A U.S.-led team of scientists has identified the complete genetic sequence of a parasite that is the leading cause of relapsing malaria.

Working at The Institute for Genomic Research/J. Craig Venter Institute in Rockville, Md., the scientists studied the parasite Plasmodium vivax. Unlike three other species of Plasmodium that cause malaria, the researchers said P. vivax cannot be grown in the laboratory, severely limiting its scientific study.

"Completion of the P. vivax genome promises to provide new insights into the biology of vivax malaria and new leads for therapies and vaccines," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which funded the study.

More than 2.6 billion people, mostly in Asia and Latin America, risk infection from P. vivax, the scientists said.

The researchers say knowing the parasite's genetic sequence will help scientists learn the genetic diversity of P. vivax and understand the problems of drug resistance and relapse.

The study appears in the journal Nature.