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Officials warn: Where water stands, mosquitoes get buzzy, busy

Sat., May 31, 2008

Some mosquito species transmit West Nile virus.
 (Associated Press / The Spokesman-Review)
Some mosquito species transmit West Nile virus. (Associated Press / The Spokesman-Review)

Springtime, and a young mosquito’s thoughts turn to love.

Or at least reproduction.

After a snowy winter and soggy spring, health officials are keeping an eye on mosquito populations and urging homeowners to do what they can to eliminate breeding grounds for the pests. Of particular concern in recent years is the mosquito-borne West Nile virus – though the virus has been notoriously unpredictable, and it’s unclear whether this summer will be cloudier with mosquitoes than in years past.

“Anytime we get reasonably warm weather and there’s a fair amount of standing water, you’re going to see mosquito growth occur,” said Steve Main, environmental health specialist with the Spokane Regional Health District. “It’s really going to depend a lot on our weather” in coming months.

Standing water – whether it’s in puddles, natural hollows or backyard birdbaths – is where the pests flourish, and a wet 2008 has left more of it all over.

If weather remains warm and humid, mosquitoes could begin producing generations more and more quickly. However, if it gets hotter and dry – as is typically the case in the region – a lot of standing water evaporates, Main said.

So far, there is no official measure of increased mosquito populations, and officials emphasize there’s no reason for panic over West Nile. Most people who contract the disease never even have symptoms, but it’s fatal in a small number of people infected.

The disease has not followed a more typical pattern of infections, which usually spread from one place to the place next to it, officials said. Instead, some places go years with few cases or none, and then get hit with a big year.

Idaho went from having the most cases in the country two years ago – more than 1,000 infections, including 23 deaths – to having 103 cases last summer.

“Everybody’s been trying to second-guess the numbers of West Nile virus, and it’s just defied any predictions,” said Marc Klowden, a professor of entomology at the University of Idaho and an expert on bugs that carry and transmit diseases.

Mosquitoes carry health implications for animals as well as humans, especially horses and livestock. Officials have been urging horse owners to have their animals vaccinated against the virus just to be safe.

Charlie Powell, spokesman for Washington State University’s school of veterinary medicine, said people in the veterinary community keep expecting it to be Washington’s turn to be hit with the disease. Last year, Washington’s infections were limited to a bird and eight horses.

“We’ve been anticipating our year in Washington now for a couple of years, and thankfully it hasn’t occurred,” he said.

No local districts

Neither Spokane County nor Kootenai County has a mosquito control district, although many counties in the region have formed such districts to take on spraying and other attempts to control the pests. In Washington, Grant and Adams counties have the districts. Several counties in Southern Idaho formed them after the West Nile outbreak.

Attempts in Spokane County to create a district – which would have to be approved by voters – have run aground over property rights concerns.

Kootenai County, meanwhile, recently adopted a plan for creating a mosquito district in the case of an emergency.

Health district officials emphasize that homeowners can have a big impact on the spread of mosquitoes. Anything that might catch and hold water in a small space is a potential breeding ground. With each female mosquito producing between 100 and 200 eggs per fertilization, every location for the eggs to grow can have a big effect.

“If you dump the standing water, then you’re going to lower the number of mosquitoes out there,” said Cynthia Taggart, spokeswoman for the Panhandle Health District in Coeur d’Alene.

The health district plans to start gathering mosquitoes at sites around North Idaho to look for signs of West Nile and the species that carry it, Taggart said.

Tick time, too

Just as spring is the start of the growth season for mosquitoes, it’s a boom time for ticks, as well. Ticks can transmit Lyme disease.

“Those eggs hatch this time of year, and then you get this enormous population of young ticks just looking to feed on blood,” Klowden said.

People should be careful about brushing against grasses, brush and other foliage, and wear long sleeves and pants when they’re in the country. If you find a tick on yourself or a pet, you should try – perhaps using special tweezers – to pull it out gently until the tick releases, officials said.

Klowden – who edits a journal on disease-transmitting insects and has had a species of long-legged fly named after him – says it’s important to keep the risk of such diseases in perspective. A minuscule portion of those bitten by mosquitoes ever contract a disease; he’s been bitten thousands of times over his career researching the insects, he said.

“We don’t want to have any panic,” he said. “It’s not something to really worry about so much.”

Tags: mosquitoes

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