June 9, 2019
Through genetic modification, researchers have weaponized the fungus Metarhiziumpingshaense, which is a natural pathogen to mosquitos that carry malaria. Trials performed in a contained, near-natural environment demonstrated that the fungus successfully suppressed a malaria-carrying anopheline mosquito population.
Writing in Science, Brian Lovett, a doctoral student in the department of entomology at the University of Maryland, and colleagues explained that M. pingshaenseeffectively delivers mosquito-eliminating toxins to Anopheles species mosquito populations that have developed resistance to insecticide.
“The application of Metarhizium spores inside traditional houses in Tanzania reduced the number of infectious bites, but complete protection was prevented by the pathogen’s low virulence (slow killing and high inoculum loads) and low persistence,” Lovett and colleagues wrote. “To remedy these deficiencies, we engineered a strain of Metarhizium pingshaense (Mp-Hybrid).”
In the laboratory, mosquitos were killed faster using lower spore doses with the Mp-Hybrid, as opposed to the wild-type M. pingshaense fungus. Following these experiments, the researchers conducted a trial in near-field conditions in Burkina Faso, a malaria-endemic country that reported more than 7.9 million cases of malaria in 2017. This was accomplished using what they called the “MosquitoSphere” — near-natural environment complete with animals, huts, plants, and breeding sites made of plastic sheets buried in soil — all enclosed in a greenhouse frame with walls of mosquito netting.