Differentiation of psittacine herpesvirus field isolates by restriction endonuclease analysis

Thirty-one viruses were isolated from 15 different psittacine species. They were all identified as herpesviruses on the basis of chloroform sensitivit y, inhibition of replication in cell cultures by 5-iodo-2'-deoxyuridine and morphology by electron microscopy. DNA from all 31 field isolates of psitt acine herpesviruses ( PsHV) was analysed by cleavage with restriction endon ucleases EcoRI, PstI, and BglII. Using this technique, 12 different restric tion patterns were recognizable. In previous work, we have differentiated P sHV strains according to their serological interrelationships. Restriction endonuclease profiles confirmed the results of conventional serogrouping bu t additional differences were observed among the five established serologic al subtypes. Using this method, it was possible to demonstrate a spontaneou s reinfection of parrots in an aviary with a serologically and genetically different PsHV strain 4 years after the first outbreak of Pacheco's parrot disease (PPD). The results of this study reaffirm that antigenetically and genetically different PsHV exist and can cause PPD.