37.4.2  Mode of transmission of lymphatic filariasis

The parasites that cause lymphatic filariasis are transmitted from human to human through the bites of Culex and Anopheles mosquitoes. The female mosquitoes take the microscopic forms of the parasitic worm (microfilaria) from an infected person during a blood meal (Figure 37.20a). The microfilaria develop into larvae, and when the mosquito feeds on another person, the larvae enter the skin punctured by the mosquito bite (Figure 37.20b). The larvae travel via the lymphatic vessels, where they develop into adult worms all over the body (Figure 37.20c). After mating, the females lay millions of eggs which develop into microfilaria, completing the lifecycle.

View larger image

Figure 37.20  Life cycle of lymphatic filariasis. (Source: WHO at http://www.who.int/lymphatic_filariasis/en/)