It is unclear whether respiratory and enteric bovine coronavirus (BoCV) strains are distinctive in biological, antigenic and genetic characteristics. In the present study, we analyzed the nucleotide and amino acid sequence of the S1 subunit of the S glycoprotein, including the cleavage site, of both respiratory (n=5) and enteric (n=3) BoCV isolates including two paired isolates from the same feedlot animals and compared them with the prototype Mebus and two enteric and one respiratory BoCV strains from Quebec. A total of 75 polymorphic nucleotides were identified in the S1 subunit of the spike glycoprotein of BoCV isolates compared with the Mebus strain. These polymorphisms led to 42 amino acid changes at 38 distinct sites. The amino acid changes were distributed throughout the S1 subunit with clustering around residues 40-118, 146-179, and 458-531. Among these variations, only 19 amino acid substitutions altered the charge, hydrophobicity and surface probability of the protein. Based on phylogenetic analysis, our respiratory and enteric isolates clustered into two major groups with two subgroups. Although, there were only a few amino acid changes between the respiratory and enteric paired isolates, the other two respiratory isolates, one isolated from the same farm as a paired strain and the other from a different farm, showed more sequence diversity. Amino acid alterations in residues 113, 115, 118, 146, 148, 501, 510 and 531 of respiratory isolates conferred significant changes in the predicted secondary structure compared with the prototype winter dysentery (WD) and the calf diarrhea (CD) strains of BoCV. In conclusion, the data suggests that respiratory strains of BoCV may differ genetically from the classical calf enteric and adult WD strains.

Bovine coronavirus (BCoV) is an etiological agent associated with winter dysentery (WD), prevalent in adult cattle during the winter. Although we previously detected, isolated, and characterized BCoV strains from adult cattle with WD (WD-BCoV strains) during the winter in South Korea, the precise epidemiology, as well as the causative agent of diarrhea in adult cattle in the warmer seasons, has not been examined. We examined 184 diarrheic fecal specimens collected from 75 herds of adult cattle from seven provinces during the spring (warm), autumn (warm), and summer (hot) seasons. Bovine coronavirus-positive reactions were detected for 107 (58.2%) diarrheic fecal samples (in 47/75 herds). Of these 107 positive samples, 90 fecal samples from 33 herds tested positive for BCoV alone and 17 fecal samples from 14 herds also tested positive for other pathogens. Biological comparisons between the 9 BCoV strains isolated in this study and the 10 previously isolated WD-BCoV strains revealed that there was no receptor-destroying enzyme (RDE) activity against mouse erythrocytes in the 9 BCoV strains but the 10 WD-BCoV strains had high RDE activity. Phylogenetic analysis of the spike (S) and hemagglutinin/esterase (HE) proteins revealed that all the Korean BCoVs clustered together regardless of season and were distinct from the other known BCoVs, suggesting a distinct evolutionary pathway for the Korean BCoVs. These and previous results revealed a high prevalence and widespread geographical distribution of BCoV, suggesting that this virus is endemic in adult cattle with diarrhea in all seasons in South Korea.

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ABSTRACT. A total of 804 goat sera were collected from 144 goat farms in five regions of South Korea during a period between 2005 and 2006 and screened for the antibodies of viral pathogens in ruminants. The individual seropositive rates for each virus were 13.7% (110/ 804) for bovine herpesvirus-1 (BHV-1), 9.5% (76/804) for bovine parainfluenza type-3 virus (PI-3V), 5.5% (44/804) for Akabane virus (AKAV), 13.3% (107/804) for Aino virus (AINV), 2.0% (16/804) for Chuzan virus (CHUV) and 1.0% (8/804) for bovine coronavirus (BCoV). Compared with other areas, Chungcheong Province showed higher seropositive rates of 13.6% for PI-3V, 22.3% for AKAV and 28.2% for AINV. The results indicate that among the six viral diseases, BHV-1 infection is quite prevalent, while BCoV infection is less prevalent on domestic goat farms in Gyeongsang and Jeonla Provinces.

BMD temporarily decreased after low-dosage prednisolone administration; however, it gradually improved during tapering of the prednisolone dosage. These results have suggested that a low dosage of prednisolone can be used with little concern for development of osteopenia in dogs.