Into the Mild
Between sterile labs and raw nature, mosquitoes need a halfway house to give up their malaria secrets
Story by Emily Mullin • Infographic by Don Foley
The most deadly creatures on the planet are tricky to study. Individual mosquitoes are nearly impossible to track in the wild. And laboratory born and bred mosquitoes don’t act like their natural counterparts—they even differ biologically.
The solution? Build a halfway house for the winged arthropods, say Johns Hopkins Malaria Research Institute (JHMRI) scientists Marcelo Jacobs-Lorena, George Dimopoulos, Douglas Norris and Jennifer Stevenson.
They found their research into the Anopheles mosquitoes that transmit the malaria parasite Plasmodium was limited by sterile lab conditions. The mosquito house “acts as a step between the lab and the field, ” says Stevenson, who is based in Macha, Zambia, where JHMRI constructed the facility.
The scientists will be able to evaluate novel insecticides, attractants and, eventually, mosquitoes genetically modified to be resistant to malaria—all in a more real-world environment.
- The house, which cost $160,000 to build, is based on existing malaria research facilities at the Ifakara Health Institute in Tanzania.
- Researchers also plan to test sugar solutions containing bacteria and fungi that block the development of malaria parasites. (See related box below.)
- More than 40 species of Anopheles are important in malaria transmission. WHO estimates they caused 198 million cases of infection and 584,000 deaths in 2013.
- 98 feet long and 66 feet wide, the mosquito house is built on a steel frame with walls made of netting. 6 inside rooms can mimic the local climate and ecosystem without letting mosquitoes in or out.
- The team will build a hut in one of the rooms—creating “indoor/outdoor” venues for tests.
- Along with native plants and grasses of the region, compartments may also host cattle or rodents so researchers can study local mosquitoes’ host of choice.
- Safely ensconced in a net “pup tent,” a worker can serve as bait for hungry female Anopheles to test the effectiveness of different insecticides on nets.
Will malaria-thwarting bacteria thrive in wild mosquitoes?
George Dimopoulos identified bacteria that block malaria infection in lab mosquitoes, but wild mosquitoes have a different intestinal microbiome.
Before trying the strategy in the wild, Dimopoulos and his team will use the mosquito house to test delivery methods like sugar solutions or plant sprays. And to discover the mosquitoes’ favorite haunts—in homes or outside them—they will track individual mosquitoes by sprinkling fluorescent dust in different locations.
Knowing the prime locales and delivery methods will improve chances that wild mosquitoes ultimately will ingest the bacteria and spread it throughout the population when they mate and breed.