– For years, campaigns such as Nothing But Nets have been trying to control the scourge of malaria—a blood disease spread by mosquito bites—by sending insecticide-laced nets to hard-hit regions (mostly in Africa). But a University of California-Davis study has some bad news: Researchers have discovered a hybrid "super mosquito" that seems to be resistant to the treated nets. The study published in Proceedings of the National Academy of Sciences indicates that Anopheles coluzzii mosquitoes in Mali that cross-bred with the A. gambiae variety created the superinsect—"'super' with respect to its ability to survive exposure to the insecticides," says Gregory Lanzaro, the study's lead author, in a press release. Although he's not surprised insecticide resistance is rising, it's still worrisome: "It is resulting in the failure of the nets to provide meaningful control." There were about 584,000 deaths from malaria in 2013, 90% of them occurring in Africa, according to the World Health Organization; every 60 seconds a child there dies from the disease, Nothing But Nets adds. But inroads have been made: Intervention tactics, including insecticide-treated nets, helped cut the mortality rate 54% in Africa between 2000 and 2013, the WHO notes—and in 2013, 49% of all African residents at risk for the disease (up from a mere 3% in 2004) had access to insecticide-laced nets. This new finding could throw a wrench in that progress, and new preventative measures will need to be explored. (Another study: Pantyhose help reveal why mosquitoes prefer humans.)