Key facts:

• Among the 3 main forms of leishmaniases – visceral, also known as kala-azar is the most serious form of the disease.
• Caused by the protozoan Leishmania parasites which are transmitted by the bite of infected female phlebotomine sandflies.
• An estimated 900 000–1.3 million new cases and 20 000 to 30 000 deaths occur annually.

    (source: WHO)

Figure 1: Areas affected by Kala-azar

VL was first described in 1824 in the west of the country, in Jessore, Khulna Division.

Epidemics with a Case Fatality Rate of around 95% occurred every 15-20 years.  One outbreak killed 75,000 (1824-27).

In the period 1931 to 1943 there were more than 1,000,000 cases.

DDT spraying for malaria was thought to eliminate VL after 1970s. Resurgence of VL occurred after the DDT campaign stopped, with 73,467 cases in the period 1994-2001.

Figure 2: Trend of Visceral Leishmaniasis

Many areas are currently endemic, e.g. Mymensingh.  In 2007 there were an estimated 136,500 active cases but less than 5,000 were reported, so underreporting is a major challenge.

VL mostly affects the poorest households.  Risk factors include living close to an active case, poor nutrition, and poor housing.  Environmental changes including urbanization, domestication of the transmission cycle, and the incursion of agricultural farms and settlements into forested areas- also affect the incidence of leishmaniasis include.

Leishmaniasis is climate-sensitive, and strongly affected by changes in rainfall, temperature and humidity. Global warming and land degradation together affect the epidemiology of leishmaniasis.

Post-kala-azar dermal leishmaniasis (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- which has become another threat due to kala-azar incidences. The rising PKDL incidence threatens the regional visceral leishmaniasis elimination initiative and underscores the urgent need for more effective PKDL diagnosis and treatment.