Infectious disease control (IDC) is an important issue in any equine operation or facility. Many factors are involved in the spread and control of disease. There are common viral, bacterial and parasitic agents that are likely to be found in all areas with a high concentration of horses, but some simple prevention and control measures and having a plan for quickly acting to control potential outbreaks can minimize the impact of these issues on your barn.
The primary ways in which disease is transmitted between horses are airborne, direct contact (nose to nose), or via fomites (wheelbarrows, brushes, tack, buckets, people, etc). IDC is aimed at minimizing these types of transmissions.
Quarantine is a mainstay of infectious disease control.
- New horses should be housed in an area where nose to nose contact is not possible with other horses
- Ideally greater than 60 feet from any other horse
- The quarantine area should have its own cleaning tools that are not used in the regular barn area.
- Cleaning tools should be disinfected with dilute bleach or Nolvasan (chlorhexidine)
- The minimum effective quarantine period is 21 days.
- Footbaths are a great way to prevent the spread of disease on boots. A low plastic tub with dilute bleach (1oz per gallon of water) or Nolvasan (3oz per gallon) works very well.
- Disposable exam gloves and coveralls used when handling all sick or quarantined horses will greatly reduce the transfer of disease, as will hand washing between horses.
- Diseases such as Influenza virus, Rhinopneumonitis and other common respiratory viruses can spread quickly through a barn, and often most horses are exposed before it becomes apparent that the initiating horse is sick.
- Airborne diseases are the most difficult to contain, and often complete control is not feasible, especially in barns that hold events with horses coming in and out frequently.
- For horses at boarding barns, or places where there is horse movement on and off the property, Strangles vaccination is recommended.
- Vaccination is not 100% effective, but greatly reduces the chance of infection after exposure, and should infection occur can reduce the severity of the disease and the amount of bacteria shed by the infected horse.
- Horses with draining Strangles abscesses should be kept from nose to nose contact with other horses and they should not share their water source.
- Pus and drainage material should be removed and the areas it contacted disinfected with Chlorhexidine (Nolvasan) or bleach.
- Similar control is recommended for horses with draining Pigeon Fever abscess.
- Remember that during hot weather flies can carry both Strangles and Pigeon Fever from horse to horse through contact with abscess material, so good fly control is paramount in preventing the spread of disease.
- Rain Rot (Dermatophilus congolensis), Ringworm (Dermatophytosis) and Scratches (Greasy Heel, Pastern Dermatitis) are somewhat easier to control, but can be labor intensive.
- Dermatological conditions can be controlled by avoiding direct contact between horses and ensuring that infected horses have their own grooming supplies, tack and blankets.
- Infectious skin conditions may take quite some time to show evidence of healing after treatment has begun, and all brushes and tack should be disinfected thoroughly before being used on another horse and after the affected horse is healed.
- GI parasites are usually considered less of an epidemic threat to equine health than the diseases mentioned above, but anytime there is an increased number of horses on a property or heavy horse traffic on and off the property, risk of parasite infection is increased.
- Good manure removal programs and a standardized deworming protocol can minimize the impact of GI parasites at large barns. Cleaning stalls twice daily and disposing of manure away from the barns is ideal.
- Ask your veterinarian about deworming rotations and periodic fecal testing to determine your parasite populations and the possible presence of anthelmintic resistance in your herd.
- In the event of a disease outbreak, early intervention and strict IDC protocol can often prevent a major barn epidemic.
- Any horse suspected or confirmed to be infected with respiratory disease should be quarantined immediately.
- Ask your veterinarian about length of quarantine, as different infectious agents are shed into the environment for different lengths of time after clinical signs have resolved.
- Have infected horses cared for by people that do not interact with the healthy horses, if possible, and have designated isolation tools that are not removed from the quarantine area.
- Premises that experience an all-out outbreak of disease should stop any movement of horses on or off the property and should be considered contaminated for four weeks after the outbreak.
- Insect Control
- Barn fly spray systems, prompt and thorough manure and urine removal from stalls, and Fly Predator bugs are all good ways to reduce transmission of disease by flies.
- Fly and mosquito control is also important in controlling the spread of vector and insect borne diseases such as West Nile Virus, Equine Encephalitis or Cutaneous Habronemiasis (Summer Sores).
- Enforcing vaccination for respiratory viruses and strangles for your boarders and for horses attending events at your property can greatly reduce the incidence of respiratory virus infection.
- Routine vaccination for mosquito vectored diseases (WNV, EEE, WEE, etc) is an important control measure.
- Vaccination protocols are important to reduce viral shedding in affected horses, to reduce severity of disease and to reduce the number of horses that become infected after exposure.
- Having a quarantine stall or paddock and standardized quarantine protocols in place are essential components of infectious disease control.
Take Home Message
Disinfect everything a sick horse comes into contact with. Don’t forget to disinfect fence railings, feeders, water buckets and stall walls, as horses will generally rub their noses over all these things.
Remember, an ounce of prevention is worth a pound of cure, so develop a standardized quarantine program for any new horses coming into the barn, de-worm and vaccinate all horses on the premises, and call your veterinarian a the first sign of a sick horse.