Characterization of a Novel Reassortant Epizootic Hemorrhagic Disease Virus Serotype 6 Strain Isolated from Diseased White-Tailed Deer (Odocoileus virginianus) on a Florida Farm

Abstract

We report an outbreak of a novel reassortant epizootic hemorrhagic disease virus serotype 6 (EHDV-6) in white-tailed deer (WTD) on a Florida farm in 2019. At necropsy, most animals exhibited hemorrhagic lesions in the lung and heart, and congestion in the lung, liver, and spleen. Histopathology revealed multi-organ hemorrhage and congestion, and renal tubular necrosis. Tissues were screened by RT-qPCR and all animals tested positive for EHDV. Tissues were processed for virus isolation and next-generation sequencing was performed on cDNA libraries generated from the RNA extracts of cultures displaying cytopathic effects. Six isolates yielded nearly identical complete genome sequences of a novel U.S. EHDV-6 strain. Genetic and phylogenetic analyses revealed the novel strain to be most closely related to a reassortant EHDV-6 strain isolated from cattle in Trinidad and both strains received segment 4 from an Australian EHDV-2 strain. The novel U.S. EHDV-6 strain is unique in that it acquired segment 8 from an Australian EHDV-8 strain. An RNAscope® in situ hybridization assay was developed against the novel U.S. EHDV-6 strain and labeling was detected within lesions of the heart, kidney, liver, and lung. These data support the novel U.S. reassortant EHDV-6 strain as the cause of disease in the farmed WTD.

Epizootic Hemorrhagic Disease Virus: Current Knowledge and Emerging Perspectives

“…Moreover, authors pointed out this virus as a minor parent of the EHDV-6 Indiana strain [ 47 ]. Another EHDV-6 strain isolated in the USA had an Australian origin [ 82 ]. Multiple reassortment events as well as preferential reassortment have been observed between USA-circulating EHDV strains of serotypes 1, 2 and 6 [ 83 , 84 ].…”

Epidemiological Analyses of the First Incursion of the Epizootic Hemorrhagic Disease Virus Serotype 8 in Tunisia, 2021–2022

“…Since 1965, EHDV has attracted researchers’ attention through an outbreak in New Jersey, USA, which caused the death of more than 500 deer [ 2 ]. Since then, the virus has also been detected in Canada and Mexico, as well as in other parts of the world: South America, Africa, the Middle East, Japan, Southeast Asia, and Australia [ 3 ]. To date, seven serotypes of EHDV have been reported, named 1–2 and 4–8, which were identified based on phylogenetic studies, sequencing data, and cross-neutralization assays [ 4 ].…”

“…3 Global Drainage Basin Database GDBD. Released Version 1.0: 29 May 2007 (http: //www.cger.nies.go.jp/db/gdbd/gdbd_index_e.html, last accessed on 6 September 2023) 4.…”