GI HELMINTHS QUIZ WITH 100%
CORRECT ANSWERS [GRADED A+]
What is a definitive host? - ✔✔An animal that harbors adult worm in
intestine where it lays eggs
What is an intermediate host? - ✔✔Animal in which eggs develop into
larvae (larval cysts) but larvae do not develop into adults
Enterobius vermicularis (Pinworm) - ✔✔-Most common helminth in the US
-All regions socioeconomic groups affected
-Transmission not fecal - oral
-Most cases are young children, spread by eggs on hands or clothing
-Eggs are ingested, develop into larvae, then to adults that lay eggs. Adults
live for a month
-All stages in GI tract, no animal intermediate hosts
-Adults migrate at night through the anus, lay eggs, and die
©morren2025/2026.Year published 2026.
, -Increased risk with crowding as in institutionalized children or large
families
Enterobius vermicularis (pinworm) symptoms - ✔✔-Most cases are
asymptomatic
-Some have perianal itching
-Mild disease: no tissue invasion, no eosinophilia
Enterobius vermicularis (pinworm) diagnosis - ✔✔-Adult usually not
visible, eggs usually not in stool
-Scotch tape pressed to perianal skin in early morning can reveal eggs
under microscope
-Treat both the patient and the family contacts with anti-parasitic
medication in order to control its spread
Ascaris - ✔✔-Eggs in unsanitary environment ingested
-Eggs hatch in intestine, larvae cross bowel to reach blood
-Larvae enter lung, migrate up trachea and are swallowed
-Adult worms develop in the intestine and lay eggs into feces; transmission
is fecal-oral
©morren2025/2026.Year published 2026.
CORRECT ANSWERS [GRADED A+]
What is a definitive host? - ✔✔An animal that harbors adult worm in
intestine where it lays eggs
What is an intermediate host? - ✔✔Animal in which eggs develop into
larvae (larval cysts) but larvae do not develop into adults
Enterobius vermicularis (Pinworm) - ✔✔-Most common helminth in the US
-All regions socioeconomic groups affected
-Transmission not fecal - oral
-Most cases are young children, spread by eggs on hands or clothing
-Eggs are ingested, develop into larvae, then to adults that lay eggs. Adults
live for a month
-All stages in GI tract, no animal intermediate hosts
-Adults migrate at night through the anus, lay eggs, and die
©morren2025/2026.Year published 2026.
, -Increased risk with crowding as in institutionalized children or large
families
Enterobius vermicularis (pinworm) symptoms - ✔✔-Most cases are
asymptomatic
-Some have perianal itching
-Mild disease: no tissue invasion, no eosinophilia
Enterobius vermicularis (pinworm) diagnosis - ✔✔-Adult usually not
visible, eggs usually not in stool
-Scotch tape pressed to perianal skin in early morning can reveal eggs
under microscope
-Treat both the patient and the family contacts with anti-parasitic
medication in order to control its spread
Ascaris - ✔✔-Eggs in unsanitary environment ingested
-Eggs hatch in intestine, larvae cross bowel to reach blood
-Larvae enter lung, migrate up trachea and are swallowed
-Adult worms develop in the intestine and lay eggs into feces; transmission
is fecal-oral
©morren2025/2026.Year published 2026.
