Question

Which one of the following life cycles stages of Wuchereria bancrofti is infective to man?

• A. Microfilaria
• B. 1${}^{st}$stage larva
• C. 2${}^{nd}$stage larva
• D. 3${}^{rd}$stage larva

Answer 1

The correct option is D 3${}^{rd}$stage larva

The life cycle of Wuchereria bancrofti starts when a male and a female mate inside the lymphatic vessels of an infected human. The female releases thousands of microfilariae into the bloodstream. When the host is awake, the microfilariae tend to stay in deep blood vessels. During the sleep, they travel near the surface in peripheral blood vessels. This behaviour enables them to get ingested by the night-biting mosquito. When ingested by the mosquito, the microfilariae migrate through the midgut eventually reaching the thoracic muscles. Within 1-2 weeks, they mature into first stage larvae and eventually into the third-stage infective larvae. which migrate through the haemocoel to the mosquito's proboscis. When the mosquito bites another person, the larvae are injected into the human skin. They migrate to the lymph vessels and mature into adults. So, the correct answer is option D.