Ovale malaria

Scientists investigating ovale malaria, a form of the disease thought to be caused by a single species of parasite, have confirmed that the parasite is actually two similar but distinct species which do not reproduce with each other, according to research published in The Journal of Infectious Diseases.
Researchers from the London School of Hygiene & Tropical Medicine, the Hospital for Tropical Diseases and Mahidol University, Bangkok collaborated last year in order to share their research after noticing that the single parasite Plasmodium ovale, though visible through a microscope, was not detected by forensic DNA tests designed to identify the species.
Dr Colin Sutherland, lead researcher at the London School of Hygiene & Tropical Medicine, says " We used DNA technology to compare the parasites from 56 patients with ovale malaria, from across the tropical world. It was a great surprise to find that, not only are these two species completely distinct from each other by every test we carried out, they actually occur in people living side by side in the same African and Asian countries, and even in the same towns and villages. We hope to continue our work so we can unravel the mysterious differences between these two newly recognised human pathogens."
http://www.eurekalert.org/pub_releases/2010-04/lsoh-nso041910.php