DALLAS -- No matter how hard they work, mosquito control units across North Texas can't contain a growing population of infected insects.
"We are concerned that these are not going to be enough, or effective enough to avoid further cases and fatalities," said Dr. Rick Snyder, president of the Dallas County Medical Society (DCMS).
That's why the medical society sent a letter, with background documents, signed by some of the area's best experts in infection and outbreaks to the Dallas County Health Department, recommending controversial aerial pesticide spraying.
"The EPA has stated and judged that the risk is not unreasonable of using mosquito pesticides, when you compare to the ongoing risk of infections and fatalities," Snyder said.
In a letter sent to Dallas County health authority Dr. Christopher Perkins, the DCMS has recommended "selective adaptation of aerial applications to specific areas with highest numbers of ongoing human cases despite usual ground-based control activities."
Other information presented by the DCMS Community Emergency Response Committee points out that ground treatment has limited access, while aerial spraying can blanket areas with pesticides. It also suggests spraying could be done at night.
"I'm not ready to make that recommendation to commissioners court," said Dallas County Health Department Director Zach Thompson.
Thompson instead told county commissioners Tuesday morning that the Dallas County Vector Control Department will step up targeted ground spraying in affected areas. Beginning later his week or early next week, Thompson said the county will be spraying three nights in a row in specific areas.
Thompson is not convinced chemicals rained down on highly-populated areas is the best solution.
"This is not 1966," Thompson said. "We're talking about 2012, when you've got close to three million people in Dallas County. We want to see a similar city, not one that has a wetland, not one that has a large, rural area. If you're talking about aerial spraying over an urban area, we really need some information and research to really look at how effective that's going to be."
In 1966, aerial pesticide spraying stopped a Dallas outbreak of St. Louis encephalitis, which is also spread by mosquitoes. Aerial spraying is being done right now in Massachusetts and California to combat West Nile virus before there are even any human cases.
A study printed by the Center for Disease Control after aerial spraying in Sacramento in 2005 showed the number of people and infected mosquitoes dropped dramatically. Information based on the impact of the pesticides on people, pets, plants, and other beneficial insects is less readily available.
"If we bring that recommendation to the court and the court says, 'You can do it,' we don't want any type of repercussions from citizens who may have some kind of health issues," Thompson said. "There's a lot of dynamics."
With West Nile season set to peak in the next two weeks, time is clearly pressing. The Dallas County Health Department plans to begin their three-night-a-week, targeted spraying by next week. The medical society said a decision about aerial spraying should be made in the next two-to-four days to get the best result.
The DCMS points out the West Nile virus outbreak in North Texas is unprecedented and decisions being made in Dallas County will have to be, too.
"Unfortunately, we're on new ground here," Snyder said. "This is really, has not been seen in Dallas County, or really any other urban areas. So you have to use your experience and judgment."