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2020 Vesicular Stomatitis Virus (VSV) 

Situation Report – November 13, 2020

Information current as of 8:00 am MST, 11/13/2020

Since the last situation report (10/29/2020), there have been no new VSV-positive premises 

identified and there are no active quarantines remaining on previously VSV-affected 

premises in the U.S. since October 15, 2020. This is the final situation report issued for the 

2020 VSV outbreak. 

VSV-affected states during the 2020 outbreak included Arizona, Arkansas, Kansas, 

Missouri, Nebraska, New Mexico, Oklahoma, and Texas. 

Classification of Cases

Premises that had laboratory diagnostic results meeting the VSV confirmed case definition were

categorized as confirmed positive premises. Once a county was confirmed as VSV-positive, new 

equine premises presenting with clinical signs of VSV in that county were not required to be 

tested for confirmation of the disease, but the premises was quarantined and classified as a 

suspect premises. Premises may also have been classified as suspect if clinical animals on the 

premises failed to meet confirmed case definition, but there was diagnostic evidence of recent 

VSV infection. 

Quarantines

Confirmed positive and suspect premises were quarantined for at least 14 days from the onset 

of lesions in the last affected animal on the premises. 

Summary of the Outbreak

The 2020 VSV outbreak began on April 13, 2020, when the National Veterinary Services 

Laboratories (NVSL) in Ames, Iowa confirmed the first VSV-positive premises in Dona Ana 

County, New Mexico. Arizona, Texas, Kansas, Nebraska, Oklahoma, Missouri, and Arkansas

subsequently broke with VSV cases which were confirmed by NVSL on April 22, 2020 (Cochise

County, Arizona), April 23, 2020 (Starr County, Texas), June 16, 2020 (Butler County, Kansas), 

June 24, 2020 (Buffalo County, Nebraska), July 7, 2020 (Washington County, Oklahoma), July 

13, 2020 (Newton County, Missouri), and July 27, 2020 (Benton County, Arkansas). 

Since the start of the outbreak, 326 VSV-affected premises were identified (206 confirmed 

positive, 120 suspect). Three hundred thirteen (313) of these premises had only equine species 

clinically affected, 12 premises had clinically affected cattle (McMullen, Starr, and Zapata 

Counties, Texas; Butler, Cowley, Marion, and Montgomery Counties, Kansas; Cedar and Ozark 

Animal and Plant 

Health Inspection 

Service

Veterinary 

Services
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Counties, Missouri), and 1 premises had both equine species and cattle clinically affected (Cedar 

County, Missouri). 

Arizona identified 19 affected premises (18 confirmed positive, 1 suspect) in 7 counties (Apache, 

Cochise, Gila, Maricopa, Pima, Pinal, and Santa Cruz Counties). Arkansas identified 4 affected 

premises (4 confirmed positive) in 1 county (Benton County). Kansas identified 196 affected 

premises (101 confirmed positive, 95 suspect) in 26 counties (Allen, Bourbon, Butler, Chase,

Cherokee, Coffey, Cowley, Crawford, Elk, Franklin, Greenwood, Harvey, Johnson, Labette, 

Linn, Lyon, Marion, Miami, Montgomery, Morris, Neosho, Riley, Sedgwick, Sumner, Wilson 

and Woodson Counties). Missouri identified 54 affected premises (37 confirmed positive, 17

suspect) in 12 counties (Camden, Cedar, Dallas, Douglas, Jasper, Lawrence, McDonald, Newton, 

Ozark, Phelps, St. Clair, and Texas Counties). Nebraska identified 5 affected premises (5 

confirmed positive) in 3 counties (Buffalo, Gage, and Johnson Counties). New Mexico identified 

16 affected premises (13 confirmed positive, 3 suspect) in 6 counties (Bernalillo, De Baca, Dona 

Ana, Eddy, Grant and Sierra Counties). Oklahoma identified 22 affected premises (18 confirmed 

positive, 4 suspect) in 9 counties (Adair, Cherokee, Craig, Nowata, Osage, Ottawa, Rogers, 

Tulsa, and Washington Counties). Texas identified 10 affected premises (10 confirmed positive, 

0 suspect) in 6 counties (El Paso, Hudspeth, Kerr, McMullen, Starr, and Zapata Counties). 

All VSV-quarantined premises have been released in New Mexico (since June 4, 2020), Texas 

(since June 8, 2020), Arizona (since July 8, 2020), Nebraska (since July 30, 2020), Arkansas 

(since August 19, 2020), Oklahoma (since August 26, 2020), Kansas (since September 23, 

2020), and Missouri (since October 15, 2020). 

Summary of VSV-Affected Premises

Table 1. Location, number, and status of VSV-affected premises.

ARIZONA

Confirmed 

Positive 

Premises

Suspect 

Premises

Premises 

Released from 

Quarantine

Current 

Premises 

Quarantined

Apache County

Cochise County

Gila County

Maricopa County

Pima County

Pinal County

Santa Cruz County

2

4

1

7

1

2

1

0

0

0

1

0

0

0

2

4

1

8

1

2

1

0

0

0

0

0

0

0

TOTAL: 7 COUNTIES 18 1 19 0

ARKANSAS

Benton County 4 0 4 0

TOTAL: 1 COUNTY 4 0 4 0
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KANSAS

Confirmed 

Positive 

Premises

Suspect 

Premises

Premises 

Released from 

Quarantine

Current 

Premises 

Quarantined

Allen County

Bourbon County

Butler County

Chase County

Cherokee County

Coffey County

Cowley County

Crawford County

Elk County

Franklin County

Greenwood County

Harvey County

Johnson County

Labette County

Linn County

Lyon County

Marion County

Miami County

Montgomery County

Morris County

Neosho County

Riley County

Sedgwick County

Sumner County

Wilson County

Woodson County

3

1

31

1

6

1

9

1

1

1

2

1

1

2

2

3

2

3

6

1

3

1

13

2

3

1

5

0

24

1

7

2

8

1

0

0

2

0

1

4

1

2

0

6

10

1

10

0

1

4

5

0

8

1

55

2

13

3

17

2

1

1

4

1

2

6

3

5

2

9

16

2

13

1

14

6

8

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TOTAL: 26 COUNTIES 101 95 196 0

MISSOURI

Camden County

Cedar County

Dallas County

Douglas County

Jasper County

Lawrence County

McDonald County

Newton County

Ozark County

Phelps County

St. Clair County

Texas County

2

3

2

1

8

1

5

8

3

2

1

1

0

0

0

0

6

1

2

7

1

0

0

0

2

3

2

1

14

2

7

15

4

2

1

1

0

0

0

0

0

0

0

0

0

0

0

0

TOTAL: 12 COUNTIES 37 17 54 0

NEBRASKA

Buffalo County 3 0 3 0
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Gage County

Johnson County

1

1

0

0

1

1

0

0

TOTAL: 3 COUNTIES 5 0 5 0

NEW MEXICO

Confirmed 

Positive 

Premises

Suspect 

Premises

Premises 

Released from 

Quarantine

Current 

Premises 

Quarantined

Bernalillo County

De Baca County

Dona Ana County

Eddy County

Grant County

Sierra County

1

2

6

1

1

2

0

0

1

0

0

2

1

2

7

1

1

4

0

0

0

0

0

0

TOTAL: 6 COUNTIES 13 3 16 0

OKLAHOMA

Adair County

Cherokee County

Craig County

Nowata County

Osage County

Ottawa County

Rogers County

Tulsa County

Washington County

1

3

1

1

2

4

1

1

4

0

0

1

0

1

0

2

0

0

1

3

2

1

3

4

3

1

4

0

0

0

0

0

0

0

0

0

TOTAL: 9 COUNTIES 18 4 22 0

TEXAS

El Paso County

Hudspeth County

Kerr County

McMullen County

Starr County

Zapata County

1

1

1

1

4

2

0

0

0

0

0

0

1

1

1

1

4

2

0

0

0

0

0

0

TOTAL: 6 COUNTIES 10 0 10 0

TOTAL PREMISES ALL 

STATES 206 120 326 0
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Map 1 (Current). Counties with Current VSV-Quarantined Premises

There are no active quarantines remaining on previously VSV-affected 

premises in the United States. 

Map 2 (Cumulative). Counties with Premises Quarantined for VSV in 2020
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Table 2. Cumulative count of species clinically affected on VSV-positive premises.

State Premises with 

clinically 

affected 

equine species

Premises with 

clinically 

affected 

bovine species

Premises with 

clinical signs 

in both equine 

and bovine 

species 

Premises with 

clinical signs 

in other 

susceptible 

species

Total affected 

premises

ARIZONA 19 0 0 0 19

ARKANSAS 4 0 0 0 4

KANSAS 190 6 0 0 196

MISSOURI 51 2 1 0 54

NEBRASKA 5 0 0 0 5

NEW MEXICO 16 0 0 0 16

OKLAHOMA 22 0 0 0 22

TEXAS 6 4 0 0 10

TOTAL 313 12 1 0 326

Table 3. VSV Serotypes Identified During the 2020 Outbreak

Both VSV-Indiana (VSV-IN) and VSV-New Jersey (VSV-NJ) serotypes were identified during the 

2020 outbreak. VSV-IN occurred in the U.S. in 2019, while VSV-NJ was last isolated in the U.S. 

in the 2014-2015 outbreak. Both serotypes are known to circulate in endemic cycles in southern 

Mexico. The last U.S. outbreak involving both serotypes occurred in 1997-1998. 

*Livestock in the southwestern and Rocky Mountain regions of the U.S. have been exposed to 

both VSV-NJ and VSV-IN in recent outbreak years. New infection with either serotype in 2020 

can cause elevated antibody titers to both serotypes if previously encountered. The current 

infection serotype on a premises may not be able to be confirmed if elevated antibodies to both 

State Premises with 

VSV-IN 

serotype 

confirmed

Premises with 

VSV-NJ 

serotype 

confirmed

Premises with 

VSV serotype 

unconfirmed*

Total VSV 

affected 

premises

ARIZONA 17 0 2 19

ARKANSAS 4 0 0 4

KANSAS 109 0 87 196

MISSOURI 38 0 16 54

NEBRASKA 5 0 0 5

NEW MEXICO 13 0 3 16

OKLAHOMA 20 0 2 22

TEXAS 3 7 0 10

TOTAL 209 7 110 326
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serotypes are present in the animals and antigen detection tests (RT-PCR and virus isolation) are 

negative. Additionally, VSV serotype will not be known in suspect cases in which diagnostic 

testing does not occur. 

Figure 1. Epidemic Curve of 2020 VSV Outbreak

Table 4. Timeline of Events

Date Event

April 13, 2020 VSV index case for the U.S. confirmed at NVSL – Dona Ana County, New 

Mexico. New affected county confirmed – Sierra County, New Mexico

April 20, 2020 New affected county confirmed – Eddy County, New Mexico

April 22, 2020 VSV index case for Arizona confirmed – Cochise County, Arizona

April 23, 2020 VSV index case for Texas confirmed – Starr County, Texas

April 27, 2020 New affected county confirmed – Pinal County, Arizona

April 29, 2020 New affected county confirmed – El Paso County, Texas

May 4, 2020 New affected county confirmed – Grant County, New Mexico

May 6, 2020 New affected counties confirmed – Gila County, Arizona; Zapata County, 

Texas

May 7, 2020 New affected counties confirmed – Pima, County, Arizona; Bernalillo and 

De Baca Counties, New Mexico

May 19, 2020 New affected county confirmed – McMullen County, Texas

May 20, 2020 New affected county confirmed – Hudspeth County, Texas

May 21, 2020 New affected counties confirmed – Santa Cruz County, Arizona; Kerr 

County, Texas

May 22, 2020 New affected county confirmed – Maricopa County, Arizona

May 29, 2020 New affected county confirmed – Apache County, Arizona

June 4, 2020 All VSV quarantines released in New Mexico

June 8, 2020 All VSV quarantines released in Texas
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June 16, 2020 VSV index case for Kansas confirmed – Butler County, Kansas

June 17, 2020 New affected county confirmed – Cowley County, Kansas

June 19, 2020 New affected county confirmed – Sedgwick, Kansas

June 24, 2020 VSV Index case for Nebraska confirmed – Buffalo County, Nebraska. New 

affected county confirmed – Sumner County, Kansas

July 2, 2020 New affected counties confirmed – Greenwood and Marion Counties, 

Kansas. 

July 7, 2020 VSV index case for Oklahoma confirmed – Washington County, 

Oklahoma. New affected county confirmed – Montgomery County, 

Kansas. 

July 8, 2020 All VSV quarantines released in Arizona

July 9, 2020 New affected county confirmed – Johnson County, Nebraska. 

July 10, 2020 New affected county confirmed – Morris County, Kansas

July 13, 2020 VSV index case for Missouri confirmed – Newton County, Missouri. New 

affected counties confirmed – Chase and Miami Counties, Kansas. 

July 15, 2020 New affected county confirmed – Craig County, Oklahoma

July 17, 2020 New affected counties confirmed – Allen, Coffey, Lyon, Neosho, and 

Wilson Counties, Kansas; Jasper County, Missouri; Osage and Ottawa 

Counties, Oklahoma.

July 20, 2020 New affected counties confirmed – Cherokee, Elk, and Labette Counties, 

Kansas; Lawrence County, Missouri. 

July 21, 2020 New affected county confirmed – Tulsa County, Oklahoma

July 22, 2020 New affected counties confirmed – Bourbon and Woodson Counties, 

Kansas; Gage County, Nebraska; Adair and Nowata Counties, Oklahoma. 

July 23, 2020 New affected counties confirmed – Linn County, Kansas; Cedar County, 

Missouri. 

July 24, 2020 New affected counties confirmed – Riley County, Kansas; McDonald 

County, Missouri; Rogers County, Oklahoma

July 27, 2020 VSV index case for Arkansas confirmed – Benton County, Arkansas

July 28, 2020 New affected counties confirmed – Crawford and Franklin Counties, 

Kansas

July 29, 2020 New affected county confirmed – Cherokee County, Oklahoma

July 30, 2020 All VSV quarantines released in Nebraska

July 31, 2020 New affected counties confirmed – Ozark and St. Clair Counties, Missouri

August 7, 2020 New affected county confirmed – Camden County, Missouri

August 11, 2020 New affected counties confirmed – Harvey and Johnson Counties, 

Kansas; Douglas County, Missouri

August 19, 2020 All VSV quarantines released in Arkansas

August 26, 2020 All VSV quarantines released in Oklahoma

August 28, 2020 New affected county confirmed – Dallas County, Missouri

September 3, 2020 New affected county confirmed – Phelps County, Missouri

September 23, 2020 All VSV quarantines released in Kansas

October 8, 2020 New affected county confirmed – Texas County, Missouri

October 15, 2020 All VSV quarantines released in Missouri