CHARACTERIZATION OF AUSTRALIAN OVINE ADENOVIRUS ISOLATES

We have characterised two groups of adenoviruses isolated from sheep i n Australia. Restriction endonuclease maps for enzymes BamHI, ClaI, Sa lI, SmaI and SphI have been determined for the genome of ovine adenovi ruses related to bovine adenovirus serotype 7 (BAV 7) from sheep in We stern Australia. Although previously serotyped as BAV 7 these isolates are different from bovine isolates of BAV 7 based on comparison with published restriction endonuclease profiles and maps of BAV 7 cattle i solates. Additional adenovirus isolates obtained from Victorian sheep have been serotyped as ovine adenovirus type 5 (OAV 5). On the basis o f restriction endonuclease analysis these viruses are different from t he sheep BAV 7 isolates. Following infection of sheep with ovine BAV 7 and OAV 5 isolates, virus was recovered from nasal and rectal swabs f or several days. Antibodies detected by ELISA and serum neutralisation tests (SN) developed by 15 days after infection. Virus also spread fr om the infected sheep to an incontact control and one of ten sheep pur chased for infection studies had SN antibodies to BAV 7 suggesting tha t BAV 7-like viruses naturally infect sheep in Victoria and Western Au stralia. With further development, these ovine adenoviruses may be sui table as vectors for the delivery of vaccine antigens to sheep and cat tle.