NAME: Ascaris spp.
SYNONYM OR CROSS REFERENCE: Ascariasis, roundworm infection
CHARACTERISTICS: Large intestinal roundworm
PATHOGENICITY: Helminthic infection of small intestine; pulmonary manifestations may occur; serious complications, including bowel obstruction or obstruction of bile duct, pancreatic duct and appendix; may be fatal
EPIDEMIOLOGY: Worldwide; commonly occurring in tropical countries; greatest in children aged 3-8 years
HOST RANGE: Varies with species (A. lumbricoides - humans, occasionally swine; A. suum - swine)
INFECTIOUS DOSE: Unknown
MODE OF TRANSMISSION: By ingestion of infective eggs from soil contaminated with human faeces or from uncooked food contaminated with soil containing infective eggs; transmission of infection by dust is also possible; fresh faeces do not contain infective eggs
INCUBATION PERIOD: 4-8 week life cycle of the parasite
COMMUNICABILITY: Not transmitted directly from person to person
RESERVOIR: Intestinal tract of humans, swine; soil
ZOONOSIS: Yes, can be indirectly transmitted from faeces of swine containing infective eggs
VECTORS: None
DRUG SUSCEPTIBILITY: Mebendazole and albendazole are efficacious
SUSCEPTIBILITY TO DISINFECTANTS: Half-and-half mixture of xylol and 95% ethanol was found to be effective in killing eggs on moist surfaces; one-to-one mixture of phenol and xylol is also rapidly lethal; phenol alone also is effective but slower acting (20 min)
PHYSICAL INACTIVATION: Eggs are resistant to desiccation, low temperatures; destruction by UV is questionable
SURVIVAL OUTSIDE HOST: Eggs can remain infective for years in favourable soil conditions
SURVEILLANCE: Identification of eggs in faeces or passage of adult worms; pulmonary involvement confirmed by identifying larvae in sputum or gastric washing
FIRST AID/TREATMENT: Administer appropriate drug therapy
IMMUNIZATION: None
PROPHYLAXIS: None
LABORATORY-ACQUIRED INFECTIONS: Infective stage has caused laboratory infection (8 cases reported); allergic reaction to various antigenic components of nematodes (aerosolized Ascaris antigens) may occur in sensitized individuals
SOURCES/SPECIMENS: Infective eggs in faeces, soil; larvae in sputum or gastric washings
PRIMARY HAZARDS: Ingestion of infective eggs; skin or mucosal penetration of infective larvae; accidental injection
SPECIAL HAZARDS: Exposure to aerosolized antigens frequently results in hypersensitivity
CONTAINMENT REQUIREMENTS: Biosafety level 2 facilities and operational practices for activities involving infective stages; hypersensitive individuals should conduct work in a biological safety cabinet to avoid exposure to aerosolized antigens
PROTECTIVE CLOTHING: Laboratory coat; gloves when contact with infective materials is unavoidable
OTHER PRECAUTIONS: Excellent hygienic habits should be encouraged; agricultural workers should wear personal protection (i.e. boots, gloves etc.) when working in soil contaminated with animal or human faeces
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with paper towels and apply disinfectant, starting at the 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: 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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