The neurological form may last for several weeks without involving other systems while disease of the lungs and liver may result in death within a week. Generalized toxoplasmosis in the dog is most common in dogs under 1 year of age. The most dramatic clinical signs in older dogs are associated with the neural and muscular systems. Seizures, cranial nerve deficits, tremors, ataxia and paralysis are all reported. Ocular lesions are also reported.
Diagnosis is determined by the phase of infection, the host involved, and availability of testing.
Hematologic and biochemical parameters are of value in acute cases in both the dog and cat. Radiographic findings, especially in the cute phase, consist of a diffuse interstitial to alveolar pattern with a mottled lobar distribution. Fecal examination of felines is of little value since cats usually shed T. gondii oocysts for only a few weeks after their first exposure. Serologic testing is useful with new tests that detect changes in immunoglobulin classes becoming available. A similar tissue cyst-forming organism , Neospora spp has been reported from canines and bovines causing myocarditis, encephalitis and myosistis.