Saskatchewan has had what is believed to be the first death related to West Nile virus in the province this summer.

Chief medical health officer Dr. Ross Findlater says the person was in their 80s and lived in the Sun Country Health Region. The person tested positive for West Nile virus but officials don't have enough information to say whether the illness was the direct cause of death.

There are now 339 confirmed or suspected human cases of West Nile virus in Saskatchewan. That's up dramatically from only 20 confirmed or suspected cases throughout all of last year.

Earlier this week, Manitoba announced that it had confirmed 213 cases. Two West Nile virus-related deaths were also reported in Manitoba. In one, West Nile was the likely cause of death; in the other, it is the suspected cause.

Of the new Manitoba cases, 18 were identified by Canadian Blood Services routine screening. The donated blood units were discarded.

Alberta has had more than 90 West Nile cases as of Aug. 18, with more than half reported the week before. And Ontario health officials confirmed two cases of West Nile, the province's first cases this year.

This year's numbers are a significant jump from 2006, when there were only 127 cases across the whole country.

The Prairies have seen ideal weather conditions this year for Culex tarsalis mosquitoes, the type that carries West Nile virus. Weather conditions have been hot and humid, providing the mosquitoes with lots of places to breed.

Many of the cases being identified now were likely contracted weeks ago. Peak exposure to west Nile is late-July to mid-August and the infection can take up to three weeks to surface.

Most people who contract West Nile -- about 80 per cent -- have no symptoms. Those who do fall ill develop flu-like symptoms such as fever, headache, fatigue and body aches. Children, the elderly and people with weakened immune systems are at greater risk of developing symptoms.

In rare cases, it can cause a serious neurological disorder that can lead to death. The number of severe cases usually ranges from one to 35 cases per summer.

It is too early to predict the number of severe cases that will be reported this year.