Ke Dong, Ph.D. ’93, Neurotoxicology
By now, you’ve probably heard about the rise of antibiotic-resistant bacteria. We’re all so used to taking amoxicillin for head colds and covering our hands in Purell at every opportunity that we’ve created the perfect evolutionary environment for the rapid creation of generations of ever-stronger superbugs. It’s not a pretty picture, but it gets worse: the same thing is happening with actual bugs.
That’s right, mosquitoes, bed bugs, roaches and fleas are all losing resistance to certain pesticides that have been used extensively. But not to worry. Ke Dong is hard at work building a better pest killer.
Dong’s research focuses on the inner workings of tiny bug brains; namely, the sodium channels that are targeted by a commonly-used class of insecticides known as pyrethroids. By understanding how pesticides kill bugs, Dong can develop new methods that may be more effective.
According to Dong, who leads her own lab at Michigan State University, the idea that pesticides are losing their efficacy is a very real threat, and one that becomes more pressing every year.
“It’s a race against time,” she says, “because this is a very rapid evolutionary process.” Mosquitoes and other insects may not reproduce as quickly as drug-resistant bacteria, but relative to humans, they still have time on their side. Changes that might take hundreds of years to develop across dozens of human generations can take place in the blink of an eye. “In some cases,” Dong says, resistance can develop in “one or two years if you use [certain pesticides] extensively enough in the field.”
Pyrethoids work by latching onto receptor sites within the sodium channel—basically, they prop open a door that would ordinarily be closed, and the insect dies as a result of a flood of sodium. But certain mutations have been developing in the mosquito population that block the pyrethoids’ attempts to grab onto receptor sites.
Dong and her team, however, have discovered that insects also have another variety of sodium channel, one not found in mammals. Her goal is to develop pesticides that will target this channel, where mosquitoes are not known to have resistance—hopefully creating a less itchy future for us all.