Hepadnavirus DNA Is Detected in Canine Blood Samples in Hong Kong but Not in Liver Biopsies of Chronic Hepatitis or Hepatocellular Carcinoma

Abstract

Chronic hepatitis and hepatocellular carcinoma (HCC) caused by the hepadnavirus hepatitis B virus (HBV) are significant causes of human mortality. A hepatitis-B-like virus infecting cats, domestic cat hepadnavirus (DCH), was reported in 2018. DCH DNA is hepatotropic and detectable in feline blood or serum (3.2 to 12.3%). Detection of HBV DNA has been reported in sera from 10% of free-roaming dogs in Brazil, whereas 6.3% of sera from dogs in Italy tested positive for DCH DNA by real-time quantitative PCR (qPCR). If DCH, HBV, or another hepadnavirus is hepatotropic in dogs, a role for such a virus in the etiology of canine idiopathic chronic hepatitis (CH) or HCC warrants investigation. This study investigated whether DCH DNA could be detected via qPCR in blood from dogs in Hong Kong and also whether liver biopsies from dogs with confirmed idiopathic CH or HCC contained hepadnaviral DNA using two panhepadnavirus conventional PCRs (cPCR) and a DCH-specific cPCR. DCH DNA was amplified from 2 of 501 (0.4%) canine whole-blood DNA samples. A second sample taken 6 or 7 months later from each dog tested negative in DCH qPCR. DNA extracted from 101 liver biopsies from dogs in Hong Kong or the USA, diagnosed by board-certified pathologists as idiopathic CH (n = 47) or HCC (n = 54), tested negative for DCH DNA and also tested negative using panhepadnavirus cPCRs. This study confirms that DCH DNA can be detected in canine blood by qPCR, although at a much lower prevalence than that reported previously. We identified no evidence to support a pathogenic role for a hepadnavirus in canine idiopathic CH or HCC.

Conserved use of the sodium/bile acid cotransporter (NTCP) as an entry receptor by hepatitis B virus and domestic cat hepadnavirus

“…The DCH-derived preS1 peptide bound to NTCP from a wide range of mammals ( Figures 4B and 4C ). Although possible transmission cases of DCH to dogs have been reported (Choi et al, 2022; Diakoudi et al, 2022), the binding of the DCH-derived preS1 peptide to dog NTCP was weak.…”

The detection and full genomic characterization of domestic catOrthohepadnavirusesfrom Türkiye

“…Our phylogenetic analysis results showed that all positive samples obtained from domestic cats from Türkiye localized into Orthohepadnavirus genus. These findings raise the question of whether DCH can affect other domestic (Capozza, Decaro et al, 2021;Capozza et al, 2023;Choi et al, 2022;Diakoudi et al, 2022) or wild carnivores. We believe that future studies investigating hepadnaviruses in different carnivorous species are needed to understand the origin of DCH and its relationship with other species.…”

Domestic Cat Hepadnavirus and Pathogenic Retroviruses; A Sero-Molecular Survey of Cats in Santiago, Chile

“…For samples testing DCH-positive by cPCR and/or qPCR, genome sequencing was carried out using overlapping nested PCRs (nPCR) designed here, and a panhepadnavirus nPCR described previously [ 21 , 22 ]. Primers and PCR conditions for the PCRs are shown in Table 2 .…”