Discovery of a novel bandavirus using metagenomic sequencing in a retrospective analysis of an unresolved 2020 mortality event involving black vultures in the northeastern United States

Investigations of wildlife diseases and mortality events can sometimes lead to inconclusive results due to limitations in diagnostics combined with an ever-increasing number of emerging viruses. The use of tools such as unbiased metagenomic next generation sequencing (mNGS) can facilitate the identification of causative agents where conventional investigation methods fail. We performed a retrospective mNGS analysis on RNA isolated from postmortem samples collected during a black vulture ( Coragyps atratus , family: Cathartidae) mortality event that occurred in eastern Pennsylvania and western New Jersey in 2020. We describe the discovery and identification of a novel species of bandavirus ( Phenuiviridae family) in case specimens from this die-off, as well as some of the associated pathological findings. The Bandavirus genus comprises tickborne viral species that have been reported across five continents and implicated in outbreaks in a variety of mammalian hosts, including humans, and in avian species making them important potential sources of zoonotic spillover events. Genomic and phylogenetic analysis of the bandavirus detected in this study indicate its closest relative corresponds to Hunter Island virus, a bandavirus previously implicated in albatross mortality events off the coast of Tasmania, Australia. Follow-up PCR testing of samples from additional vultures from the same cohort confirmed that this new bandavirus is the likely cause of death.