Vesicular Stomatitis (VSV) in Texas Situational Update No. 9

Texas Animal Health Commission
“Serving Texas Animal Agriculture Since 1893”
Andy Schwartz, DVM  Executive Director
P.O. Box l2966  Austin, Texas 78711  (800) 550-8242
For more information contact the Public Information Dept. at 512-719-0750 or at

AUSTIN – Since Friday, August 30, 2019, the Texas Animal Health Commission has received reports of 1 new confirmed case of vesicular stomatitis virus (VSV) in Hill County and 1 new suspect case in Hays county.

The newly confirmed and suspect premises are under quarantine by the TAHC. Affected horses and cattle will be monitored by regulatory and authorized veterinarians until premises are eligible for quarantine release 14 days after clinical VSV signs are observed.
To date, 170 premises in 37 Texas counties have been quarantined for VSV. Currently affected counties include: Bell, Collin, Dallas, Ellis, Hays, and Hill counties. Of the 170 premises quarantined, 158 have been released.

Classification of Cases
Premises that have laboratory diagnostic confirmation of VSV are categorized as confirmed positive premises. Once a county is confirmed as VSV-positive, new premises presenting with clinical signs of VSV in that county are not required to be tested for confirmation of the disease, but the premises will be quarantined and classified as a suspect premises.

Summary of the Outbreak
The 2019 VSV outbreak began on June 21, 2019, when the National Veterinary Services Laboratories (NVSL) in Ames, Iowa confirmed the first VSV-positive premises in Kinney County, Texas. All cases of VSV had been found on equine premises until July 30, 2019 when the first case of VSV was confirmed in cattle in Gonzales County. New Mexico, Colorado, Nebraska, Oklahoma, Utah, and Wyoming broke with VSV cases confirmed by NVSL.

What Veterinarians Need to Know:

Several states are imposing enhanced entry requirements on Texas livestock due to the VSV cases. For information, contact the state of destination. For a list of state animal health offices visit
If you suspect your client’s horse has VSV, contact your TAHC Region Office for paperwork, procedures, and important sample submission information.

What Equine and Cattle Owners Need to Know:

  • VSV is a viral disease that primarily affects horses and cattle.
  • In the past decade, southwestern and western states have experienced a number of VSV outbreaks. Outbreaks usually occur during the warmer months, often along waterways.
  • VSV normally has an incubation period of 2-8 days before the infected animal develops blisters that swell and burst, leaving painful sores. The virus can be transmitted through direct contact with infected animals or by blood-feeding insects.
  • If VSV is confirmed, infected animals are quarantined for 14 days after clinical signs of lesions are observed. This short-term quarantine helps prevent the movement of animals and the spread of the disease to other premises, fairs or markets.

Strategies for Preventing VSV

  1. Even with the best defensive measures, VSV could infect a herd. However, these tips may help protect livestock:
    Control biting flies
  2. Keep equine animals stalled or under a roof at night to reduce exposure to flies
  3. Keep stalls clean
  4. Don’t visit a ranch that’s under quarantine for VSV. Wait until the animals have healed

TAHC sends out VSV updates every Friday and all cases will be reported to the Equine Disease Communication Center. For VSV history and past TAHC updates click here.To view the USDA 2019 VSV situation reports click here.