A novel bluetongue virus serotype 2 strain isolated from a farmed Florida white-tailed deer (Odocoileus virginianus) arose from reassortment of gene segments derived from co-circulating serotypes in the Southeastern USA.

Bluetongue disease is a reportable animal disease that affects wild and farmed ruminants, including white-tailed deer (WTD). This report documents the clinical findings, ancillary diagnostics, and genomic characterization of a novel reassortant bluetongue virus serotype 2 (BTV-2) strain isolated from a dead Florida farmed WTD in 2022. Our analyses support that this BTV-2 strain likely stemmed from the acquisition of genome segments from co-circulating BTV strains in Florida and Louisiana. In addition, our analyses also indicate that genetically uncharacterized BTV strains may be circulating in the Southeastern USA; however, the identity and reassortant status of these BTV strains cannot be determined based on the VP2 and VP5 genome sequences. Hence, continued surveillance based on complete genome characterization is needed to understand the genetic diversity of BTV strains in this region and the potential threat they may pose to the health of deer and other ruminants.

Characterization of two novel reassortant bluetongue virus serotype 1 strains isolated from farmed white-tailed deer (Odocoileus virginianus) in Florida, USA.

Hemorrhagic diseases caused by epizootic hemorrhagic disease virus or by bluetongue virus (BTV) are the most important orbivirus diseases affecting ruminants, including white-tailed deer (WTD). Bluetongue virus is of particular concern for farmed WTD in Florida, given its lethality and its wide distribution throughout the state. This study reports the clinical findings, ancillary diagnostics, and genomic characterization of two BTV serotype 1 strains isolated from two farmed WTD, from two different farms in Florida in 2019 and 2022. Phylogenetic and genetic analyses indicated that these two novel BTV-1 strains were reassortants. In addition, our analyses reveal that most genome segments of these strains were acquired from BTVs previously detected in ruminants in Florida, substantiating their endemism in the Southeastern U.S. Our findings underscore the need for additional research to determine the genetic diversity of BTV strains in Florida, their prevalence, and the potential risk of new BTV strains to WTD and other ruminants.