Test One Flashcards
What is the scientific name for pinworms?
Enterobius vermicularis
Where do the larva of pinworms hatch?
Small intestine
What is the difference between male and female pinworms?
Female is much larger than the male. male is also more curly.
Where do adult pinworms live?
Large intestine. specifically the cecum
How long does it take for pinworm eggs to embryonate?
4-6 hours
How long is the pinworm life cycle?
2-4 weeks.
Describe the life cycle of pinworms.
Embryonated eggs are eaten. They hatch in the small intestine and the larva begin growing. They reach the L5 stage in the large intestine. The females crawl out of the anus and lay their eggs, or more correctly explode their uterus. Itching by the affected person and then contact with the mouth re-infects the person.
Define retroinfection
Larva that come from eggs hatching around the anus crawl back into the host.
What is the most common helminthic infection in the US?
Pinworm infection.
How long is a fully grown female? Male?
Female: 8-12 mm, Male: 2-5 mm
What are coprolites?
ancient poo
What is the distribution of pinworm infections?
20 million in the US, 200 million worldwide. Found in 10,000 year old coprolites. Primarily infects school children.
What are the clinical manifestations of a pinworm infection?
Pruitis ani (itchy butt)
Vaginitis
Irritibility, insomnia, bed wetting
Secondary perianal rash and infection
How long will pinworm eggs remain viable?
for up to a week in cool, moist environments
What is required for a laboratory diagnosis of pinworms?
Female in perineum area. Eggs around the anus
Describe the pinworm eggs
Clear shell, planoconvex shape. 20X50 micrometers
Describe the method of collecting pinworm eggs for diagnosis
Scotch tape on a stick. Stick it between the perianal folds and then stick the tape on a microscope slide.
Also can do a fingernail scraping
Define “alae”
Fins seen in a cross section of a pinworm in tissue.
What is the treatment for pinworm infection?
Mebendazole. repeat in two weeks. Leave house for a week to give enough time for the eggs to die.
What is the connection to D. fragilis
D. fragilis (a single celled parasite) can be transmitted by pinworm eggs.
What is the scientific name for whipworms?
Trichuris trichiura
Describe the shape of a whipworm.
Looks like a whip. Head end is skinny and the tail end is thick.
How long can an adult whipworm grow?
3-5 cm
Where do whipworm eggs embryonate? how long does it take to embryonate?
Embryonate in the soil. Takes around 3 weeks
How long does it take a whipworm to mature?
3 months
How long does a whipworm live?
1-8 years.
Describe the life cycle of Ascaris lumbricoides.
Eggs embryonate in the soil and are eaten. They hatch in the stomach and penetrate the intestinal wall. They get into the blood stream where they travel around until they get to the liver. They molt in the liver, penetrate the tissue and migrate to the lungs. In the lungs they go up the trachea in mucus and are swallowed. Become adults in the large intestine.