RENO — As a helicopter took to the sky early Thursday morning on a mission to kill mosquitoes, Washoe County Health District officials were on the ground with a we’ll-do-the-best-we-can attitude.

At a meeting on May 11, the Washoe County Board of Commissioners voted to take $375,000 from a health district fund and put it in the general fund to help with the county’s mounting deficit. Commissioners said it was extra money that was not being used, but health officials say it was being used for multiple things, including eradication of disease-spreading mosquitoes.

As a result, what would have been the first of 10 such flights to spread chemicals that destroy mosquito larvae, Thursday’s helicopter mission will be the first of just six for the season, according to the district.

Bob Sack, director of environmental health services for the county, called such efforts a “very important control strategy” for the winged insects that spread such diseases as West Nile virus and Western equine and St. Louis encephalitis viruses.

“There probably will be more adult mosquitoes out there but we will be doing the best we can do with dollars that are out there,” Sack said.

At the May 11 meeting, Commissioner Kitty Jung, who sits on the health district board, said the funds taken by the county were part of a rainy day account created when voters in 2004 approved a half-cent tax for vector-borne disease control. County Manager Katy Simon added that the 2004 measure was an advisory-only question, meaning the commissioners had the right to redirect the money for other uses. Simon and the commissioners also said the vector-borne disease control program is “fully funded” for 2010-2011 with a budget of $961,750.

“Is it a rainy day? We believe it is,” Jung said at the meeting.

Health district spokesperson Tracie Douglas agreed that the program’s budget is met for the year, though the district had dipped some into the roughly $600,000 a year created by the half-cent tax for prevention and some marketing programs. Sack said the district had been authorized to use $350,000 of that money each year but actually had been using $106,000 annually.

What the money transfer means, Sack said, is a 40 percent reduction in the number of trips into the air to treat for mosquitoes.

“How well that will work to control disease, we don’t know,” Sack said. “We’ll see, but it will be a significant reduction.”

On Thursday, pilot Joel Dozhier of California-based Alpine Helicopters flew with a giant bucket under the belly of his vehicle over Rosewood Lakes Golf Course. A click of a button and the bucket spread Altosid, a black powder that kills mosquito larvae but is purported to be harmless and have no ill effect on drinking water. The Environmental Protection Agency’s website says the chemical poses small risks to some aquatic life but not to humans or animals.

Altosid is a little more expensive for a vector-borne disease control program, coordinator Scott Monsen said, but also has a longer-lasting effect after the initial application.

During each flight, about 1,100 acres are covered from Washoe Lake to Rosewood Lakes, Lemmon Lake, Damonte Ranch and Spanish Springs. The areas include open space wetlands and recreation areas in close proximity to residential areas and busy streets. As the weather warms up, water will evaporate and about 700 acres will need to be covered, but some standing water where mosquitoes breed is present all year where natural runoff accumulates. Each acre gets about three pounds of Altosid and the application costs between $8,000 and $10,000 per day for the helicopter plus the cost of the chemical.

Before the helicopter hits the air, health district inspectors study the various areas known for mosquito breeding to check the populations and set traps to test for viruses.

Mike Teglas, an assistant professor of veterinary microbiology and epidemiology at the University of Nevada, Reno, came to the May 11 county meeting to voice concern over cutting of preventative programs. He said by phone Thursday that even if there are no cases in humans, viruses are ever present in local insect and rodent life. Cumulative cuts around the state, including to the Nevada state veterinarian’s office, will have a long-term effect on the area’s ability to cope in the event of a major outbreak, he said.

“At some point it leaves you so vulnerable that when something bad does happen we won’t have the facilities and people adequately trained to deal with it,” Teglas said. “I guess I’d like (the county commissioners) to think a little more long-term than a year from now.

“But I know it’s tough right now,” he added. “They don’t want to lay people off.”