Mosquitoes swarm near loops; West Nile a concern

Mosquitoes are swarming near the Loop 101-202 interchange, breeding in pools created by road construction and potentially loaded with the West Nile virus.

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State, county and tribal officials are scheduled to meet this morning in the Salt River bottom to decide how to combat the mosquito problem in an area where jurisdictions overlap and crowds congregate at nearby shopping centers.

Traps along the Salt River bottom from Dobson to McClintock roads are picking up thousands of culex mosquitoes, the variety that most commonly carry the West Nile virus.

"We are getting huge counts," said John Townsend, manager of Maricopa County's vector control program. "To see over one thousand in one night is huge. You don't usually see those kind of numbers."

Townsend said work by the Arizona Department of Transportation to widen bridges and add carpool lanes to Loop 101 are creating pools of water that allow mosquitoes to breed.

But ADOT spokeswoman Laura Douglas said it remains to be seen whether the problem areas are on state property.

"ADOT is currently working with Maricopa County vector control and we will cooperate in more precisely determining any areas of concern in ADOT right-of-way," she said.

The land borders the Salt River Pima-Maricopa Indian Community, which isn't covered by the county's mosquito abatement program.

A preliminary field test showed that mosquitoes in the area carried the West Nile virus, but samples have been sent to the state Department of Health Services laboratory for confirmation. Lower readings, as these were, can come back negative.

Results are due in a week or two. In the meantime, the county tonight will fog the area from Van Buren to Loop 202 and from Mill Avenue to 56th Street.

Fogging also is scheduled tonight for Queen Creek, where tests also show the possibility of West Nile mosquitoes there.

Craig Levy, head of the state health department's vector-borne and zoonotic diseases section, said this year has been quieter than last, with just three confirmed West Nile mosquito pools in Chandler, Yuma and Pinal counties. The only human case was confirmed in January.

That's likely to change soon, however.

"We are seeing some increasing numbers, but we are not seeing any increase in virus activity as of yet," Levy said. "But once this monsoon really gets going ... that's what's going to cause things to pick up quite a bit."

Last year, the first West Nile-packing mosquitoes were confirmed in Yavapai County in April and sickened 97 people by year's end. In 2006, the virus infected 150 people and killed 11 of them, including six in Maricopa County. That put Arizona fifth in the country in the number of 2006 West Nile fatalities.

In 2005, there were 106 human cases and four deaths; and 391 cases, with 16 deaths, in 2004.

Most people bitten by infected mosquitoes won't develop any symptoms, about 20 percent will develop flulike symptoms and fewer than 1 percent develop encephalitis. Those most at risk are the elderly and people with compromised immune systems.

Townsend said the sheer number of mosquitoes near the Loop 101-202 interchange, together with the nearby gathering spots of Tempe Marketplace, Mesa Riverview and Tempe Town Lake, increase the chances that someone eventually will become infected.

"The potential is there for something to break loose fairly quickly," Townsend said, "unless we can get these people together and get something figured out."

More information

For information or to report a mosquito problem or get free mosquito-eating fish, contact Maricopa County Vector Control, (602) 506-0700, or go to www.maricopa.gov/wnv

You can also find information online at www.westnileaz.com or call a 24-hour hotline at (800) 314-9243 or (602) 364-4500.