Health officials in the province's southwest attributed the death of a 71-year-old man in Windsor-Essex County to the virus Thursday.
Public Health Ontario says there have been 220 confirmed and probable cases of West Nile in the province as of Sept. 25.
That includes a 74-year-old Toronto man whose death two weeks ago has been attributed to the virus.
The only year Ontario had more cases was in 2002 — the first year West Nile virus cases were reported in Canada; that year there were 394 human cases.
The acting medical director of communicable diseases at the provincial health agency says two deaths linked to the virus isn't unexpected given the large number of cases.
Dr. Colin Lee says people should still take steps to protect themselves from mosquitoes until at least mid-October.
"Two is fortunately a small number," Lee said, noting that one in five people who get infected develop symptoms.
Of that number only one in 150 people will have their infection turn into a serious illness, he said.
Lee said the man who died in southwestern Ontario after contracting the virus was likely infected earlier this month or in late August, since it takes about two weeks for symptoms to appear.
He said the onset of cooler temperatures is reducing the number of mosquitoes that carry the virus.
"Given that the weather has turned and we are getting colder nights and colder days, certainly the number of infected mosquitoes are decreasing rapidly."
Until the risk is gone, Lee said people should cover up exposed skin and wear anti-insect repellent while outdoors, and avoid going out at dusk or dawn — the busiest time for mosquito activity.
U.S. health officials have reported more than 3,500 West Nile cases involving people and 147 deaths this season.
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