Viagra was famously discovered when researchers testing a high blood pressure drug found it had a curious side effect: erections. The pill may have another unexpected benefit too: A new study in human blood cells finds that Viagra — or drugs like it — could be used to prevent the transmission of malaria.
And the world desperately needs new ways to treat malaria. The disease affects nearly 200 million people a year, and resistance to drugs is on the rise. The parasites that cause malaria, which belong to the genus Plasmodium, have a complex life cycle that require it to move between humans and mosquito. Drugs like Viagra could keep Plasmodium out of human blood, breaking the cycle of transmission.
Here’s how it works. As Diane Kelly recently explained in our awesome new sex vertical, Throb, Viagra grabs onto enzymes that break down a molecule called cGMP. cGMP relaxes blood vessels in the penis to create erections, hence Viagra’s main selling point.
But Viagra also inhibits a similar enzyme that break down a similar molecule called cAMP, increasing levels of cAMP. And here things get interesting. When blood cells infected with the malaria parasite are exposed to more cAMP, they become hard and stiff, an obvious sign of infection. These hard, unhealthy cells can be filtered out of the blood by the spleen. Mosquitoes biting an infected human won’t pick up the parasite any more.
Unfortunately, this isn’t a cure for a person already infected with malaria. But it could prevent transmission by mosquitoes to even more victims, a novel way of fighting the disease. In any case, though, the active ingredient of Viagra may have to be modified for this to work — so it doesn’t have, you know, an undesired erectile effect.
[PLOS Pathogens via Popular Science]
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