Wuchereria bancrofti is a human parasitic roundworm that causes filariasis. The microfilariae are found mainly in the peripheral blood and can be found at peak amounts from 10 pm to 4 am. They migrate between the deep and the peripheral circulation exhibiting unique diurnal periodicity. During the day, they are present in the deep veins, and during the night, they migrate to the peripheral circulation. So, in order to collect the filarial larvae, the peripheral blood should be collected during the night