Although the incidence of malaria fell by nearly a quarter between 2000 and 2015, the trend has reversed over the past decade, with global incidence rising by 8.5% since 2015. Experts say the growing threat of resistance to anti-malarial medicines could complicate efforts to eliminate the disease and reverse gains.

India currently holds about 1.4% of the global malaria burden, marking a decline from previous decades. Estimated cases in the country fell from 6.4 million in 2017 to nearly two million in 2023, while malaria-related deaths declined by about 68% during the same period, leading to India’s move from the WHO’s High Burden to the High Impact list.

Much of the progress has been driven by improvements in diagnosis, treatment and vector control, along with the efforts of community health workers. Suresh Kumar D., senior specialist in infectious diseases, Apollo Speciality Hospitals, Chennai, said door-to-door screening and early diagnosis by Accredited Social Health Activists (ASHAs) played a crucial role in reducing transmission, particularly in rural areas.

Challenges ahead

However, experts say the gains still remain fragile. Transmission persists in tribal and forest regions where access to diagnostics and medicines remains inadequate. India also continues to carry a substantial burden of Plasmodium vivax, accounting for nearly 46% of the global burden of the species. The country’s malaria case mix comprises approximately 57% P. falciparum and 43% P. vivax.

While P. falciparum remains responsible for most severe and fatal infections, P. vivax poses a different challenge. “Vivax may be less deadly, but it relapses and continues silently seeding transmission,” Dr. Suresh said.

Resistance to frontline medicines

For the past two decades, malaria treatment has largely relied on artemisinin-based combination therapies (ACTs), which pair a fast-acting artemisinin drug with another medicine that helps clear the remaining parasites. However, resistance to these therapies is emerging as one of the biggest concerns in malaria control.

According to Melissa Sathyan, consultant in internal medicine, Rela Hospital, Chennai, resistance to artemisinin and some of the partner drugs used in ACTs has been reported primarily in Southeast Asia and parts of Africa. The greatest concern remains P. falciparum, which is responsible for the majority of severe malaria cases.

Partial resistance to artemisinin has been linked to mutations in the parasite’s kelch13 (K13) gene. Dr. Suresh said mutations such as R561H, first reported in Rwanda, have spread into neighbouring regions including Tanzania, while other K13 variants have expanded across the Great Rift Valley. At least eight African countries have reported confirmed or suspected resistance.

Though these mutations have not emerged as a major problem in India, the risk of spread cannot be discounted. P. Praveen Kumar, consultant in general medicine, SRM Prime Hospital, Chennai, said there was also increasing concern over reduced responsiveness of P. vivax parasites to certain therapies.

Contributing factors

Several factors are contributing to the emergence of resistant strains, including incorrect use of anti-malarial medicines, poor adherence to treatment, circulation of counterfeit or substandard drugs, and historical use of artemisinin monotherapy before combination therapies became standard. Weaknesses in vector control and growing insecticide resistance further complicate the picture.

For patients, the consequences can be severe. Delayed parasite clearance, prolonged illness, treatment failure and the need for second-line therapies can increase healthcare costs and the risk of severe malaria and death, Dr. Sathyan noted.

Climate change also adds to the challenge. The spread of Anopheles stephensi, a mosquito species adapted to urban environments, along with changing climatic conditions, could accelerate transmission.

Need for stronger surveillance and strategies

Despite the threat posed by resistance, ACTs continue to be recommended by the WHO and India’s national guidelines as first-line treatment for uncomplicated malaria. Severe malaria is treated with intravenous artesunate followed by oral ACTs.

Experts said newer drug combinations and alternative treatment strategies were being evaluated in response to evolving resistance patterns.

For severe malaria, intravenous artesunate remains the preferred standard of care. For uncomplicated P. vivax malaria, chloroquine and primaquine continue to be widely used. Primaquine is particularly important because it targets hypnozoites , dormant forms of the parasite in the liver that can trigger relapses.

Future approaches may involve rotating different first-line therapies across regions and employing triple ACT combinations, which pair artemisinin with two partner drugs, thereby making it more difficult for parasites to overcome treatment. Approved malaria vaccines are also being introduced in high-risk regions as part of broader control strategies.

Surveillance would be central to containing resistance. Routine therapeutic efficacy studies and molecular surveillance to detect K13 mutations, along with monitoring insecticide resistance, are becoming increasingly important.

Operational surveillance and India’s test-track-treat strategy had been key to managing local outbreaks. Experts also underscored the importance of early diagnosis, prompt treatment, insecticide-treated bed nets, indoor residual spraying and community awareness programmes.

Research priorities include the development of next-generation anti-malarial drugs with mechanisms different from those of artemisinin and continued efforts to develop vaccines. Ensuring the quality of medicines and sustaining investments in community health worker networks will also be critical, particularly as the remaining pockets of transmission are concentrated in hard-to-reach regions.

With India aiming to eliminate malaria by 2030 and the global burden showing signs of resurgence, experts say sustained vigilance and innovation will be essential to prevent drug resistance from eroding decades of progress.