While signs of declining malaria deaths in Africa are raising hopes of eradicating the disease worldwide, a stubborn form of the disease, from a parasite known as Plasmodium vivax, has medical researchers concerned.
"This map helps us understand just how difficult it is going to be to eradicate malaria," said Peter Gething of the Oxford University team that produced the study of vivax. "It shows that in substantial parts of the world, vivax malaria is endemic and transmission is significant.
"Unfortunately, the tools for fighting this type of malaria range from ineffective to non-existent."
While not as deadly as the Plasmodium falciparum malaria parasite found in Africa, vivax is more common throughout the world, with an estimated 2.85 billion people at risk of infection, the researchers report in an article in the American Journal of Tropical Medicine and Hygiene.
The persistence of the vivax parasite, despite a massive global campaign to eliminate malaria, has led some malaria experts to dub it "the last parasite standing."
"It's time to step-up the fight against vivax malaria and stop looking at this form of the disease as relatively mild and tolerable," infectious disease expert Peter J. Hotez said.