Disease Alerts

Comments: Since the last VSV situation report (9/18/2026), 1 VSV-confirmed positive equine premises has been identified in Mesa County, Colorado (New Affected County) and 1 new VSV-presumptive positive equine premises has been quarantined in Delta County, Colorado. All confirmed cases in the 2025-26 outbreak have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows: Colorado • Delta County – 1 new presumptive positive equine premises • Mesa County (New Affected County) – 1 confirmed positive equine premises • Since the last situation report (9/18/2026), 3 previously VSV-affected premises have been released from quarantine, 1 in Delta County and 2 in Montezuma County.;

Comments: Since the last VSV situation report (9/14/2026), 2 VSV-presumptive positive equine premises have been identified, 1 in Delta County and 1 in Montezuma County, Colorado. All confirmed cases in the 2025-26 outbreak have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows: Colorado • Delta County – 1 new presumptive positive equine premises • Montezuma County – 1 new presumptive positive equine premises • Since the last situation report (9/14/2026), 2 previously VSV-affected premises have been released from quarantine, 1 in La Plata County and 1 in Montezuma County. For more information go to https://www.aphis.usda.gov/sites/default/files/vsv-sitrep-9-18-26.pdf

Comments: Since the last VSV situation report (9/3/2026), 1 VSV-presumptive positive equine premises has been identified in Montezuma County, Colorado. All confirmed cases in the 2025-26 outbreak have been vesicular stomatitis New Jersey virus (VSNJV) serotype. 

Updates are as follows: Colorado • Montezuma County – 1 new presumptive positive equine premises • Since the last situation report (9/3/2026), no additional premises have been released from quarantine. New Mexico • No new VSV-affected premises have been quarantined. 

Since the start of the outbreak, 47 VSV-affected premises have been identified (32 confirmed positive, 15 presumptive positive) in 3 states, Arizona, Colorado, and New Mexico. Forty-four (44) premises have had only equine species clinically affected and three (3) premises have had only cattle clinically affected. Of the 47 affected premises, 15 were located in 6 Arizona counties (Cochise, Gila, Maricopa, Pinal, Santa Cruz, and Yavapai Counties), 15 premises were located in 5 Colorado counties (Archuleta, Delta, La Plata, Montezuma, and Montrose Counties), and 16 premises were located in 4 New Mexico counties (Rio Arriba, Sandoval, Santa Fe, and Valencia Counties).;

For more information, go to https://www.aphis.usda.gov/livestock-poultry-disease/cattle/vesicular-stomatitis

Comments: A new USDA Vesicular Stomatitis situation report, including quarantine release information, is available here https://www.aphis.usda.gov/sites/default/files/vsv-sitrep-9-3-26.pdf

Comments: Since the last VSV situation report (8/13/2026), three presumptive positive equine premises in La Plata County and Montezuma County, Colorado, have been quarantined. All confirmed cases in the 2025-26 outbreak have been vesicular stomatitis New Jersey virus (VSNJV) serotype. 

Updates are as follows: • La Plata County – 1 new presumptive positive equine premises • Montezuma County – 2 new presumptive positive equine premises. Since the last situation report (8/13/2026), 1 previously VSV-affected equine premises has been released from quarantine in La Plata County. 

Since the start of the outbreak, 45 VSV-affected premises have been identified (31 confirmed positive, 14 presumptive positive) in 3 states, Arizona, Colorado, and New Mexico. Forty-three (43) premises have had only equine species clinically affected Of the 45 affected premises, 15 were located in 6 Arizona counties (Cochise, Gila, Maricopa, Pinal, Santa Cruz, and Yavapai Counties), 14 premises were located in 5 Colorado counties (Archuleta, Delta, La Plata, Montezuma, and Montrose Counties), and 16 premises were located in 4 New Mexico counties (Rio Arriba, Sandoval, Santa Fe, and Valencia Counties).;

For more information, go to https://www.aphis.usda.gov/livestock-poultry-disease/cattle/vesicular-stomatitis

Comments: Since the last VSV situation report (8/10/2026), 1 new confirmed VSV-positive equine premises has been identified in La Plata County, Colorado. All confirmed cases in the 2025-26 outbreak have been vesicular stomatitis New Jersey virus (VSNJV) serotype. 

Updates are as follows: Colorado • La Plata County – 1 new confirmed positive equine premises • Since the last situation report (8/10/2026), 2 previously VSV-affected equine premises have been released from quarantine in Montrose County. 

New Mexico • No new VSV-affected premises have been quarantined. 

Since the start of the outbreak, 40 VSV-affected premises have been identified (30 confirmed positive, 10 presumptive positive) in 3 states, Arizona, Colorado, and New Mexico. All 40 premises have had only equine species clinically affected with 15 premises located in 6 Arizona counties (Cochise, Gila, Maricopa, Pinal, Santa Cruz, and Yavapai Counties), 9 premises located in 4 Colorado counties (Archuleta, La Plata, Montezuma, and Montrose Counties), and 16 premises located in 4 New Mexico counties (Rio Arriba, Sandoval, Santa Fe, and Valencia Counties).;

For more information, go to https://www.aphis.usda.gov/livestock-poultry-disease/cattle/vesicular-stomatitis

Comments: Since the last VSV situation report (7/24/2026), 2 new confirmed VSV-positive equine premises have been identified in Montrose County, Colorado. All confirmed cases in the 2025-26 outbreak have been vesicular stomatitis New Jersey virus (VSNJV) serotype. 

Updates are as follows: Colorado • Montrose County – 2 new confirmed positive equine premises • Since the last situation report (7/24/2026), 4 previously VSV-affected equine premises have been released from quarantine in Archuleta County (2), La Plata County (1), and Montezuma County (1). 

New Mexico • Since the last situation report (7/24/2026), 2 previously VSV-affected equine premises have been released from quarantine in Rio Arriba and Valencia Counties. 

Since the start of the outbreak, 39 VSV-affected premises have been identified (29 confirmed positive, 10 presumptive positive) in 3 states, Arizona, Colorado, and New Mexico. All 39 premises have had only equine species clinically affected with 15 premises located in 6 Arizona counties (Cochise, Gila, Maricopa, Pinal, Santa Cruz, and Yavapai Counties), 8 premises located in 4 Colorado counties (Archuleta, La Plata, Montezuma, and Montrose Counties), and 16 premises located in 4 New Mexico counties (Rio Arriba, Sandoval, Santa Fe, and Valencia Counties).;

For more information, go to https://www.aphis.usda.gov/sites/default/files/vsv-sitrep-8-10-26.pdf