Remarkable similarity between domestic cat hepatitis B virus strains identified in stray cats and outbreak-associated strains from a cat shelter in Okinawa, Japan.

We recently identified a domestic cat hepatitis B virus (DCHBV) outbreak at a cat shelter in Okinawa, Japan. Viral genome sequencing showed that this particular strain was highly conserved and distinct from previously reported Japanese strains, suggesting that a single strain had spread within the shelter. However, the origin of this strain remained unclear. DCHBV strains were also identified in two stray cats in central Okinawa. The outbreak strain shared 99.4-99.8% and 99.5-99.8% nucleotide identity with the strain from stray cat #1 and #2, respectively, indicating a close genetic relationship among all DCHBV strains identified in Okinawa. Our findings highlight the importance of screening stray cats for DCHBV before admission to shelters to help prevent outbreaks.