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SECTION I - INFECTIOUS AGENT
NAME: Echinococcus multilocularis
SYNONYM OR CROSS REFERENCE: Alveolar hydatid disease, Multilocular echinococcosis.
CHARACTERISTICS: Cestode, tapeworm consisting of 3 to 5 segments, usually I cm long; hydatid cyst buds exogenously
to form a multilocular cyst; parasite infiltrates host tissues like a malignancy by external proliferation of the
germinal membrane to form new cysts.
SECTION II - HEALTH HAZARD
PATHOGENICITY: Disease depends on the size and location of the larval masses; cysts grow slowly in humans
(abnormal host), since a person may be infected for 30 years before symptoms appear; primary lesion in alveolar
hydatid disease is always the liver and contiguous organs to produce chronic spaceoccupying lesions; pieces of
the germinal membrane may metastasize to infect the brain, lungs and mediastinum.
EPIDEMIOLOGY: Distribution is limited to areas in the Northern Hemisphere: central Europe, Commonwealth
of Independent States, northern Japan, Alaska, Canada and north-central USA; disease usually diagnosed in adults;
high risk individuals include hunters and fur traders.
HOST RANGE: Humans are abnormal host; definitive host is foxes, but wolves, coyotes, dogs and cats have
been infected; intermediate hosts include voles, lemmings, shrews and mice.
INFECTIOUS DOSE: Not known.
MODE OF TRANSMISSION: Ingestion of infected eggs passed in feces of infected Canidae and Felidae; fecally
soiled dog hair, harness and environmental fo"tes serve as vehicles of infection.
INCUBATION PERIOD: Variable, from months to years, depending on the site and number of cysts.
COMMUNICABILITY: Not directly transmitted from person-to-person.
SECTION III - DISSEMINATION
RESERVOIR: Adult tapeworm found in foxes, wolves, coyotes, dogs and cats; intermediate hosts are voles,
shrews, lemmings and mice; commonly maintained in nature in fox-rodent cycle.
ZOONOSIS: Yes - infection is acquired from infected Canidae and Felidae.
VECTORS: None.
SECTION IV - VIABILITY
DRUG SUSCEPTIBILITY: Sensitive to mebendazole, albendazole, praziquantel.
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite (20% commercial bleach), 2% glutaraldehyde.
PHYSICAL INACTIVATION: Sensitive to heat.
SURVIVAL OUTSIDE HOST: Cysts can survive cold climates.
SECTION V - MEDICAL
SURVEILLANCE:Monitor for symptoms; confirm by serology and microscopic examination of tissues for cysts.
FIRST AID/TREATMENT: Surgical removal of mass, if possible; mebendazole may inhibit growth.
IMMUNIZATION: None available.
PROPHYLAXIS: Praziquantel may be administered in case of accident.
SECTION VI - LABORATORY HAZARDS
LABORATORY-ACQUIRED INFECTIONS: None reported to date.
SOURCES/SPECIMENS: Tissue biopsy specimens, stool.
PRIMARY HAZARDS: Ingestion; droplet exposure of mucous membrane.
SPECIAL HAZARDS: Contact with fecal matter from experimentally infected animals.
SECTION VII - RECOMMENDED PRECAUTIONS
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment equipment for all activities involving
the infective stages of the parasite and 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.
SECTION VIII - HANDLING INFORMATION
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover the spill with absorbent
paper towel and apply 1% sodium hypochlorite (20% commercial bleach) 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 labeled.
Date prepared: October 11, 1997 Prepared by: Canadian Office of Biosafety Information edited by the Colorado State
University Office of Biosafety- June 16, 1998.
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