Health officials estimate 10,000 Manitobans may have been infected with the West Nile virus this summer, although only one-fifth may have actually become sick.

In total, 542 cases of West Nile virus have been reported to health officials in the province.

Of those, 283 have been classified as asymptomatic ornon-neurological syndrome, while 214 cases are still under investigation.

Forty-fivehave been diagnosed with neurological syndrome, whichcan cause paralysis, coma or —in rare cases —death.

Based on those numbers, the province's chief medical officer of health, Dr. Joel Kettner, says he can make further estimates about the number of unreported cases of West Nile this year.

"It's probably a reasonable estimate that 10,000 Manitobans were infected with West Nile virus this summer," Kettner said Tuesday.

Most people who are infected with West Nile do not experience symptoms and probably did not know they were infected. Kettner estimates about 2,000 people actually felt sick.

Three deaths in Manitoba this year have been associated with the mosquito-borne virus, all in men over the age of 60, coming from the Assiniboine, Central and Interlake health regions.

A fourth individual who tested positive for the virus also died, but an investigation concluded the virus did not play a role in the death, health officials said.

The regions reporting the largest number of both mild and serious forms of the disease were in southwestern Manitoba, including Brandon, and an area southwest of Winnipeg.

Mosquito counts were high in those areas, too, Kettner noted.

Infected peoplenow likely immune: Kettner

Manitobans who were infected and either experienced no illness or recovered do have one small blessing, Kettner said: they are probably immunized from further West Nile infection.

"In a way, the best thing that could happen or could have happened to a Manitoban this past summer is to have been infected with either the asymptomatic type or the mild form," Kettner said.

"They're fine now, and they have antibodies; hopefully, that will protect them for the rest of their lives."

That's small consolation for Mike Reimer, one of the 45 unlucky Manitobans who came down with the neurological form of the infection.

Reimer, an athletic 15-year-old, was diagnosed in July. He is still in hospital.

"Basically, they say I'm going to walk, so I'm looking forward to that," he told CBC News. "It sucks being in a wheelchair."