Characterization of turkey coronavirus from turkey poults with acute enteritis

Abstract

The present study was to characterize turkey coronavirus associated with turkey poult enteritis and mortality. Intestinal contents or intestines from affected turkey poults and inoculated turkey embryos contained coronaviruses as revealed by electron microscopy or were positive for turkey coronavirus by immunofluorescent antibody assay. Sucrose density gradient ultracentrifugation of the virus-containing intestinal homogenate yielded two opalescent bands corresponding to the buoyant densities of 1.14-1.15 and 1.18-1.20 g/ml, respectively. Coronaviral particles from intestinal contents or the sucrose density gradient preparation were mainly spherical in shape and had envelope and central depression. They were surrounded by a fringe of regularly spaced petal-shaped projections attached to the particles by a short stalk. Purified viruses hemagglutinated rabbit erythrocytes with a titer of 16. Major protein bands of purified viruses analyzed by SDS-PAGE were located at 200, 100-110, 50-60, and 30-35 kDa. The patterns of protein bands were consistent with those of Minnesota or Quebec turkey coronavirus isolates. A 568 bp nucleotide fragment of turkey coronavirus spike protein gene was amplified from RNA of inoculated turkey embryo intestine or purified virus. Sequence analysis of the 568 bp PCR product revealed high degree of identity with the corresponding spike protein gene sequence of human and bovine coronaviruses. The results indicated that turkey coronavirus was associated with turkey poults with acute enteritis.

Genotyping of turkey coronavirus field isolates from various geographic locations in the Unites States based on the spike gene

“…The most apparent gross lesions are markedly distended intestines with gaseous and watery content, particularly in the ileum and ceca. Salient histopathologic findings include shortening of the intestinal villi, an increase in crypt depth, and widening of intervillous spaces [1]. When turkeys are infected with TCoV and other infectious agents such as astrovirus, small round virus, and Escherichia coli (E. coli), they can develop poult enteritis-mortality syndrome (PEMS), which causes high mortality [2,3].…”

Infection with a pathogenic turkey coronavirus isolate negatively affects growth performance and intestinal morphology of young turkey poults in Canada

“…Infections initiated with TCoV alone in 2-day-old or in 28-day-old poults caused reductions in weight gain following infection. Significantly lower weights persisted for the duration of the trial (44 days), suggesting that turkey poults may be permanently affected with respect to weight gain even after recovering from TCoV infections (Dea & Tijssen, 1988;Brown et al, 1997;Berslin et al, 2000;Guy et al, 2000;Lin et al, 2002;Ismail et al, 2003;Cavanagh, 2005;Culver et al, 2006). Although feed conversion was not examined directly in the present study, the gross lesions and histological appearance of the intestinal tract of the infected turkey poults would suggest that feed conversion would be adversely affected by infection with TCoV-MG10 and would contribute to the poor weight gains demonstrated by infected birds.…”

PCR Amplification and Sequencing Analysis of Full-Length Turkey Coronavirus Spike Gene

“…The most striking gross lesions are markedly distended intestine with gaseous and watery content, especially in the ileum and ceca. The salient histopathologic fi ndings include shortening of the intestinal villi, increase in crypt depth, and widening of intervillous spaces [ 1 ]. TCoV belongs to species Avian coronavirus of the genus Gammacoronavirus in the family Coronaviridae .…”