Toxoplasma Gondii

Toxoplasma Gondii

MATERIAL SAFETY DATA SHEET – INFECTIOUS SUBSTANCES

SECTION I – INFECTIOUS AGENT

NAME: Toxoplasma gondii

SYNONYM OR CROSS REFERENCE: Toxoplasmosis, congenital toxoplasmosis, Toxoplasma infection

CHARACTERISTICS : Obligate intracellular sporozoan; both sexual (enteroepithelial) and asexual (extraintestinal) reproductive cycles occur felines, other species only undergo extraintestinal infection; major morphologic forms of the parasite are oocyst containing sporozoites, tachyzoites , and bradyzoites in tissue cysts; oocyst is ovoid, measures 10-12 µm in diameter; tachyzoites are crescent shaped and measure 3-7 µm; tissue cysts measure 10-200 µm in diameter

SECTION II – HEALTH HAZARD

PATHOGENICITY: Most infections are asymptomatic; mild cases with a localized lymphadenopathy accompanied with fever, sore throat, rash, mimicking infectious mononucleosis in some individuals; immunocompromised host suffers from widespread dessimination of the infection with pneumonitis, myocarditis, and encephalitis; some immunocompetent individuals develop severe symptoms; congenital cases can result in abortion and stillbirth, live births may result in severe central nervous system involvement along with chorioretinitis; transplacental infection is least likely during 1st trimester, but these cases are the most severe; responsible for 35% of chorioretinits cases in US and Europe

EPIDEMIOLOGY: Worldwide; 3-70% of healthy adults are seropositive; increased cases of cerebral toxoplasmosis in AIDS patients (up to 50%); higher incidence in the tropics and lower in cold, arid regions

HOST RANGE: Cats and other felines; most warm blooded animals and birds; humans

INFECTIOUS DOSE: Not known

MODE OF TRANSMISSION: Consuming undercooked infected meats (pork, mutton, beef); ingestion of infective oocysts in milk, food or water; inhalation of oocysts; transplacental; contact with soil containing infected cat feces; transmission through blood transfusions or organ transplantations is possible although rare; may be transmitted to food by flies or cockroaches; at least one outbreak attributed to contaminated water supply

INCUBATION PERIOD: 10-23 days – following ingestion of contaminated meat 5-20 days – associated with cats (presumably ingestion or inhalation)

COMMUNICABILITY: Not directly transmitted from person-to-person except in utero; oocysts shed by cats become infective (sporulate) on average 1-5 days later, but varies with temperature; remain infectious for up to 1 year in water or moist soil; cysts in meat are infectious as long as meat is edible and uncooked

SECTION III – DISSEMINATION

RESERVOIR: Definitive hosts are cats; intermediate hosts are sheep, goats, rodents, swine, cattle, chicken, and birds

ZOONOSIS: Yes, direct or indirect contact of mucous membrane with oocysts from feces of infected animals

VECTORS: None

SECTION IV – VIABILITY

DRUG SUSCEPTIBILITY: Sulfonamides and pyrimethamines are effective

SUSCEPTIBILITY TO DISINFECTANTS: Oocysts are susceptible to iodine and formalin, resistant to most disinfectants; tachyzoites and tissue cysts are susceptible to most disinfectants; l% sodium hypochlorite, 70% ethanol

PHYSICAL INACTIVATION: Oocysts are inactivated by temperature> 66° C in less than 10 min; tachyzoites are inactivated at pH < 4.0; tissue cysts are inactivated by freezing and thawing; cysts do not survive in 6% or higher NaCl solution

SURVIVAL OUTSIDE HOST: Oocysts are very stable and can survive up to 1 year in water or moist soil; tachyzoites can survive in body fluids up to 1 day, in whole blood for up to 50 days at 4° C; tissue cysts can survive for weeks at room temperature in body fluids

SECTION V – MEDICAL

SURVEILLANCE: Monitor patients for clinical signs and confirm by demonstration of agent in tissues or fluids, or through serology; women intending on becoming pregnant should be tested for Toxoplasma infection

FIRST AID/TREATMENT: Pyrimethamine combined with sulfadiazine is indicated for pregnant women or patients with organ involvement; spiramycin to prevent placental transmission; clindamycin for ocular involvement; Pyremethamine is contraindicated during firs 16 weeks of pregnancy

IMMUNIZATION: None

PROPHYLAXIS: Pyrimethamine combined with sulfadiazine and folinic acid in special cases

SECTION VI – LABORATORY HAZARDS

LABORATORY-ACQUIRED INFECTIONS: Most common laboratory-acquired parasitic infection; 28 cases with one death reported up to 1976; cases were caused by accidental inoculation, splashing, inhalation, ingestion

SOURCES/SPECIMENS: Blood and blood products; semen; feces; tissue

PRIMARY HAZARDS: Accidental parenteral inoculation, ingestion, contamination of broken skin and mucous membranes; inhalation

SPECIAL HAZARDS: Feces from infected animals, ie. changing litter

SECTION VII – RECOMMENDED PRECAUTIONS

CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment facilities for activities involving infectious stages of the parasite; work should be conducted in a biosafety cabinet

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

OTHER PRECAUTIONS: Pregnant women should be discouraged from working with Toxoplasma spp.

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 center; allow sufficient contact time (30 mins) 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: 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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