Question

The intermediate host in the life cycle of Tapeworm is
A. Snail
B. Pig
C. Dog
D. Man only

Answer 1

Hint: Tapeworm like Taenia saginata (beef tapeworm) and Taenia solium (pork tapeworm). The infection caused due to tapeworms is known as taeniasis. It is transmitted to animals through human faeces which contaminates their food and it returns back to humans through consumption of uncooked and raw pork that contains the tapeworm cysts.

Complete answer:
> Option A- Snail
Snail causes snail fever also known as Schistosomiasis. The parasitic flatworms are released in freshwater by snails, thus contaminating the water. The infected part of the human body after consumption is the urinary tract or intestines. Symptoms include abdominal pain, diarrhoea, blood in urine etc.

> Option B- Pig
The pig consumes the eggs of the tapeworm where these eggs develop into larvae, oncospheres and finally into tapeworm cysts. This infected pig is then consumed in the form of undercooked or uncooked pork by humans, which causes taeniasis.

> Option C- Dog
They cause infections such as rabies, bacterial infections including salmonella, brucella, campylobacter, staphylococcus etc.

> Option D- Man only
Humans are the definitive host which by ingesting the cysts of tapeworm, get infected with taeniasis. The cysts develop into an adult worm in the small intestine of the human body. The worms then increase in size by using the nutrients from surroundings.

Hence, the correct answer is option (B).

Note: Length of the adult worm varies from 2 to 7 metres. The adults can produce proglottids which on maturation get detached from the worm and are passed in the stools through the anus. It can produce an average of 1000 proglottids and 50,000 to 1,00,000 eggs per proglottid.