Syncytia formation: an aid in the diagnosis of canine distemper encephalomyelitis.

Syncytia formation has been observed in response to experimental Canine Distemper Virus (CDV) infection in specific-pathogen-free Beagle dogs. Multinucleated giant cells are most frequently found in white matter lesions of the brain and in the anterior uvea of the eye. Lymph nodes and the lung are occasionally positive, while the leptomeninges will also rarely harbour syncytia. The mechanism of syncytia formation and their possible importance in the pathogenesis of the disease are briefly discussed. Widespread tissue syncytia formation is a feature of CDV infection which should assist in identifying cases of non-suppurative encephalitis in the dog caused by this agent.