Equine Infectious Disease Control 2

Following on from our previous article – Equine Infectious Disease Control by Aoife Hand, a fourth year student of Veterinary Medicine in UCD, in this piece, Aoife explores more about the best protocols for vaccination, deworming and certain infectious diseases in horses.

Vaccination/Deworming

Liaise with your vet on what the best vaccination protocol is for your particular needs. Written records allow you to quickly determine vaccination history, making it easy to determine when a horse needs a booster. They also allow personnel other than the owner/manager to have accurate information regarding the horses’ vaccination, deworming and medical history.

A new needle and syringe should always be used for each individual horse, as it is very easy to transmit blood-borne diseases between horses if the same needles or syringes are used.

Although deworming at regular intervals was previously recommended, resistance to dewormers is becoming a problem, and has lead to a need to work closely with your vet to determine an optimal parasite control program based on individual faecal egg counts. If the horses are not harbouring any intestinal parasites then there is no need to deworm frequently.

Sick Horses

Early recognition of health problems, whether contagious or not, allows your horse to be treated sooner.  Healthy horses are more resistant to infectious diseases. Early detection also allows you to better manage the contagious aspect of a disease situation. It is best to promptly contact your vet in order to develop a plan for disease control.

When a horse on your premises becomes sick, all staff should be notified immediately and a vet should be called. A treatment plan should be developed in conjunction with your vet.

Control disease spread:

• Only contact the isolated sick horse after you tend to all the healthy horses.
• Leave the feeding and other care of the sick horse until last so as to not spread disease, or better yet have a person dedicated solely to the care of the sick horse.
• After working with the sick horse, make sure you properly clean or disinfect your hands, clothes and footwear, and keep a designated set of food and water containers that are only used with the sick horse.
• Never share any equipment between sick and healthy horses.

Isolation of sick horses away from direct contact with, and out of the same airspace as other horses is one of the most beneficial ways of minimising contagious disease spread. It is important along with the separation, that protocols for movement of people be used as well, as solely physical isolation of the horse doesn’t eliminate the risk of infectious disease spread.

In a disease outbreak situation, communication of an action plan is key. Written protocols should be developed so that all personnel know exactly how to handle the situation. These protocols should be developed in conjunction with your vet.

If an outbreak of contagious disease has occurred in horses on your premises, working with your vet to determine how best to prevent future occurrences is recommended. A lot can be learned from previous outbreaks enabling you to prevent any future reoccurrences.

Written Protocols

Written protocols ensure that all personnel who have contact with horses is aware of the required procedures for infectious disease prevention and control on your premises.

Written protocols are most important on larger facilities, where there are multiple people performing handling and caring for the horses on a daily basis.

These should be drawn up in conjunction with your vet.

Strangles (Strep. Equi)

Strangles is characterised by sudden onset of fever followed by thick yellow nasal discharge and swelling in the lymph nodes under the jaw. The severity of the disease varies a lot depending on the immunity of the animal. The disease is highly contagious. Horses become contagious 2-3 days after the first fever and remain contagious for 2-3 weeks. Early detection of fever can allow cases to be isolated before they become contagious.

The disease spreads through direct horse-to-horse contact, but also through the sharing of contaminated equipment, water sources, feed or feeding utensils, twitches, tack and clothing/equipment and hands of handlers. Apparently healthy horses recovering from recent disease might continue to spread disease after apparent recovery. This carrier state occurs in the guttural pouch of the horse and these horses remain contagious indefinitely. This form occurs in one in ten affected animals.

The best diagnosis of Strangles is through lab analysis of nasal swab samples.

Hygiene measures can greatly decrease the risk of spread of this disease. Personnel should use dedicated protective clothing and equipment when dealing with contagious animals. Manure and waste feed from contagious animals should be composted in an isolated location. Care should be taken to disinfect water troughs at least once daily during an outbreak. Trailers should be hosed clean and disinfected after each use.

To prevent the spread of this disease, wherever possible, animals being introduced to a new population of horses should be quarantined for 2 weeks, temperatures monitored twice a day and screened for recent exposure to S. equi.

Complications associated with S.equi infection occur in about 1 in 5 cases. Therefore, any animal presenting with signs of Strangles should not be ignored. The main complications include pneumonia, spread of the infection to internal organs (Bastard or Metastatic Strangles), persistence of the bacteria in the guttural pouch, and other serious conditions.

For Strangles outbreaks, the key to control is early detection and isolation of infected horses. Prevention is better and easier on your purse than cure, so monitor new arrivals carefully.

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