Recombinant canine coronaviruses in dogs, Europe

Abstract

Coronaviruses of potential recombinant origin with porcine transmissible gastroenteritis virus (TGEV), referred to as a new subtype (IIb) of canine coronavirus (CCoV), were recently identified in dogs in Europe. To assess the distribution of the TGEV-like CCoV subtype, during 2001-2008 we tested fecal samples from dogs with gastroenteritis. Of 1,172 samples, 493 (42.06%) were positive for CCoV. CCoV-II was found in 218 samples, and CCoV-I and CCoV-II genotypes were found in 182. Approximately 20% of the samples with CCoV-II had the TGEV-like subtype; detection rates varied according to geographic origin. The highest and lowest rates of prevalence for CCoV-II infection were found in samples from Hungary and Greece (96.87% and 3.45%, respectively). Sequence and phylogenetic analyses showed that the CCoV-IIb strains were related to prototype TGEV-like strains in the 5' and the 3' ends of the spike protein gene.

Figure

Phylogenetic analysis of canine coronavirus (CCoV) type IIb. Maximum parsimony trees based on partial 5´ (A) and 3´ (B) ends of the spike protein gene of group-1a coronaviruses (CoVs). For phylogenetic tree construction, the following reference strains were used (GenBank accession numbers are in parentheses): porcine transmissible gastroenteritis virus (TGEV) Purdue (NC_002306), TS (DQ201447), 96-1933 (AF104420), porcine respiratory coronavirus (PRCoV, only 3´ end) RM-4 (Z24675), 86-137004 (X60089), CCoV-IIa CB/05 (DQ112226), Insavc-1 (D13096), BGF10 (AY342160), CCoV-IIb 341/05 (EU856361), 174/06 (EU856362), 430/07 (EU924790), 118/08 (EU924791), UCD-1 (AF116248, only 5´ end), CCoV-I Elmo/02 (AY307020), 23/03 (AY307021), feline coronavirus (FCoV) type I Black (EU186072), KU-1 (D32044), UCD-1 (AB088222), FCoV-II 79-1146 (NC_007025), 79-1183 (X80799). The tree is rooted on the group-2 CoV canine respiratory coronavirus (CRCoV) 240/05 (EU999954). Statistical support was provided by bootstrapping >1,000 replicates. Scale bars indicate estimated numbers of nucleotide substitutions per site.