Leveraging mosquitoes to mitigate malaria transmission

Malaria remains one of the major public health burdens globally, particularly in Africa.

It is a leading cause of disease and deaths in many developing countries, including Ghana. The ones who suffer the most when it comes to malaria mobility and mortality are children -especially those under five- and pregnant women.

The reason is that these children have not fully developed immunity to fight off malaria yet. And for pregnant women, their body’s natural defenses are a bit weaker during pregnancy, making them easier targets for the disease.

According to WHO’s latest World malaria report, there were an estimated 263 million cases and 597 000 malaria deaths worldwide in 2023.

This represents about 11 million more cases in 2023 compared to 2022, and nearly the same number of deaths.

Approximately 95 per cent of the deaths occurred in the WHO African Region, where many at risk still lack access to the services they need to prevent, detect and treat the disease.
In each year, many countries in Africa spend huge budgets on malaria related activities.

For instance, according to WHO, in 2018, an estimated US$ 2.7 billion was invested in malaria control and elimination efforts globally and that nearly three quarters of the investments in 2018 were spent in the WHO African Region.

The Ghana Context
The cost of malaria to individuals, families, communities, and nations are enormous. In spite of the several efforts been done to combat the disease, malaria still remains a major public health challenge in Ghana. However, not all hope is lost. Ghana is making some strides in combating the disease.

The reduction in malaria prevalence in Ghana can be largely credited to the various control measures implemented in accordance with the National Strategic Plan.

Some of the key interventions have been the distribution of Long Lasting Insecticide Nets (LLINs), Indoor Residual Spraying for areas with high parasite prevalence, Laval Source Management, seasonal malaria chemoprevention, and prevention of malaria among expectant mothers.
In a study titled: “Estimating the risk of declining funding for malaria in Ghana: the case for continued investment in the malaria response” published on June 10, 2020, via www.malariajournal.biomedcentral.com, estimated that it will cost Ghana $961 million between 2020 and 2029 to eliminate malaria.

The disease, according to the National Malaria Control Programme (NMCP), accounted for 42.8 per cent of Outpatient Department (OPD) cases, 22.2 per cent of in-patients admissions and 1.1 per cent of in-patient deaths in 2019.

Currently, malaria accounts for about 34 per cent of OPD cases and 22 per cent of in-patients cases and 2.1 per cent of in-patients death in Ghana, according to the Ghana Health Service.

Even though Ghana’s efforts toward reducing malaria deaths and cases are commendable, the country is still part of the 11 highest malaria burdened countries in the world, with the country recording 333 malaria deaths at the end of 2019.
Approximately 70 per cent of the world’s malaria burden is concentrated in just 11 countries – 10 in sub-Saharan Africa. The countries are Burkina Faso, Cameroon, Democratic Republic of the Congo, Ghana, Mali, Mozambique, Niger, Nigeria, Uganda and United Republic of Tanzania. The 11th country is India.
Considering the high burden of malaria cases in Ghana, particularly in Sub-Saharan Africa due to drug and insecticide resistance, inadequate access to prevention tools, research scientists in the Sub-Saharan countries are collaborating with their counterparts around the world to research into how genetic solutions could be used to fight malaria transmissions on the continent and the world as a whole.
Genetic bio-control tools, such as gene drive modified mosquitoes (GDMMs), have emerged as promising new tools that could be deployed within an integrated vector management system to improve malaria control and elimination prospects. These technologies are rapidly gaining interest due to their potential to overcome many of the major challenges of current malaria control tools and strategies.
GDMMs are genetically modified mosquitoes that have an additional mechanism that biases the inheritance of a particular gene, enhancing its probability of passing it on to offsprings. This in turn ensures a spread of specific genetic modifications throughout the mosquito population. Two approaches of GDMMs are being considered, namely population suppression, which aims to significantly reduce and potentially eliminate populations of certain vector species and population replacement, which aims to introduce novel genetic constructs that block disease transmission by a vector species.
Experts Views
Dr Fred Aboagye-Antwi, the In-Country Principal Investigator for the Target Malaria team in Ghana, who is also a Senior Lecturer in Medical Entomology and Parasitology at the Department of Animal Biology and Conservation Sciences (DABCS) of the University of Ghana, explains the role of the Ghanaian scientists and that of other Africans toward the use of gene drive technology to fight malaria in Africa.
Dr Aboagye-Antwi, stated that “No single tool is the magic wand to end malaria transmission in Ghana and by extension, Africa.”
According to him, other tools needed to be embraced including gene drive to eliminate malaria.
Dr Aboagye-Antwi, who doubles as a Senior Lecturer in Medical Entomology and Parasitology at the Department of Animal Biology and Conservation Sciences (DABCS) of the University of Ghana, stated that malaria elimination is possible but demands a lot of commitment from all stakeholders.
“If we relax on our efforts, malaria can go out of hand. We need to bring all stakeholders on deck,” he noted, stressing that malaria stakeholders included everyone “since we are all affected by malaria in one way or the other.”

For him, gene drive mosquitoes are an important emerging technology for vector control, adding that gene drive mosquitoes may be an additional tool to complement Insecticide treated nets and spraying of insecticides by blocking or reducing the transmission of Plasmodium, the malaria parasite to humans.

“It is important to mention that in 2020, the African Union’s High-Level Panel on Emerging Technologies singled out gene drive mosquitoes as one of three priority technologies to contribute to malaria elimination,” he added.

Dr Aboagye-Antwi explained that because gene drive (mosquitoes) could alter the traits of entire populations of organisms, they represent a potentially powerful tool to reduce the population of malaria carrying mosquitoes enough to stop the transmission of the disease.

For him, combining gene drive with genome editing techniques, several research teams are able to genetically modify the Anopheles mosquito genome and push modifications through the natural mosquito population to either suppress the population or replace it with genetically engineered mosquitoes.

He said African-based scientists in Ghana, Burkina Faso, Mali and Uganda, are working on various aspects of the Target Malaria’s gene drive initiative, adding that Burkina Faso has carried out the first phase of the project by conducting a small-scale experimental release of non- gene drive genetically modified sterile male mosquitoes in 2021.

Dr Aboagye-Antwi said although Ghana is currently not working on any gene drive mosquitoes, Ghanaian scientists are carrying out research work to answer some questions relating to the technology, hence contributing to the overall project.

He explained that the Ghanaian team is carrying out ecological observatory study to identify the role of the Anopheles gambiae mosquito in the environment.

For him, gene drive “is a non-invasive tool to fight malaria infections” and that “with gene drive, we are hoping to develop a potential tool that could contribute towards the future elimination of malaria.”

He, however, said although the technology presents a great potential, it ought to be well regulated by national, regional and international authorities, as well as supported by the affected populations in malaria-endemic countries.

“The Ghanaian scientists on the project must have a stakeholder engagement and communication strategy that involves working closely with all government bodies, including Wildlife Division of the Forestry Commission, the Environmental Protection Agency and the National Biosafety Authority; as well as rural communities where ecological research activities take place” he stated.

He also called on African governments and development partners to build the capacities of African scientists to be able to contribute to such scientific investigations.

Minister’s remarks
Dr Ibrahim Murtala Muhammed, the Minister of Environment, Science, and Technology hinted Ghana’s interest in exploring gene drive technology as a new approach to combatting malaria.

He said the country is open to adopting technology that is cost-effective, efficient, harmless and has the potential to significantly reduce malaria transmission, especially in areas where traditional control methods have failed.

Describing Malaria as a “serious threat,” Dr Muhammed said the burden of malaria on Africa’s economy was high as the continent spent millions of dollars on malaria control.

He said Ghana would adopt emerging technologies to help support disease prevention including those that affect crops “as long as it does not affect our survival as human beings.”

Professor Fredros Okumu, a Public Health Researcher and Mosquito Biologist, said Africa required innovative and transformative tools that could crash malaria with about 90 per cent efficiency.

He said evidence from the laboratories indicates that gene drives “might be the answer” to the quest for efficient and affordable technology to eliminate malaria.

“We have four-dose vaccines now for malaria. That tells you how weak our malaria arsenals are. So, we need new tools,” Prof. Okumu said.

By Benedicta Gyimaah Folley