Pondering resistance
Microwaving deltamethrin can renew the insecticide’s ability to kill mosquitoes that have become resistant to it. Scientists are working to add the improved insecticide to bed nets, Tina Hesman Saey reported in “Restoring an insecticide’s mosquito-killing power” (SN: 6/17/23, p. 4).
Although the finding “sounds like a welcome discovery,” reader Linda Ferrazzara wrote, “might the newer, more effective version of the insecticide also have more serious adverse effects on the human beings it’s supposed to protect?”
Deltamethrin is so commonly used as an insecticide because it’s much more lethal for insects than it is for mammals, says Bart Kahr, a crystallographer at New York University. The lethal dose for a human, which is based on toxicology data for rats, would be more than 100 billion times what it is for a mosquito, he says.
Since microwaving deltamethrin changes its crystal structure but not its chemical composition, the lethal dose would not be expected to change, Kahr says. The new form might be faster at delivering deltamethrin to both humans and mosquitoes, but it would still take incredibly prolonged contact with a high amount of the insecticide to be consequential to a mammal. “Of course, no one has made such an experiment, but it stands to reason from the data that we have,” he says.
Understanding pain
Brain implants in four people with chronic pain revealed a potential biomarker of the debilitating condition. The brain signal could one day help doctors track treatment responses, Laura Sanders reported in “Implants track chronic pain in the brain” (SN: 6/17/23, p. 10).
Some readers on social media wondered what the discovery might mean for other types of long-lasting pain. “Am SO hoping that this will one day be expanded to those of us who have [the autoimmune disorder lupus],” Twitter user @SusanFi84657717 wrote. Meanwhile, Facebook user Wernell Loell hoped the finding…
Read the full article here