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Toxoplasma gondii Biological Agent Reference Sheet (BARS)

Updated December 1, 2023
Disclaimer: Risk group, biosafety level, and all other precautions noted here are subject to change after a risk assessment by EHS.


Agent Type Risk Group Biosafety Level Animal Housing Biosafety Level
Parasite RG-2 BSL-2 ABSL-2

Agent Characteristics 

Risk Group: RG-2 associated with human disease, rarely serious; preventive or therapeutic interventions often available.

Agent Type: Parasite 

DescriptionToxoplasma gondii belong to the phylum Apicomplexa and family Sarcocystidae. They are obligate intracellular parasitic protozoa. Toxoplasma
is a parasite of birds and mammals. Felines are the only definitive host and the only animals that pass infective oocysts in their feces. Warm-blooded animals, including humans, are intermediate hosts that harbor tissue cysts in their bodies. Three major infectious stages and major morphological forms occur: oocyst-containing two sporocysts and four sporozoites each, quicklymultiplying tachyzoites, and slow-growing bradyzoites contained in persistent tissue cysts.  
Host Range: Cats and other felines, humans, and warm-blooded vertebrates, including most mammals and birds.

Host Shedding: Blood, Feces, Saliva, Urine, Sputum, Tears, Semen, Milk, Tissue                   

Route of Exposure to Humans: Aerosol/Inhalation, Mucous Membranes, Vertical Transmission, Contaminated Items, Ingestion, Percutaneous, Broken skin

Infectious Dose: 10 sporulated oocysts                             Incubation Period: 2-3 days post-infection

Health Hazards

Signs and symptoms of infection may include:

  • Flu-like symptoms (i.e. fever, headache, dehydration, weight loss, lethargy)
  • Cutaneous symptoms (i.e. skin lesions, rash)
  • Lymphoreticular symptoms (i.e. enlarged internal organs or lymph nodes)
  • Reproductive Health concerns (i.e. abortion, fetal abnormalities)

Immunizations: None available                                        Prophylaxis*: pyrimethamine (25 mg/day), cotrimoxazole, pyrimethamine-sulfadoxine(75mg/1500mg. A treatment of sulfadiazine-pyrimethamine, and folinic acid is suitable for most patients.

*Formal medical advice is obtained during medical consultations with Cornell Health or primary healthcare provider as needed.

Agent Viability 

Survival Outside Host Disinfection Inactivation

In moist soil or water for up to 18 months; in uncovered feces for 46 days and for 334 days when covered.

 1:10 bleach Dilution

70% Ethanol

10% formalin

6% NaCl solutions, gamma irradiation = 1.0 kGy, temperature ≥ 67°C

For more guidance on disinfection see:  disinfectant selection.

Laboratory Hazards 

  • High energy-creating activities (centrifugation, sonication, high pressure systems, vortexing, tube cap popping)
  • Handling of sharps (needles, scalpels, microtome blades, broken glass, etc.)
  • Splash/droplet-creating activities (shaking incubators, liquid culturing, mechanical pipetting)
  • Equipment contamination
  • Exposed skin/uncovered wounds

Laboratory Acquired Infection (LAI) History: 47 cases of laboratory infections have been reported as of 1999, as well as one death

Laboratory Handling Guidelines 

Laboratory Biosafety Level (BSL): BSL-2


Lab Engineering Controls Personal Protective Equipment
  • Single gloves
  • Additional gloves (recommended)
  • Snap-front lab coat with cinch cuffs
  • Additional mucous membrane protection

Waste Management: Regulated Medical Waste (RMW)

Shipping Guidance: Refer to EHS Biological Materials Shipping 

Animal Vivarium Guidance

Animal Housing Biosafety Level (ABSL): ABSL-2

Animal Biosecurity: Experimental animals are housed separately

Perform InoculationsBiosafety Cabinet, Cage Changing station

Change CagesBiosafety Cabinet, Cage Changing Station

Exposure and Spill Procedures 

Mucous Membranes: Flush eyes, mouth, or nose for 15 minutes at an eyewash station.See: responding to exposures.

Other Exposures: Wash with soap and water for 15 minutes (open wounds, sores, etc.) or a minimum of 20 seconds for areas with intact skin. See:  responding to exposures.

Small Spills: Notify others working in the lab. Evacuate area and allow 30 minutes for aerosols to settle. Don appropriate PPE. Cover area of the spill with paper towels and apply disinfectant, working from the perimeter toward the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials. See:  spill cleanup

Large Spills: Request assistance from the EHS Spill Team by calling CUPD dispatch. Call 911 from a campus phone or 607-255-1111 from a mobile phone.

Incident Reporting: Immediately report the incident to supervisor and complete the EHS online injury/illness report as soon as possible.

Medical Follow-Up:

  • For students, seek medical attention at Cornell Health or local primary care provider. Call Cornell Health at 607-255-5155 (24-hour phone consultation line) or a local urgent care. 
  • For faculty and staff, seek medical evaluation with a local primary care provider or urgent care. Cornell Health does not see employees for post-exposure care. 
  • Emergencies: Call 911 from a campus phone or 607-255-1111 from a mobile phone. 
Cornell EHS would like to thank Emory University for the use of their Biological Agent Reference Sheet (BARS) format and some content. 

More Information


  1. Toxoplasma gondii. Pathogen Safety Data Sheet. Public Health Agency of Canada.