Aerial spraying should not be ruled out in the battle against Arizona’s mushrooming West Nile virus outbreak, county health officials decided Monday.
Maricopa County Supervisor Don Stapley, R-Mesa, said Monday that he’s worried about the disease’s spread as the monsoon season continues, but any aerial spraying effort will need regional support.
"We’re only going to do it if the mayors, the Centers for Disease Control, the (Arizona Department of Health Services) and the governor’s office are all on board, then we’ll do it," he said.
The Board of Supervisors will consider the question Thursday.
The county is already pouring millions of additional dollars into its environmental services department as it deals with an outbreak that is hitting local victims especially hard.
Normally, six fogging trucks and vector control officers are in use. By the middle of this month, officials plan to have 35 trucks with foggers, 35 vector control officers and as many as 200 mosquito traps for West Nile tests.
County officials hope these measures will control the outbreak, but environmental services director Al Brown and county health director Dr. Jonathan Weisbuch said the county may need to resort to aerial spraying if these steps don’t work.
Brown said planned resources and personnel will cost $1.6 million in county contingency funds, while one aerial shot will run $2 million.
Anvil, already being applied at ground level in a nightly basis, is "very, very low in toxicity and it’s very, very effective in killing mosquitoes, and that’s what we do," Weisbuch said. "We are mosquito assassins."
Many are uncomfortable around pesticides — and they should be, Brown said.
"Our exposure to even the safest insecticides ever invented, like this stuff, should be minimized," he said.
Dr. Doris Rapp, a retired medical environmental specialist and allergist who lives in Scottsdale, led a protest over the weekend against the use of the insecticide, especially through aerial application.
One chapter of her latest book, "Our Toxic World," is titled "What You Should Do if They’re Going to Spray in Your City," she said. "When I wrote that, I never dreamed I’d have to defend my own city."
She said anybody could be potentially harmed by the pesticide applications, but has a long list of people who should be particularly concerned, including asthma sufferers, those with compromised immune systems, pregnant women, the elderly and children.
She also contends aerial spraying is ineffective. Brown said studies have found aerial application kills between 50 percent and 90 percent of mosquitoes.
Colorado was the epicenter of the West Nile virus last year and aerial spraying was used in some areas, including Larimer County, population 274,000, had 546 West Nile cases last year, 63 of which were neuroinvasive and nine fatal, county health education supervisor Ann Watson said.
Insecticide was sprayed two nights in September in unincorporated areas of the county, including near Fort Collins and Loveland, she said.
"After the county sprayed the numbers went way, way down," she said. By then they were nearing the end of the mosquito season, which was likely a contributing factor, she said.
Brown told the health board Monday that in most infected areas of the nation, 20 percent of the human West Nile cases involve more serious symptoms such as muscle weakness or coma. In Arizona, it’s 50 percent.
"And that’s unusual," he said.
The state has reported 232 West Nile cases, all but nine in Maricopa County. Of those, 110 suffered the more serious symptoms, and 58 others had "unknown" symptoms that could eventually prove more severe. Maricopa County is also reporting a much higher infection rate than normal among the mosquitoes it does test. Eighty-five samples, 10 percent of the total number of samples, taken in the county this year have tested positive for West Nile. The infection rate has been 20 to 40 per 1,000, instead of the expected 1 to 2 per 1,000.
While the Valley is seeing more than its share of the more serious cases, they’re still rare. Brown said the state health department estimates there could be up to 30,000 infections statewide, with either no symptoms or milder flulike ones.