Identification of the novel lapine rotavirus genotype P[22] from an outbreak of enteritis in a Hungarian rabbitry

Application of improved molecular techniques in the detection and characterization of rotavirus strains has led to the recent description of several new combinations, specificities, and genetic variants of the outer capsid genes, VP7 and VP4. In spite of the enormous diversity of mammalian rotavirus strains, the few lapine rotaviruses characterized to date, appear to carry a narrow range of such antigen combinations; only P[14], G3 and, based on a more recent study, P[22], G3 rotaviruses have proved to be epidemiologically important in rabbits. In the present study, we characterized a lapine group A rotavirus with a super-short electropherotype detected in an outbreak of fatal enteritis in a Hungarian commercial rabbitry. Based on sequence and phylogenetic analysis of the VP7, VP4, and NSP4 genes, our lapine strain is a P[22], G3 rotavirus that carries the NSP4 genotype shared by most lapine rotaviruses. Although the P[22] VP4 specificity has been newly identified, the relatively high sequence variation between our strain and those identified in Italy (89.1–90.4% nucleotide identity; region VP8*) implies that these strains diversified far before they were described for the first time, strongly suggesting that this genotype may have circulated in rabbitries or in nature without prior detection. We conclude that genotype P[22] lapine rotaviruses show a wider geographical dispersal than previously thought, although understanding their true epidemiological significance needs further investigation.