A new bird calicivirus detected in feces of cormorants

The incidence of reporting caliciviruses in wild birds is less common than in other animals, and the majority of cases remain unclassified. A strain of calicivirus was discovered in this study in the feces of cormorants collected at Xiamen Horticulture Expo Garden in 2021 and was named Cormcali01. The genome of Cormcali01 was 8,561 bp in length which contained characteristic motifs present in other caliciviruses. Furthermore, it demonstrated a significant deviation from all existing calicivirus nucleotide sequences, exhibiting the highest amino acid identity (47.34%) to the unclassified Ruddy turnstone calicivirus A. A pairwise comparison of the VP1 protein showed that Cormcali01 had the highest amino acid identity of 43.90% with the unassigned Ruddy turnstone calicivirus A. Phylogenetic analysis demonstrated that VP1 of Cormcali01 clustered with unassigned caliciviruses. Therefore, based on phylogenetic analysis and pairwise comparison, Cormcali01 should be affiliated with the unassigned calicivirus, which were suggested to comprise a new calicivirus genus, the Sanovirus genus. After investigating the prevalence of Cormcali01, we discovered that 22.22% of fecal samples (10/45) were tested positive. These findings expand our understanding of the genetic variation of caliciviruses and provide valuable epidemiological information regarding a potential outbreak of calicivirus disease in birds.