They’re pretty small but mosquitos are in fact one of the deadliest animals in the world, killing hundreds of thousands of people a year. One Texas Tech researcher wants to chip in as much information as possible to help stave off severe outbreaks of Zika, West Nile or other mosquito-borne diseases.
It’s hot and really humid inside a small room where Steve Presley sometimes works. It’s a perfect environment to grow mosquitos and they’re buzzing around inside three plastic cylinders. The professor and director of the Biological Threat Research Lab at the Institute of Environmental and Human Health Institute, is helping state officials test insecticides used to combat mosquitos — the kind that can carry diseases like West Nile, Zika and Chikungunya.
Presley got a $200,000 grant from the Department of State Health Services to do his study of insecticides used against two species of mosquitos. “This is focused on finding out if what we’re currently using, the public-used pesticides that are currently used, are effective or not,” he says.
Presley, who in 2016 testified about Zika before a US House, has gathered mosquito eggs from dozens of Texas counties and raised them to adulthood. He then anesthetizes them and puts them in small containers. The sides of the containers have been swabbed with a specific concentration of a particular insecticide, which allows Presley and his team to gauge whether mosquitos are resistant to it.
Up through Sept. 6, there were 229 US cases of Zika in travelers returning from affected areas; 22 of those were in Texas.
The data Presley gets is shared with participating counties so that officials in cities and towns charged with spraying for mosquitos have the best information.
“Most of the more effective ones, the more progressive ones, will rotate the type, the class of insecticides that they use,” Presley says. “So that’s to at least slow down or prevent resistance occurring in the populations in that specific area.”
It’s the females who bite and suck blood. Presley says there’s a reason for that. “They need the protein from the blood to make the egg,” he explains. “So she’ll take a blood meal and gestate her eggs and then lay her eggs, go take another blood meal for another clutch of eggs.”
Vector control operations are done when mosquitos are most active: dawn and dusk. There are also ways people can treat small bodies of water to kill mosquito larvae, as well as growth regulators that keep larvae from growing.
Inside Texas Tech: Preventing One of the World's Deadliest Parasites
But spraying neighborhoods with insecticides is critically important. “It creates droplet sizes between 5-20 microns,” Presley says. “It does that so that they stay in the air—that’s tiny—it’s smaller than smoke or fog. So that droplet stays airborne a longer period of time because it’s lighter and it moves around with air.”
Residents can also follow the four Ds to reduce the chance of being bitten. Drain any standing water around your home; dress in long pants and shirts when outside, avoid being outside during dawn and dusk hours and use DEET.
Presley says that for mosquitos, the dose is the poison. So it takes a lot of citronella around you on your deck and patio for it to be effective. Some have said that drinking beer can keep skeeters at bay. Presley welcomed the chance to comment on that rumor. “I know that it has been scientifically proven that if you drink enough you don’t care.”
