Detection of non-primate hepaciviruses in UK dogs

Abstract

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.

Keywords: Canine hepacivirus; Hepaciviruses; ISH; NPHV; NPHV tropism; RT-PCR.

Fig. 1

Phylogenetics analysis by the Maximum Likelihood method of (A) NS3, (B) E1/E2 and (C) 5′UTR of non-primate hepacivirus sequence amplified in this study. The evolutionary history was inferred by using the maximum Likelihood method of the MEGA 6 programme based on the Kimura- 2 Model for NS3, Hasegawa–Kishino–Yano model for E1/E2 and Tamura–Nei model for 5′UTR. Initial tree(s) for the heuristic search were obtained automatically by applying Neighbor–Join and BioNJ algorithms to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach, where the topology with superior log likelihood of each tree was selected. The numbers at the nodes (bootstrap values) indicate the frequencies of occurrence for 500 replicate trees. (ο) Published canine hepacivirus sequence, (□) published equine hepacivirus sequence, (Δ) published hepacivirus sequence in bat and (⋄) M62321/HCV subtype 1a was used as an outgroup. (●) Canine hepaciviruses sequenced in this study are indicated. Tree scales represent branch length measured in the number of substitution per site.

Fig. 2

In situ hybridisation of CnNPHV RNA in canine trachea, lung and liver. Slides A, B, C are CnNPHV RNA-positive dogs and slides D, E, F are from an uninfected dog. Bright red dots indicate probe bound to CnNPHV genomic RNA as indicated by arrows. Nuclei are stained blue by haematoxylin.