‘Tis the season for West Nile

August is West Nile virus season

  • Aug. 5, 2011 7:00 a.m.

The irritating and increasingly common buzz of mosquitoes prompted the B.C Centre for Disease Control to issue a warning to Okanagan residents — August is West Nile virus season.

“If  you look at historical data, human cases take place at this time of year,” said Dan Ferguson, assistant director of health protection at the Interior Health Authority, explaining what prompted the alert.

And this year the threat rose with flood waters that awakened eggs that were sitting dormant for what Ferguson said were two, three or four years.

Cool temperatures stopped those newborns from breeding, but rising mercury is giving them a chance to catch up and some newborns may carry West Nile virus.

“We measure the number of high degree days because that’s the timeframe that a mosquito can produce another generation,” according to Ferguson.

“It needs to be warm and they need to be feeding.”

That said, there’s been no cases of the virus showing up just yet, said Ferguson.

“Across B.C., 116 human samples were tested for West Nile as of July 21, and they were all negative,” he said.

“Also, 584 mosquito pools were tested and they too were all negative.”

There have also been no positive test results from human, animal, or mosquito samplings in Oregon, or Washington State, which are among the key indicators for how this region will fare.

Historically, there have only been eight cases of West Nile in B.C.

This year, there’s only been one case reported, and that was a Canadian who had been travelling out of the country.

“However, individuals still need to be vigilant and take precautions to avoid being bit,” said Dr. Bonnie Henry, physician epidemiologist with the B.C. Centre for Disease Control.

“Simple things such as using repellents outdoors, particularly in the evening and early morning when mosquitoes are most active, is a good protective measure.”

For more information about West Nile virus or tips to keep safe, check out www.bccdc.ca.