NAME: Giardia lamblia
SYNONYM OR CROSS REFERENCE: G. intestinalis, G. duodenalis, giardiasis, giardia enteritis, Lambliasis, lamblia intestinalis, "beaver fever"
CHARACTERISTICS: Single celled flagellated protozoa, trophozoite (9-21 µm long, 5-15 µm wide and 2-4 µm thick), "tear drop" shape, contains 2 nuclei at anterior end and 5 flagella with tumbling motility; cyst form develops in the colon (13 µm long, oval shape and 2 nuclei)
PATHOGENICITY: Varies from asymptomatic in most individuals to a sudden onset of diarrhea with foul-smelling, greasy-looking stool that lacks mucous and blood; associated with abdominal cramps, bloating, fatigue and weight loss; restricted to upper small intestine with no invasion; normally illness lasts 1 - 2 weeks; chronic infections can last months to years
EPIDEMIOLOGY: Worldwide; prevalent in areas with poor sanitation; outbreaks more common in children than in adults; waterborne outbreaks are common where unfiltered waters are routinely contaminated by human and animal feces; daycare centres and cause of travellers diarrhea; most frequent cause of non-bacterial diarrhea in North America (25 % of gastrointestinal disease)
HOST RANGE: Humans; wild (beavers and bears) and domestic animals (dogs and cats)
INFECTIOUS DOSE: Less than 10 cysts when given orally, may even be as low as 1 cyst
MODE OF TRANSMISSION: Person-to-person, faecal-oral route is most important (hand to mouth transfer of cysts); infected food handlers; one person can pass 106 cysts each day; ingestion of fecally-contaminated water and food are also mechanisms for transmission, found in soil and on surfaces; anal intercourse also facilitates transmission
INCUBATION PERIOD: From 3 - 25 days, usually 7 - 10 days
COMMUNICABILITY: Cysts are shed during the entire period of infection, often months
RESERVOIR: Humans, wild and domestic animals
ZOONOSIS: Beaver considered zoonotic reservoir for water-borne infection in headwaters of many cold water streams
VECTORS: None
DRUG SUSCEPTIBILITY: Sensitive to quinacrine hydrochloride, metronidazole, tinidazole, albendazole and furazolidone
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite (chlorine in drinking water not sufficient, especially if water is cold), 2% glutaraldehyde
PHYSICAL INACTIVATION: Boiling for minimum of 1 minute
SURVIVAL OUTSIDE HOST: Cysts remains infectious for prolonged periods in the environment, cysts are resistance to adverse environmental conditions
SURVEILLANCE: Monitor for symptoms; confirm by microscopic demonstration of trophozoite and cysts in feces, stained preparations or unstained wet mounts; ELISA
FIRST AID/TREATMENT: Administer appropriate drug therapy
IMMUNIZATION: None available
PROPHYLAXIS: None available
LABORATORY-ACQUIRED INFECTIONS: Two cases were reported up to 1987
SOURCES/SPECIMENS: Feces, duodenal secretions
PRIMARY HAZARDS: Ingestion
SPECIAL HAZARDS: None
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment facilities are recommended for activities with infective stages of mammalian Giardia spp. and infectious body fluids and tissues
PROTECTIVE CLOTHING: Laboratory coat; gloves when skin contact with infectious materials is unavoidable
OTHER PRECAUTIONS: Good personal hygienic practices - hand washing before handling food and before eating
SPILLS: Allow aerosols to settle; wearing protective clothing gently cover the spill with absorbent paper towel and apply 1% sodium hypochlorite 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 labelled
Date prepared: April, 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
To share this page just click on the social network icon of your choice.