Genetic diversity of domestic cat hepadnavirus in Taiwan

Domestic cat hepadnavirus (DCH) is an infectious disease associated with chronic hepatitis in cats, suggesting a similarity with hepatitis B virus infection in humans. Since its first identification in Australia in 2018, DCH has been reported in several countries with varying prevalence rates, but its prevalence in Taiwan has not yet been investigated. Here, we aimed to identify the presence and prevalence of DCH infections in Taiwan. Among 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) co-infection, one (25%) was positive for FIV while none for FeLV (0%). In addition, we performed whole genome sequencing of six samples to determine the viral genome sequences. Phylogenetic analyses identified a distinct lineage compared with previously reported sequences. Considering the recent findings suggesting the potential risk of DCH for interspecies or zoonotic transmission, this study suggests the importance of continuous surveillance of DCH and further research to elucidate the pathophysiology and transmission route of DCH.