Health officials debate strategy to fight West Nile virus

By Dan MacArthur
Correspondent

While it's not yet clear what will trigger their response, public health officials agree that they must have the big guns ready to attack the West Nile virus harder and faster this year.

"We were way too complacent last year," said Larimer County Commissioner Kathay Rennels. "We need to start much sooner." The county, she added, already has set aside as much as $2 million toward eliminating the mosquitoes that transmit the virus.

Rennels was among those attending a March 11 West Nile virus planning session in Loveland. It brought together state and public health officials from Larimer, Weld and Boulder counties. They reviewed last year's statistics and strategies while plotting a new approach for combating the virus this year.

The three counties were particularly hard hit in 2003, with 1,398 of the 2,945 lab-confirmed cases and 20 of the 58 deaths in Colorado. Larimer reported the most of any county in the state with nine deaths and 545 confirmed cases.

Participants concurred that larvicidal efforts will take precedence to kill mosquitoes before they hatch. There was no consensus, however, on when to begin aerial spraying should West Nile still reach epidemic proportions. It was agreed that any spraying must take place before human infection reports are received because by that time the population of West Nile virus-bearing mosquitoes already would be burgeoning.

"If you're waiting for your human cases to come up, you're already behind the curve because they were infected two weeks ago," explained John Pape, an epidemiologist with the Colorado Department of Public Health and Environment's Communicable Disease Program.

But Pape said the indicators that would trigger such a response are still subject to debate. "There is a little uncertainty with those numbers," he conceded. "If you're looking for that magic number to show up, it ain't going to be there."

While the health professionals agreed to continue attempting to identify those triggers, such as human blood banks or "sentinel" animals such as birds and horses, Boulder County public health director Chuck Stout reminded them that time already is growing short.

"By the end of March we better have a pretty good idea what we're going to do," he said.