A child from Bihar comes with fever. Blood examination shows sheathed microfilaria with nuclei upto tail tip. The diagnosis is -

Ans. is 'a' i.e., Br. Malayi 'Sheathed microfilaria with nuclei upto the tip' is a feature of Br. Malayi. Note Loa - Loa also has sheathed microfilaria with nuclei up to tail tip, but it is uncommon in India and it does not cause fever. It causes subcutaneous swelling - calabar swelling or fugitive swelling.