LIFE CYCLE

Question 1

• Eggs ingested → Hatch in intestine → Cysticercoids develop → Mature into adults → Eggs excreted (direct cycle) or ingested by insects → Humans ingest infected insects (indirect cycle).

Answer 1

Hymenolepis nana (Dwarf Tapeworm)

Question 2

• Eggs in rodent feces → Ingested by insects → Develop into cysticercoids → Infected insects eaten by rodents or humans → Adult tapeworm in intestine → Eggs excreted.

Answer 2

Hymenolepis diminuta (Rat Tapeworm)

Question 3

• Eggs excreted by dogs → Ingested by intermediate hosts (sheep, cattle, humans) → Oncospheres form hydatid cysts in organs → Dogs eat infected organs → Adult tapeworms develop in the intestine.

Answer 3

Echinococcus granulosus (Hydatid Tapeworm)

Question 4

• Eggs excreted by foxes/dogs → Ingested by rodents or humans → Larvae form alveolar cysts in the liver → Foxes eat infected rodents → Adult tapeworms in fox intestines.

Answer 4

Echinococcus multilocularis (Alveolar Hydatid Tapeworm)

Question 5

• Eggs excreted by humans → Cattle ingest eggs → Oncospheres form cysticerci in muscle → Humans eat raw/undercooked beef → Cysticerci mature into adult tapeworms.

Answer 5

Taenia saginata (Beef Tapeworm)

Question 6

• Eggs excreted by humans → Pigs ingest eggs → Cysticerci develop in muscle → Humans eat infected pork → Adult tapeworms develop.

Answer 6

Taenia solium (Pork Tapeworm)

Question 7

• Eggs in water → Hatch into coracidia, ingested by copepods → Develop into procercoids, then plerocercoids in fish → Humans eat raw/undercooked fish → Adult tapeworms mature in intestine.

Answer 7

Diphyllobothrium latum (Fish Tapeworm)