Disease Alerts

Number Confirmed: 4; 
Number Suspected: Unknown; 
Number Exposed: Unknown; 
Comments: Multiple cases of Pigeon Fever reported in Gallatin, Missoula, and Beaverhead Counties in Montana. 4 cases confirmed, additional cases are suspected. Horses confirmed have been placed under quarantine. Unknown how many additional horses have been exposed.;

Number Suspected: 1; 
Number Exposed: 3; 
Facility Type: Boarding Facility; 

Horse 1: 
Age: 9; Gender: Mare; Breed: Quarter Horse (QH); Clinical Signs: Fever, nasal discharge, lethargy; Horse Status: Recovering; Vaccination Status: Unvaccinated;

Comments: Ruptured retropharyngeal abscesses into guttural pouches; on guttural pouch endoscopy. Recovering;

Number Confirmed: 1; 

Horse 1: 
Age: 6; Gender: Gelding; Breed: Warmblood (WB); Onset of Clinical Signs: 7/30/2026; Clinical Signs: ataxia (all 4 limbs), hypersensitivity, muscle fasciculations, wall leaning; Horse Status: Affected And Alive; Vaccination Status: Vaccinated;

Comments: The fourth (4th) equine case of West Nile Virus in California in 2026 was confirmed in Merced County. On August 6, 2026, a vaccinated 6-year-old Warmblood gelding in Merced County displaying neurologic signs was confirmed positive for West Nile Virus. The gelding is alive and recovering.;

Number Confirmed: 1; 
Number Exposed: 2; 
Facility Type: Private Facility;

Number Confirmed: 1; 
Number Suspected: 2; 
Number Exposed: Unknown; 
Facility Type: Farm; 

Horse 1: 
Age: 5; Gender: Gelding; Breed: Belgian; Onset of Clinical Signs: 7/25/2026; Clinical Signs: This gelding became acutely recumbent on July 25th, was sent to a referral hospital for treatment but was euthanized due to his worsening condition. West Nile virus was confirmed by PCR on brain tissue. This gelding was one of 3 horses on the property that had recently died with acute neurologic signs.; Horse Status: Euthanized; Vaccination Status: Unvaccinated;

Comments: This is the first confirmed case of equine WNV in Ontario this year . To see past and present WNV cases in Ontario go to: https://www.oahn.ca/resources/ontario-equine-disease-alerts/ and enter the disease surveillance portal.;

Number Confirmed: 1; 
Number Suspected: 1; 
Number Exposed: 3; 
Facility Type: Private Facility; 

Horse 1: 
Age: 4; Gender: Gelding; Breed: Quarter Horse Cross; Usage: Trail Riding; Onset of Clinical Signs: 7/17/2026; Clinical Signs: Initially off, suspected colic and treated with anti-inflammatories. Day 3 went down, began presumptive WNV treatment including supportive care and WNV plasma for 4 days. Now recovered.; Confirmation Date: 7/21/2026; Horse Status: Recovered; Vaccination Status: Unvaccinated;

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

Number Confirmed: 1; 
Number Exposed: Unknown; 
Facility Type: Private Facility; 
Comments: Due to respiratory distress caused by compression of the airway due to strangles abscessed horse required emergency tracheostomy;

Number Suspected: 5; 
Number Exposed: Unknown; 
Facility Type: Private Facility; 

Horse 1: 
Age: 3; Gender: Gelding; Breed: Quarter Horse (QH); Clinical Signs: Respiratory stridor causing compression of the airway due to strangles abscesses; Vaccination Status: Unvaccinated;

Comments: Due to respiratory distress horse required emergency tracheostomy;

Number Suspected: 20; 
Number Exposed: Unknown; 
Facility Type: Boarding Facility; 

Horse 1: 
Age: 9; Gender: Gelding; Breed: Quarter Horse (QH); Clinical Signs: Respiratory stridor due to compression on the airway due to strangles abscesses; Vaccination Status: Unvaccinated;

Horse 2: 
Age: 7; Gender: Stallion; Breed: Quarter Horse (QH); Clinical Signs: Respiratory stridor due to compression of the airway due to strangles abscesses; Vaccination Status: Unvaccinated;

Comments: Both horses required emergency tracheostomy;