RAT PARVOVIRUS TYPE-1 - THE PROTOTYPE FOR A NEW RODENT PARVOVIRUS SEROGROUP

A newly recognized parvovirus of laboratory rats, designated rat parvo virus type 1a (RPV-1a), was Pound to be antigenically distinct. It was cloned, sequenced, and compared with the University of Massachusetts strain of rat virus (RV-UMass) and other autonomous parvoviruses. RPV- 1a VP1 identity with these viruses never exceeded 69%, thus explaining its antigenic divergence. In addition, RPV-1a had reduced amino acid identity in NS coding regions (82%), reflecting phylogenetic divergenc e from other rodent parvoviruses. RPV-1a infection in rats had a predi lection for endothelium and lymphoid tissues as previously reported fo r RV. Infectious RPV-1a was isolated 3 weeks after inoculation of infa nt rats, suggesting that it, like RV, may result in persistent infecti on. In contrast to RV, RPV-1a was enterotropic, a characteristic previ ously associated with parvovirus infections of mice rather than rats. RPV-1a also differed from RV in that infection was nonpathogenic for i nfant rats under conditions where RV infection causes high morbidity a nd mortality. Thus, RPV-1a is the prototype virus of an antigenically, genetically, and biologically distinct rodent parvovirus serogroup.