Kala azar (visceral leishmaniasis)

Largely unknown in high-income countries (although it is present in the Mediterranean basin), kala azar - Hindi for ‘black fever’ - is a tropical, parasitic disease transmitted through bites from certain types of sand fly. It is endemic in 76 countries, and of the estimated 200,000-400,000 annual cases, 90 per cent occur in Bangladesh, India, Ethiopia, South Sudan, Sudan and Brazil. Kala azar is characterised by fever, weight loss, enlargement of the liver and spleen, anaemia and immune-system deficiencies. Without treatment, kala azar is almost always fatal.

In Asia, rapid diagnostic tests can be used for diagnosis of the disease. However, these tests are not sensitive enough for use in Africa, where diagnosis often requires microscopic examination of samples taken from the spleen, bone marrow or lymph nodes. These are invasive and difficult procedures requiring resources that are not readily available in developing countries.

Treatment options for kala azar have evolved over recent years. Liposomal amphotericin B is becoming the primary treatment used in Asia, either alone or as part of a combination therapy. This is safer and involves a shorter course of treatment than previously used medication. However, it requires intravenous administration, which remains an obstacle to its use in local clinics. In Africa, the best available treatment is still a combination of pentavalent antimonials and paromomycin, which is toxic and requires a number of painful injections. Research into a simpler treatment is underway and it is hoped it will soon be available.

Co-infection of kala azar and HIV is a major challenge, as both diseases influence each other in a vicious spiral as they attack and weaken the immune system.

MSF treated 5,400 patients for kala azar in 2015.