Africa has long been the epicentre of malaria, battling the deadly disease with a combination of strategies, including insecticide-treated bed nets and indoor spraying. However, the landscape of this fight is rapidly changing.

Mosquitoes are increasingly developing resistance to insecticides, undermining these critical interventions. Additionally, new mosquito species, previously not found in certain regions, are now making their presence felt, posing new threats and challenges.

But what does the emergence of this double tragedy mean to the continent and what actions are being taken?

Dr Willy Kiprotich Tonui, EBS, the Chairman and Executive Director at Environmental Health Safety who also doubles up as the Founder and Head of the Secretariat at the African Genetic Biocontrol Consortium says that the emergence of these challenges means that new solutions must be developed and that is why scientists have been working day and night to come up with new solutions.

So far new compounds, DIF-1(+3), which has demonstrated significantly stronger growth inhibitory effects against Plasmodium falciparum have been synthesised, including strains resistant to chloroquine and artemisinin.

This compound showed near-complete suppression of parasite growth in vivo tests, indicating its potential as a new treatment option in areas with high levels of drug resistance.

“New insights into how malaria parasites invade host cells have also been revealed. This is useful in understanding mechanisms that can aid in developing targeted treatments and vaccines to prevent the parasite from establishing infection in the first place,” says Dr Tonui.

The development of whole sporozoite vaccines (WSVs), which use whole malaria parasites to induce immunity, has also shown promising results. These vaccines can generate robust immune responses by targeting the pre-erythrocytic stages of the malaria parasite, potentially offering high levels of protection.

Despite challenges in manufacturing and delivering these vaccines, they represent a significant advancement in malaria prevention.

“New approaches are also being explored to address the spread of drug-resistant malaria, particularly strains spread by Anopheles stephensi mosquitoes. Research is focusing on understanding the genetic and biological mechanisms that contribute to resistance, which could lead to more effective interventions and treatments,” adds Dr Tonui.

Scientists are also turning to new technologies, such as gene drives. Unlike traditional inheritance, where a gene has a 50 per cent chance of being passed on to offspring, gene drives increase this probability to nearly 100 per cent. This powerful tool has significant potential for controlling mosquito populations and reducing the spread of diseases, such as malaria.

“Gene drives can be designed to target various genes within mosquito populations. For example, they can be used to reduce fertility, increase disease resistance, and create a biased sex ratio,” he explains.

The most common method to create gene drives uses the Clustered Regularly Interspaced Short Palindromic Repeats- associated protein 9 (CRISPR-Cas9) gene-editing system, which allows for precise modifications of DNA within organisms.

For instance, if the goal is to render mosquitoes infertile, the gene drive will include a fertility-suppressing gene. When the modified mosquito mates, the CRISPR-Cas9 machinery ensures that the gene drive is copied into the genome of the offspring, thereby spreading the gene drive rapidly through the population.

“Research on gene drives for malaria control is currently in advanced stages, with some good developments and ongoing trials. Gene drives have been successfully tested in laboratory settings to reduce mosquito fertility and spread resistance genes against the malaria parasite. Field trials and pilot studies are also underway to test the effectiveness and safety of gene drives in real-world environments,” says Dr Tonui.

He said gene drives have the potential to significantly impact the control of malaria-transmitting mosquitoes by rapidly spreading genetic modifications that can reduce mosquito populations or render them incapable of transmitting the malaria parasite. The technology is unlikely to be a standalone solution.

It will form part of an integrated pest management strategy that includes other control measures, such as complementing existing insecticidal use programmes; reducing mosquito breeding sites and using biological controls that can work alongside gene drives; and encouraging efforts to vaccinate populations and treat malaria patients.​

Dr Tonui says that though gene drive technology has been identified as a potential new option to augment existing interventions, it has its limitations. One of the potential challenges is that the introduction of gene drives into wild populations could have unforeseen ecological impacts, such as disruption of ecosystems, unintended harm to non-target species, and the possibility of the gene drive spreading beyond the target population.

“Target organisms also may develop resistance to the gene drive over time. Mutations can occur that prevent the gene drive from functioning effectively, reducing its long-term efficacy,” he adds.

Apart from that, the deployment of gene drives also raises significant ethical issues, including consent from affected communities, potential misuse, and the long-term implications of altering wild populations. Public acceptance and ethical considerations are critical for the success and acceptance of gene drive technologies.

There is also a lack of comprehensive regulatory frameworks to manage the deployment of gene drives.