Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii About Toxoplasmosis | Toxoplasmosis | CDC. The parasite is found worldwide and most healthy humans, if infected, will have no symptoms and will resolve without treatment. It is estimated that 11% of the United States population over the age of 6 years have had an infection. Toxoplasmosis is a problem in pregnant women and individuals who are immunocompromised Toxoplasmosis: Causes, Symptoms, Diagnosis & Treatment. Symptoms range from flu-like, generalized pain and lymph nodes may be swollen. Other areas affected in severe cases are organs such as liver, brain and ocular damage. Unborn children can be exposed and show no symptoms until later in life. The parasite can survive for months in the soil, especially in humid climates. 

Cats serve as the definitive host for Toxoplasma gondii, and they are imperative for Toxoplasma reproductive cycle and play a key role in spreading the disease Toxoplasmosis in Animals - Generalized Conditions - Merck Veterinary Manual. Cats become infected by eating birds and small animals that are infected. Other animals, birds and humans serve as intermediate hosts. Toxoplasmosis infections can occur through the direct contact from contaminated untreated water, eating undercooked meats or shellfish (pork, lamb, venison/mussels, oysters, clams), eating contaminated unwashed fruits or vegetables, cleaning cat litter boxes or working in soil and not washing your hands afterwards. Toxoplasma can be passed to an unborn child and in rare instances through blood transfusion or organ donation. The infected mother during pregnancy can cause a miscarriage or stillborn. If the infant survives immediate signs can be an enlarged head, some may have no symptoms until later in life, were vision loss, seizures or mental disability can occur. Diagnosis is through blood tests. Treatment in healthy people is usually not necessary; in immunocompromised individuals there are a combination of drugs that are used. 

One of the problems in immunocompromised patients and children who acquired it through transplacental infection is the parasite can wall itself off in the body by forming a protective cyst Toxoplasmosis: An Important Message for Cat Owners. When the individual’s immune system ‘attacks’ the cyst an active infection can start, even years later. Only when an active infection is happening can drug treatment be effective. Prevention is by washing your hands after working outside, cooking food to proper temperatures and refrigerating/freezing within two hours after cooking, washing fruits and vegetables, washing hands after cleaning the litter box, and if you have outside cats do not clean their litter box if pregnant. The best prevention for cats is to keep them indoors decreasing their chances of being exposed to Toxoplasma gondii.