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Leishmania donovani in a bone marrow cell

Public Health Image Library (PHIL)

[NEW DELHI] The first rapid test for kala-azar, a deadly parasitic disease also known as visceral leishmaniasis, was launched on Friday (10 February) in India.

Unlike the current method, the new test is quick, painless and can be used in remote areas that lack electricity or hospitals. It is 100 per cent effective and costs less than US$2 — one-fifth of the current cost of diagnosis.

Kala-azar is caused by the parasite Leishmania donovani, which is transmitted to people by the bite of sandflies. It causes fever, weakness, anaemia and swelling of the liver and spleen.

Untreated, the disease can be fatal. Of the five million people who get it each year, more than 60,000 die.

Until now, the only way of detecting infections has been to take samples from the bone marrow or spleen in a painful procedure that only skilled doctors can perform.

The new test uses a strip of special paper with a 'dot' containing a protein made by the parasite.

When a blood sample from an infected person touches the paper, antibodies made by their immune system attach to the protein, making the dot change colour.

"It just takes eight minutes," says Sarman Singh of the All India Institute of Medical Sciences, which developed the test with funds from India's Department of Biotechnology. 

Singh adds that the test can detect the parasite within 15 days of infection, which is important as symptoms appear only after the parasite has completed an incubation period of up to three months.

His team hopes to convince India's health ministry to adopt the test in its programme to eradicate leishmaniasis by 2012. They will also ask the World Health Organization to use the test in other countries.

Leishmania parasites are found in at least 88 countries. Most cases of visceral leishmaniasis, the deadliest form of infection, occur in Bangladesh, India, Nepal and Sudan. 

There is already a rapid test for a related parasite called Leishmania chagasi. It occurs mainly in Latin America and parts of the Middle East, and causes a milder infection called cutaneous leishmaniasis affecting the skin.