Researchers have unveiled a new malaria map that is the first to identify on a global scale where the long-lasting and potentially deadly form of malaria has a firm foothold in large swaths of South Asia and parts of Latin America.
Hotspots for vivax malaria highlighted by new research include substantial parts of India. Papua New Guinea also has a high rate of infections and transmission, as do significant parts of Indonesia and Myanmar.
A separate study released by Population Services International (PSI) earlier this year said as many as 800 people are dying of malaria each year in PNG, and there are around one million malaria cases reported annually in PNG. The health organisation also says 18 per cent of all deaths at PNG hospitals are malaria-related.
The ‘malaria map’ was revealed this week at the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH)
“This map helps us understand just how difficult it is going to be to eradicate malaria,” said Peter Gething, PhD, who led the University of Oxford’s Malaria Atlas Project (MAP) team that produced the study of vivax burden. “It shows that in substantial parts of the world, vivax malaria is endemic and transmission is significant. Unfortunately, the tools for fighting this type of malaria range from ineffective to non-existent.”
While not as deadly as the Plasmodium falciparum malaria parasite that is predominant in Africa, vivax is more common throughout the world, with an estimated 2.85 billion people at risk of infection. Vivax is also harder to detect and cure.
Researchers considered an area to be a vivax malaria hot spot if the data analysis yielded infection rates that exceeded 7 percent. Gething says while this threshold might be considered relatively low for falciparum infections, it’s high for vivax in part because the figure accounts only for parasites that are detectable in the blood, and also because vivax disease rates have proven hard to reduce.
Bednets and indoor spraying, which, coupled with ACTs, have helped reduce malaria deaths in Africa, appear to have had little impact on vivax. This persistence of the vivax parasite in the face of a massive global campaign to eliminate malaria has prompted some malaria fighters to dub it “the last parasite standing.”
“It’s time to step-up the fight against vivax malaria and stop looking at this form of the disease as relatively mild and tolerable,” said Peter J. Hotez, MD, PhD, noted infectious disease expert and president of ASTMH. “We expect to emerge from this year’s conference with a far better view of the state of vivax infections around the world and with new knowledge on treatment challenges that can guide a global strategy focused on eradicating all forms of malaria.”
Ric Price, a malaria researcher at Menzies, and a co-author of the study, said it is difficult to state with confidence how many people are dying of vivax because so many malaria patients also have other illnesses.
“It’s often hard to say if patients are dying of vivax or with vivax,” he said. “From our work, I believe the greatest threat from vivax malaria is the severe anemia, particularly in young children, that is caused by repeated episodes of the disease.”