Outbreak Alert: August 27, 2021 – West Nile Virus in multiple counties in ID, CO, CA

West Nile Virus in Malheur County, ID

Idaho Department of Agriculture

Number Confirmed: 1;
Number Exposed: 30;
Facility Type: Private Facility;
Age: 15; Gender: Mare; Breed: Paint; Onset of Clinical Signs: 8/24/2021;
Clinical Signs: facial/skin fasciculations, tachycardia, tachypnea, Hyperesthetic muzzle; Confirmation Date: 8/27/2021; Horse Status: Affected And Alive; Vaccination Status: Status Unknown;
Notes: WNV factsheet


West Nile Virus in Payette County, ID

Idaho Department of Agriculture

Number Confirmed: 1;
Number Exposed: 6;
Facility Type: Private Facility;
Age: 18; Gender: Mare; Breed: Quarter Horse (QH); Onset of Clinical Signs: 8/24/2021; Clinical Signs: lethargy, tachycardia, Muzzle hyperesthesia, facial/skin fasciculations, tachypnea; Confirmation Date: 8/27/2021; Horse Status: Recovering; Vaccination Status: Unvaccinated;
Notes: WNV factsheet


West Nile Virus in Adams County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Number Exposed: 3;
Onset of Clinical Signs: 8/12/2021; Confirmation Date: 8/16/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Weld County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Number Exposed: 7;
Onset of Clinical Signs: 7/30/2021; Confirmation Date: 8/4/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Otero County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Number Exposed: 3;
Onset of Clinical Signs: 8/17/2021; Confirmation Date: 8/24/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Boulder County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Number Exposed: 8;
Onset of Clinical Signs: 8/9/2021; Confirmation Date: 8/11/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Adams County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Onset of Clinical Signs: 8/10/2021; Confirmation Date: 8/13/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Elbert County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Onset of Clinical Signs: 8/12/2021; Confirmation Date: 8/16/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Morgan County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Number Exposed: 65;
Onset of Clinical Signs: 8/12/2021; Confirmation Date: 8/16/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Adams County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Number Exposed: 5;
Onset of Clinical Signs: 8/13/2021; Confirmation Date: 8/17/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Weld County, CO

Colorado State Veterinarian

Number Confirmed: 1;
Number Exposed: 8;
Onset of Clinical Signs: 8/23/2021; Confirmation Date: 8/24/2021; Horse Status: Not Reported; Vaccination Status: Not Reported;
Notes: WNV factsheet


West Nile Virus in Ada County, ID

Idaho Department of Agriculture

Number Confirmed: 1;
Number Exposed: 20;
Facility Type: Private Facility;
Age: 6; Gender: Mare; Breed: Not Reported; Onset of Clinical Signs: 8/22/2021;
Clinical Signs: Recumbent, hind limb paralysis; Confirmation Date: 8/23/2021; Horse Status: Euthanized; Vaccination Status: Undervaccinated;
Notes: With a lot of 20 horses most under vaccinated. For more information go to: WNV factsheet


West Nile Virus in Merced County, CA

California Department of Food and Agriculture

Number Confirmed: 1;
Number Suspected: Not Reported;
Number Exposed: Not Reported;
Facility Type: Private Facility;
Age: 1; Gender: Stallion; Breed: Quarter Horse (QH); Onset of Clinical Signs: 8/16/2021;
Clinical Signs: Acute recumbency, Nervousness, Twitching; Confirmation Date: 8/26/2021; Horse Status: Deceased; Vaccination Status: Unvaccinated;
Notes: For more information go to:  https://www.cdfa.ca.gov/ahfss/animal_health/Wnv_Info.html

All information is sourced from
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