Contents

Search

Echinococcus granulosus

Epidemiology: 1) prevalent in areas where livestock is raised in association with dogs - Australia, Argentina, Chile, Africa, eastern Europe, Middle East, New Zealand, Mediterranean 2) definitive hosts are dogs that pass eggs in their feces 3) intermediate hosts are sheep, cattle, goats, camels, horses & humans 4) adults are 5 mm with 5-20 month life span in jejunum of dogs 5) organism has 3 proglottids, immature, mature & gravid 6) eggs are extremely hardy * Life cycle of Echinococcus granulosus (image) [3] Pathology: 1) embryos escape from ingested eggs, penetrate intestinal mucosa, enter portal circulation & invade various organs, especially liver & lungs 2) produces unilocular cystic lesions 3) 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 granulosus IgE in serum - Echinococcus granulosus IgG in serum - 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

Related

echinococcosis (hydatid disease) Echinococcus antibody in serum

General

Echinococcus

Properties

KINGDOM: animal PHYLUM: helminth

References

  1. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 932
  2. Grimm L What's Eating You: 12 Common Intestinal Parasites. Medscape. November 25, 2019 https://reference.medscape.com/slideshow/intestinal-parasites-6010996
  3. Grim L You've Got Worms! Common Intestinal Parasites Medscape. Jan 23, 2023 https://reference.medscape.com/slideshow/intestinal-parasites-6014593