Identification and whole genome characterization of novel anelloviruses in masked palm civets (Paguma larvata): Segregation into four distinct clades

The members of the family Anelloviridae are small and single-stranded DNA viruses with marked diversity in sequence and length, which ubiquitously infect many vertebrates, including mammals, birds and reptiles. The anelloviruses isolated from mammals are currently classified into 11 assigned and four proposed genera; some anelloviruses remain unassigned. The present study was conducted to identify anelloviruses in wild-caught masked palm civets (Paguma larvata) in Japan using a rolling-circle amplification method. Thirteen novel anellovirus strains were identified from 8 of 10 masked palm civets and their entire genomic sequences (2039-2535 nucleotides) were determined; they were classifiable into four distinct clades. Comparative analyses of all reported anelloviruses for which the entire or near-entire genomic sequences have been determined, including the 13 strains obtained in the present study, revealed that anelloviruses can provisionally be classified into 20 clades, which may correspond to 20 genera (including 11 assigned and four proposed genera) by a >70% amino acid sequence difference in open reading frame 1 (ORF1). This study suggested that novel anelloviruses of marked diversity are circulating in animals worldwide, and that the rolling-circle amplification method would be useful for identifying novel anelloviruses and other viruses with a circular DNA genome.