Dum-dum fever is caused by Leishmania donovani, a protozoan parasite that is transmitted to humans through the bite of infected female sand flies. Here's a detailed explanation of the disease:

Leishmaniasis
Leishmaniasis is a parasitic disease caused by the Leishmania parasite, which is transmitted to humans through the bite of infected female sand flies. The disease is prevalent in many parts of the world, including Africa, Asia, South America, and the Mediterranean basin. There are three main forms of the disease: cutaneous leishmaniasis, mucocutaneous leishmaniasis, and visceral leishmaniasis (also known as kala-azar).

Visceral leishmaniasis (VL)
Visceral leishmaniasis, also known as kala-azar, is the most severe form of the disease, and if left untreated, it can be fatal. The disease is characterized by fever, weight loss, enlargement of the spleen and liver, and anemia. In some cases, the disease can also affect the bone marrow and cause leukopenia and thrombocytopenia.

Dum-dum fever
Dum-dum fever is a colloquial term used to describe visceral leishmaniasis (VL) in India. The term "dum-dum" is derived from the name of a place in West Bengal, India, where the disease was first reported in the early 20th century.

Transmission
The Leishmania parasite is transmitted to humans through the bite of infected female sand flies of the genus Phlebotomus in the Old World and Lutzomyia in the New World. The sand fly injects promastigote forms of the parasite into the skin of the host during blood feeding. The promastigotes are then taken up by macrophages and transform into amastigotes, which multiply within the host cells and cause the disease.

Treatment
Visceral leishmaniasis can be treated with drugs such as sodium stibogluconate, amphotericin B, and miltefosine. However, the treatment is often prolonged and can cause side effects. Prevention measures include controlling the sand fly population, using insecticide-treated bed nets, wearing protective clothing, and avoiding outdoor activities during peak biting hours.

Conclusion
In conclusion, Dum-dum fever is caused by Leishmania donovani, a protozoan parasite transmitted to humans through the bite of infected female sand flies. The disease is prevalent in many parts of the world and can be fatal if left untreated. Treatment and prevention measures are available.