- Kala-azar (visceral leishmaniasis) is primarily endemic in India, Bangladesh, and Sudan due to the presence of the Phlebotomus sandfly vector and suitable environmental conditions favoring transmission.
- These regions report the highest burden of disease, especially in the Indian subcontinent and East Africa.
- The disease predominantly affects poor rural populations, and control efforts focus on these endemic areas.
- Other listed countries do not have a significant endemicity of visceral leishmaniasis.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Infectious Diseases, Chapter on Leishmaniasis/Page 1067