Echinococcus species

Background

• Cestode

Microbiology

• Echinococcus granulosus sensu stricto (G1 to G3), the major cause of cystic echinococcosis
• Echinococcus equinus (G4)
• Echinococcus ortleppi (G5)
• Echinococcus canadensis (G6 to G10)
• Echinococcus multilocularis, the major cause of alveolar echinococcosis
• Echinococcus vogeli
• Echinococcus oligarthrus
• Echinococcus felidis
• Echinococcus shiquicus

Epidemiology

Species	Intermediate Hosts	Definitive Hosts	Distribution	Risk Factors
Echinococcus granulosus	sheep, cattle, pigs, camels, and goats	dogs and other canids	worldwide, with highest prevalence in Mediterranean, Russia, China, central Asia, north and east Africa, Australia, and South America	shepherds, exposure to feral dogs, slaughterhouse, unsanitary living conditions
Echinococcus multilocularis	rodents, domestic pigs, wild boars, dogs, monkeys	foxes, dogs, cars	mostly described in Europe and Asia, rare in North America
Echinococcus vogeli	rodents	bush dogs	Central and South America
Echinococcus oligarthus

Clinical Manifestations

Cystic Echinococcus

• Liver most common site followed by lung
• Can infect brain and rarely other sites
• Can cause anaphylaxis when ruptures
• Can cause cholangitis

Alveolar Echinococcus

• Presents as liver cancer or metastases of unknown primary