The Toxoplasma parasite can persist for long periods of time in the bodies of humans (and other animals), possibly even for a lifetime.
More than 40 million men, women, and children in the U.S. carry the Toxoplasma parasite, but very few have symptoms because the immune system usually keeps the parasite from causing illness.
People can only become infected with Toxoplasma gondii parasites through contact with infected animal faeces (usually cat faeces).
The toxoplasma parasites may infect tissues of the inner eye. This can occur in people with healthy immune systems. But the disease is more serious in people with weakened immunity. Signs and symptoms of ocular toxoplasmosis can include reduced vision, blurred vision, pain (often with bright light), redness of the eye, and sometimes tearing.
Most infants who are infected while still in the womb have no symptoms at birth, but they may develop symptoms later in life. A small percentage of infected newborns have serious eye or brain damage at birth.
People with weakened immune systems are likely to have more-serious disease from toxoplasmosis. A toxoplasmosis infection from earlier in life may become active again. The toxoplasmosis parasite can cause a long-term infection. Following infection, a small number of parasites can remain locked inside cysts within certain parts of the body, such as the brain, lungs and muscle tissue.
People at risk include those living with HIV/AIDS, people receiving cancer treatment and people with a transplanted organ. The most common symptoms in people with HIV infection are headache, confusion, and fever. Other symptoms include seizures, poor coordination, and nausea or vomiting.
Rarely, people can also become infected by receiving infected blood via transfusion. Laboratory workers who handle infected blood can also acquire infection through accidental inoculation.
Toxoplasmosis by Toxoplasma gondii
