NAME: Trichinella spp.
SYNONYM OR CROSS REFERENCE: Trichinellosis, Trichinosis, Trichiniasis, Trichina spiralis
CHARACTERISTICS: Intestinal nematode (roundworm); adults 1.2-2.2 mm x 60-90 µm; reproduce sexually in the intestinal mucosa; larvae (trichinae) 100 µm x 6 µm
PATHOGENICITY: Symptoms variable depending on size of inoculum from inapparent infection to fulminating fatal disease; gastrointestinal symptoms may result from consumed larvae penetrating the intestinal mucosa and multiplying; malaise, nausea, diarrhea, abdominal cramping; larvae migrate to and become encapsulated in the muscles; muscle soreness and pain, edema of upper eyelids common; eosinophilia, ocular pain, photophobia, pneumonitis, may follow; remittent fever; cardiac and neurologic complications may develop
EPIDEMIOLOGY: Worldwide with sporadic cases and localized outbreaks
HOST RANGE: Humans; domestic and wild animals; marine mammals
INFECTIOUS DOSE: Unknown
MODE OF TRANSMISSION: By ingestion of encysted larvae in raw or undercooked flesh of mammals (chiefly pork, pork products, wild game)
INCUBATION PERIOD: Systemic symptoms develop in 2-4 weeks (may be longer depending on dose); gastrointestinal symptoms develop in a 1-2 days
COMMUNICABILITY: Not transmitted from person-to-person
RESERVOIR: Swine, dogs, cats, rats, wild animals (fox, bears, marine mammals seals)
ZOONOSIS: Yes, transmitted from flesh of animals containing viable larvae
VECTORS: None
DRUG SUSCEPTIBILITY: Thiabendazole effective in intestinal stage; mebendazole in the muscular stage
SUSCEPTIBILITY TO DISINFECTANTS: One-to-one mixtures of xylol and 95% ethanol, and of phenol and xylol were found to be lethal to infective stages of nematodes
PHYSICAL INACTIVATION: Susceptible to heat (at least 77° C) and freezing (-15° C for 30 days or -25° C for 10 days; arctic strains are cold-resistant); low level gamma irradiation (0.15 kGy) effectively kills larvae
SURVIVAL OUTSIDE HOST: Meat from animal hosts can remain infected for long periods
SURVEILLANCE: Serologic testing; confirmation by biopsy of skeletal muscle
FIRST AID/TREATMENT: Administer antihelminthic drug therapy; corticosteroids in severe cases to decrease inflammatory reaction in CNS and cardiac muscle
IMMUNIZATION: None
PROPHYLAXIS: None
LABORATORY-ACQUIRED INFECTIONS: Infective stage has caused laboratory infections
SOURCES/SPECIMENS: Muscle tissue
PRIMARY HAZARDS: Ingestion, accidental injection, skin or mucosal penetration of infective larvae;
SPECIAL HAZARDS: None
CONTAINMENT REQUIREMENTS: Biosafety level 2 facilities and operational practices for activities involving infective stages; Agriculture Canada may also require additional conditions for use or importation
PROTECTIVE CLOTHING: Laboratory coat, gloves
OTHER PRECAUTIONS: None
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with paper towels and apply disinfectant, starting at perimeter and working towards the centre; allow sufficient contact time before clean up
DISPOSAL: Decontaminate before disposal; steam sterilization, incineration, chemical disinfection
STORAGE: In sealed containers that are appropriately labelled
Date prepared: March, 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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