 1-866-408-5465 (LINK).