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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 © [Material Safety Data Sheets - Index]
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Last Updated: 2001-01-23 | ![]() |