RESEARCH COMMUNICATIONS OF THE 28th ECVIM-CA CONGRESS

The aim of this study was to identify potential viral copathogens from FIV‐associated lymphoma using transcriptome analysis. TruSeq paired‐end libraries were prepared from ribosome‐depleted RNA from 13 high‐grade B‐cell lymphomas arising in FIV‐infected cats. Total RNA sequencing yielded 40‐50 million reads per library. Bioinformatics analyses identified eight hepatitis‐B virus‐associated reads sharing 73‐94% amino acid identity with the core protein, surface protein, and polymerase of hepadnaviruses, suggesting a novel virus. The presence of genome fragments was validated by PCR and sequencing of tumour DNA. The entire 3187bp genome was subsequently obtained by PCR. Polymerase, surface, core and X ORFs typical of orthohepadnaviruses were identified. Analyses of polymerase protein revealed 63.2% to 68.7% amino acid identity with known orthohepadnaviruses. This genetic distance merits assignment of a new species within the genus Orthohepadnavirus, tentatively named domestic cat hepadnavirus.