Question

Before reaching intestine, the larva of Ancylostoma travels through.

• A. Lungs and trachea
• B. Oesophagus
• C. Heart
• D. All the above

Answer 1

The correct option is D All the above

Eggs of Ancylostoma are passed in the stool and under favourable conditions (moisture, warmth, shade), larvae hatch in 1 to 2 days. The released rhabditiform larvae grow in the faeces and/or the soil, and after 5 to 10 days (and two moults) they become filariform (third-stage) larvae that are infective. These infective larvae can survive 3 to 4 weeks in favourable environmental conditions. On contact with the human host, the larvae penetrate the skin and are carried through the blood vessels to the heart and then to the lungs. They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed. The larvae reach the small intestine, where they reside and mature into adults. Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host. Most adult worms are eliminated in 1 to 2 years, but the longevity may reach several years.

So, the correct answer is 'All the above'.