Parasitology Flashcards
4 year old white British girl. Systemically well, but waking at night for past month. Grabbing at underwear, perianal scratching.
No foreign travel. Recently started at a new pre-school.
Stools - ova, cysts and parasites negative x 3.
What parasite is causing her symptoms?
Enterobius vermicularis - threadworm.
What is enterobius vermicularis (threadworm)
A roundworm (nematode)
What is the route of transmission of enterobius vermicularis.
Faeco-oral
Who is most often affected by enterbius vermicularis.
Young children (and their families)
What are the most common signs of enterobius vermicularis infection. (2)
Itching.
Sleep disturbances.
Why is enterobius vermicularis hard to get rid of.
Auto-infection occurs frequently - infection can continue for a while.
How do you diagnose enterobius vermicularis?
Sellotape slide test for eggs.
What is the treatment for enterobius vermicularis. (2)
Hygiene measures.
Mebendazole x 2.
17 year old student - white British male. Blue light call - collapsed during a rugby match. Tachycardic, hypotensive and flushed. Wheezy, urticarial rash.
No foreign travel, grew up in rural Wales.
What is the most likely parasite responsible?
Echinococcus granulosus (cestode)
What are the principle carriers of echinococcus granulosus? (2)
Tapeworm in dogs.
Cysts in sheep.
What is characteristic of hydatid disease.
Usually liver cysts, but can also be elsewhere in the body.
What are the usual symptoms of hydatid disease (2).
Abdominal discomfort.
Biliary obstruction.
When is hydatid disease usually diagnosed?
Usually incidentally.
What causes an acute presentation for hydatid disease.
Rupture of the cysts - potentially causes anaphylaxis.
Contact sports make rupture more likely.
What are the treatment options for hydatid disease. (3)
Long term - albendazole/praziquantel.
Aspirate and inject cysts.
Surgical removal of cysts.
32 year old white Births woman. Claims she found a worm in the toilet. Panicked and flushed - no pictures.
No symptoms, examination is normal.
routine bloods including eosinophils are normal.
Stool - first sample negative for ova, cysts and parasites.
Foreign travel - spent the previous summer volunteering for an aid agency in Timor-Leste.
What is the most likely causative parasite?
Ascaris lumbricoides.
What type of parasite is ascaris lumbricoides?
A roundworm (nematode)
What is the route of transmission of ascaris lumbricoides.
Faeco-oral transmission.
However, also needs time in soil.
How many people are infected with ascaris lumbricoides worldwide.
1 billion.
When do symptoms develop in a patient infected with ascaris lumbricoides.
When the worm burden is high.
What is the treatment for ascaris lumbricoides? (2)
Medical therapy is usually fine.
Surgery may be required if worm burden is high or causing intestinal obstruction.
27 year old female. Normally fit and well. Itchy and painful rash on her foot. Just come back from a Caribbean holiday.
What is this condition?
Cutaneous larva migrans
What is cutaneous larva migrans usually caused by.
Animal hookworm (e.g. ancyclostoma braziliense)
What is the life cycle of animal hookworm infection?
Worm cannot go beyond the subcutaneous tissues - will die there.
What is the treatment for cutaneous larva migrans.
Ivermectin speeds up death of worm.