Killing mosquitoes — fighting malaria: Promising results from tests in Africa

World Malaria Day, observed annually on April 25, draws attention to the more than 400,000 people, mostly children, who die from malaria every year. It reminds us that malaria persists as a global health menace only because of the resilience of the Anopheles mosquito. NSF, therefore, continues to support the development of effective technologies that specifically target mosquitoes and, unlike the banned insecticide DDT, are safe for humans and the environment.

ISCA Technologies has recently completed real life studies on its innovative mosquito larva-killer in Tanzania. NSF support of the research of ISCA president and chemical ecologist Agenor Mafra-Neto helped develop the mosquito control product called SPLAT-BAC®.

Larva of the Anopheles mosquito. Credit: CDC/H. Weinburgh

The product is designed to reduce mosquito populations and help eliminate malaria by specifically attracting the egg-laden female mosquito and inducing it to lay its eggs. A chemical in the product, which is safe for humans, entices the larvae from the hatched eggs to eat the product.

SPLAT-BAC® is laced with Bacillus thuringiensis israelensis bacteria, which specifically infect the larvae and kill them by producing deadly toxins in their guts. Targeting the mosquito in this way means that only the mosquito population drops and, beneficial insects such as bees and butterflies are spared.

Testing in Tanzania

The studies were conducted in villages in the Muheza district of Tanzania, an area in which malaria is endemic. SPLAT-BAC® was applied weekly to potential breeding sites from June through August of 2018. This was during the rainy season, which typically runs from April to September. This is a period of high mosquito population growth because rain water collects in ponds and forms puddles that provide ideal conditions for mosquitoes to breed.

Results from the Tanzania studies. Credit: ISCA Technologies/A. Mafra-Neto

During the testing period, the average weekly counts of larvae in the areas that were not treated with the product went up, reflecting the breeding cycles of the female Anopheles. These are larvae that would mature into potential malaria-carrying Anopheles mosquitoes.

By contrast, in the villages treated with SPLAT-BAC®, the larvae population dropped to zero after the first week of application and stayed at negligible levels throughout the testing period. The result, explained Mafra-Neto, was that “the mosquito population in the treated villages ground to a halt. It went down to zero.”

Mafra-Neto envisions the use of the product in comprehensive malaria elimination programs in Sub-Saharan Africa and other malaria-endemic regions of the world.