Mosquito counts rising in Regina; take precautions for West Nile

Gardeners, joggers and ball players have known this for a while and now City of Regina statistics back them up mosquito numbers are on the rise.

That means Saskatchewan residents should take precautions against mosquitoes that may carry West Nile virus.

The city monitors mosquito traps in six zones and uses those counts to assess the how numbers compare to average years.

The type of mosquitoes that carry the West Nile virus are Culextarsalis mosquitoes. Monitoring the numbers of those mosquitoes is part of this process.

"We trap the mosquitoes, count the mosquitoes, count the numbers of mosquitos infected (with West Nile virus), and then we also look at the heat days, and other factors," said Dr. Denise Werker, deputy chief medical health officer for Saskatchewan.

Earlier this spring, mosquito counts were below the historical average, but that changed in June.

Counts for the week endingJune 17 averaged 59 mosquitoes per trap, which is about three times the historical average.

Although the number of mosquitoes isunusually high for this time of year, Phil Curry, the West Nile coordinator for the Ministry of Health, says these mosquitoes are mostly nuisance mosquitoes.

"We have detected Culex tarsalis in low numbers in the southern portions of the province," said Curry.

"The nuisance mosquitoes that are out that have been bothering people over the last few weeks, the goods news is, theyare on the decline, and should, barring any large rain events, we should start to see lower numbers of them."

However, with July coming up, Curry said that this is the time of year where we start to seethe mosquitoes carrying the virus.It all is dependent on the weather.

"Even though we're seeing a low risk right now, we're expecting to see that rise somewhat in the next couple weeks," said Curry.

"Hot weather, hot/wet weather, hot/dry weather, really causes this mosquito to become quite active and virus transmission to increase."

With our early spring this year, Curry said that he has seen an early start to mosquito season.

"If we get a lot of hot weather this can really speed up the development of this mosquito, the number of generations it can have, and more importantly it has many nights it can fly and bite birds, and bite humans," said Curry.

Most who are exposed to the virus will not develop any symptoms, or only mild fever, headache and body aches.

There is a small risk of the virus developing into a more serious neurological issue, called West Nile virus neuroinvasive disease,that causes swelling of the brain.

"Often we don't see human cases until 3-4 weeks after the fact," said Curry.

"It's very important for people to get out and enjoy the weather, but just be mindful they are out there, and there may be some periods of time when the risk is starting to increase."

Since 2003, there have been 157 severe neurological cases and 17 deaths from West Nile virus in Saskatchewan.

Last year, there were no severe cases of West Nile virus.

"We know that for every one case of Culex tarsalis, there are probably about 150 West Nile Virus infections in humans that we may not in fact detect," said Werker.

There were two years with several severe cases. In 2003, there were 63 cases, and in 2007, there were 76.

The Ministry of Health advises Saskatchewan residents to seek medical help immediately if you develop symptoms 2-15 days following a mosquito bite, like persistent fever, confusion, neck stiffness, or an unusually severe headache.

Tips to avoid mosquito bites:

• Use appropriate insect repellent when outdoors;
• Cover up. Wear light coloured, loose-fitting, long-sleeved and long pants when outdoors;
• Reduce the amount of time spent outdoors during peak mosquito hours -- between dusk and dawn.