Aug. 16, 2006: A 50-year-old man from Dryden, Ont., is believed to be the province's first human case of West Nile virus this year.
Aug. 16, 2006: The Saskatchewan Health Department confirms its first human case of West Nile virus this year. The infected person, detected by Canadian Blood Services through routine screening of donated blood, has no symptoms.
Aug. 15, 2006: Alberta health officials confirm the first two human cases of West Nile virus in the province this year.
Aug. 3, 2006: Five human cases of West Nile virus are confirmed in Manitoba. All of the infected people are men over the age of 40.
Aug. 3, 2006: P.E.I.'s chief health officer reports that the Culex mosquito, carrier of the West Nile virus, has had its numbers knocked down this year by regular rain. Frequent rain dilutes stagnant water with fresh water; without stagnant water, mosquitoes can't breed as easily.
Aug. 5, 2005: Canada's public health agency warns that a warmer and dryer summer than last year could mean increased cases of West Nile virus. So far there have been eight confirmed cases in Canada.
Aug. 4, 2005: Toronto's medical officer of health confirms that this year's first case of West Nile virus was diagnosed three weeks earlier than the first 2004 case. Officials say higher 2005 summer temperatures have spurred early mosquito breeding.
July 29, 2005: A blood donation made in Ottawa tests positive for West Nile virus. Canadian Blood Services notifies the donor and all related public health units.
Sept. 17, 2004: Health Canada reports there have been only four confirmed cases of West Nile virus in Canada in the summer of 2004. Three of the cases were in Ontario and one in Saskatchewan. There were also 15 probable cases that were never confirmed. No one died of West Nile virus in Canada in 2004.
Aug. 19, 2004: Saskatchewan reports its first human cases of West Nile virus for 2004. Officials say eight people show signs of infection, though only five caught the virus this year. The other three may have carried virus antibodies in their systems from last season, they say.
Aug. 10, 2004: Mosquitoes infected with West Nile virus after found near Vulcan, Alta., the first sign of the virus in the province in 2004.
Aug. 6, 2004: A Windsor-area woman is admitted to hospital after being diagnosed with the first probable case of West Nile virus in Ontario in 2004.
July 26, 2004: Manitoba health officials warn that mosquitoes infected with West Nile have been found near Winnipeg.
July 20, 2004: Protesters gather in the early morning to try to stop Winnipeg city trucks from leaving their compound to fog for mosquitoes. Police escort the trucks out shortly after 2 a.m., and crews start fogging four hours behind schedule.
July 19, 2004: Winnipeg Mayor Sam Katz orders fogging for mosquitoes to resume. Protesters objecting to the use of the pesticide malathion had blocked city trucks on July 17, forcing the suspension of fogging for the weekend.
An Ontario Superior Court judge dismisses the government's attempt to have a lawsuit against the province thrown out. About 40 families infected with West Nile in Ontario have sued the government, saying it didn't implement a plan to deal with the virus.
May 28, 2004: Canada's first case of West Nile virus in 2004 is confirmed when a blue jay tests positive for the disease.
Sept. 24, 2003: Health officials in Saskatchewan announce the deaths of three more people, two men from Moose Jaw and a woman from Swift Current, bringing the total number of deaths in the province attributed to West Nile to six.
Sept. 17, 2003: Officials in Regina announce that two deaths in the previous month were related to West Nile. One man died of a heart attack, but a fever from West Nile is listed as a contributing cause. The other died of West Nile neurological syndrome. Both were from the Regina area.
Sept. 14, 2003: A man from Portage la Prairie, Man., dies after catching West Nile disease. He had already been suffering from a chronic medical condition.
Sept. 9, 2003: Harley Ehmen, a man in his 80s from west central Saskatchewan, dies from a serious form of West Nile disease affecting the brain.
Sept. 5, 2003: A 92-year-old Ottawa man dies of pneumonia, with West Nile as a contributing factor. It is the second West Nile-related death in Ontario.
Sept. 4, 2003: A man in Windsor, Ont., dies of a stroke, with encephalitis caused by West Nile listed as a secondary cause. B.C. reports its first human case of West Nile.
Sept. 3, 2003: Canadian Blood Services orders a recall of all blood products donated in Saskatchewan in August because of an "epidemic" of West Nile.
Aug. 12, 2003: Alberta confirms its first human case of West Nile virus in a woman in her 20s showing no symptoms of the disease. The virus was found when she donated blood.
Aug. 9, 2003: Health officials announce that an elderly Ottawa man has tested positive for the virus.
July 25, 2003: Saskatchewan reports that a person from Assiniboia, southwest of Regina, has tested positive for West Nile virus after donating blood. It is the first case of a person contracting West Nile in Canada this summer.
July 24, 2003: Ontario health officials announce that someone in Renfrew County, Ont., tested positive for West Nile, but likely contracted the disease in the United States.
July 10, 2003: A magpie found near Camrose, Alta., has tested positive for the virus, provincial health officials announce. It is the first time the virus is found in Alberta.
July 1, 2003: Canadian Blood Services begins to screen blood donations nationwide for West Nile virus.
May 22, 2003: A crow found dead near the Ottawa City Hall had the West Nile virus, health officials say.
December 2002: Canadian Blood Services pulls a series of products made from blood donated in Ontario between June and October 2002 because several people in the province had contracted West Nile.
Sept. 13, 2002: The Ontario Health Ministry reports that two men, 60 and 70, from Peel Region, west of Toronto, have tested positive for West Nile.
Sept. 12, 2002: American health officials say four people who received organ transplants got West Nile from the organs, the first time the virus has been shown to spread in this way.
Sept. 7, 2002: A man from Burlington, Ont., becomes the first person in Canada known to have contracted West Nile virus.
Aug. 16, 2002: The Ministry of Health in Quebec confirms that mosquitoes infected with West Nile have been found in the province.
July 12, 2002: Manitoba health officials say they have found West Nile in a dead crow. It marks the first time the virus has been found in Canada west of Ontario.
Aug. 22, 2001: Ontario health officials confirm that a crow found dead in Windsor, Ont., two weeks before had West Nile virus. By the end of the summer, 128 birds would test positive for the disease in Ontario.
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- West Nile Virus Surveillance Program
- West Nile Virus, Public Health Agency of Canada
- World Health Organization
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Quick Facts
According to the U.S. Centers for Disease Control:
Family: Flaviviridae
Genus: Flavivirus Japanese Encephalitis Antigenic Complex
Complex includes: Alfuy, Cacipacore, Japanese encephalitis, Koutango, Kunjin, Murray Valley encephalitis, St. Louis encephalitis, Rocio, Stratford, Usutu, West Nile, and Yaounde viruses.
Flaviviruses: share a common size (40-60nm), symmetry (enveloped, icosahedral nucleocapsid), nucleic acid (positive–sense, single stranded RNA approximately 10,000-11,000 bases), and appearance in the electron microscope.