Scientists develop simple, rapid test for drug-resistant malaria

Scientists from the US and Cambodia have developed a novel and rapid way to test if the most common and lethal form of malaria is resistant to artemisinin, the key anti-malarial drug.

'In the race against time to stop the spread of artemisinin-resistant malaria, new diagnostic tools are urgently needed to identify and track resistant parasites. These simple in vitro and ex vivo ring-stage survival assays (RSAs) can clearly identify artemisinin-resistant, slow-clearing Plasmodium falciparum (the protozoa that causes malaria) parasites in people with malaria, and can deliver results much faster than the current clinical approach used to monitor response to drugs in patients', explained study leader Didier Menard from the Institut Pasteur du Cambodge in Cambodia. (Also read: Top 10 facts you should know about malaria)

The findings of the study were published on Wednesday in The Lancet Infectious Diseases journal.

More than 200 million people are infected with the malaria parasite P falciparum, which kills between 655,000 and 1.2 million people every year. Antimalarial control efforts are mainly dependent on artemisinin-based combination treatments (called ACTs), having replaced older drugs that the malaria parasite developed resistance to.

Should these regimens fail, no other drugs are ready for widespread use, and eliminating malaria in the near future might then prove impossible. (Also read: Neem and Tulsi, effective remedies to keep malaria out of your home)

The emergence of P falciparum resistance to artemisinin has been described by the World Health Organisation as an urgent public health concern, threatening the sustainability of the ongoing global effort to reduce the burden of malaria.

In this study, a team of researchers from the Cambodian National Malaria Centre, the Institut Pasteur, Phnom Penh and Paris, and the US National Institutes of Health set out to test if a novel in vitro RSA could distinguish slow-clearing from fast-clearing parasites, investigate the in vitro response to dihydroartemisinin (DHA; the active metabolite of all artemisinins) of three different blood stages of parasites, and assess whether an ex-vivo RSA might detect artemisinin-resistant P falciparum infections.

In a linked comment, Carol Hopkins Sibley from the WorldWide Antimalarial Resistance Network remarked: 'These assays will allow the rapid validation of candidate molecular markers by directly testing the correlation of proposed markers with the output from their survival assay. The in vitro test will also provide a platform for understanding the mechanism of the reduced artemisinin response. With these simple methods in place, rapid tracking of the geographical and temporal changes in artemisinin resistance will be feasible in many sites. This far more comprehensive information will allow policy makers to design effective responses to the threat of artemisinin failure, and prolong the useful therapeutic life of ACTs.'

What is malaria?

Malaria is an infectious disease that is caused by mosquito-borne plasmodium parasite which infects the red blood cells. It s one of the deadliest diseases in India. There s no vaccine for malaria yet and immunity occurs naturally through repeated infection. Common symptoms are fever, chills, vomiting, nausea, body ache, headache, cough and diarrhoea. If untreated, it can lead to complications like jaundice, dehydration, anaemia, brain malaria, liver failure and kidney failure. Children, pregnant women, and the elderly anyone with decreased immunity is at a greater risk. (Read more..)

With inputs from DNA