Domestic cat hepadnavirus detection in blood and tissue samples of cats with lymphoma

Domestic cat hepadnavirus (DCH), a relative hepatitis B virus (HBV) in human, has been recently identified in cats; however, association of DCH infection with lymphoma in cats is not investigated. To determine the association between DCH infection and feline lymphoma, seven hundred and seventeen cats included 131 cats with lymphoma (68 blood and 63 tumor samples) and 586 (526 blood and 60 lymph node samples) cats without lymphoma. DCH DNA was investigated in blood and formalin-fixed paraffin-embedded (FFPE) tissues by quantitative polymerase chain reaction (qPCR). The FFPE lymphoma tissues were immunohistochemically subtyped, and the localization of DCH in lymphoma sections was investigated using in situ hybridization (ISH). Feline retroviral infection was investigated in the DCH-positive cases. DCH DNA was detected in 16.18% (11/68) (p = 0.002; odds ratio [OR], 5.15; 95% confidence interval [CI], 2.33-11.36) of blood and 9.52% (6/63) (p = 0.028; OR, 13.68; 95% CI, 0.75-248.36) of neoplastic samples obtained from lymphoma cats, whereas only 3.61% (19/526) of blood obtained from non-lymphoma cats was positive for DCH detection. Within the DCH-positive lymphoma, in 3/6 cats, feline leukemia virus was co-detected, and in 6/6 were B-cell lymphoma (p > 0.9; OR, 1.93; 95% CI, 0.09-37.89) and were multicentric form (p = 0.008; OR, 1.327; 95% CI, 0.06-31.18). DCH was found in the CD79-positive pleomorphic cells. Cats with lymphoma were more likely to be positive for DCH than cats without lymphoma, and infection associated with lymphoma development needs further investigations.

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.

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 of domestic cat hepadnavirus by next-generation sequencing and epidemiological survey in Japan

The novel domestic cat hepadnavirus (DCH), a member of the Hepadnaviridae, was first detected in Australia and has recently been identified in more countries. In this study, we explored the DCH genome using next-generation sequencing of a plasma sample from a cat with a fever of unknown cause. Nucleotide sequence analysis showed the virus to be relatively genetically distant from the first reported DCH in Australia, showing 89% homology. Then we conducted an epidemiological survey by PCR of plasma samples collected from 203 cats that visited a veterinary hospital for diagnosis and treatment. Two of the 203 surveyed cats a were positive for DCH. One of the two positive cases had elevated liver enzymes of unknown etiology, and the other had hepatoma. Our study indicated that DCH infection was observed in domestic cats in the Tokyo area of Japan as well as other reported areas in the world. Further investigations are needed to define the clinical importance of DCH.

Development of a direct duplex real-time PCR assay for rapid detection of domestic cat hepadnavirus

Domestic cat hepadnavirus (DCH) is a novel hepadnavirus, first identified in 2018. DCH is generally detected using conventional PCR assays, which include time-consuming agarose gel electrophoresis. We developed a rapid, sensitive, and specific real-time PCR (rtPCR) assay for the detection of the DCH genome. To streamline the procedure, our rtPCR assay was carried out using blood samples, without DNA extraction. A consensus primers/probe set was designed based on the nucleotide sequences of the surface/polymerase gene of all DCH strains available in GenBank. To exclude the possibility that the PCR reaction was blocked by anticoagulants, we also used a primers/probe set for amplifying the cat beta-actin gene as a reference gene. Our direct duplex rtPCR assay had high sensitivity, with a limit of detection of 10 copies/μL of blood for DCH. Our direct duplex rtPCR assay should be a useful tool for DCH detection and surveillance.