Toxoplasma gondii infection in cats: ABCD guidelines on prevention and management

Abstract

Overview: Toxoplasma gondii infection is common in cats, but the clinical disease is rare. Up to 50% of cats, especially free-roaming ones, have antibodies indicating infection and the presence of cystic stages.

Disease signs: Clinical signs only appear in few cats when they become immunosuppressed - in these situations cystic stages can be reactivated. Commonly affected are the central nervous system (CNS), muscles, lungs and eyes. HUMAN INFECTION: Cats can pose a risk for humans when they shed oocysts. However, this happens only once in their lifetime, usually only for 3-10 days after ingestion of tissue cysts. Thus, cats that have antibodies to T gondii no longer shed oocysts, and do not pose a risk to humans.

Figure 1

Myositis in a cat caused by T gondii cysts. The cat presented in lateral recumbency, was unable to get up, and showed severe muscle hyperaesthesia. Courtesy of Katrin Hartmann, Ludwig Maximilians University, Munich, Germany

Figure 2

Thoracic radiograph (laterolateral view) of a cat with pulmonary toxoplasmosis. Courtesy of Katrin Hartmann, Ludwig Maximilians University, Munich, Germany

Figure 3

Cytology of a fine-needle aspirate from a cat with pulmonary toxoplasmosis and lung consolidation, showing numerous intracellular and extracellular T gondii tachyzoites and cysts (arrows). Courtesy of George Reppas, Vetnostics, Australia