Cetacean morbillivirus (CeMV) can be divided into six strains in cetaceans throughout the world, causing widespread mortality events in Europe, North America, and Australia. Studies have indicated that characteristics of CeMV may be more closely associated with disease in ruminants than carnivore species, which is representative of their evolutionary histories. Common disease presentation includes broncointerstitial pneumonia, encephalitis, lymphocytopenia, and increases in multinucleated cells. CeVM causes immunosuppression, increasing risk to secondary infection following acute resolution of clinical signs. Hypothesized transmission routes include via aerosol and trans-placentally.