The cat is the definitive host of the coccidian parasite Toxoplasma gondii, with sexual stages in the gut resulting in oocyst shed in faeces. Clinical disease is not common in cats. Except initially, oocyst excretion is sporadic, with small numbers.

The asexual proliferative stages of Toxoplasma gondii, with formation of tissue cysts, cause disease in a wide range of intermediate animal hosts (including humans) that are infected by

• Consuming sporulated T gondii oocysts shed by cats,
• Consuming tissues of other intermediate hosts containing T gondii cysts, or
• Transplacentally.

Oocysts of Toxoplasma gondii are highly infectious to humans and animals.

There is no routine serological test available. Serological tests are not reliable in cats.

Faecal examination will only be performed in special circumstances after prior arrangements have been made with the laboratory. Such examinations pose a high risk to laboratory workers. In instances where clinical disease requires confirmation in the dead animal, fixed sections in buffered formalin of small intestine, liver, kidney, heart, muscle, spleen, and brain should be submitted for histopathology.