Transmissible enteritis of turkeys: experimental inoculation studies with tissue-culture-adapted turkey and bovine coronaviruses.

ABSTRACT

Four Quebec isolates of turkey enteric coronaviruses (TCVs) and three isolates of bovine enteric coronaviruses (BCVs) were serially propagated in HRT-18 and compared for their pathogenicity in turkey embryos and turkey poults. By immunoelectron microscopy, hemagglutination-inhibition, and Western immunoblotting assays, tissue-culture-adapted Quebec TCV isolates were found to be closely related to the reference Minnesota strain of TCV and the Mebus strain of BCV. Genomic relationships between TCV isolates and the reference BCV strain were confirmed by hybridization assays with BCV-specific radiolabeled recombinant plasmids containing sequences of the N and M genes. Only TCV isolates could be propagated by inoculation in the amniotic cavity of chicken and turkey embryonating eggs, and induced clinical disease in turkey poults. Nevertheless, coronavirus particles or antigens were detected by electron microscopy or indirect enzyme-linked immunosorbent assay in the clarified intestinal contents of BCV-infected poults up to day 14 PI, and genomic viral RNA was detected by slot-blot hybridization using BCV cDNA probes.