The genomes of two malaria parasites are published today, in what malariologists say is a great step forward for their research.

Plasmodium vivax is not the nastiest type of malaria. That’s Plasmodium falciparum, which had its genome published in 2002. But while it might not get as much attention as its more deadly cousin, malaria parasite Plasmodium vivax is an increasing problem, say the researchers who have just published its genome in Nature.

Depending on which press release you read P. vivax is responsible for 125 million, 206 million, or 300 million cases of malaria world wide. The Nature paper that details the genome puts it at between 25% and 40% of the roughly 515 million annual cases.

“Although seldom fatal, the parasite elicits severe and incapacitating clinical symptoms and often causes relapses months after a primary infection has cleared,” write the authors. “Despite its importance as a major human pathogen, P. vivax is little studied because it cannot be propagated continuously in the laboratory except in non-human primates.”

The genome may enable researchers to find new ways of fighting this form of malaria. “It’s going to be a very powerful tool,” says study author Jane Carlton, of New York University Langone Medical Center (Reuters).

Fellow researcher Mary Galinski of the Emory University School of Medicine says the genome might help scientists figure out what is happening when the vivax is lying dormant in liver cells, which it can do for years after infection.

“That’s one of the areas we hope to crack, but it will only be possible by combining the new genetic information with experiments in living animals,” she says (press release).

P. vivax is debilitating to such the degree that those infected cannot support themselves, or their families, says USA Today. “Vivax is one of the stealth reasons that poor people can’t escape poverty,” says Peter Hotez, president of the Sabin Vaccine Institute at George Washington University.

In another paper in Nature the genome of another malaria parasite, Plasmodium knowlesi, is also revealed.

“Plasmodium knowlesi is an intracellular malaria parasite whose natural vertebrate host is Macaca fascicularis (the ‘kra’ monkey); however, it is now increasingly recognized as a significant cause of human malaria, particularly in southeast Asia,” write the authors.

Also on Nature

Editorial: Malaria’s watershed

Review: Malaria research in the post-genomic era

Image: blood infected with Plasmodium vivax (infected red blood cells bright purple, uninfected cells in grey) / JoAnn Sullivan and William Collins, Division of Parasitic Diseases, Centers for Disease Control and Prevention