The WHO World Malaria Report 2020 reveals that despite tremendous global progress in reducing malaria, headway has slowed since 2015, hitting a plateau in the last three years. The WHO warns that if new tools are not forthcoming, key targets of its global malaria strategy will likely be missed. Current interventions, such as drug treatments, LLIN and IRS, have helped to lower the burden of malaria but have not been able to eradicate the disease in many countries.
Target Malaria is a not-for-profit consortium, currently running programs in Burkina Faso, Ghana, Mali and Uganda, which believes that it can find the required solutions. The consortium is researching genetic technologies to find new approaches to controlling malaria, focusing on reducing the number of mosquitoes that transmit the disease. Their aim is to develop and share new, cost-effective and sustainable genetic technologies to modify mosquitoes and reduce malaria transmission.
By reducing the population of malaria-transmitting mosquitoes in sub-Saharan Africa, Target Malaria’s goal is to reduce the transmission of the disease, allowing people in affected areas to live without the burden of malaria and freeing up resources currently used to combat the disease. Their strategy focuses on decreasing the number of female vector mosquitoes in a population, as they determine future population size and are the ones that transmit malaria when they bite. The technology should not affect other species or insects as it specifically targets the Anopheles species. Prof. Austin Burt describes gene drive as “a genetic phenomenon that occurs in nature and causes a selected trait to spread rapidly through a species via sexual reproduction over several generations. Normally genes have a 50/50 chance of being inherited but gene drive systems can increase the chance up to 99%”.
The goal of the gene drive approaches under investigation is to produce genetically modified Anopheles gambiae mosquitoes that can pass a genetic modification on to a high percentage of their offspring, so the modification is established throughout the specific population relatively quickly and is effectively self-sustaining. To reduce the number of female Anopheles gambiae mosquitoes they are introducing genes that produce enzymes (called nucleases) into Anopheles gambiae. These enzymes recognize and cut very specific sequences of DNA of interest to researchers, such as fertility genes or sex determination genes that will impact reproduction and thus population size. This approach results in the relatively cost effective and sustainable reduction of the malaria mosquito population as the mosquitoes themselves do the work.
Target Malaria’s work currently focuses on biasing the sex ratio of mosquito populations and reducing female fertility. Although results have been promising, Target Malaria cautions that research is still at an early stage with a long way ahead before malaria is under control. Sustainable and cost-effective malaria control by mosquito control is definitely something to look forward to.