Wright's stain, 1000x

Toxoplasma gondii is a coccidian which is an obligatory cellular inhabitant which affects most mammals, including humans. Both domestic and wild felines are the definitive host, whereas other species act as intermediate hosts. Infection can originate in utero, or by the ingestion of oocysts in food or water. Manifestation of clinical symptoms depends upon many factors including the extensiveness of the lesions and their localization. Certain animals may not present any clinical signs of infection.  Some infections can be fatal despite the fact that most animals will successfully combat the infection.  Many systems can be affected including the respiratory, gastro-intestinal, nervous and ocular systems.  Serological tests indicate that this infection is prevalent in the pet population with an important amount (30%) of cats and dogs possessing antibodies against the organism.