Disease Alerts

Updates on current disease outbreaks are listed here as they occur and will include the date listed, disease name, location and current status. Specific premises will not be named but the general location by town, county and state will be listed. When locations, events or horses are at risk they will be listed. Updates will be posted as they are received.



Hillsdale County, MI
Outbreak Identifier: 6067
Alert ID: 3516
December 05, 2023
Confirmed Case(s) - Voluntary Quarantine

Michigan Department of Agriculture and Rural Development

Number Confirmed: 1; 
Number Exposed: 3; 

Horse 1: 
Age: 6; Gender: Gelding; Breed: Quarter Horse (QH); Onset of Clinical Signs: 11/13/2023; Clinical Signs: Fever and difficulties swallowing; Confirmation Date: 11/30/2023; Horse Status: Recovering; Vaccination Status: Unvaccinated;

Dickson County, TN
Outbreak Identifier: 6066
Alert ID: 3515
December 05, 2023
Confirmed Case(s) - No Quarantine

State Department of Agriculture

Number Confirmed: 1; 
Number Suspected: Unknown; 
Number Exposed: Unknown; 
Facility Type: Farm;

Bedford County, TN
Outbreak Identifier: 6065
Alert ID: 3514
December 05, 2023
Confirmed Case(s) - Voluntary Quarantine

State Department of Agriculture

Number Confirmed: 1; 
Number Suspected: Unknown; 
Number Exposed: Unknown; 
Facility Type: Farm;

Contra Costa County, CA
Outbreak Identifier: 6064
Alert ID: 3513
December 04, 2023
Confirmed Case(s) - Official Quarantine

California Department of Food and Agriculture

Number Confirmed: 1; 
Number Exposed: 14; 

Horse 1: 
Age: 22; Gender: Mare; Breed: Quarter Horse (QH); Clinical Signs: neurologic, ataxic in hind end, fever, anorexia; Confirmation Date: 11/30/2023; Horse Status: Affected And Alive; 

Comments: A 22-year-old Quarter Horse mare from Contra Costa County displaying mild neurologic signs was confirmed positive for Equine Herpesvirus Myeloencephalopathy (EHM) secondary to Equine Herpesvirus-4 (EHV-4) on November 30th. The mare is alive and under veterinary care at an offsite veterinary hospital. Fourteen (14) potentially exposed horses at the home premises in Contra Costa County were quarantined on December 1st with enhanced biosecurity measures implemented. There has been no recent history of travel on or off these premises. CDFA was onsite, and will continue to actively monitor the situation.;

City of Toronto, ON
Outbreak Identifier: 6063
Alert ID: 3512
December 04, 2023
Confirmed Case(s) - Voluntary Quarantine

OMAFRA

Number Confirmed: 5; 
Number Exposed: Unknown; 

Horse 1: 
Age: 24; Gender: Mare; Onset of Clinical Signs: 11/30/2023; Clinical Signs: This mare developed submandibular abscesses and two others developed a fever. These three horses plus two more close contacts are positive for S. equi on PCR.; Confirmation Date: 12/2/2023; Horse Status: Recovering; 

Comments: The facility owner has implemented voluntary movement restrictions and biosecurity protocols under veterinary supervision.;

Grey County, ON
Outbreak Identifier: 6062
Alert ID: 3511
December 04, 2023
Confirmed Case(s) - Voluntary Quarantine

OMAFRA

Number Confirmed: 1; 
Number Exposed: Unknown; 
Facility Type: Private Facility; 

Horse 1: 
Age: 8; Breed: Standardbred; Onset of Clinical Signs: 11/23/2023; Clinical Signs: Fever and Nasal discharge.; Confirmation Date: 11/24/2023; Horse Status: Recovering; 

Comments: The farm owner has implemented voluntary movement restrictions and biosecurity protocols under veterinary supervision.;

Regional Municipality of Durham, ON
Outbreak Identifier: 6061
Alert ID: 3510
December 01, 2023
Confirmed Case(s) - Voluntary Quarantine

OMAFRA

Number Confirmed: 1; 
Number Suspected: Unknown; 
Number Exposed: Unknown; 
Facility Type: Boarding Facility; 

Horse 1: 
Age: 3; Gender: Filly; Onset of Clinical Signs: 11/19/2023; Clinical Signs: This filly developed a persistent deep cough with significant mucopurulent nasal discharge and low grade fever (38.7 C). Several horses at the barn have had clinical signs consistent with a viral respiratory infection.; Confirmation Date: 11/28/2023; Horse Status: Recovering; 

Comments: The filly is recovering under veterinary care.;

Rock County, WI
Outbreak Identifier: 6060
Alert ID: 3509
November 29, 2023
Confirmed Case(s) - Voluntary Quarantine

Wisconsin Department of Agriculture, Trade and Consumer Protection

Number Confirmed: 1; 
Number Exposed: 20; 
Facility Type: Boarding Facility; 

Horse 1: 
Age: 16; Gender: Mare; Breed: Quarter Horse (QH); Onset of Clinical Signs: 11/15/2023; Clinical Signs: Respiratory symptoms, nasal discharge, T=101.5, cough, golf ball size swelling under jaw; Confirmation Date: 11/22/2023; Horse Status: Affected And Alive; Vaccination Status: Status Unknown;

Ottawa County, MI
Outbreak Identifier: 6059
Alert ID: 3508
November 28, 2023
Confirmed Case(s) - Voluntary Quarantine

Michigan Department of Agriculture and Rural Development

Number Confirmed: 1 
Number Suspected: 1
Number Exposed: Unknown

Horse 1: 
Age: 21; Gender: Gelding; Breed: Thoroughbred (TB); Clinical Signs: nasal discharge, ruptured submandibular abscess; Confirmation Date: 11/27/2023; Horse Status: Recovering; Vaccination Status: Status Unknown

Comments: Two horses were purchased on November 18, 2023 from a Michigan seller. Both were ill at the time of purchase with strangles-like signs. One was tested and confirmed to have strangles.

Fresno, Madera, Mariposa, Merced, Tuolumne County, CA
Outbreak Identifier: 5645
Alert ID: 3507
November 28, 2023
Confirmed Case(s) - Official Quarantine

USDA

Number Confirmed:
Number Suspected: 6
Number Exposed: Unknown
Comments: VSV Situation Report 11/28/2023: Since the last situation report (11/16/2023), there have been 9 new VSV-affected premises identified (3 confirmed positive, 6 suspect) in California, including a new affected county, Merced County. All confirmed cases to date have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows: California Fresno County – 1 new confirmed positive equine and 1 suspect cattle premises Madera County – 4 new suspect equine premises Mariposa County – 1 new confirmed positive equine and cattle premises Merced County (New Infected County) – 1 confirmed positive equine premises Tuolumne County – 1 new suspect equine premises Additionally, since the last situation report (11/16/2023), the following previously confirmed positive or suspect premises have been released from quarantine: 18 premises in Fresno County, 3 premises in Inyo County, 1 premises in Kings County, 5 premises in Madera County, and 5 premises in Mariposa County. Since the start of the outbreak (5/17/2023), 307 VSV-affected premises have been identified (90 confirmed positive, 217 suspect) in 3 states, California, Nevada, and Texas. Two hundred ninety-seven (297) of these premises have had only equine species clinically affected, seven (7) premises had only clinically affected cattle (Fresno County, San Diego County, and Santa Barbara County, California), two (2) premises had both equine and cattle clinically affected (Fresno County and Mariposa County, California), and one (1) premises had clinically affected rhinoceros (San Diego County, California). California has identified 304 affected premises (87 confirmed positive, 217 suspect) in 16 counties (Fresno, Inyo, Kings, Los Angeles, Madera, Mariposa, Merced, Orange, Riverside, San Bernardino, San Diego, San Luis Obispo, Santa Barbara, Tulare, Tuolumne, and Ventura Counties). Texas identified 2 affected premises (2 confirmed positive) in 2 counties (Maverick and Shackelford Counties). Nevada identified 1 affected premises (1 confirmed positive) in 1 county (White Pine County, Nevada). Of the 307 total VSV-affected premises, 275 premises have completed the quarantine period with no new clinical cases and have been released from quarantine. Thirty-two (32) premises remain quarantined in California. Additional information and maps are accessible at the following link: https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/equine/vsv/vesicular-stomatitis

Previous Alerts: 3496, 3491, 3489, 3475, 3464, 3450, 3436, 3413, 3401, 3376, 3350, 3314, 3282, 3263, 3210, 3174, 3152, 3145, 3126, 3115, 3111, 3099, 3090, 3085, 3071, 3066, 3060