Abstract: Vaccine compositions which are protective against circovirus infections, including porcine circovirus and psittacine beak and feather disease virus, in animals, comprising a nucleic acid vector comprising a eukaryotic cis-acting transcription/translation regulatory sequence functionally linked to a nucleic acid encoding an animal circovirus polypeptide, wherein the nucleic acid lacks a viral origin of replication are disclosed. Nucleic acid vectors for the transient expression of one or more circovirus polypeptides in a eukaryotic cell comprising a nucleic acid vector comprising a eukaryotic cis-acting transcription/translation regulatory sequence functionally linked to the nucleic acids of the invention are described.

Abstract: The present invention provides a vaccine which is protective against avian polyomavirus infection in a bird which is classified as being a member of the Psittaciformes order which comprises an immunogenic amount of a modified live avian polyomavirus in a pharmaceutically acceptable carrier. Methods are also provided for preventing avian polyomavirus infection in a bird, or in several different species of birds, classified as being a member of the Psittaciformes order, comprising administering a vaccine comprising an immunogenic amount of a modified live avian polyomavirus and a pharmaceutically acceptable carrier. A preferred embodiment provides a modified live avian polyomavirus vaccine for prevention of wild-type infection in a Budgerigar, lovebird or Cockatiel.