Evaluating the presence of domestic cat hepadnavirus viraemia in cats with biochemical alterations suggestive of liver disease

Hepadnavirus Infection in a Cat with Chronic Liver Disease: A Multi-Disciplinary Diagnostic Approach

A 3-year-old female stray, shorthair cat, with clinical signs and serum chemistry markers indicative of hepatic disease, was diagnosed with domestic cat hepadnavirus (DCH) infection. Coupling molecular and serological data, the infection was seemingly contextualized into a chronic phase, since IgM anti-core antibodies, a marker of early-stage Hepatitis B Virus (HBV) infection, were not detected. However, the cat possessed IgG anti-core, a common indicator of chronic HBV infection in human patients and did not show seroconversion to the anti-DCH surface antigen, considered protective during HBV infection and associated with long-term protective immunity. On genome sequencing, the DCH strain showed 98.3% nucleotide identity to strains previously identified in Italy.

Genetic Diversity of Domestic Cat Hepadnavirus in Southern Taiwan

Domestic cat hepadnavirus (DCH) is an infectious disease associated with chronic hepatitis in cats, which suggests a similarity with hepatitis B virus infections in humans. Since its first identification in Australia in 2018, DCH has been reported in several countries with varying prevalence rates, but its presence in Taiwan has yet to be investigated. In this study, we aimed to identify the presence and genetic diversity of DCH infections in Taiwan. Among the 71 samples tested, eight (11.27%) were positive for DCH. Of these positive cases, three cats had elevated levels of alanine transaminase (ALT) and aspartate transaminase (AST), suggesting an association between DCH infection and chronic hepatitis. Four DCH-positive samples were also tested for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) coinfection. One sample (25%) was positive for FIV, whereas there was no positive sample for FeLV (0%). In addition, we performed whole genome sequencing on six samples to determine the viral genome sequences. Phylogenetic analyses identified a distinct lineage compared with previously reported sequences. This study highlights the importance of continuous surveillance of DCH and further research to elucidate the pathophysiology and transmission route of DCH.

The detection and full genomic characterization of domestic cat Orthohepadnaviruses from Türkiye

BACKGROUND

Domestic cat hepadnaviruses (DCHs) have been described as a novel virus that can infect cats.

OBJECTIVE

The aim of our study is the first identification and molecular characterizations of DCH infection in Turkish domestic cats.

METHODS

The blood, organ and ascites fluid samples from 550 cats were randomly sampled. The presence of DCH nucleic acid was investigated by using both in the literature and newly designed primers.

RESULTS

It was found that the hepadnavirus positivity rate is 4% (22/550) in Türkiye. The full genomic characterization was performed on 13 of 22 samples, and others were characterized as nearly full genome. In this study, we highlight that whole blood samples should be also screened for DCH, not only serum samples as has frequently been done in other studies. DCH-infected cats were also found positive (54.54%, 12/22) for Feline leukaemia virus infection. BLAST results revealed that Turkish DCHs have 86.32%-99.08% homology with strains in the GenBank database, enabling us to construct phylogenetic trees.

CONCLUSIONS

According to this study's results, it is suggested that this infection should be added to veterinary diagnostic panels worldwide. Additionally, we suggest that our new synthesized primers for the amplification of X gene can also be used for diagnosis.

Detection and genetic characterization of domestic cat hepadnavirus in cats with cavitary effusions

After the identification of the novel domestic cat hepadnavirus (DCH) in 2018, its potential pathogenetic role in feline hepatic diseases has been suggested. Following the detection of DCH in a cat's serum and peritoneal effusion, the aim of this study was to retrospectively investigate the presence of DCH in cats with and without cavitary effusions along with DCH presence in effusions. Stored serum and effusion samples from cats with and without effusions admitted to the Veterinary Teaching Hospital of Lodi (Italy) in 2020-2022 were included based on results of hematobiochemical parameters. Effusions were classified based on cytological and physicochemical findings. The likelihood of liver damage was estimated based on clinical and laboratory findings. Samples were tested for DCH presence by quantitative PCR (qPCR). Positive samples were subjected to whole genome sequencing and phylogenetic analysis. DCH was detected in both serum and peritoneal effusion samples of 2/72 (2.8%) enrolled cats, included in the group with effusions (2/33; 6.1%), with one cat showing inflammatory and the other non-inflammatory effusion. Both DCH-positive cats belonged to the group with a likelihood of liver damage (2/22, 9.1%). Phylogeny showed that the DCH sequences from this study clustered with the prototypic Australian strain but were not included in the clade with other Italian DCH sequences. Results suggest the circulation of different DCH variants in Italy and show the presence of DCH in effusion samples from DCH-positive cats, mirroring the presence of HBV in body fluids from HBV-infected humans. Further studies are still recommended to define the pathogenic role of DCH in cats.

Domestic Cat Hepadnavirus: Molecular Epidemiology and Phylogeny in Cats in Hong Kong

Domestic cat hepadnavirus (DCH) is an emerging virus related to the hepatitis B virus (HBV). The pathogenic potential of DCH in cats remains to be established. The molecular prevalence of DCH varies widely in the regions investigated so far. The aim of this study was to determine the prevalence, load, and risk factors for DCH detection among cats in Hong Kong, and to generate molecular and epidemiological data on the DCH strains circulating in cats in Hong Kong. DCH DNA was detected using DCH-specific qPCR in 57/513 (11.1%) residual diagnostic blood samples from owned cats. The median viral load was 8.85 × 103 copies/mL of whole blood (range for the 5th to the 95th percentile, 3.33 × 103 to 2.2 × 105 copies per mL). Two outliers had higher viral loads of 1.88 × 107 copies/mL and 4.90 × 109 copies/mL. DCH was detected in cats from 3 months to 19 years of age. Sex, age, neuter status, breed, or elevated serum alanine aminotransferase were not statistically associated with DCH DNA detection. On phylogenetic analysis based on 12 complete genome sequences, the Hong Kong DCH viruses clustered in Genotype A with viruses from Australia and Asia (clade A1), distinct from viruses from Europe (clade A2). Sequence analysis found that DCH has similar epsilon and direct repeat regions to human HBV, suggesting a conserved method of replication. Based on our findings, the DCH strains circulating in Hong Kong are a continuum of the Asiatic strains.

Global Prevalence of Domestic Cat Hepadnavirus: An Emerging Threat to Cats’ Health?

Hepatitis B is an infectious hepatocellular disease of global concern caused by hepatitis B virus (HBV), which belongs to Hepadnaviridae. Recently, a novel HBV-like virus, domestic cat hepadnavirus (DCH), was detected from an immunocompromised cat with a hepatic disease in Australia. Subsequent molecular investigation by independent research groups revealed that its prevalence rates were 6.5% in Australia, 10.8% in Italy, 12.4% in Thailand, 12.3% in Malaysia, 3.08% in the United Kingdom, and 0.78% in Japan. Although the correlation between DCH infection and hepatic diseases remains to be elucidated, understanding the diversity of circulating DCH will contribute to its prevention and control in domestic cats. Herein, we summarize the current epidemiological data of DCH in these countries.