Your Scent May Change When You're Infected with Malaria: Natural Mosquito Attractant

What's that smell? It could be the scent of malaria. Scientists have found that an infection with malaria pathogens actually changes the scent of infected mice and makes them more attractive to mosquitoes. The findings could have implications for humans with the infection.

Malaria is a disease that is transmitted to humans by the anopheles mosquito. The pathogen itself is a protozoan and if left untreated, malaria can be deadly. In order for the protozoan to complete its lifecycle, though, it needs to be acquired by another mosquito and transferred to another person. But are new mosquitoes attracted by chance or by something less random? That's what scientists wanted to find out.

The researchers found that mosquitoes were most attracted to infected mice with a high concentration of gametocytes, the plasmodium parasite's reproductive cells, in their blood. They also found that while the pathogens don't appear to trigger the expression of unique scent components, they do alter the levels of compounds already present in the scent of uninfected individuals. In other words, they change the scent of the individual.

"There appears to be an overall elevation of several compounds that are attractive to mosquitoes," said Consuelo De Moraes, one of the researchers, in a news release.

It's possible that infected people smell more attractive but do not form highly specific body odors, especially since the malaria pathogen can have adverse effects on mosquitoes. This means that it would make sense for the pathogen to exaggerate existing body cues rather than having its own scent.

More interesting, though, is the fact that the malaria infection leaves its mark on body odor for life. Even when the infected mice no longer had symptoms, their body odor showed that they were carriers of the pathogen.

That said, more studies need to be conducted before researchers confirm that this same occurrence happens in humans. Yet it's very likely that similar effects might be involved in the attraction of mosquitoes to infected people.

The findings are published in the journal Proceedings of the National Academy of Sciences.