The drug, nitisinone, is already approved by the US Food and Drug Administration for treating certain rare genetic disorders, and researchers have now found that it is also highly effective at killing malaria-carrying mosquitoes. The idea is simple: When a mosquito bites a person or animal treated with ivermectin, the drug enters the mosquito’s system and ultimately kills it. Unlike traditional insecticides, which typically target the mosquito’s nervous system, nitisinone disrupts a crucial enzyme (HPPD) that mosquitoes need to digest their blood meal.