Rotavirus strain A253, isolated from the faeces of a diarrhoeic piglet in Venezuela, was classified as serotype G11 by cross-neutralization studies and by comparison of the deduced amino acid sequence of the VP7 surface protein. The epitopes involved in neutralization of the two G11 porcine rotavirus strains A253 and YM were analysed using neutralization-resistant mutants selected with seven neutralizing monoclonal antibodies (MAbs), monotype-specific (M-) MAbs and serotype-specific (S-) MAbs, produced against VP7 of strain A253. Crossneutralization tests and sequence analysis of the escape

Polyacrylamide gel electrophoresis of nucleic acids extracted from porcine faecal samples revealed in several samples the presence of two discrete bands. The bands were resistant to digestion with of DNase I and RNase T1, but not with RNase A in low salt conditions, indicating that they consisted of double stranded (ds) RNA. The two bands from different samples varied in sizes, in a range between 2.4-2.6 kbp and 1.7-1.9 kbp for the slow and fast moving band respectively. The bands cosedimented in CsCl gradients at an average density of 1.415 g/ml with icosahedral virus particles of a diameter of 34 nm and a triangulation number equal to 3. Aggregates of virus, which appeared to be immunocomplexes, were seen in one sample. From 244 faecal samples collected in one farm, 27 (11.1%) were found to contain the characteristic dsRNA pattern, with a higher prevalence in samples from animals 15 to 35 days old. The agent was equally distributed among samples from diarrhoeic or non-diarrhoeic animals. These results confirm the circulation among pigs of a novel virus, possibly of vertebrates, with a bisegmented double stranded RNA genome, similar to viruses previously described in humans, wild rats, guinea pigs, pigs, and chickens, for which the name "picobirnavirus" has been proposed.

No abstract

No abstract

No abstract