Viruses (May 2022)

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

  • Thaís C. S. Rodrigues,
  • Pedro H. O. Viadanna,
  • Kuttichantran Subramaniam,
  • Ian K. Hawkins,
  • Albert B. Jeon,
  • Julia C. Loeb,
  • Juan M. C. Krauer,
  • John A. Lednicky,
  • Samantha M. Wisely,
  • Thomas B. Waltzek

DOI
https://doi.org/10.3390/v14051012
Journal volume & issue
Vol. 14, no. 5
p. 1012

Abstract

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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.

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