Bats from the Colombian Caribbean Reveal a new subtype of Influenza A (H18N12)

Influenza viruses have an excellent capacity for mutation and adaptation in mammalian hosts, which makes them viruses of medical and veterinary importance. Influenzaviruses have been studied mainly in birds but minor in bats. It is unknown whether Chiroptera are reservoirs of influenza viruses. However, circulation in bats showed molecular divergence from H17N10 (Guatemala) and H18N11 (Peru), and they were designated as new subtypes. The study aimed to characterize the influenza A virus detected in the fishing bat Noctilio albiventris. A surveillance study of pathogens of public health interest was carried out; rectal samples were taken from four fishing bats (N. albiventris) captured in Talaigua Nuevo, Bolivar, Colombia. The samples were sequenced by NGS using DNBseq (MGI-G50(R)) and analyzed with bioinformatics tools. Eight viral contigs associated with the Orthomyxoviridae family were obtained. The identified segments showed around 90% similarity with H18N11, except for the neuraminidase (N). The phylogenetic analysis of the N protein showed the appearance of a basal branch to the N11 subtype, and the molecular clock indicates that it does not share a recent common ancestor. 3D modeling indicates that the N protein of N. albiventris presents three mutations (K363R, T242K, and I139V) near the hypothetical active site of the protein. These mutations potentially increase the interaction with the HLA-DR of bats, which could have significant implications for the viruss behavior. The phylogenetic, evolutionary, and antigenic divergence of the N protein of N. albiventris suggests a new subtype called H18N12. Its role as a pathogen must be studied.