New West Nile virus counts for Ontario show the province has already had the worst year for the illness since 2002.
The weekly report from Public Health Ontario says the province's case count jumped another 36 per cent last week, to 158 confirmed and probable cases as of Sept. 8.
Ontario has seen a higher case count just once in 2002 – during which time 394 human cases were reported – the first year the virus was reported in Canada.
About 1/3 of this year's Ontario cases have occurred in Toronto.
Four other provinces have reported West Nile cases this year — Alberta, Saskatchewan, Manitoba and Quebec; with five, two, 29 and 20 cases, respectively.
But so far this year, there have been no reported deaths.
That isn't the case south of the border, where the U.S. is on track to have its worst West Nile year ever.
Officials of the U.S. Centers for Disease Control announced Wednesday that 1,405 serious illnesses and 118 deaths have been reported this season.
The bulk are in Texas – but Louisiana, Mississippi, Oklahoma, South Dakota and Michigan have also seen substantial numbers.