We aim at the presentation of a newly emerging domestic cat hepadnavirus
(DCH), the causative agent of chronic hepatitis, hepatic fibrosis and hepatocellular
carcinoma, which was recently identified in several countries. The first report
is from 2018 and describes DCH isolation from immunocompromised cat.
DCH is a partially double stranded, circular, small DNA virus belonging to
the Orthohepadnavirus genus, Hepadnaviridae family. It has a genome of
approximately 3.2 kb of compact DNA, which encodes in four overlapping
open reading frames (ORFs), for the polymerase (L), surface (S), core (C), and
X proteins, similarly to other hepadnaviruses. Transmission is likely direct, but
indirect iatrogenic infection via blood transfusion is also possible. DCH infection
is more frequent in feline leukemia (FeLV) or feline immunodeficiency virus (FIV)
infected pet cats. In addition to the hepadnavirus viremia and liver pathologies,
positive-DCH immunoreactivity was found in various other organs, including
kidneys, lungs, heart, intestine, brain, and lymph nodes, providing evidence of
systemic inflammatory disease. Only a small proportion of cats with biochemical
alterations indicating liver disease were DCH positive. The testing for DCH is
based on histopathological analysis of liver biopsies, and blood or hepatic tissue
PCR screening. The control consists of limiting iatrogenic and nosocomial virus
transmission. No specific vaccine exists for DCH.