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Disease Outbreak 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.

Alert ID: 1272
June 14, 2019
Kent County, MI
Confirmed Case(s): No Quarantine
Source: Michigan Department of Agriculture and Rural Development

Number Confirmed: 1;
Number Exposed: Not Reported;
Age: 20; Gender: Gelding; Breed: Quarter Horse (QH); Onset of Clinical Signs: 6/4/2019;
Clinical Signs: Enlarged submandibular lymph nodes, Fever; Confirmation Date: 6/8/2019; Horse Status: Recovering; Vaccination Status: Vaccinated;
Notes: Number of horses at farm are unknown, but all are alive.;

Alert ID: 1271
June 13, 2019
Island County, WA
Confirmed case(s): Official Quarantine
Source: Washington State Department of Agriculture

Number Confirmed: 1;
Number Exposed: 1;
Number Quarantined: 25;

Age: 18; Gender: Gelding; Breed: Quarter Horse (QH); Onset of Clinical Signs: 6/7/2019;
Clinical Signs: Back Sore, Difficulty Rising, Bladder Atony; Confirmation Date: 6/11/2019; Horse Status: Recovering; Vaccination Status: Vaccinated;
Notes: Horse was WNV, EPM, and EHV tested. Horse is EPM and EHV-1 wild type positive. Mild neuro signs.

Alert ID: 1270
June 11, 2019
Southern Saskatchewan, SK
Confirmed Case(s): Voluntary Quarantine
Source: Canadian Animal Health Surveillance System

Equine Herpesvirus- Neurologic; Southern Saskatchewan, Canada; Confirmed Case(s): Official Quarantine

Number Confirmed: 6;
Number Exposed: 70;
Clinical Signs: Severe Neurologic signs; Confirmation Date: 6/7/2019; Horse Status: 5 horses euthanized Vaccination Status: Not Reported;
Notes: An outbreak of neurologic equine herpes virus (nEHV) has been confirmed on a single premises in southern Saskatchewan. The first symptoms noted were sporadic abortions (6) in a group of 70 late-term brood mares, followed by severe neurological symptoms in 5 horses which were subsequently euthanized. Equine herpes virus -1 (EHV-1) was confirmed by PCR on June 4. The premises has self-quarantined, under supervision of the herd veterinarian; it is anticipated that all animals currently on the premises will not be moved for a period of several months. No animals were moved off the premises in the weeks prior to the outbreak. Animal movements onto the farm in the weeks prior to the outbreak are being investigated to try to identify a potential source of introduction of the virus.;


Alert ID: 1269
June 06, 2019
Clackamas County, OR
Confirmed Case(s): Voluntary Quarantine
Source: Attending Veterinarian
Number Confirmed: 2;
Number Exposed: 9;

Age: Yearling; Gender: Gelding; Breed: Quarter Horse (QH); Onset of Clinical Signs: 5/26/2019;
Clinical Signs: coughing, Enlarged submandibular lymph nodes, Fever; Confirmation Date: 5/29/2019; Horse Status: Recovering; Vaccination Status: Vaccinated;

Age: 15; Gender: Mare; Breed: Quarter Horse (QH); Onset of Clinical Signs: 5/30/2019;
Clinical Signs: Enlarged submandibular lymph nodes, Clear Nasal Discharge; Horse Status: Recovering; Vaccination Status: Vaccinated;
Alert ID: 1268
June 05, 2019
Maui County, HI
Confirmed Case(s): Voluntary Quarantine
Source: Hawaii Department of Agriculture, Animal Disease Control Branch

Number Confirmed: 3;
Number Exposed: 25;
Age: Not Reported; Gender: Not Reported; Breed: Not Reported; Onset of Clinical Signs: Not Reported; Clinical Signs: Not Reported;  Horse Status: Recovering; Vaccination Status: Status Unknown;
Notes: Only polo ponies involved. Last case occurred and resolved in May 2019.;

Alert ID: 1267
June 04, 2019
Municipality of Squamish-Lillooet Subd. B, BC
Confirmed case(s): Official Quarantine
Source: Canadian Animal Health Surveillance System

Number Confirmed: 1;
Clinical Signs: None; Confirmation Date: 5/29/2019
Notes: On May 29, 2019, a positive EIA result was confirmed by the CFIA’s national reference laboratory for a horse located on a premise in the municipal district of Squamish?Lillooet, Subd. B, in the province of British Columbia. The horse had been sampled by an accredited veterinarian at the owner’s request prior to moving the horse to another premise in Canada. No clinical signs of disease were noted at the time of sampling. A CFIA investigation is underway and as per program policy, a quarantine has been placed on the infected horse and its on-premises contact animals. Initial reports indicate there are several equines on the affected premise. The quarantine will remain until all disease response activities have been completed, including follow-up testing and ordering the destruction of positive cases. Trace-out activities may require the CFIA to undertake actions at additional premises as outlined in the current policy. ;

Alert ID: 1266
June 04, 2019
Canyon County, ID
Confirmed case(s): Official Quarantine
Source: Idaho Department of Agriculture

Number Confirmed: 1;
Number Exposed: 100;
Age: Not Reported; Gender: Gelding; Breed: Quarter Horse (QH); Onset of Clinical Signs: Not Reported;
Clinical Signs: None; Confirmation Date: 6/3/2019; Horse Status: Euthanized; 
Notes: The affected horse had recently returned to Idaho from Washington state and was being tested as a part of a large group for interstate movement. The animal has been euthanized and all other exposed horses will remain under quarantine for a minimum of 60 days until test negative;

Alert ID: 1265
May 23, 2019
Chester County, PA
Outbreak Update
Source: Pennsylvania Department of Agriculture

The Chester County, PA horse that tested positive for EHV-1 died on May 17 in isolation on a private farm. The post-mortem results indicate that the horse died of an unrelated medical issue, not from equine herpes myeloencephalopathy (EHM, the disease caused when EHV affects the central nervous system). There have been no other horses showing signs of EHV-1 infection and there is no “outbreak” as has been reported elsewhere. The horse had been placed in isolation at its home farm on May 15 when it began to show signs of illness, including abnormal gait and stance and a high fever. As EHV-1 was detected in the horse’s nasal swab sample, all horses at the Chester County farm were quarantined. Based on the post-mortem findings, the low levels of EHV detected on the nasal swab sample, and the absence of EHV-related illness in any of the horses on the premises, there appears to be little risk even for the horses that were in direct contact with the horse that died. Furthermore, the two horses that had moved off the farm prior to the horse getting sick pose an even lower risk of spreading EHV-1. These two horses have returned to the home farm, also remain under close monitoring and have shown no signs of illness. Following national guidelines, and in consultation with EHV regulatory experts, the horses on the home premises will remain under quarantine with monitoring for a minimum of 14 days from when the affected horse was isolated (beginning May 15). No quarantined horses have shown any signs of illness to date. EHV-1 causes illness in some horses and others may carry virus without showing clinical disease. In particular, horses that are under stress may be more likely to shed the virus.  For more information about EHV-1 go to

Alert ID: 1264
May 22, 2019
King County, WA
Confirmed Case(s): Voluntary Quarantine
Source: Washington State Department of Agriculture

Number Confirmed: 1;
Number Exposed: 5;
Age: 11; Gender: Gelding; Breed: Belgian; Onset of Clinical Signs: 5/13/2019;
Clinical Signs: Fever, Nasal Discharge; Confirmation Date: 5/15/2019; Horse Status: Affected And Alive; Vaccination Status: Undervaccinated;

Alert ID: 1262
May 21, 2019
Snohomish County, WA
Confirmed Case(s): Voluntary Quarantine
Source: Washington Department of Agriculture

Number Confirmed: 2;
Number Exposed: 10;
Age: 4Gender: GeldingBreed: ArabianOnset of Clinical Signs: 5/11/2019;
Clinical Signs: Fever, Nasal Discharge, Swollen Lymph NodesConfirmation Date: 5/15/2019Horse Status: RecoveringVaccination Status: Undervaccinated;

Age: 4; Gender: Mare; Breed: Arabian; Onset of Clinical Signs: 5/11/2019;
Clinical Signs: Fever, Nasal Discharge, Swollen Lymph Nodes; Confirmation Date: 5/15/2019; Horse Status: Recovering; Vaccination Status: Undervaccinated;

Notes: Two confirmed cases have mild symptoms and the remaining 8 were exposed. None were vaccinated for Strangles