Infectious diarrhea of infant rats produced by a rotavirus-like agent

Abstract

During the investigation of an outbreak of diarrhea in suckling rats, a virus morphologically identical to but antigenically distinct from rotaviruses was identified. The disease was characterized clinically by erythema and cracking and bleeding of the perianal skin associated with the excretion of poorly formed fecal pellets, liquid, and gas. Light microscopy-observable changes consisted of small intestinal villous atrophy, villous epithelial necrosis, and villous epithelial syncytial cell formation. The cytoplasm of the epithelial syncytial cells contained large numbers of 80-nm viral particles that were often associated with reticular aggregates of electron-dense material. Viral infection principally involved the luminal one-fourth to one-third of the intestinal villi as determined by indirect immunofluorescence. This rotavirus-like agent contained 11 double-stranded RNA segments; however, the migration pattern of these segments in polyacrylamide gels differed from the electrophoretic pattern which is characteristic of the typical rotaviruses. The agent had a buoyant density in CsCl of 1.36 to 1.4 g/cm3 and was labile at pH 3 and at 56°C; however, infectivity of viral inocula was not altered by extensive treatment with ether or by pH 5 buffers. This disease, which we have named infectious diarrhea of infant rats, is the first recognized viral diarrhea of rats and appears to be a good model for the study of the recently recognized group of atypical rotaviruses.

Viral Disease

“…The eight species of rotaviruses are classified as groups AeH. Infectious diarrhea of infant rats (IDIR), a nonlethal illness in rats that resembles rotavirus-caused epizootic diarrhea of infant mice (Vonderfecht et al, 1984), is caused by a group B rotavirus antigenically distinct from epizootic diarrhea of infant mice virus (group A) (Vonderfecht et al, 1985). Group B rotaviruses infect humans, rats, piglets, lambs, and calves (Vonderfecht et al, 1985).…”

“…Group B rotaviruses infect humans, rats, piglets, lambs, and calves (Vonderfecht et al, 1985). Suckling rats inoculated with IDIR develop clinical signs within 2 days, which include diarrhea for up to 1 week accompanied by cracking and bleeding of the perineal region; dry, flaky skin; and transient weight loss (Salim et al, 1995;Vonderfecht et al, 1984). Gross lesions included distended ilea and colons (Vonderfecht et al, 1984).…”

“…Suckling rats inoculated with IDIR develop clinical signs within 2 days, which include diarrhea for up to 1 week accompanied by cracking and bleeding of the perineal region; dry, flaky skin; and transient weight loss (Salim et al, 1995;Vonderfecht et al, 1984). Gross lesions included distended ilea and colons (Vonderfecht et al, 1984). One day postinoculation, small intestinal villous epithelial syncytia, villous epithelial necrosis, and villous shortening were evident, and cytoplasmic inclusions of viral particles were seen in syncytial cells (Huber et al, 1989;Vonderfecht et al, 1984).…”

Small mammal virology

“…Infectious diarrhea of infant rats, caused by an atypical rotavirus, was identified as the causative agent of a spontaneous outbreak of diarrhea in suckling rats in 1984 [5]. Rats orally inoculated with rotavirus isolated from the spontaneous outbreak produced signs similar to those of natural infection, including diarrhea of 5 to 6 days' duration, growth retardation, and drying and flaking of the skin.…”

“…Rats orally inoculated with rotavirus isolated from the spontaneous outbreak produced signs similar to those of natural infection, including diarrhea of 5 to 6 days' duration, growth retardation, and drying and flaking of the skin. Rats more than 2 weeks of age were generally considered resistant to clinical disease [5]. This disease has been experimentally replicated numerous times; however, no additional spontaneous outbreaks have been reported, thus its significance in the pet rat population is unknown.…”