Echinococcus granulosus
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Epidemiology
- prevalent in areas where livestock is raised in association with dogs
- Australia, Argentina, Chile, Africa, eastern Europe, Middle East, New Zealand, Mediterranean
- definitive hosts are dogs that pass eggs in their feces
- intermediate hosts are sheep, cattle, goats, camels, horses & humans
- adults are 5 mm with 5-20 month life span in jejunum of dogs
- organism has 3 proglottids, immature, mature & gravid
- eggs are extremely hardy
* Life cycle of Echinococcus granulosus (image)[3]
Pathology
- embryos escape from ingested eggs, penetrate intestinal mucosa, enter portal circulation & invade various organs, especially liver & lungs
- produces unilocular cystic lesions
- new larvae develop in cysts (hydatid cyst)
Clinical manifestations
- pulmonary alveolar cysts may not manifest for 5-15 years[2]
- rupture of hydatid cysts may result in fever, pruritus, anaphylaxis[2]
Laboratory
- examination of feces
- eggs indisinguishable from eggs of Taenia
- Echinococcus granulosus serology
- Echinococcus antigen in stool
- Echinococcus DNA by PCR
- eosinophila may result for rupture of hydatid cysts[2]
Radiology
- abdominal ultasound or abdominal CT will show cyst with well demarcated cyst wall & septate daughter cysts
* image[2]
Differential diagnosis
- hepatic abscess
- abdominal CT will show intrahepatic lesion that contains gas & fluid
More general terms
Additional terms
References
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 932
- ↑ 2.0 2.1 2.2 2.3 2.4 Grimm L What's Eating You: 12 Common Intestinal Parasites. Medscape. November 25, 2019 https://reference.medscape.com/slideshow/intestinal-parasites-6010996
- ↑ 3.0 3.1 Grim L You've Got Worms! Common Intestinal Parasites Medscape. Jan 23, 2023 https://reference.medscape.com/slideshow/intestinal-parasites-6014593