Review of the 2019 and 2020 Vesicular Stomatitis Outbreaks in the United States

Authors: PELZEL-MCCLUSKEY, ANGELA - Animal And Plant Health Inspection Service (APHIS); CHRISTENSEN, BRADLEY - Animal And Plant Health Inspection Service (APHIS); Humphreys Jr, John; Bertram, Miranda; KEENER, ROBERT - Fort Hays State University; Ewing, Robert; Cohnstaedt, Lee; TELL, RACHEL - Animal And Plant Health Inspection Service (APHIS); Peters, Debra; Rodriguez, Luis

Submitted to: Pathogens
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2021
Publication Date: 8/6/2021
Citation: Pelzel-McCluskey, A.M., Christensen, B., Humphreys Jr, J.M., Bertram, M.R., Keener, R., Ewing, R.D., Cohnstaedt, L.W., Tell, R., Peters, D.C., Rodriguez, L.L. 2021. Review of the 2019 and 2020 Vesicular stomatitis outbreaks in the United States. Pathogens. https://doi.org/10.3390/pathogens10080993.
DOI: https://doi.org/10.3390/pathogens10080993

Interpretive Summary: This research provides a review and summary of Vesicular stomatitis (VS) disease outbreaks in horses and cattle documented between 2019-2020. The paper provides descriptive statistics and places disease outbreaks documented in 2019-2020 in context with those from prior years. VS cases observed in 2019-2020 represented the greatest quantity documented in the last 40 years.

Technical Abstract: Vesicular stomatitis (VS) is a vector-borne disease of livestock in the Americas caused by Vesiculoviruses, vesicular stomatitis New Jersey virus (VSNJV) or vesicular stomatitis Indiana virus (VSIV). The disease circulates annually in endemic cycles in northern South America, Central America, and Mexico and only occasionally moves far enough northward to cause incursion and outbreaks in equids and cattle in the United States. Over the past 20 years, VS outbreaks have mainly been confined to the southwestern and Rocky Mountain region states with VSNJV as the most common viral serotype with significant incursion years often followed by overwintering of the virus and subsequent expansion years of outbreaks. A robust state and federal regulatory response by animal health officials is deployed during outbreaks to prevent spread from lesioned and exposed animals by quarantining the affected livestock premises. The 2019 VS outbreak was the largest in the past 40 years of recorded history lasting from June to December 2019 with a total of 1,144 VS-affected premises identified in 111 counties in 8 states (Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, Utah, and Wyoming) and was confirmed to be VSIV serotype, which had not been isolated in the U.S. since the 1997-1998 outbreak. A subsequent outbreak occurred from April to October 2020 in which 326 VS-affected premises were identified in 70 counties in 8 states (Arizona, Arkansas, Kansas, Missouri, Nebraska, New Mexico, Oklahoma, and Texas). While the primary serotype in 2020 was VSIV in all states, a separate incursion of VSNJV occurred simultaneously in 4 counties in south Texas. Summary characteristics of the 2019 and 2020 outbreaks are presented along with results of VSV-vector sampling in Kansas in 2020 and preliminary phylogenic analysis of the 2019 and 2020 VSIV isolates which provide strong evidence of overwintering of the virus between the two outbreak years.