Genetic Diversity of Malaria in a Single Mosquito Bite May Be Huge

New blood tests help to track disease-causing Plasmodium strains

Plasmodium falciparum in ring stage in human red blood cells. Credit: Ed Reschke Getty Images


Malaria struck an estimated 228 million people worldwide in 2018. Yet questions remain about how the mosquito-borne malaria parasite, Plasmodium, infects humans—and how antimalarial-drug-resistance genes spread. Different strains of the parasite can exchange genes with one another when they reproduce sexually inside an individual mosquito, and the resulting mixed strains infect humans through the mosquito's bite. A new study paints a detailed picture of how Plasmodium trades genes, and it finds that all the genetic diversity within an actively infected human host—up to 17 parasite strains—can come from just one bite. The work was published in January in Cell Host and Microbe.

Plasmodium spends part of its life cycle in humans and part in mosquitoes. In the mosquito, it reproduces, mixing and matching genes. Until now, the most efficient way to study Plasmodium's genetic diversity was to grind up whole mosquitoes and sequence the mix. The new technique lets scientists determine whether a patient's particular parasites were the product of reproduction within a single mosquito or were introduced separately by different ones.

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