Question

The causal organism for Kala-azar is
A. Plasmodium vivax
B. Leishmania donovani
C. Trypanosoma lewisi
D. Wuchereria bancrofti

Answer 1

Hint: The name Kala azar characterises the obscuring of skin that is observed in the patients suffering from this disease. It is caused by a parasite that belongs to Phylum-Protozoa of the Kingdom- Protista. The parasites of protozoa are all free living aquatic and perform locomotion by 1 or 2 or many thread like flagella. These parasite undergoes asexual reproduction by binary fission but sexual reproduction is absent.

Complete answer:
Kala-azar, also known as Dum-Dum fever or Leishmaniasis is characterised by bouts of fever, anaemia, swelling of liver and spleen. It can result in death of the patient if it is left untreated. It is caused by a dimorphic and digenetic parasite ‘Leishmania donovani’. It migrates to the body's internal organs and causes sickness. ‘Sandfly’ plays an important role in the spread of this disease as it acts as a carrier in Visceral Leishmaniasis. Different sand flies carry and transmit different parasites of Leishmania. Leishmania donovani is transmitted by a particular carrier i.e. female Phlebotomus Argentipes.

Therefore the correct option is (B) Leishmania Donovani.

Note: Leishmania Donovani is an intracellular parasite that belongs to the class Mastigophora or Flagellata of Protozoa. It involves two different hosts to complete its life cycle. The parasite exists in Amastigote form in mammals and in Promastigote form in sand fly which can be seen in midgut of female sand fly. This parasite migrates into the spleen, bone marrow etc. and spreads infection in the reticulo endothelial system. The disease can be both symptomatic and asymptomatic. In asymptomatic condition, the infection is cleared naturally most of the time.