AP/Washington Post examines experimental malaria vaccine, mutant mosquitoes to combat malaria

Jun 9 2009

The AP/Washington Post examines attempts to create a live vaccine and mutant mosquitoes to fight malaria.

During the 1990s, Sanaria CEO Stephen Hoffman "irradiated malaria-carrying mosquitoes to weaken the parasites inside them, and he and 13 colleagues subjected themselves to more than 1,000 bites," according to the AP/Washington Post. "Usually malaria parasites race to the liver and multiply before invading the bloodstream" and making their host sick, but these "weakened parasites" sat "harmlessly in the liver, unable to multiply but triggering the immune system to fend off later infections," the AP/Washington Post reports, adding that only one of the people in Hoffman's test did not achieve immunity "when bitten by regular malaria-infected mosquitoes over the next 10 months."

Hoffman said critics charged that turning his experiment into a vaccine was almost impossible and that he was "dismissed by 99 percent of the people in the malaria field." But, two weeks ago about 100 volunteers started receiving doses of Sanaria's vaccine in a first-stage FDA-approved study.

Aside from a vaccine, about "a dozen labs worldwide" are trying to combat malaria by breeding malaria-resistant mosquitoes, the AP/Washington Post reports. David O'Brochta's lab at the University of Maryland is working on ways to enable mosquitos to pass on malaria parasite resistance to their offspring, according to the AP/Washington Post. To be effective, "a malaria-resistance gene would have to spread a lot faster through mosquito populations," as a result the O'Brochta lab's main focus is how to speed that up.

Sanaria is working on a mosquito that can harbor double the number of immature parasites, to facilitate harvesting the parasites for the vaccine. O'Brochta is working on something similar and is trying to switch off a gene that protects the mosquito when it eats malaria-infected human blood. However, O'Brochta said, "No one has ever made transgenic mosquitoes with this gene knocked out," adding, "We want to cripple its immune system so when it takes an infected meal, it gets infected at very high levels" (Neergaard, AP/Washington Post, 6/8).