Ivermectin against malaria: novel idea, but can it be scaled

Several news sources have picked up on a new article in the American Journal of Tropical Medicine and Hygiene that reported when communities take annual ivermectin doses for controlling onchocerciasis and lymphatic filariasis, they may also be protecting themselves or their neighbors from malaria. Specifically the researcheds reported that ivermectin Mass Drug Administration (DA) “reduced the proportion of Plasmodium falciparum infectious Anopheles gambiae sensu stricto (s.s.) in treated villages in southeastern Senegal.”

The process works the same way that ivermectin treats head lice in that when insects take a bloodmeal from someone who has swallowed the drug, the medicine kills the insect. Sarah Boseley points out that some of the attractions of ivermectin are that it has been safely used in humans for 30 years and that it is inexpensive.

The Merck company has been supplying ivermectin (under its brand name Mectizan) free through the Mectizan Donation Program (MDP) to the African Program for Onchocerciasis Control for 16 years.  Over time coverage has reached over 100,000 villages in 18 African countries. Annual distribution in Africa contrasts with more frequent distribution in the smaller focal transmission points in Latin America where the diseases has almost been completely eliminated.

MDP reports that, “Currently, more than 70 million treatments are approved for onchocerciasis in Africa and Latin America and 80 million for lymphatic filariasis in Africa and Yemen each year.” That is a lot of free medicine and one of the largest and far reaching corporate social responsibility programs known.

Back to Senegal – the researchers found that the effect of ivermectin on mosquitoes lasted up to two weeks. They also raise the question of whether more frequent ivermectin distribution in onchocerciasis or filariasis MDA communities during the main malaria transmission season would be feasible.  Possibly a small scale operations research proposal could be submitted to the Mectizan Expert Committee.

cdi_report_08.jpgOf importance is the fact that the Community Directed Treatment with Ivermectin (CDTI) approach utilized by APOC projects has been tested and found quite accommodating to the addition of other Community Directed Interventions (CDI) such as community case management of malaria, ITN delivery and use monitoring and Vitamin A distribution among other basic health services.

The availability of tens of millions of exra ivermectin doese in communities where MDA is already occurring is unknown at present, let alone the feasibility of starting free ivermectin in malarious areas that have no onchocerciasis or filariasis.  In addition, for onchocerciasis, the idea time for distribution is before the rainy season so that microfilariae loads are seriously reduced before the black fly vectors emerge. This timing may not benefit malaria control fully.

Regardless of the unknowns, it is encouraging that people are thinking of synergistic ways to control the various endemic diseases that inflict suffering on poor communities.

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