The ‘laboratory in a suitcase’ is considered a breakthrough in field testing for the disease which is spread by the female sandfly and is known as kala-azar in the Indian subcontinent. According to WHO, 90 per cent of all cases of kala-azar occur in Bangladesh, Brazil, India, Nepal and Sudan. Bangladesh reported some 600 new cases in 2014—2015.
On infection, the patient develops irregular bouts of fever, substantial weight loss, swelling of the spleen and liver, and serious anaemia which, if not quickly treated, is fatal.
Dinesh Mondal, principal researcher and senior scientist at the International Centre for Diarrhoeal Disease, Bangladesh (icddr,b), tells SciDev.Net, that his team’s endeavour was to come up with a portable kit capable of “confirmed diagnosis of new kala-azar, kala-azar relapse, dermal leishmaniasis and asymptomatic risk for development of disease.”
Developed in collaboration with the University of Gottingen, Germany, and funded by WHO-Tropical Disease Research, the kit is described by Mondal and his colleagues in Parasites & Vectors published May.
Conventional methods of diagnosing kala-azar rely on antibody tests and clinical symptoms. Molecular diagnosis is more accurate but requires using the real-time polymerase chain reaction (PCR) method to detect the DNA of the L. donovani parasite in the blood of infected people.
In contrast, the new kit uses recombinase polymerase amplification (RPA) to detect L. donovani DNA. Unlike PCR, RPA does not require repeated cycles of heating and cooling and yet provides 100 per cent accuracy. Furthermore, the new kit takes 30 minutes to run tests on eight samples simultaneously against the laboratory method which requires over three hours to test a single sample.
“PCR is the most sensitive test for detection of leishmania DNA, but it needs a specialised lab and highly trained personnel. It also costs about US$ 30—40 per test, while tests using the new kit costs just US$ 6 per test,” Mondal says.
“If the device proves effective in the next phase of field trial it could play a significant role in vector control strategies and surveillance capacity of the disease elimination programme in countries where the disease is a major burden,” Shamuzzaman, director at the communicable diseases department of Bangladesh’s directorate of health services, tells SciDev.Net. This piece was produced by SciDev.Net’s South Asia desk.