USDA Updates Vesicular Stomatitis Report

Insect vectors are the primary source of transmission of VSV although mechanical transmission occurs in some species. ( John Maday )

As the summer heats up and insect disease vectors multiply, the USDA has begun issuing its weekly reports on cases of vesicular stomatitis virus (VSV) in livestock. Earlier this summer, USDA confirmed cases in Colorado, Texas and New Mexico. This week’s report shows some new cases in those three states, but no confirmed cases elsewhere. The report confirms these new cases:

Colorado

  • One new VSV-infected equine premises has been confirmed in Larimer County, Colorado (New Infected County).
  • One new VSV-infected equine premises has been confirmed in Weld County, Colorado.

New Mexico

  • One 1 new VSV-infected equine premises has been confirmed in Los Alamos County, New Mexico (New Infected County).
  • One new VSV-infected equine premises has been confirmed in Valencia County, New Mexico (New Infected County).
  • One new VSV-infected equine premises has been confirmed in Sandoval County New Mexico.

Texas

  • One new VSV-infected equine premises has been confirmed in Coleman County, Texas (New Infected County)
  • One new VSV-infected equine premises has been confirmed in Kerr County, Texas (New Infected County)
  • One new VSV –infected equine premises has been confirmed in Tom Green County, Texas.

VSV is classified as a rhabdovirus, and there are two serotypes of VSV – New Jersey and Indiana. According to a USDA fact sheet, VSV causes blister-like lesions to form in the mouth and on the dental pad, tongue, lips, nostrils, hooves, and teats. These blisters swell and break, leaving raw tissue that is so painful that infected animals generally refuse to eat and drink and show signs of lameness. Severe weight loss usually follows, and dairy cows commonly exhibit a severe drop in milk productions. Affected dairy cattle can appear to be normal but eat only about half of their normal feed intake.

Insect vectors are the primary source of transmission of VSV although mechanical transmission occurs in some species. Fly control is a key component in preventing spread of the virus.

Rarely, VS can affect humans, typically those who are in contact with infected animals. In humans the disease typically causes flu-like symptoms. 

In related news, the Texas Animal Health Commission (TAHC) has confirmed three additional anthrax cases since mid-June. All this summer’s cases have occurred in an area of Texas where anthrax is historically found. The first anthrax case of the year was confirmed in one captive antelope on a premises in Uvalde County on June 19, 2019. Since that time, anthrax was confirmed in goats on a new Uvalde County premises on June 24, one Sutton County horse was confirmed to have anthrax on July 3, and cattle were confirmed to have anthrax on a separate Sutton County premises on July 4.

TAHC Executive Director Andy Schwartz, DVM, says it is common to see an increase in anthrax cases after periods of wet, cool weather, followed by hot, dry conditions. “During these conditions, animals ingest the anthrax bacteria when they consume contaminated grass and hay, or inhale the spores. Outbreaks usually end when cooler weather arrives.”

Click here for more anthrax information from TAHC.

For more on VSV and emerging diseases, see these articles from BovineVetOnline:

Summer Brings Risk of Vesicular Stomatitis

USDA’s Emerging Animal Disease Plan Provides Response Framework

Vesicular Stomatitis, Anthrax Emerge in SW

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