NAME: Echinococcus granulosus
SYNONYM OR CROSS REFERENCE: Echinococcosis, Unilocular echinococcosis, Cystic hydatid disease (CHD)
CHARACTERISTICS: Tapeworm consisting of 3 to 5 segments, usually 3-6 mm long; scolex has 4 suckers followed by a germinative neck region, one developing segment and one gravid segment containing several segments; cyst usually is slow growing, generally are 1-7 cm in diameter, but may exceed 10 cm
PATHOGENICITY: Manifestation depends on the site and size of the cyst (hydatid) of the lungs, liver and subcutaneous tissues may be asymptomatic for many years, but pressure effects may develop; in sensitive areas, hydatids may cause blocking effects and mechanical compression leading to collapse of infected bones, blindness and epiletiform seizures; the rupture of a hydatid cyst may induce sudden anaphylactic shock
EPIDEMIOLOGY: Most common in temperate sheep-raising areas; southern South America, southern and central Commonwealth of Independent States, south western Asia, Meditarranean coast, Australia, New Zealand, Middle East, northern Africa, western USA, northwest Canada and Alaska; most common species
HOST RANGE: Definitive hosts are the dog, wolf, dingo and other Canidae; usual intermediate host is the herbivore (sheep, bovines, swine, goats, equine, camelids) and man
INFECTIOUS DOSE: Not known
MODE OF TRANSMISSION: Hand-to-mouth transfer of tapeworm eggs from dog feces; fecally contaminated food and water; in northwest Canada, disease is maintained in a wolf-moose cycle, from which the dog bring the parasite to people
INCUBATION PERIOD: Variable, from 12 months to years, depending on the site and number of cysts
COMMUNICABILITY: Not directly transmitted from person-to-person; dogs begin to pass eggs 7 weeks after infection; most infections are lost after 6 months; adult worms may survive for 2-3 years
RESERVOIR: Humans, dogs, wolf, sheep, goat, pig, cattle
ZOONOSIS: Yes, infection is mostly acquired through contact with canines
VECTORS: coprophagic flies may serve as mechanical vector of the eggs, carrion birds and arthropod
DRUG SUSCEPTIBILITY: Sensitive to albendazole, mebendazole, praziquartel (dogs), experimental use oxfendazole
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite, 2% glutaraldehyde
PHYSICAL INACTIVATION: Sensitive to heat and desiccation
SURVIVAL OUTSIDE HOST: Eggs may survive for several months in pasture, garden, and on household fomites; survives in water and damp sand for 3 weeks at 30° C, 225 days at 6° C and 32 days at 10-21° C
SURVEILLANCE: Monitor for symptoms; confirm by ultrasonographic and serologic tests (laxtex agglutination test)
FIRST AID/TREATMENT: Administer appropriate drug therapy; surgical removal of large solitary liver cysts
IMMUNIZATION: None available
PROPHYLAXIS: Mebendazole and albendazole have been used successfully
LABORATORY-ACQUIRED INFECTIONS: None reported to date
SOURCES/SPECIMENS: Sputum, tissue biopsy
PRIMARY HAZARDS: Ingestion; droplet exposure of the mucous membrane
SPECIAL HAZARDS: Ingestion of eggs by hand-to-mouth transfer
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment equipment for all activities involving the infective stages of the parasite or any potentially infectious body fluids or tissues
PROTECTIVE CLOTHING: Laboratory coat; gloves when skin contact with infectious materials is unavoidable
OTHER PRECAUTIONS: Work with this parasite (gravid segments) should be conducted in a biosafety cabinet or its equivalent.
SPILLS: Allow aerosols to settle; wearing protective clothing gently cover the spill with absorbent paper towel and apply 1% sodium hypochlorite starting at the perimeter and working towards the center; allow sufficient contact time (30 min) before clean up
DISPOSAL: Decontaminate all wastes before disposal; steam sterilization, chemical disinfection, incineration
STORAGE: In sealed containers that are appropriately labelled
Date prepared: January, 2001
Prepared by: Office of Laboratory Security, PHAC
Although the information, opinions and recommendations contained in this Material Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright ©
Health Canada, 2001
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