VL rapid diagnostics may be inadequate in Brazil and East Africa
A new paper on visceral leishmaniasis rapid diagnostic tests shows the accuracy varies between the major endemic regions. Many tests performed well in the Indian subcontinent but results in Brazil and East African countries suggest that several tests are inadequate in those areas for excluding a diagnosis. The results were published in Clinical Infectious Diseases 31 August, 2012.
A global comparative evaluation of commercial immunochromatographic rapid diagnostic tests for visceral leishmaniasis
Visceral leishmaniasis is a parasitic disease transmitted through the bite of an infected phlebotomine sandfly. The disease starts with fever and weight loss, leading to further problems that are nearly always fatal if left untreated. Almost 400 000 cases occur every year in six countries: Bangladesh, Brazil, Ethiopia, India, Nepal and Sudan.
Parasitological confirmation remains the reference standard for diagnosis but is not very sensitive unless a spleen puncture is performed, so new tests that are easier to use in field situations have been developed. Commonly referred to as rapid diagnostic tests (RDTs), they are increasing in number and being marketed, but there are few head-to-head comparisons of diagnostic accuracy in the peer-reviewed literature. Furthermore, essential characteristics such as heat stability are rarely assessed.
Consequently, TDR coordinated a multiregional head-to-head laboratory-based evaluation of four commercially available RDTs in three global regions of VL endemicity, and a fifth RDT was also evaluated only in the Indian subcontinent. The evaluation found that the performance of some products was adversely affected by high temperatures. More research, however, is needed to assess ease-of-use and to compare performance using whole blood instead of serum and in HIV-co-infected patients.
The work was conducted by the WHO/TDR Visceral Leishmaniasis Laboratory Network, including:
- Institute of Tropical Medicine, Antwerpen, Belgium
- Rajendra Memorial Research Institute of Medical Science, Patna, India
- Department of Medical Microbiology & Parasitology, University of Khartoum, Sudan
- Laboratório de Soroepidemiologia e Imunobiologia, Instituto de Medicina Tropical de São Paulo, Brasil
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
- Kenya Medical Research Institute (KEMRI) Nairobi, Kenya
- Institute Endemic Diseases, University of Khartoum, Sudan
- Centro de Pesquisas René Rachou-FIOCRUZ, Bello Horizonte, Brasil
- B.P. Koirala Institute of Health Sciences, Dharan, Nepal
- Banaras Hindu University, Varanasi, India
- Royal Tropical Institute/Koninklijk Instituut voor de Tropen (KIT); Amsterdam, Netherlands
- London School of Hygiene & Tropical Medicine, London, UK
For more information, please contact:
Dr Jane Cunningham