ABSTRACT
The main sources of N. caninum infections in dogs are related to ingestion of tissue cysts in prey or food. Serological prevalences of N. caninum in the general canine population indicate that subclinical neosporosis is common worldwide. Dogs can die suddenly of severe myocarditis and heart failure without the obvious involvement of other tissues. In adult dogs, multifocal encephalomyelitis, myocarditis, polymyositis, dermatitis, or multifocal dissemination to inner organs including lung and liver are observed. In prenatally infected young dogs, lesions are seen in the spinal cord and brain stem with demyelination, neuronal degeneration with neurophagia and areas of malacia. Toxoplasma gondii infections are also common in dogs and dual infections with T. gondii and N. caninum can coexist in the same dog. Dogs develop antibodies against N. caninum antigens after postnatal infection, by ingesting infectious tissue cysts containing feed-food, but also when puppies are infected prenatally via transplacental transmission.
