Author
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Wesley, Ronald |
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Submitted to: Virus Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/5/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Many or most pet dogs in the United States are vaccinated with a modified-live-vaccine for canine coronavirus (CCV). Recent scientific papers published in the 1990s have shown CCV strains to be similar to feline coronaviruses. However, one CCV strain of U.S. origin that we have used has infected pigs and has behaved in the laboratory like the pig coronavirus. Therefore, a selected part of this CCV strain and of other CCV reference strains was sequenced. We found that marked sequence differences occurred in this CCV strain because of a recombination event between this virus and the pig coronavirus. This research is important for veterinarians, scientists, and vaccine producers because genetic recombination could account for different biological properties of CCV strains and could affect the efficacy of CCV vaccines. Technical Abstract: To gain insight into the genetic relationships among 6 canine coronavirus (CCV) strains, the variable region of the spike (S) protein gene was sequenced. The CCV strains were: 2 ATCC reference strains, the Insavc-1 vaccine strain, the current NVSL challenge strain, and 2 California field isolates from the 1970s. By reverse transcription - polymerase chain reaction analysis, all 6 strains contained sufficient genetic size for an ORF 7b, and thus, none were TGEV-like since TGEV lacks ORF 7b. By sequence analysis of the variable domain at the 5' end of the S gene, 5 of the 6 CCV strains had a high degree of homology with FIPV. However, one CCV field isolate was different and had a high degree of homology with the 5' end of the TGEV S gene. This suggests that RNA recombination occurred at this site between antigenically related coronaviruses. These marked sequence differences in the S gene may account for some biological variation among CCVs. |
