Serum samples from fruit bats of several species collected both before and after the outbreak, were virus neutralization test positive. However, virus has not been isolated from bats. Samples from rodents, birds, cattle, sheep, cats and a dog were all seronegative. The family Paramyxoviridae includes three genera which contain many important viruses of both animals and humans. In the genus Morbillivirus are canine distemper virus, rinderpest virus, peste des petits ruminants virus, equine morbillivirus and the human measles virus.
Intestinal signs are also common.
Transmission is generally by direct contact as virus is usually shed in all secretions. A carrier state is present in Newcastle disease with virus shedding for at least four weeks post infection. The gross pathologic lesions and histopathology described in reports of the Australian outbreak of this new virus, are consistent with a neurotropic paramyxovirus. Morbidity in adult sows is extremely low, with reproductive failure the primary clinical effect. Newcastle disease virus and equine morbillivirus are other paramyxoviruses reported to cause zoonotic illness.