The cat is the only species where the parasite can fulfill both sexual and asexual stages of their life cycle. Cats get this infection as intermediate hosts after weaning due to consumption of contaminated raw meat or eating of infected rodents. The incidence is higher in wild cats and outdoor cats compared to indoor as they always stay home. In sexual phase of toxoplasmosis in cats, oocysts is shed in the feces for 1-3 weeks after the initial infection. Once the infection is full blown, oocysts rarely shed again. The intestinal phase of infection does not cause serious clinical problems in cats. It is the asexual stage that can cause illness, especially among immunodeficient cats and kittens and cats infected with feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV or feline AIDS virus).
Symptoms of toxoplasmosis
Most cats infected with T. gondii have no symptoms. Toxoplasmosis disease can be seen clinically sometimes. This disease affects and starts developing when the immune system of the cat is not strong enough to stop the spread of forms of tachyzoites. The disease is more likely in cats with weakened immune systems, including kittens and cats of feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV).
Fever, loss of appetite and lethargy are the most common symptoms of toxoplasmosis. Other symptoms may occur depending on whether the infection is acute or chronic and where the parasite is found in the body. Pneumonia is caused in the lungs with T. gondii which would lead to breathing difficulties gradually increasing severity. Eyes and central nervous system, causing inflammation of the retina or the anterior chamber of the eye, pupil size and abnormal sensitivity to light, blindness, head pressing, tenderness, changes in personality, circling, tremors of the ears, difficulty in chewing and swallowing food, convulsions and loss of control over urination and bowel movements are also the most common diseases that are affected in toxoplasmosis.
Diagnosis of toxoplasmosis
History, signs of the disease, and the results of laboratory tests are the main source of diagnosis for toxoplasmosis. The major way to diagnose Toxoplasmosis is the measurement of IgG and IgM anti-Toxoplasma gondii in the blood. The cat has been infected if significant presence of IgG antibodies from T. gondii in a healthy cat and are now more likely immune and do not excrete oocysts. The strong presence of IgM antibodies to T. gondii suggests an active infection of the cat. Absence of antibodies to T. gondii in a healthy cat suggests that the cat is susceptible to infection, and therefore it would shed oocysts for one to two weeks after infection.
Treatment of toxoplasmosis
Recovery is possible with treatment for most cats that are infected with toxoplasmosis. Treatment generally involves a course of an antibiotic called clindamycin. Other drugs used include pyrimethamine and sulfadiazine, which work together to prevent the reproduction of T. gondii. If the disease is confirmed in the cat after diagnosis then treatment should begin as soon as possible and continued for several days after the signs have disappeared. In acute illness, treatment is often initiated on the basis of a high titer of antibody in the first test. If clinical improvement is not seen in two or three days, the diagnosis of toxoplasmosis is questioned. There is no vaccine to prevent infection by both T. gondii and toxoplasmosis in cats, humans or any other species.
Since cats shed organism for few days in their life, the likelihood of human exposure is low. It is unlikely that one will be exposed to the parasite by touching an infected cat; because cats are not usually carry the parasite in the skin. It is also unlikely that you can be infected by cat bites or scratches. In addition, the cats kept indoors do not hunt prey or cats that are not fed raw meat are less likely to be infected by T. gondii.