నైరూప్య

Vivax malaria: more severe and more resistant

Blaise Genton and Ivo Mueller

The current dogma is that Plasmodium falciparum can lead to severe disease and death, whereas Plasmodium vivax is usually benign. Recent large prospective studies have demonstrated that P. vivax alone is associated with severe manifestations similar to those defining P. falciparum malaria. The proportion of severe malaria among P. vivax patients in Papua ranged from 3 to 23%, and the case-fatality rate from 0.8 to 1.6%. The prominent clinical features differ from site to site, severe anemia being the most common in Papua, respiratory distress in Papua New Guinea and hepatic failure and jaundice in India. This new paradigm is complicated by the spread of P. vivax resistance to chloroquine with rate of treatment failures as high as 50% in Indonesia and Papua New Guinea. Artemisinin-based combination therapies offer a good alternative to chloroquine, but further studies are needed to rationalize regimens containing both asexual and hypnozoite activity. The goal of malaria elimination will not be achieved without considering the specificities of P. vivax. New tools (drugs and vaccines) and innovative strategies to target the dormant forms of the parasites are required.