Elimination of Plasmodium vivax Malaria: Problems and Solutions

Abstract

Malaria is caused by multiple parasitic species of the genus Plasmodium. Although P. falciparum accounts for the highest mortality, P. vivax is the most geographically dispersed and the most common species outside of Africa. Several unique biological features make P. vivax less responsive to conventional control measures and allow it to persist even after elimination of P. falciparum. The ability of P. vivax to develop in diverse vectors at lower ambient temperatures bestows it a greater distribution range and resilience to ecological changes. Its tropism for reticulocytes often causes low-density infections below the levels detectable by routine diagnostic tests, demanding the development of more sensitive diagnostics. P. vivax produces gametocytes early enabling transmission before the manifestation of clinical symptoms, thus emphasizing the need for an integrated vector control strategy. More importantly, its dormant liver stage which engenders relapse is difficult to diagnose and treat. The deployment of available treatments for the liver hypnozoites, including primaquine and the recent U.S. Food and Drug Administration-approved tafenoquine, requires point-of-care diagnostics to detect glucose-6-phosphate dehydrogenase deficiency among endemic human populations. Here we review the continued challenges to effectively control P. vivax and explore integrated technologies and targeted strategies for the elimination of vivax malaria.