Incidence of malaria-causing Plasmodium vivex worldwide. Red indicates local
infection rates greater than 7 percent; Light blue: one percent. More about map here.
When most people think of malaria, they usually think of its most deadly variety, caused by the parasite Plasmodium falciparum, the form most prevalent in Africa. But it’s not the only one: a second type, Plasmodium vivax, is a growing and overlooked disease in Southeast Asia and elsewhere in the world. More resources may need to be devoted to halt it’s spread, say researchers who presented the first comprehensive map of the disease’s worldwide prevalence Tuesday at the ongoing annual meeting of the American Society for Tropical Medicine and Hygiene in Philadelphia. Currently 97 percent of malaria-eradication funds are focused on P. falciparum, Oxford University researcher Peter Gething tells Nature News.
But Plasmodium vivax may cause as many as 40 percent of the 400 million cases of malaria each year, and is the predominant form of malaria in South America, India, and Southeast Asia, according to researcher Andrew Bright. The disease has also shown resistance to primaquine, currently the only licensed drug capable of a radical cure. Presentations by Bright, Gething, and others challenge the previous perception of P. vivax as mostly harmless. Though it isn’t often fatal, researchers say, it often causes severe symptoms such as repeated episodes of high fever, nausea, and diarrhea, and re-infection can happen months after symptoms have vanished. Vivax malaria can be so debilitating that sufferers, most of whom are poor, can’t support themselves or their families, researcher Peter Hotez told USA Today. “Vivax is one of the stealth reasons that poor people can’t escape poverty,” he says.
And P. vivax is only one of five types of malaria that can affect humans. There’s also Plasmodium knowlesi, more typically found in long-tailed macaques but also a growing human threat, which had its genome sequenced along with P. vivax in 2008. The final two are Plasmodium malariae and Plasmodium ovale.
[via Nature News]
Image credit: Malaria Atlas Project