Widespread occurrence in Australian marsupials of neutralizing antibodies to a herpesvirus from a parma wallaby.

Serum neutralizing antibodies to a parma wallaby herpesvirus (PWHV) have been detected in a wide range of marsupials from different locations across Australia, including several islands. A study of 242 animals (mostly macropods) sampled in the wild showed that 23% had antibodies; a significantly higher frequency (41%) of 116 animals in captivity had antibodies, which were generally at higher levels than those of animals in the wild. Antibodies to PWHV were also detected among parma wallabies from a colony on Kawau Island, New Zealand. The highest antibody levels were found in a group of captive tammar wallabies during recurrent outbreaks of clinical infection. It is suggested that PWHV has evolved along with a marsupial host, and that the high antibody levels among captive animals reflects ease of virus transmission due to crowding, or to conditions of stress leading to expression of latent virus.