In a major scientific breakthrough, researchers at the BRIC-RGCB here have discovered a previously unknown mechanism by which malaria parasites evade the effects of artemisinin, the world’s most widely used antimalarial drug.

The findings, published as an Editor’s Choice article in 'The Journal of Infectious Diseases' by Christeen Davis and colleagues, show that young red blood cells, known as reticulocytes, create a protective biochemical environment that helps malaria parasites withstand drug-induced stress.

The study challenges the prevailing view that artemisinin resistance is driven primarily by genetic changes within the parasite.

Instead, it demonstrates that host cells themselves can significantly influence treatment outcomes, according to a statement issued here on Wednesday.

The research at Rajiv Gandhi Centre for Biotechnology, an institution under the Biotechnology Research and Innovation Council (BRIC), was carried out in collaboration with scientists from IISER Thiruvananthapuram, Cosmopolitan Hospital, Thiruvananthapuram, and CSIR–National Chemical Laboratory (NCL), Pune.

“Our findings demonstrate that the biology of the host cell can significantly influence how malaria parasites respond to treatment,” said Dr Rajesh Chandramohanadas, senior author of the study and Principal Investigator at RGCB.

“The parasite is not acting alone. It exploits the natural antioxidant defences present in young blood cells to protect itself from drug-induced stress,” he said.

The study is particularly relevant for children, anaemic patients, and individuals recovering from blood loss or infection, all of whom often have elevated levels of reticulocytes in circulation. Such conditions may create a more favourable environment for parasite survival during treatment, it said.

Malaria parasites live and multiply inside human red blood cells. While previous research has largely focused on genetic changes within the parasite that lead to drug resistance, the new study shows that host cells can also play a major role in determining treatment outcomes, the study said.

Using highly purified human reticulocytes and advanced analyses, the RGCB team found that these immature blood cells contain abundant nutrients, antioxidants, and protective enzymes.

When malaria parasites infect reticulocytes, they gain access to this protective environment, allowing them to grow faster and better tolerate oxidative damage caused by artemisinin treatment, the study said.

The team observed that parasites developing inside reticulocytes were significantly less susceptible to artemisinin and related compounds compared with those growing in mature red blood cells.

Importantly, this protective effect disappeared when the parasites were transferred back into mature cells, demonstrating that the phenomenon is driven by the host cell environment rather than permanent genetic changes in the parasite.

Dr Beena Pillai, Director, BRIC-RGCB, said, “The significant findings will help explain why some malaria infections show delayed clearance or persistence despite treatment, even when known genetic markers of drug resistance are absent.” Beyond malaria, the work highlights a broader principle in infectious disease biology: the success of a pathogen can depend not only on its own genetic makeup but also on the physiological state of the host cells it infects.

The researchers believe that future malaria therapies may benefit from targeting host–parasite interactions in addition to the parasite itself.

Understanding how parasites exploit antioxidant pathways within reticulocytes could open new avenues for improving the effectiveness of existing antimalarial drugs and reducing treatment failures.

Malaria continues to affect hundreds of millions of people worldwide and remains a major public health challenge in many tropical countries.

By revealing how host blood cells influence parasite survival, this discovery provides an important new perspective on the disease and its treatment, the statement added.