Schistosoma spp

Schistosoma spp.

MATERIAL SAFETY DATA SHEET - INFECTIOUS SUBSTANCES

SECTION I - INFECTIOUS AGENT

NAME: Schistosoma spp.

SYNONYM OR CROSS REFERENCE: Schistosoma mansoni, S. japonicum, S. haematobium, Bilharziasis, Snail fever, Schistosomiasis

CHARACTERISTICS: Trematode, flatworm, blood flukes; two distinct sexual forms; adult worms are 12-16 mm in length and 0.3-0.6 mm in width, male worms are shorter thicker than the longer slender females; eggs are round or oval and the size varies within species; cercariae (infective larva) are 400-600 µm in length, and contain a pear-shaped head and a forked tail

SECTION II - HEALTH HAZARD

PATHOGENICITY: Symptoms are related to amount and location of eggs in the human host; infections with Schistosoma mansoni and S. japonicum results in primarily hepatic and intestinal symptoms including diarrhea, abdominal pains, and hepatosplenomegaly; S. haematobium produces urinary manifestation including dysuria and hematuria; important complications that arises from chronic infections includes liver fibrosis, portal hypertension and possibly colorectal malignancy in the intestinal form; also CNS manifestations can occur; papular rash can result at points of entry by cercariae in these and other Schistosoma spp. (swimmer's itch)

EPIDEMIOLOGY: S. mansoni is found in Africa, the Arabian Peninsula, Brazil, Surinam and Venezuela and some Caribbean islands; S. haematobium is found in Africa, and the Middle East; S. japonicum is found China, Japan, the Philippines and Indonesia; an estimated 500-600 million people are infected in 75 countries; geographic distribution of schistosomiasis confined to an area between 36 degree north and 34 degree south latitude, where freshwater temperature averages 25-30° C; distribution of each species is dependant on the presence of an appropriate snail population

HOST RANGE: Principally humans for S. haematobium and S mansoni; humans, dogs, cats, pigs, cattle, water buffalo, horses, and rodents in S. japonicum

INFECTIOUS DOSE: Not known

MODE OF TRANSMISSION: Mainly by contact with contaminated water. Infective free-swimming larval forms (cercariae) penetrate directly through the skin

INCUBATION PERIOD: 2-6 weeks after exposure

COMMUNICABILITY: Not directly transmitted from person-to-person; infective person will release eggs in urine and feces; infective snails will release cercariae as long as they live (several weeks to 3 months)

SECTION III - DISSEMINATION

RESERVOIR: Humans, cats, dogs, cattle, horses, water buffalo, pigs, rodents

ZOONOSIS: animals serve as reservoirs, possible role in the indirect spread of the disease

VECTORS: Snails - Bulinus spp. for S. haematobium
Biomphalaria spp. for S. mansoni
Onocomelania spp. for S. japonicum

SECTION IV - VIABILITY

DRUG SUSCEPTIBILITY: All are sensitive to praziquantel, oxamniquine can be used for S. mansoni, and metrifonate can be used to treat S. japonicum

SUSCEPTIBILITY TO DISINFECTANTS: All infective stages are susceptible to 2% glutaraldehyde, 1% sodium hypochlorite: 70% ethanol will inactivate surface cercariae

PHYSICAL INACTIVATION: Sensitive to freezing

SURVIVAL OUTSIDE HOST: Not known

SECTION V - MEDICAL

SURVEILLANCE: Monitor for symptoms; confirm by parasitologic examination of excrement or serological analysis

FIRST AID/TREATMENT: Administer appropriate drug therapy

IMMUNIZATION: None available

PROPHYLAXIS: None available

SECTION VI - LABORATORY HAZARDS

LABORATORY-ACQUIRED INFECTIONS: One case was documented up to 1987

SOURCES/SPECIMENS: Feces, biopsy specimens, urine

PRIMARY HAZARDS: Ingestion; cercariae-containing droplet exposure to the skin or mucous membranes

SPECIAL HAZARDS: Hand to mouth transfer of metacercariae following contact with contaminated aquatic vegetation

SECTION VII - RECOMMENDED PRECAUTIONS

CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment facilities for all activities involving the infective stages of the parasite and potentially infectious body tissues or fluids

PROTECTIVE CLOTHING: Laboratory coat; gloves when skin contact with infectious materials is unavoidable

OTHER PRECAUTIONS: Travelers should avoid contact with bodies of fresh water in endemic areas

SECTION VIII - HANDLING INFORMATION

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, incineration, chemical disinfection

STORAGE: In sealed containers that are appropriately labelled

SECTION IX - MISCELLANEOUS INFORMATION

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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