Psittacid herpesvirus 3 infection in rose-ringed parakeets in southern Brazil

Abstract

We diagnosed disease caused by psittacid herpesvirus 3 (PsHV-3), a novel psittacid pathogen, in rose-ringed parakeets ( Psittacula krameri) housed in an exotic psittacine breeding colony in southern Brazil. The disease affected several adult birds. Clinical signs included apathy, tachypnea, and wheezing. Four birds were autopsied, and sections of lungs and liver were examined histologically and by electron microscopy (EM), revealing pulmonary congestion, bronchopneumonia, or multifocal necrosis of tertiary bronchi, with syncytial cells and eosinophilic intranuclear inclusion bodies. Viral particles morphologically compatible with herpesviruses were observed by EM in lung sections. PCR with pan-herpesvirus primers performed on total DNA extracted from paraffinized tissue resulted in a 278-bp product. Sequencing of the amplicon revealed 93% nucleotide identity with a PsHV-3 sequence available in GenBank. Phylogenetic analysis grouped the obtained sequence with the only PsHV-3 DNA polymerase gene sequence available (GenBank accession JX028240) and separated the sequence from psittacid herpesviruses 1 and 2. The clinical, pathologic, and molecular findings support the association of PsHV-3 with pneumonia found in these rose-ringed parakeets in southern Brazil.