Mosquito Nets Cut Malaria Sharply, But Resistance Threatens Hard-Won Gains

As India pushes towards its ambitious target of eliminating malaria by 2030, a new international analysis has reaffirmed the importance of one of the oldest and most effective weapons against the disease — insecticide-treated mosquito nets.

At the same time, the study has sounded a warning that evolving mosquito behaviour and growing insecticide resistance could threaten decades of progress if control strategies are not continuously adapted.

Published in the peer-reviewed journal Infectious Diseases, the analysis reviewed evidence from 25 studies conducted across Africa and Asia and found that insecticide-treated nets (ITNs) reduced malaria cases by as much as 68% in some settings.

Researchers, however, observed considerable variation in effectiveness across regions, suggesting that local conditions play a crucial role in determining outcomes.

The findings arrive at a significant moment for India, which has recorded a dramatic decline in malaria burden over the past two decades. According to government data, malaria cases and deaths have fallen sharply through a combination of surveillance, early diagnosis, prompt treatment, indoor residual spraying and widespread distribution of long-lasting insecticidal nets in endemic districts.

Yet, public health experts caution that the final stretch towards elimination is often the most difficult. As transmission declines, remaining cases tend to cluster in hard-to-reach tribal, forested and border regions where healthcare access is limited and mosquito-control measures are more challenging to sustain.

Malaria remains one of the world's most persistent infectious diseases. The World Health Organization estimated around 282 million malaria cases and 610,000 deaths globally in 2024. The disease is caused by parasites transmitted through the bites of infected female Anopheles mosquitoes.

Against this backdrop, insecticide-treated nets have become a cornerstone of malaria prevention. Besides providing a physical barrier against mosquito bites during sleeping hours, the insecticide coating helps kill mosquitoes and reduce transmission within communities.

To assess their real-world impact, researchers analysed data from 25 experimental studies conducted in eight African and four Asian countries. The studies included children, pregnant women, households and entire communities and followed participants for periods ranging from two months to five years.

The results confirmed the substantial protective effect of ITNs. In Asian settings, malaria incidence was reduced by up to 68%, while malaria-related deaths declined by 18%. In Africa, reductions in malaria cases ranged from 29% to 40%.

However, the study also highlighted significant differences in effectiveness between locations.

Researchers believe these variations may be driven by factors such as differences in mosquito species, levels of insecticide resistance, environmental conditions and how consistently communities use mosquito nets.

"While this study reinforces that ITNs remain one of the most powerful weapons we have against malaria, it is also a warning that we cannot afford to become complacent," said Dr. Gbeminiyi Otolorin, doctoral researcher at James Cook University, Australia, and a veterinary public health clinician and researcher at the University of Jos, Nigeria.

"Mosquitoes are developing resistance and adapting their behaviour, and a tool that works well in one place may already be failing in another. We must continuously monitor, evaluate and tailor our control strategies as we strive towards global elimination of the disease," he said.

The warning is particularly relevant for countries such as India, where malaria transmission patterns vary considerably across States and ecological zones. Areas dominated by forest malaria, for instance, may require different interventions compared to urban or peri-urban settings.

India's malaria elimination strategy already emphasises district-level planning and targeted interventions. Public health specialists say the new findings strengthen the case for localised approaches rather than relying on a single solution nationwide.

The study notes that insecticide-treated nets have saved millions of lives over the past two decades but should increasingly be viewed as part of a broader package of interventions.

"ITNs are undeniably an effective tool that has saved millions of lives and will continue to do so, but relying on them alone is not enough, particularly in areas with established insecticide resistance," Dr. Otolorin said.

"Integrated strategies that combine nets with other interventions should now be considered essential. Otherwise, we risk losing ground in the fight against a disease that still kills hundreds of thousands of people every year," he added.

Experts point out that integrated malaria control may include indoor residual spraying, larval source management, environmental modification, rapid diagnostic testing, timely treatment and strengthened surveillance systems capable of quickly identifying outbreaks.

The researchers have called for additional studies examining the long-term durability of mosquito nets, patterns of insecticide resistance and community compliance with net usage.

The latest World Health Organization (WHO) malaria report highlights that malaria remains a major global public health challenge despite decades of control efforts. In 2024, the disease infected an estimated 282 million people and caused about 610,000 deaths, marking an increase compared with the previous year and underscoring the need for renewed action.

The burden of malaria continues to fall overwhelmingly on the African Region, which accounted for 94% of global malaria cases and 95% of malaria-related deaths. Children under the age of five remained the worst-affected group, representing the majority of malaria fatalities across the continent.

In the WHO South-East Asia Region, India continued to bear the largest share of the malaria burden, accounting for 73.3% of all reported cases and 88.7% of deaths in the region. The figures underline the importance of strengthening surveillance, diagnosis, treatment and vector-control measures, particularly in vulnerable districts.

The report notes that several new interventions are beginning to make a difference. WHO estimates that malaria vaccines, dual-insecticide-treated mosquito nets and preventive treatment programmes helped avert nearly 170 million malaria cases and around one million deaths in 2024. These innovations are increasingly being viewed as critical tools in accelerating malaria control efforts.

A major development has been the growing adoption of malaria vaccines. According to the report, 24 countries have now introduced WHO-recommended malaria vaccines into their routine immunisation programmes, offering new hope in protecting children living in malaria-endemic regions.

The global elimination movement has also recorded important successes. Forty-seven countries and one territory have achieved malaria-free status, with Egypt and Timor-Leste becoming the latest to receive WHO certification in 2025, demonstrating that elimination is achievable with sustained commitment and investment.

However, the report cautions that global progress has largely stalled since 2015, raising concerns about the world's ability to meet the malaria reduction targets set for 2030. WHO has warned that without accelerated investment, stronger health systems, wider access to prevention tools and targeted interventions in high-burden areas, the goal of substantially reducing malaria cases and deaths by the end of the decade could remain out of reach.