A total of 12 clinically ill cats previously diagnosed as feline infectious peritonitis (FIP) were treated with a combination of recombinant feline interferon and glucocorticoid. A complete remission (over 2 years) and a partial remission (2 to 5 months) were observed in four (33.3%) and four (33.3%) cases, respectively. Those that survived for more than 2 years were all older cats (6 to 16 years old) with the effusive form of FIP.

The hepatitis B virus (Hepadnaviridae) induces chronic hepatitis and hepatic cancer in humans. A novel domestic cat hepadnavirus (DCH) was recently identified in several countries, however, the DCH infection status of cats in Japan is unknown. Therefore, we investigated the DCH infection rate of 139 cat samples collected in Japan. We identified one positive blood sample (0.78%) from a 17-year-old female cat with chronically elevated alanine aminotransferase. Phylogenetic analysis demonstrated that the DCH strain identified in this study is genetically distinct from strains in other countries. Further investigations are required to elucidate the evolution of DCH and the impact of DCH infection on hepatic diseases in domestic cats.