A child from Bihar was brought to OPD with fever. On blood examination,sheathed microfilaria with two nuclei in tail tip is seen . The diagnosis is:

This is the characteristic feature of microfilaria of Brugia malayi. Adults localise in the lymphatics and female lays microfilaria Shows nocturnal periodicity, Sheathed, have a non-continuous row of blurred nuclei throughout the length of the body. There are two terminal nuclei in the tail that are distinctly separated from the other nuclei.