Cows against malaria

Malaria is one of the most widespread diseases in the world, affecting 228 million people in 2018. The World Health Organization (WHO) has been trying to control or eradicate malaria for decades and it has had notable success in recent years. Even so, the disease remains a major killer, particularly in sub-Saharan Africa and among children.

One of the most successful WHO initiatives has been the introduction of insecticide-sprayed bed nets. These protect people from being bitten and reduce the number of indoor species of malaria-carrying mosquitoes, by killing them as they come into contact with the sprayed nets, attracted by the human “live bait” sleeping under them. The initiative has had a noticeable impact on the incidence of malaria but the threat from outdoor feeding species of malaria mosquitoes remains. Bed nets indoors are clearly powerless against such varieties, which is problematic as many rural African communities spend their evenings outdoors, where children often fall asleep and only later are carried inside to bed.

Having followed the success of the Stamp Out Sleeping Sickness (SOS) initiative, where insecticide-sprayed cattle serve as “live bait” for tsetse flies, a group of researchers from Liverpool University and the London School of Hygiene & Tropical Medicine wanted to try something similar. They decided to test whether cattle sprayed with insecticide with the same formulations as those used by SOS Uganda might also have a knock-down and mortality effect on the different species of malaria-carrying mosquitoes prevalent in an area in Kenya bordering Lake Victoria. The idea particularly appealed as there is a strong overlap between malaria prevalence and cattle rearing regions in rural parts of sub-Saharan Africa.

IKARE, together with ex-portfolio company Ceva, sponsored a research study that involved testing the thesis in a few villages in the target area. The study began in autumn 2013 with baseline sampling and fine-tuning of the test protocols. All children in the test villages were screened for malaria before and after the study, with those testing positive receiving treatment. The study was, after some initial and unforeseen delays, successfully completed during 2016. Its findings, conclusions and recommendations were, on 10 January 2017, published in the online journal Parasites and Vectors

In summary, the study concluded that if cattle are sprayed with the same formulations as those used in the SOS initiative, they can also act as live bait for certain species of malaria-carrying mosquitoes, but the effect wears off more quickly (after a week) than for ticks and tsetse (after two to four weeks). So, while cattle as live bait can potentially serve as another tool in the malaria prevention toolbox, more research and formulation testing are needed to perfect it against these species of mosquitoes. In addition, the study found that a larger number of species of mosquitoes than expected were found to carry the malaria parasites.

As an one-off, IKARE sponsored this in-field research (based on the successful use of insecticide-sprayed cattle as “live bait” for tsetse by Stamp Out Sleeping Sickness (SOS) Uganda) that could provide another tool in the fight against malaria, one of the most widespread diseases in the world, affecting millions of people. Similar to the SOS initiative, it is a “One Health” intervention aimed at simultaneously addressing animal and human welfare.

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