Most adult cats will not pass oocysts eve year. Although the majority of infected infants show no symptoms of toxoplasmosis at birth, many are likely to develop signs of infection later in life. Loss of vision, mental retardation, loss of hearing, and death in severe cases, are the symptoms of toxoplasmosis in congenitally infected children. Ideally, women who are in frequent contact with cats should be serologically tested for Toxoplasma gondii before becoming pregnant, because, if they are already seropositive, they are not at risk of asymptoms of toxoplasmosis, there have been cases in cats associating toxoplasmosis with pneumonia, liver damage, and loss of vision. Why some cats show symptoms and other cats do not is not known.
Treatment can be effective if the disease is diagnosed early.
A blood test for Toxoplasma antibodies helps in diagnosis of toxoplasmosis in sick cats. Keep cats indoors and do not allow them to hunt rodents and birds. Feed cats only cooked meat or processed food from commercial sources. At present there is no vaccine for toxoplasmosis in cats. Efforts are, however, underway to market a vaccine to prevent Toxoplasma oocyst shedding by cats.