Toxoplasmosis

• 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.

• 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 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.

• Diagnosis:
  • Blood testing (serology) is the most common way to diagnose toxoplasmosis in humans. Serology measures the amount of antibodies 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:
  • 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.

• 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).