Health Alert for Respiratory Disease Outbreak in Horses on Hawaii Island

Posted on Mar 5, 2018 in Main

March 5, 2018

The Hawaii Department of Agriculture (HDOA) is alerting horse owners statewide about an ongoing outbreak of a horse flu, Equine Influenza Virus H3N8 (EIV) occurring on Hawaii Island.  Other animal species and humans are not affected.

EIV is common in horse populations.  Fall and winter are the typical times of the year when respiratory illnesses in horses have occurred historically in Hawaii.  Since early February HDOA’s Animal Industry Division has continued to receive reports of clusters of ill horses on Hawaii Island.  Symptoms include fevers, cough and nasal discharge and lasts approximately 2-3 weeks. Most horses recover uneventfully.  Horses that were vaccinated recently (<4 months) for EIV appear to be resistant and are not becoming ill.  The Animal Disease Control Branch will continue to monitor the situation and provide updates.

It is recommended that Hawaii horse owners take the following steps to protect the health of their horses:

  • Contact their veterinarians to discuss preventive measures and/or treatment in the case of horses that become sick. Vaccination appears to be protecting horses from the outbreak.
  • Practice good biosecurity, especially at events where horses mingle such as horse shows, rodeos, roping events, ranch brandings, etc. Sick horses should not be taken to these events.
  • Be cautious about allowing new horses to mingle with resident populations immediately, keep new horses separated until it is clear they are free from disease.
  • Do not share tack or equipment between healthy and sick horses. Shared equipment, contaminated clothing and hands can spread the infection.

The Animal Disease Control Branch will continue to contact practicing equine veterinarians and horse owners throughout the State to monitor the outbreak.  Horse event managers should be contacting their veterinarians to set up or update preventive measures such as vaccination requirements, biosecurity measures and disallow sick horses from entering events.

HDOA’s website will update information on this outbreak and provide additional information on horse respiratory diseases for horse owners.

For more information or to report illnesses, contact HDOA’s Animal Disease Control Branch at:

Hawaii Island – (808) 974-6503

Maui County – (808) 873-3559

Oahu and Kauai – (808) 483-7106


Links to other resources:

Cornell University –

American Association of Equine Practitioners –