Gene drive could help Uganda eliminate malaria

By Verenardo Meeme

October 17, 2019

Uganda could eventually eradicate the scourge of malaria through the use of gene drive technology that limits reproduction in mosquitoes that carry the disease.

Malaria is a serious concern for Uganda. Over 90 percent of its population is at risk of the disease, which accounts for 30 to 50 percent of outpatient visits at health facilities, 15 to 20 percent of all hospital admissions and up to 20 percent of all hospital deaths, according to Uganda’s National Malaria Control Program (NMCP).

In 2018, the World Health Organization (WHO) ranked Uganda eighth in the number of malaria infections in sub-Saharan Africa, which has some of the highest reported malaria transmission rates in the world. An estimated 445,000 people died of malaria in 2016, most of them young children in sub-Saharan Africa. Some 200 million people worldwide are affected by the disease annually.

Access to the currently available malaria prevention tools is costly for individuals and countries, according to the experts leading the Target Malaria project in Uganda. Existing interventions to control malaria have reduced mortality rates, saving millions of lives, but are thought to be insufficient to eliminate the disease by themselves.

“Our project can help reduce the population of mosquitoes that transmit malaria in a manner that is long-term, sustainable, and cost-effective,” said Richard Linga,  communications officer with Target Malaria. “This, in turn, will help save sub-Saharan Africa from spending money on malaria that would other be invested in other priorities.”

Malaria costs the African continent $12 billion a year, or 1.3 percent of its total Gross Domestic Product (GDP), in economic losses, according to WHO’s 2018 World Malaria Report. Target Malaria research is aimed at reducing malaria transmission to ultimately improve people’s health and wellbeing.

Gene drives work by overriding the usual Mendelian laws of genetic inheritance, where offspring have a 50 percent chance of inheriting any particular gene variant from each parent. Gene drives work by ensuring that virtually all offspring inherit the intended gene, spreading it rapidly through the entire target population.

Researchers in the United Kingdom recently developed the first “switchable” gene drive system, potentially addressing fears that the use of gene drives to control malaria or eliminate invasive species might run out of control and have devastating unintended consequences.

“Several malaria control measures, such as the use of insecticide-treated nets, indoor residual spraying and artemisinin-based combined treatments, have reduced mortality rates, saving millions of lives, but are not enough to eliminate the disease,” Linga said. “We therefore need new control tools to complement existing ones to eliminate malaria in Africa.”

Malaria is prevalent in Uganda for various reasons, including continued emergence of parasite resistance to antimalarial medicines and mosquito resistance to insecticides, Target Malaria experts said.

“In Uganda, the research is still in its early stage, focusing on entomological mosquito collections and infrastructure upgrades before we start work on genetic technology,” Linga said. “Therefore, there is still a long way to go to reach our end goal of developing and sharing a novel tool to reduce malaria.”

Currently, scientists are employing mechanisms, such as conducting baselines studies and making infrastructural upgrades, to facilitate future work with genetically modified mosquitoes in contained conditions. Target Malaria recently finished constructing an Arthropod Containment Level – 2 (ACL-2) Insectary for mosquito rearing and research at the Uganda Virus Research Institute (UVRI).

The next stage will be equipping the facility before contained mosquito studies can start. The project will follow a step-wise development pathway in Uganda as it has in Burkina Faso and Mali, where similar research is taking place. Burkina Faso is further along, with small-scale releases of genetically modified sterile male mosquitoes already taking place.

“Uganda currently has a functional biosafety regime for experiments with GMOs in laboratories and field trials,” Linga noted. “An update to the biosafety law in Uganda is pending, but we are hopeful it will be in place and fully operational shortly.”

Image: WIKIMEDIA, CDC/JAMES GATHANY