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 sandfly. Of the estimated 50,000 – 90,000 annual cases, 90 per cent occur in Brazil, Ethiopia, India, Kenya, Somalia, South Sudan and Sudan, where the disease is endemic. 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 during recent years. Liposomal amphotericin B is becoming the primary treatment 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. An oral drug, miltefosine, is often added to optimise treatment regimens in certain categories of patients. 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 the diseases influence each other in a vicious spiral as they attack and weaken the immune system.
MSF treated 1,970 patients for kala azar in 2019.