Researchers in Portugal have found that a new antimalarial drug gives mice long-lasting protection against severe disease when exposed to malaria for a second time. 

Malaria is a life-threatening disease caused by Plasmodium parasites and spread by infected mosquitoes. The parasites first divide in the liver before entering the blood, where malaria becomes symptomatic, causing flu-like symptoms and, in severe stages, impaired consciousness and organ failure. Although malaria vaccines provide some protection, they do not give lasting protection against future infections. 

Researchers at EARA member Gulbenkian Institute for Molecular Medicine (GIMM) tested cabamiquine, a new anti-malarial drug currently in clinical trials that blocks the parasite from growing both in the liver and the blood. In mice infected with malaria parasites, a single dose given during the liver stage cleared the infection before it reached the blood. When the drug was given later, after the parasite had entered the blood, it cleared the infection and protected mice from severe disease when they were exposed to the parasite again weeks to months later.  

The findings suggest that cabamiquine, by controlling the infection while allowing the immune system to encounter the parasite, may help the body build immune memory against future exposure. 

“Next steps should include studies aimed at better understanding the relationship between cabamiquine’s pharmacological activity, the duration of exposure to parasite antigens and the development of immune memory”, said Miguel Prudêncio, from GIMM and lead author of the study published in the Journal of Infectious Diseases.