Detection of non-primate hepaciviruses in UK dogs.

Non-primate hepacivirus (NPHV) has been identified in dogs, horses, bats and wild rodents. The presence of NPHV in dogs outside of the USA however is yet to be established. Here we describe for the first time the detection of NPHV in the UK dog population (described throughout the manuscript as CnNPHV). We examined tissues collected from dogs housed in a rehoming kennel where respiratory disease was endemic. CnNPHV RNA was detected in the tracheal tissues of 48/210 dogs by RT-PCR, and in the liver, lung and/or tracheal tissues of 12/20 dogs. The presence of CnNPHV RNA, and its tropism was confirmed by in situ hybridisation. Histopathological examination demonstrated a trend toward higher histopathological scores in CnNPHV RNA positive respiratory tissues, although, this was not statistically significant. Our findings broaden the geographic distribution and our understanding of CnNPHV. Further evidence of CnNPHV replication in canids warrants investigation.

A peptide mimotope of hepatitis C virus E2 protein is immunogenic in mice and block human anti-HCV sera.

Conformational B-cell epitopes on the HCV E2 protein recognized by human antibodies were characterized by the use of a peptide mimotope named K1. K1 was identified by two HCV anti-E2 monoclonal antibodies (mAbs) following selection and purification of phage clones containing a 15-mer random peptide insert. Murine antisera to the mimotope K1 recognized the E2 protein. Five of eight human sera from patients who had cleared HCV recognized the K1 mimotope. Binding to E2 in four individuals with the capacity to block E2-CD81 interaction was inhibited by the mimotope K1. The results demonstrate that anti-E2 antibodies in sera from patients who have cleared HCV infection are directed against a conformational B-cell epitope on E2 that can be mimicked with linear synthetic peptides. These findings could have implications for vaccine design by employing linear mimotopes to direct B-cell responses against those specific E2 epitopes that may correlate with immunity.

Comparison of the efficacy of rotavirus VLP vaccines to a live homologous rotavirus vaccine in a pig model of rotavirus disease.

Rotavirus-like particles (VLPs) have shown promise as rotavirus vaccine candidates in mice, rabbits and pigs. In pigs, VLP vaccines reduced rotavirus shedding and disease but only when used in conjunction with live attenuated human rotavirus. Using a porcine rotavirus pig model, rotavirus antigen shedding was reduced by up to 40% after vaccination with VLPs including the neutralizing antigens VP7 and VP8* when used in combination with the adjuvant polyphosphazene poly[di(carbozylatophenoxy)phoshazene] (PCPP). In contrast, complete protection from rotavirus antigen shedding and disease was induced by vaccination with the virulent porcine rotavirus PRV 4F. This is the first study to demonstrate some post-challenge reductions in rotavirus antigen shedding in a pig model of rotavirus disease after vaccination with VLPs without combining with infectious rotavirus.

Molecular characterization of bovine enteric caliciviruses: a distinct third genogroup of noroviruses (Norwalk-like viruses) unlikely to be of risk to humans.

Bovine enteric caliciviruses (BoCVs) have been classified in the Norovirus (Norwalk-like virus) genus of the Caliciviridae, raising questions about zoonotic transmission and an animal reservoir for the human Norwalk-like viruses (NLVs), an important cause of nonbacterial gastroenteritis in humans. We examined the genetic relationship of human NLVs to BoCVs that were identified by using reverse transcription-PCR with primer pairs originally designed to detect human NLVs. Polymerase, capsid, and open reading frame 3 (ORF3) gene sequence analyses of BoCVs that were identified from 1976 to 2000 from throughout the United Kingdom showed that BoCVs formed a distinct third genogroup of closely related viruses distinct from the human genogroup I and II NLVs. Evidence was not obtained to support the concept that BoCVs are circulating in humans and pose a threat to human health.

Identification and molecular characterization of a bovine G3 rotavirus which causes age-independent diarrhea in cattle.

G3 rotaviruses have been reported rarely in cattle, and none have been characterized. We report the first genomic characterization of a bovine G3 rotavirus, CP-1, which had been biologically characterized in vivo and shown to cause age-independent diarrhea. CP-1 was a G3 rotavirus as its VP7 had 92 to 96% deduced amino acid identity to those of G3 rotaviruses. However, initially, CP-1 was identified as a G10 rotavirus by RT-PCR even though the CP-1 VP7 had only 81 to 85% deduced amino acid identity to those of G10 rotaviruses. Rotavirus CP-1 was of P[5] specificity, a type common in cattle, and had a bovine NSP1 and NSP4. These results added another animal species to those in which G3 rotaviruses have been found, characterized a bovine rotavirus which caused age-independent diarrhea in calves, and raised the possibility that bovine G3 rotaviruses may be misdiagnosed as G10 rotaviruses.

Rotavirus cross-species pathogenicity: molecular characterization of a bovine rotavirus pathogenic for pigs.

Rotaviruses which cause disease in heterologous animal species have been reported but the molecular basis of cross-species infectivity and disease is not established. We report the molecular characterization of a cloned rotavirus, PP-1, which was originally obtained from cattle and which had been biologically characterized in vivo in two target animal species, gnotobiotic pigs and calves. In pigs, PP-1 caused severe clinical disease but in experimental calves it replicated subclinically. PP-1 was characterized as a G3 reassortant with a porcine VP4 and NSP4 but a bovine NSP1. The PP-1 VP4 had 96 to 97% deduced amino acid identity to P[7] porcine rotaviruses and P[7] specificity was confirmed with VP4-specific monoclonal antibodies. Sequence analysis of the PP-1 NSP1 showed 94 to 99.6% deduced amino acid identity to bovine rotaviruses but the NSP4 protein had 94 to 98% identity to the NSP4 genotype B porcine rotaviruses. G-typing PCR initially classified PP-1 as a G10 rotavirus but sequence analysis revealed 92 to 96% identity of the PP-1 VP7 with porcine, simian, and human G3 rotaviruses. These results, combined with the in vivo properties of PP-1 in the two target species, supported the concept that species-specific VP4 and NSP4, but not NSP1, are required to induce rotavirus disease, at least in calves and pigs. The results illustrate experimentally that rotaviruses circulating in one animal species can pose a risk to another by the emergence of a pathogenic reassortant rotavirus under appropriate conditions.