Visceral leishmaniasis (VL, also known as kala-azar), is caused by the leishmania parasites and spread by female sand flies. Over 147 million people are at risk to develop VL and an estimated 200,000 to 400,000 new cases of VL occur worldwide each year. More than 90% of the new cases occur in 6 countries: Bangladesh, Brazil, Ethiopia, India, South Sudan and Sudan. Once the parasite enters the blood, it infects immune cells and subsequently affects several internal organs, including the spleen, liver and bone marrow which causes fever, weight loss, enlargement of organs and anaemia. Treatment is based on the severity of the disease and the patient’s underlying health conditions (HIV-infection, malnutrition, pregnancy and immunosuppression). The use of high effective treatment is not only essential to cure the disease, but also to prevent relapse and the development of post-kala-azar dermal leishmaniasis (PKDL), and to reduce the transmission of the disease. If left untreated VL is lethal.
PKDL is a sequel of visceral leishmaniasis that appears as macular, papular or nodular rash usually on the face, upper arms, trunks and other parts of the body. It occurs mainly in East Africa and on the Indian subcontinent, where up to 50% and 5–10% of patients with kala-azar, respectively, develop the condition. People with PKDL are considered to be a potential source of kala-azar infection.
Successful elimination strategy
In 2005, the governments of India, Nepal and Bangladesh, in collaboration with the WHO, developed a strategy to eliminate visceral leishmaniasis (VL) as a public health problem by 2015. This strategy consists of rapid case detection, treatment and vector control. In 2014, the number of cases globally had been reduced by 53%, while the mortality dropped by 85%. More impressive is that Nepal has eliminated VL at district level; Bangladesh has achieved the elimination target in over 90% of endemic sub-districts; and India has achieved elimination in 70% sub-districts. Furthermore, the collaboration with the Leprosy Elimination Programme as well as active community involvement have enhanced the case detection and contributed to the decline in the number of cases (650 new cases) and deaths (1% mortality rate) reported by Bangladesh in 2014.