Spring into vaccines and protect your horse!

By Dr. Amber Itle |
WA State Veterinarian

Rodeos, events and shows are in full swing this spring!  Horses are on the move and so are equine diseases. Since the first of the year, 19 States have reported contagious disease outbreaks in horses nationally.  Washington is also seeing an uptick in reports.  The most commonly reported diseases in the State are Strangles, Equine Influenza Virus, Pigeon Fever, Equine Herpes Virus and West Nile Disease. 

Now is the time to update your horse’s vaccinations to mitigate disease severity and allow for continuity of business.   Talk to your veterinarian about the right protocol and cadence for you depending on your risk to include Flu/Rhino (equine influenza and herpes), West Nile and maybe even Strep equi (strangles) in addition to the core vaccines recommended by AAEP.  This is especially critical in boarding facilities where horses come and go to shows, events and even trail rides. Any commingling event is an opportunity for disease spread. Although horses that are vaccinated can still contract the virus or bacterial infection and spread it, but the course of disease should be less severe.

As soon as the attending veterinarian gets positive laboratory results for any of these diseases, they must be reported through the Reportable Animal Disease database. WSDA also reports to the Equine Disease Communication Center and they distribute minimal information that protects personally identifying information through an alert to subscribers. Usually private practitioners manage individual cases of equine diseases by performing diagnostics, addressing individual horse treatment, implementing on farm biosecurity practices, and helping the barn manager institute a self-quarantine of infected or exposed horses. 

In some cases, when there are lots of sick horses and/or stable compliance is a problem with horse movement, the State Veterinarian can be requested to assist.  WSDA field veterinarians can issue quarantines in order to mitigate the spread of disease by not allowing any movement of horses on or off the premises. A quarantine will be in place until 14-21 days after the last “new” case, allowing for a full incubation period to pass by without clinical signs.  Horses can remain contagious for 10 days after clinical signs or fever starts.  The quarantine will require that rectal temperatures be recorded daily whenever possible so that febrile horses can be rapidly isolated, tested and monitored for clinical signs.  Often viral infections can be “dose dependent” so rapid removal of sick horses can reduce viral load and transmission.

Airborne transmission or direct contact is the most common way horses become infected with respiratory disease.  Infected horses release infective droplets into the air by coughing or snorting which are then inhaled by horses in close proximity. Horses can also be exposed to the organism by coming into contact with contaminated surfaces such as stalls, wash racks, stocks, water sources, feed, tack, grooming equipment such as wipe rags, and transport vehicles. Humans can spread microorganisms from horse to horse by contaminated hands and clothing, so the adoption of biosecurity measures is paramount. 

WSDA Field veterinarians can also assist with on-farm biosecurity plans to help mitigate viral spread.  Here are some biosecurity tips you can customize for your ranch during a quarantine period to help ensure the health and welfare of your horse.  Horse owners can find this biosecurity poster on our website to be printed and posted in your barn. 

1. Observe Strict Biosecurity
1. Limit Stress to horses
2. Control flies, vermin, vectors
3. Monitor all horses on the premises with twice-a-day temperature recording
4. Keep hoses out of free-standing water such as ponds or creeks
5. Remove compost and manure promptly
6. Wash hands frequently
7. Prevent direct contact with infected horses
8. Do not share equipment, buckets or tack
9. Tape off an “off limits” perimeter outside any symptomatic horse stall approximately 3 feet by six feet.  Only people that need to enter the stall are permitted into this area.
10. Place a foot bath outside the stall with disinfectant, to dip feet into prior to entering and again after exiting the stall. Be sure to clean your boots before you disinfect. 
11. Clean and disinfect the stall frequently
12. Designate one person to care for your horse and limit contact of personnel with exposed horses
13. Notify your veterinarian immediately if you notice any clinical signs or changes in behavior.  Horses with viral infections are prone to secondary bacterial infections.  
14. Coughing horses aerosolize the organism and can spread the organism as far as 150 feet
2. Horse Management
1. Do not move any horses on or off the farm
2. Designate an isolation stall or quarantine barn for sick horses.
3. Supportive care and treatment as prescribed by your veterinarian
4. Keep in well-ventilated stall and or paddocks to reduce inhalation of dust
5. Consider staggering outdoor paddock access to avoid nose-to-nose contact

                                                              i.      Spray any common contact areas with 10% bleach. 

6. Consider physical barriers between outdoor runs to avoid nose-to-nose contact
7. Keep dust down in the stall and hay (by wetting if needed)
2. Exercise- No sick horses should be allowed in the main arena or in shared wash racks.
1. Symptomatic horses (fever, lethargy, nasal discharge, coughing, etc)

                                                              i.      Febrile horses should remain in their stalls and allowed to rest. 

                                                            ii.      Avoid strenuous exercise and hand walk or exercise lightly for short periods of time.

·          Remember, your horse is not feeling well and may be lethargic, have painful muscles or a cough that can be exasperated by exercise.  The idea is to stretch the horses legs and provide some stress relief from being stalled. 

                                                          iii.      Lightly exercise horses in the designated round pen area away from other horses

                                                          iv.      When moving horses down the alleyway, use the closest exit and be cautious to avoid direct nose-to-nose contact with other horses.

                                                            v.      Only one horse should be exercised at a time and a schedule should be posted if needed.  

2. Exposed, non-clinical horses (No fever, no nasal discharge, rare or occasional cough)

                                                              i.      Avoid strenuous exercise, but light riding or exercise is acceptable. 

·         Remember that your horse’s immune system may be under stress from recent exposure and fighting off potential infection. Too much exercise may exasperate clinical signs or illness.

                                                            ii.      All horses should exit the barn in a way that avoids clinical horses if possible.

                                                          iii.      Exercise horses in the designated outdoor arena space

                                                          iv.      Only one horse should be exercised at a time and a schedule should be posted if needed.  

Mapping the farm can also be helpful when thinking about horse movement patterns on the farm as well as identifying access points, parking, cleaning and disinfection stations and carcass pick-up areas. 

Additional Equine Biosecurity Resources can be found on our website.