Nucleotide sequence variation of the VP7 gene of two G3-type rotaviruses isolated from dogs

The sequence of the VP7 gene of two rotaviruses isolated from dogs in south ern Italy was determined and the inferred amino acid sequence was compared with that of other rotavirus strains. There was very high nucleotide and am ino acid identity between canine strain RV198/95 and other canine strains, and to the human strain HCR3A. Strain RV52/96, however, was found to have a bout 95% identity to the G3 serotype canine strains K9, A79-10 and CU-1 and 96% identity to strain RV198/95 and to the simian strain RRV. Therefore bo th of the canine strains belong to the G3 serotype. Nevertheless, detailed analysis of the VP7 variable regions revealed that RV52/96 possesses amino acid substitutions uncommon to the other canine isolates. In addition, stra in RV52/96 exhibited a nucleotide divergence greater than 16% from all the other canine strains studied; however, it revealed the closest identity (90 .4%) to the simian strain RRV. With only a few exceptions, phylogenetic ana lysis allowed clear differentiation of the G3 rotaviruses on the basis of t he species of origin. The nucleotide and amino acid variations observed in strain RV52/96 could account for the existence of a canine rotavirus G3 sub -type. (C) 2001 Elsevier Science B.V. All rights reserved.