Isolation and characterization of a coronavirus from pigeons with pancreatitis

Abstract

Objective: To identify and partially characterize a coronaviruslike virus isolated from naturally infected pigeons.

Animals: 50 specific pathogen-free (SPF) embryonated chicken eggs, 30 White Leghorn SPF chickens, and 12 clinically normal pigeons.

Procedures: Pancreatic tissue specimens from sick pigeons were inoculated into SPF embryonated chicken eggs for viral isolation and investigation of morphologic and hemagglutinating properties of the isolate, called PSH050513. Furthermore, virulence studies in SPF chickens and experimental pigeons were performed. The spike (S) glycoprotein gene of PSH050513 was further sequenced and analyzed.

Results: PSH050513 was isolated and identified from the experimentally infected pigeons by a routine method, which was in accordance with Koch's postulates. The complete S protein (1,167 amino acids) was compared with published S protein sequences of other avian and mammalian coronaviruses. A high degree of sequence identity (79.3% to 99.6%) was observed between the S protein sequence of PSH050513 and published sequences of avian infectious bronchitis virus (IBV); only limited identity (< 37.8%) was observed with turkey coronavirus and mammalian coronaviruses. Furthermore, when the virus was inoculated into SPF chickens, pancreatitis developed.

Conclusions and clinical relevance: PSH050513 has been tentatively identified as a novel member of group 3 coronaviruses that have close genetic relationships with IBV strains.