Porcine pararotavirus: detection, differentiation from rotavirus, and pathogenesis in gnotobiotic pigs

Abstract

Some characteristics of a newly recognized porcine enteric virus are described. Tentatively, the virus was referred to as porcine pararotavirus (PaRV) because it resembled rotaviruses in respect to size, morphology, and tropism for villous enterocytes of the small intestine. However, it was antigenically distinct from porcine, human, and bovine rotaviruses and reoviruses 1, 2, and 3, and the electrophoretic migration pattern of PaRV double-stranded RNA was distinct from the electrophoretic migration patterns of the rotaviral and reoviral genomes. By passage in gnotobiotic pigs, PaRV was isolated from two suckling diarrheic pigs originating from two herds. After oral exposure of gnotobiotic pigs, villous enterocytes of the small intestines became infected as judged by immunofluorescence, resulting in villous atrophy and diarrhea. Mortality was high when gnotobiotic pigs less than 5 days old were infected. The C strain of this virus was serially passed 10 times in gnotobiotic pigs, and electron microscopy, immunofluorescence, and serological tests indicated no extraneous agents. The virus was serially passed five times in cell cultures which contained pancreatin in the medium, but replication was negligible or absent, as the number of immunofluorescent cells decreased with each passage. Since rotaviral infections are frequently diagnosed by direct electron microscopy of fecal specimens, the presence of other morphologically similar viruses, such as PaRV, should be considered. The use of immune electron microscopy is suggested as a means of helping recognize this situation.

Enteric Viral Infections of Calves and Passive Immunity

“…A bovine rotavirus-like agent (RVLA) identified in our laboratory was morphologically identical to rotavirus but differed antigenically and in the double-stranded ribonucleic acid electropherotype (63). However, this RVLA did not react antigenically or have a similar RNA electropherotype to a different RVLA which we previously identified in pigs (8,60), suggesting the existence of several antigenically distinct categories of RVLA. Whether the bovine and porcine RVLA that we identified share common antigens with recently described RVLA from other species (10) is unknown.…”

Development of nasal, fecal and serum isotype-specific antibodies in calves challenged with bovine coronavirus or rotavirus

“…The processed nasal swab fluid was tested for rotavirus or coronavirus using a cell culture immunofluorescence (CCIF) test (Saif et al, 1986;Bohl et al, 1982). Feces or rectal swab samples were processed as described previously and tested for presence of rotavirus using CCIF and ELISA assays (Bohl et al, 1982;Saif et al, 1986), or for coronavirus using immune electron microscopy on 10% fecal suspensions (IEM, Saif et al, 1977).…”

Characterization of rotaviruses isolated from pigs with diarrhoea in Venezuela

“…The recent identification of the atypical rotaviruses has been of considerable interest. At least three different strains have been studied in pigs: a Belgian isolate (Debouck and Peusaert, 1979), one from the United Kingdom (Bridger et al, 1982), and one from the United States (Saif et al, 1980;Bohl et al, 1982). A comparison of the U.K. and U.S.A. strains of atypical porcine rotaviruses revealed that they were unrelated as shown by cross-immunofluorescence studies (Pedtey et al, 1983).…”

“…However, the same polypeptide also carries one of two subgroup specificities (I or II) which is easily detected by using subgroup-specific monoclonal antibodies (Greenberg et al, 1983). Neither the group-common nor the subgroup-specific antigenicities are found on some "atypical" rotaviruses ("pararotaviruses") which have been isolated from different animal species, including pigs (Bohl et al, 1982;Bridger et al, 1982). Subgroup antigens do not appear to be related to neutralization or immunoprotection, but they provide useful markers for epidemiological studies.…”