Global analysis reveals wide regional variations in the performance of insecticide-treated nets

A major analysis of twenty-five studies conducted across Africa and Asia finds that insecticide-treated nets reduce malaria cases by up to 68% – but highlights challenges that threaten to undermine their long-term impact.

The study was published in the peer-reviewed journal Infectious diseasesHe confirms that insecticide-treated nets (ITNs) still provide strong protection against malaria – but reveals that their effectiveness varies widely between regions and communities.

These results suggest that the performance of this relatively simple, low-cost intervention is under pressure – especially in areas where insecticide resistance is already established.

The researchers warn that without locally adapted control strategies that combine insecticide-treated bed nets and other mosquito control measures, progress made over recent decades may be at risk.

“While this study reinforces that insecticide-treated mosquito nets remain one of the most powerful weapons we have against malaria, it is also a warning that we cannot become complacent,” says Dr. Gbeminiyi Otolorin, a doctoral researcher at James Cook University, Australia, and a veterinary public health physician and researcher at the School of Veterinary Medicine at the University of Jos, Nigeria.

Mosquitoes are evolving resistance and adapting their behavior — and a tool that works well in one place may actually be a failure in another. We must continually monitor, evaluate and design our control strategies as we strive toward global eradication of the disease.”

Dr. Gbeminiyi Otolorin, James Cook University

Malaria is a life-threatening disease caused by a parasite that is transmitted to humans through the bites of infected mosquitoes. In 2024, there will be an estimated 282 million cases and 610,000 deaths due to infection worldwide. Insecticide-treated mosquito nets are among the most widely used and most cost-effective tools in Malaria prevention – Protecting individuals while reducing mosquito populations and reducing transmission across entire communities.

To get a better understanding of how well insecticide-treated nets reduce malaria illness and death, researchers analyzed data from 25 experimental studies comparing the performance of insecticide-treated nets with no nets. These included 19 studies examining malaria incidence and six studies assessing malaria-related mortality, including eight African and four Asian countries. The study groups included children under five years of age, pregnant women, families, and entire communities, with follow-up periods ranging from two months to five years.

The results confirm the strong protective effect of insecticide-treated mosquito nets in these diverse settings. In Asia, insecticide-treated nets were associated with a 68% incidence. Reducing malaria Malaria cases and an 18% reduction in malaria-related deaths. In Africa, they have succeeded in reducing malaria infection rates by between 29% and 40%.

However, the researchers also identified significant variation in the effectiveness of ITNs between studies, especially in Asia. They suggest that these differences may be influenced by complex local factors, including mosquito species diversity, insecticide resistance patterns, and community compliance with bed net use.

“Insecticide-treated nets are undoubtedly an effective tool that has saved millions of lives and will continue to do so – but relying on them alone is not enough, especially in areas with established insecticide resistance,” adds Dr. Ottoloren, who specializes in infectious disease epidemiology.

“Integrated strategies that combine bed nets with other interventions must now be considered essential – otherwise we risk losing ground in the battle against a disease that still kills hundreds of thousands of people every year.”

The paper calls for further research to evaluate long-term net durability, community compliance, and patterns of insecticide resistance.

“I hope that this work will add to the existing evidence base supporting malaria control efforts and contribute to ongoing discussions about how ITNs can be improved, adapted and used effectively in communities where malaria prevention remains a priority,” Dr. Ottolorin concludes.