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Veterinary Public Health Program
313 N Figueroa St. Rm 1127
Los Angeles, CA 90012
Tel (213) 288-7060
Fax (213) 481-2375
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What is toxoplasmosis?

  • Toxoplasmosis is a disease caused by the parasite Toxoplasma gondii

  • The parasite can infect almost all animals, but the cat is the definitive host.

    • Definitive host = the only animal in which the parasite can sexually reproduce

  • The Centers for Disease Control and Prevention (CDC) estimates that:

    • Over 60 million people in the US are infected with the parasite

    • It is the 2nd leading cause of death from a foodborne illness in the US

  • Eating undercooked or raw meat is the most common way humans become infected.


How do people get infected?


  • Eating raw or undercooked contaminated meat, or foods that have been in contact with contaminated surfaces (cutting boards, utensils, knives, unwashed fruits and vegetables).

  • Drinking contaminated water or unpasteurized milk.

  • Ingesting infective parasite eggs (oocysts) from cat feces (changing the litter box, working with contaminated soil when gardening.

  • Blood transfusion, organ transplant, or mother-to-fetus during pregnancy.


What are symptoms of toxoplasmosis?

    Disease in people:

    • In humans, the parasite will encyst in tissues (muscle, heart, eye, brain)

    • Individuals with healthy immune systems usually do not have any symptoms of disease or can have mild flu-like symptoms. The immune system prevents the spread of the parasite throughout the body

    • Immune-suppressed individuals can have serious illness with symptoms including blurred vision, headaches, blindness, seizures, lung problems, and birth complications in pregnant women or birth defects in fetuses.

    Disease in pregnant women:

    • Women who have been infected with Toxoplasma gondii prior to becoming pregnant will usually have immunity that will be passed to their unborn child.

    • Women who become infected with Toxoplasma gondii for the first time while pregnant or just prior to becoming pregnant can pass the disease to their unborn child.

    Disease in cats:

    • Cats are the definitive host of Toxoplasma gondii. This means that cats are the only animals in which the parasite can sexually reproduce.

    • Cats become infected with the parasite by eating infected rodents, birds or other contaminated raw meat. This means indoor only cats fed a cooked, commercial diet are very unlikely to become infected with toxoplasmosis.

    • Once a cat is infected with the Toxoplasma gondii, they can shed parasite eggs into their feces. Most cats only shed the eggs for a few weeks and will not shed again in their lifetime if they have a healthy immune system.

    • Like humans, cats with healthy immune systems rarely develop any clinical signs of disease. However, ocular disease and other signs of illness are possible in cats.


How is toxoplasmosis diagnosed and treated?


    • Blood testing (serology) is the most common way to diagnose toxoplasmosis in humans. Serology measures the amount of antibodies in a person's immune system is producing to fight off the parasite after infection. People can be seropositive (i.e. still have these antibodies in the blood) long after their body has fought off the effects of the parasite.

    • Serologic testing is also used to diagnose cats. However, a seropositive test in a cat does not mean the cat is shedding parasite eggs. Most infected cats shed eggs only for a short time after first becoming infected and will not shed again.


    • Treatment is typically unnecessary in healthy individuals and cats.

    • Multiple medications are available for immune-compromised individuals and pregnant women, as indicated by a doctor.


What should I do to protect myself from toxoplasmosis?

  • Avoid eating undercooked or raw meat.

  • Avoid drinking raw or unpasteurized milk and untreated water.

  • Avoid cross-contamination of foods by washing all cutting boards, utensils, and dishes after each use.

  • Wash fruits and vegetables prior to eating.

  • Wash hands thoroughly with soap and water after handling raw meat, soil/sand, unwashed fruits and vegetables, or cat litter boxes.

  • Use gloves when gardening.

  • Keep cats indoors and feed a commercially prepared, cooked diet. Do not feed cats raw meat.

  • Clean cat litter boxes daily. It takes 24 hours for eggs shed in cat feces to become infective. Therefore, cleaning the litter box as soon as possible decreases the chances of contracting infective Toxoplasma eggs

  • Immunocompromised or pregnant women should avoid cleaning cat litter boxes if possible.





Since animals typically do not show signs of toxoplasmosis, there have not been reports of it to the Veterinary Public Health Program (VPH).





Centers for Disease Control and Prevention (CDC) - Toxoplasmosis


Center for Food Safety and Public Health (CFSPH) - Toxoplasmosis technical factsheet (for physicians and veterinarians)


Companion Animal Parasite Council (CAPC) - Current advice on parasite control: Toxoplasma gondii


Last updated: June 16, 2015

Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.
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