The end of malaria (or the end of artemisinins)?

From 2010-2015 new malaria cases and malaria deaths in the world fell by circa 20% and circa 30% respectively. Yet a substantial global burden remains, with almost 440,000 deaths and some 214 million new cases reported over 2016[1]. Presently drugs are the path to treat malaria infection and reduce the parasite burden and disease in patients.
In particular, artemisinin combination therapies (ACTs) have played a central role against Plasmodium falciparum (the most deadly of human malaria parasites). Artemisinins are 'harvested' from sweet wormwood (Astemisia annua). Unfortunately, resistance to these artemisinins has emerged and spread throughout Southeast Asia, casting a grim specter of losing on gains in malaria control and elimination[2].

It is especially concerning that de novo emergence of resistance (rather than spread) has now also been reported in an area of high endemicity in Africa[3].
Novel drugs are needed to target Plasmodium vivax, a second, widespread parasite species with a latent liver stage infection that is not blocked by ACTs. Given that, as malaria burdens decrease, antimalarial drugs have to eliminate malaria in the absence of blood stage immunity, there is also the need to reduce transmission by the mosquito vector, a critical focus of prevention strategies.

Since 2010, seven countries have been certified to have eliminated malaria (by achieving three consecutive years of zero locally-acquired malaria): United Arab Emirates (2007), Morocco (2010), Turkmenistan (2010), Armenia (2011), Maldives (2015), Sri Lanka (2016) and Kyrgyzstan (2016). Malaria elimination campaigns in India and Bangladesh are expected to be particularly important to stem the global spread of artemisinin and multi-drug resistant strains from Southeast Asia to the rest of the world.

Don't hold your breath. The parasite is even smarter than we give it credit for.

[1] WHO: Fact Sheet: World Malaria Report 2015
[2] Hanboonkunupakarn: The threat of artemisinin resistant malaria in Southeast Asia in Travel Medicine and Infectious Diseases – 2016. See here.
[3] Lu et al: Emergence of Indigenous Artemisinin-Resistant Plasmodium falciparum in Africa in New England Journal of Medicine – 2017

No comments:

Post a Comment