Earlier this month, researchers William Campbell⁠ and Satoshi Ōmura received the Nobel Prize for Medicine for their discovery of the antiparisitic drug ivermectin. Used primarily to treat and prevent lymphatic filariasis and river blindness, new research suggests that ivermectin may also be effective in preventing malaria transmission.

"In sub-Saharan Africa, each year the deadly malaria parasite Plasmodium falciparum kills 584,000 people–most them children. For this initial study, researchers used the MDA approach to treat villages in the West African country of Burkina Faso during the rainy season, when the risk of malaria transmission is the highest. About 2,800 people were treated with ivermectin, given every three weeks and repeated six times. As they excluded pregnant or breast feeding women and small children, about 75% of the villagers were treated. The scientists found approximately a 16% reduction in childhood malaria episodes in the four villages, even though the young children were not directly treated.

"How does this work? As Dr. Brian Foy, lead investigator, explained, only old female mosquitoes⁠ transmit malaria. It’s also interesting that the malaria parasite takes two weeks to work its way into the salivary gland of the mosquito and during that time, it may bite up to five other people. If the villagers have received ivermectin, the mosquito gets multiple exposures to the drug. Foy continued, if you give ivermectin to the 'Plasmodium in culture, nothing happens. It is not specifically toxic to Plasmodium. The effect is that when mosquitoes bite you, if you’ve taken the drug, it will die.' Transmission from person to person is thus reduced, leading to the drop in deaths. While Foy notes that 'there isn’t anything a mosquito hasn’t developed resistance to,' he’s optimistic that this pulsed dosing of a mosquitocidal drug will be an important tool.

"Not just Africa will benefit from Ivermectin. In a related study, Kevin Kobylinski of the U.S. Walter Reed Army Institute of Research (WRAIR) showed that ivermectin can block development of Plasmodium vivax parasites in mosquitoes that are common in Southeast Asia as well as killing the host Anopheles dirus mosquitoes. Kobylinski notes, 'It can be hard to convince someone to take malaria medications if they don’t have an active malaria infection,' but hopes that people will be more accepting of ivermectin, even if they don’t yet have malaria, because it will effectively treat scabies."

Sabin's president, Dr. Peter Hotez, was also quoted in the article, "the possibility that ivermectin could also affect vector transmission as it has for scabies, the impact of Anopheles mosquitoes that transmit malaria is an interesting proposal and one that should be looked at in greater depth."


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