Pathological findings in two fin whales (Balaenoptera physalus) with evidence of morbillivirus infection

Two immature female fin whales stranded on the Belgian and French coastlines, were examined post mortem. The main gross findings were massive parasitic infestation, associated with a large thrombus in one whale, and severe emaciation. Microscopical investigations revealed multinucleated syncytia with large intranuclear inclusion bodies in various tissues, and positive immunolabelling for morbillivirus antigens. Other evidence of morbillivirus infection was provided by the demonstration of specific viral structures in syncytia and in cell cultures, and the detection of neutralizing antibodies to canine distemper virus. To the authors>> knowledge, this is the first firm report of morbillivirus infection in baleen whales.