Pathogenesis of a Newly Isolated Rat Virus in Newborn and Juvenile Rats (original) (raw)

1991, Experimental Animals

The pathogenesis of the UT-1 strain, a newly isolated rat virus (RV), in juvenile and newborn rats was examined. Intracerebrally (ic) inoculated newborns developed severe pantropic infections resulting in emaciation, stunted growth, diarrhea, dehydration and icterus, and died 13 to 15 days after the inoculation. Newborns inoculated intraperitoneally (ip) developed similar, but milder diseases. The virus replicated in all the organs tested, which was followed by severe viremia. Histopathologically, diffuse vacuolation and necrosis of the hepatocytes were observed in the liver. Juvenile rats inoculated with the virus showed neither clinical signs nor histopathologic lesions, although viral recovery and antibody production were observed. Thus, we conclude that the UT-1 strain of RV caused asymptomatic infections in juvenile rats, and fatal infections with hepatic lesions in newborn rats. KEY WORDS : jovenile rat, newborn rat, pathogenesis, rat virus Rat virus (RV), a member of the family Parvoviridae, is one of the common viruses in laboratory rat colonies and often causes asymptomatic infections in adult rats, and severe diseases in fetal and newborn rats [1, 7, 11,14-16]. Little attention, however, has been paid to the RV infection in laboratory rat colonies in Japan, since there has been no information about it. We have isolated new RV strains in Japan from asymptomatic adult rats and have found the Japanese isolates to have hemagglutination patterns differing from those of the RV-13 prototype strain [5].