PathologyLesson 2 of 2 in the course Digestive System Infections

Protozoan Gastrointestinal Infections: Giardia, Cryptosporidium, Entamoeba, and Cyclospora

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Protozoa can cause gastrointestinal illness when people ingest contaminated food or water. This lesson compares giardiasis and cryptosporidiosis, two important intestinal infections that can occur in the United States and elsewhere.

Giardiasis, also called backpacker’s diarrhea or beaver fever, is caused by Giardia lamblia (also known as G. intestinalis or G. duodenalis). Transmission occurs through contaminated food or water and direct person-to-person contact. Children in day-care settings may be exposed when contaminated objects are put into their mouths.

All flashcards

How can amoebiasis spread beyond the intestine?
*Entamoeba histolytica* can invade intestinal tissue and spread to organs; the liver is an important site of abscess formation.
What can happen in chronic giardiasis?
It can cause episodic diarrhea, weight loss, and malabsorption.
Why can cryptosporidiosis be especially serious for some patients?
People with weakened immune systems are at increased risk of severe disease or death.
How may Cyclospora oocysts appear under ultraviolet fluorescence microscopy?
They may show a distinctive blue halo.
What treatment approach is used for amoebiasis?
A tissue-active medicine such as metronidazole or tinidazole is followed by a medicine to eliminate remaining cysts.

Quiz questions

  1. Which protozoan causes giardiasis?Answer: *Giardia lamblia*
  2. Which staining method can help detect *Cryptosporidium* in stool?Answer: Acid-fast staining
  3. A liver abscess associated with an intestinal protozoan infection most strongly suggests which disease?Answer: Amoebiasis caused by *Entamoeba histolytica*
  4. Which diagnostic clue is associated with *Cyclospora cayetanensis* oocysts?Answer: A blue halo under ultraviolet fluorescence microscopy
  5. Which patient has an increased risk of severe cryptosporidiosis?Answer: A person with a weakened immune system

Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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