Question

Human liver fluke has two intermediate hosts in its life cycle which are __A__ and __B__.

• A. A - snail, B - fish
• B. A - snail, B - human beings
• C. A - fish, B - human beings
• D. A - mosquito, B - housefly

Answer 1

The correct option is A A - snail, B - fish

In parasitism, out of the two interacting species, one is benefited at the expense of the other (+, -). The organism that is benefited is called the parasite, while the one that is harmed is called the host.

The liver fluke (Fasciola hepatica) is an endoparasitic worm that lives in the liver of humans and causes disease.

Humans are one of the definitive hosts (primary host) of the liver fluke as it harbours the adult parasite that reproduces sexually.

Intermediate hosts are the ones that harbour the larval stage or the asexual forms of the parasite. Liver fluke requires two different intermediate hosts in addition to a definitive host i.e., a snail and a fish.

Mosquitoes and houseflies act as vectors that transmit disease causing pathogens to humans. Mosquitoes are vectors for malaria while houseflies are known to transmit cholera.