July 06, 2011
Malaria researcher Brian Foy
Researchers have found that an inexpensive and widely-available drug used to treat river blindness in Africa and head lice in American school children is also effective in reducing malaria transmission, especially during seasonal epidemics of this worldwide scourge.
"Can you kill a mosquito when it's biting you [with] something that's in your blood," asked Brian Foy.
Malaria researcher Brian Foy of Colorado State University found out that yes, you can. He is working on a malaria control program and says there are many benefits to killing mosquitos as they bite their hosts.
Foy says that this not only is a clever way of getting a toxin directly to the malaria-causing parasite living in mosquitos, but it also saves the environment from harmful insecticides.
In a field study done on malaria transmission in Senegalese villages, Foy and his colleagues found that a drug already widely used for treating the two most common parasitic diseases in Africa - river blindness and elephantiasis - also has insecticidal properties.
"We are repurposing a really cheap and important drug for worm control potentially to control malaria," he said.
The study shows that after single doses of the drug Ivermectin were administered to residents of several Senegalese villages, there was a 79 percent reduction in mosquitoes found to be carrying the malaria parasite. In villages where the drug was not given, the malarial mosquitoes increased by 246 percent.
Researchers found that the drug circulating in people's blood killed the mosquitoes. Ivermectin is given once every year in many countries in sub-Saharan Africa to fight common infections. But researchers say that if the drug is given more often, it can provide other benefits.
"If you give it more often, [as] we are proposing for malaria transmission control, it will start to have an effect against the soil-transmitted illness that people have in their guts - things like whip worm, round worm and maybe even hookworms, which cause a lot of hidden illnesses in people," said Foy.
Peter Hotez, president of the American Society for Tropical Medicine and Hygiene, calls Foy's study groundbreaking. He says it proves what many public health researchers have long suspected - that drugs used to combat neglected tropical diseases have important collateral health benefits.
"It opens up a new pathway for discovering an additional class of drugs specifically for this purpose - maybe a drug that can circulate in the body longer and then be better targeted for malaria specifically," said Hotez.
Malaria kills almost 800,000 people around the world each year. Experts say Ivermectin would be a welcome addition to the anti-malaria arsenal of bed nets, pesticides, drugs and, perhaps one day soon, a vaccine. Public health experts say all these weapons will be needed in the years ahead to eradicate malaria permanently.