Ascaris Lumbricoides
Ascaris Lumbricoides
MATERIAL SAFETY DATA SHEET – INFECTIOUS SUBSTANCES
SECTION I – INFECTIOUS AGENT
NAME: Ascaris lumbricoides
SYNONYM OR CROSS REFERENCE: Ascariasis, roundworm infection, ascaridiasis
CHARACTERISTICS: Largest and most common intestinal nematode in humans; fertile eggs are oval to subspherical, 45-75 µm by 35-50 µm and are covered by a thick shell with a light brown mammillated, albuminous outer coat; unfertile eggs are thin-walled, ellipsoidal; found in the small intestine, particularly the jejunum
SECTION II – HEALTH HAZARD
PATHOGENICITY: Symptoms correlate with worm load: light loads are asymptomatic; heavier loads cause abdominal symptoms, diarrhea and malnutrition. A bolus of worms may obstruct the intestine; migrating larvae may cause pneumonitis and eosinophilia
EPIDEMIOLOGY: Worldwide; greatest prevalence in the moist tropical countries where incidence exceeds 50%; incidence highest in children 3-8 years old
HOST RANGE: Humans
INFECTIOUS DOSE: Not known
MODE OF TRANSMISSION: Ingestion of infective eggs from soil contaminated with human faeces, uncooked produce contaminated with soil containing infective eggs
INCUBATION PERIOD: Variable; life cycle requires 4-8 weeks to be completed; faeces contain fertile eggs about 60 days after ingestion of embryonated eggs
COMMUNICABILITY: For as long as mature fertilized female worms are alive in the intestine transmission is possible; usual life span of adult worm is 12 months, maximum is 24 months
SECTION III – DISSEMINATION
RESERVOIR: Humans; ascarid eggs in soil
ZOONOSIS: None
VECTORS: None
SECTION IV – VIABILITY
DRUG SUSCEPTIBILITY: Susceptible to mebendazole, albendazole, pyrantel pamoate
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite, 2% glutaraldehyde; ascaris eggs are resistant to chemical disinfectants and temporary immersion in strong chemicals
PHYSICAL INACTIVATION: Sensitive to heat
SURVIVAL OUTSIDE HOST: Eggs may remain viable in favourable soil for years
SECTION V – MEDICAL
SURVEILLANCE: Monitor for symptoms; confirm by microscopic examination for eggs in faeces or for passage of adult worms
FIRST AID/TREATMENT: Administer appropriate drug therapy
IMMUNIZATION: None available
PROPHYLAXIS: None available
SECTION VI – LABORATORY HAZARDS
LABORATORY-ACQUIRED INFECTIONS: Eight cases reported
SOURCES/SPECIMENS: Stool specimens
PRIMARY HAZARDS: Ingestion; direct contact of eggs with mucous membranes; skin penetration of larvae
SPECIAL HAZARDS: Avoid generation of aerosols when working with infective stages of Ascaris since frequent exposure to aerosolized antigens can lead to hypersensitivity
SECTION VII – RECOMMENDED PRECAUTIONS
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment facilities for activities involving infective stages of the parasite, infectious body tissues and fluids
PROTECTIVE CLOTHING: Laboratory coat; gloves when skin contact with infectious material is unavoidable
OTHER PRECAUTIONS: Work in a biosafety cabinet when chance of aerosolizing antigens
SECTION VIII – HANDLING INFORMATION
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with absorbent paper towel and apply 1% sodium hypochlorite starting at the perimeter and working towards the centre; 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
SECTION IX – MISCELLANEOUS INFORMATION
Date prepared: November 1999
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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