Genomic Characterisation of Canis Familiaris Papillomavirus Type 24, a Novel Papillomavirus Associated with Extensive Pigmented Plaque Formation in a Pug Dog

Abstract

Numerous large dark plaques developed over the ventrum, legs and head of a 9-year-old pug dog over a 4-year-period. Histology confirmed a diagnosis of viral pigmented plaque and a short section of a novel papillomavirus (PV) type was amplified using consensus PCR primers. Taking advantage of the circular nature of PV DNA, 'outward facing' PCR primers allowed amplification of the full sequence. As this is the 24th PV known to infect dogs, the novel PV was designated canine papillomavirus (CPV) type 24. The CPV24 genome contained putative coding regions for 5 early proteins and 2 late ones. The CPV24 open reading frame L1 showed the highest (78.2%) similarity to CPV4 and phylogenetic analysis showed that CPV24 clustered with CPV4 and CPV16 suggesting CPV24 is the third species 2 Chipapillomavirus type identified in dogs. This is the third report of extensive pigmented plaques covering a high proportion of the skin. Both previous cases were caused CPV4 and, considering the high genetic similarity between CPV4 and CP24, infection by these CPV types may predispose to more severe clinical disease. In addition, as plaques caused by CPV16 appear more likely to progress to neoplasia, the detection of a species 2 Chipapillomavirus within a pigmented plaque may indicate the potential for more severe disease.

Keywords: CPV24; canine papillomavirus (CPV); dog; neoplasia; papillomavirus; pigmented plaque; skin; viral plaque.

Figure 1

Large exophytic pigmented plaques developed over a wide area of the 9-year-old pug dog.

Figure 2

Schematic genomic organization of CPV24.

Figure 3

Unrooted Maximum likelihood phylogeny based on concatenated nucleotide alignment of E1, E2, L1 and L2 ORF sequences from putative CPV24 (arrowhead) with 84 other PV types of different species and genera. Accession numbers for the sequences used are included. Abbreviations used include Micromys minutus papillomavirus, MmiPV; Mastomys coucha papillomavirus, McPV; Canine papillomavirus, CPV; Bovine papillomavirus, BPV; Bettongia penicillata papillomavirus, BpPV; Macaca fascicularis papillomavirus, MfPV; Felis catus papillomavirus, FcaPV; Equus caballus papillomavirus, EcPV; Multimammate rat papillomavirus, MnPV; Psittacus erithacus timneh papillomavirus, PePV; Fringilla coelebs papillomavirus, FcPV; Francolinus leucoscepus papillomavirus, FlPV; Ovis aries papillomavirus, OaPV; Oryctolagus cuniculus papillomavirus, OcPV; Sylvilagus floridanus papillomavirus, SfPV; Rousettus aegyptiacus papillomavirus, RaPV; Capreolus capreolus papillomavirus, CcaPV; Odocoileus virginianus papillomavirus, OvPV; Alces alces papillomavirus, AaPV; Rangifer tarandus papillomavirus, RtPV; Erinaceus europaeus papillomavirus, EePV; Colobus guereza papillomavirus, CgPV; Mesocricetus auratus papillomavirus, MaPV; Rattus norvegicus papillomavirus, RnPV, Phocoena spinipinnis papillomavirus, PsPV; Tursiops truncatus papillomavirus. TtPV; Capra hircus papillomavirus, ChPV; Trichechus manatus latirostris papillomavirus. TmPV; Sus scrofa papillomavirus. SsPV; Ursus maritimus papillomavirus, UmPV; Macaca mulata papillomavirus. MmPV; Pan paniscus papillomavirus, PpPV, Erethizon dorsatum papillomavirus. EdPV; Procyon lotor papillomavirus, PiPV; Uncia uncia papillomavirus, UuPV; Panthera leo persica papillomavirus, PlpPV; Puma concolor papillomavirus. PcPV; Lynx rufus papillomavirus, LrPV. The PV genera are also listed. Internal branches are coloured based on inferred branch support values, as determined by 1000 replicates usin RAxML. The scale bar indicates the genetic distance (nucleotide substitutions per site).