This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Vector of kala-azar is: \nSelect and explain. \nA. Sandfly, B. Tsetse fly., C. Mites, D. Flea', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Leishmaniasis is caused by protozoan parasites belonging to the genus Leishmania.\xa0\nThe parasites are transmitted by the bite of a tiny – only 2–3 mm long – insect vector, the phlebotomine sandfly.\nThere are some 500 known phlebotomine species, but only about 30 have been found to transmit leishmaniasis.\xa0\nOnly the female sandfly transmits the parasites.\xa0\nFemale sandflies need blood for their eggs to develop, and become infected with the Leishmania parasites when they suck blood from an infected person or animal.\xa0\nOver a period of between 4 and 25 days, the parasites develop in the sandfly.\xa0\nWhen the infectious female sandfly then feeds on a fresh source of blood, it inoculates the person or animal with the parasite, and the transmission cycle is completed.\n\nRef :https://www.who.int/leishmaniasis/disease/vector/en/', 'role': 'assistant'}]