Understanding Equine Strangles
Understanding Equine Strangles
Strangles is one of the most commonly diagnosed contagious diseases of the horse. Caused by the bacteria Streptococcus equi subspecies equi (referred to as S. equi), this highly contagious disease has existed in the equine population for centuries and particularly affects young horses. The good news is that most horses with infection recover without complication.
Because the bacteria typically infect the upper airway and lymph nodes of a horse’s head and neck, nasal discharge from an infected horse is the largest source of contamination. Sources of infection can be nose-to-nose contact with an infected horse, sharing contaminated water buckets, feed tubs, twitches and tack as well as the clothing and equipment of handlers who work with infected horses. The bacteria can survive in water sources for over a month, but the primary source of recurrent infections is most likely asymptomatic carrier horses that can shed the bacteria to other horses for months or years. Outbreaks can recur as long as the bacteria are present on a farm.
Follow these suggestions from the American Association of Equine Practitioners to reduce your horse and your farm’s risk of infection from S. equi:
• Require a current health certificate for new horse arrivals on the farm.
• Ask owners of new horses about a history of strangles and consider testing new horses to see if they are shedding the bacteria.
• If feasible, quarantine new arrivals for two to three weeks and monitor their temperature.
• All horses should have individual water buckets that are routinely disinfected.
• If shared water troughs are utilized, they should be routinely disinfected.
• When traveling to shows, minimize your horse’s exposure by bringing your own feed, buckets and equipment. Minimize use of shared stalls or pastures at show grounds.
• If horses are pastured together, group them according to their age and risk level (For example, all weanlings together; all broodmares together).
If you suspect your horse has developed strangles, call your veterinarian right away. There is some evidence that treatment with antibiotics (such as penicillin) at the first sign of fever and in horses with no lymph node enlargement may prevent infection. However, early antibiotic treatment will also prevent these cases from developing immunity to the infection, and subsequently makes them susceptible to reinfection sooner. Because strangles is a reportable disease in some states, the state veterinarian may need to be notified as well.
Many owners choose to vaccinate their horses against strangles. Vaccination can be effective but cannot guarantee disease prevention. With strangles, vaccination will likely reduce the severity of disease in the majority of horses that are infected. In general, if your horse travels routinely and is exposed to varied or new populations of horses regularly, vaccination should be considered. Broodmares on farms with a history of strangles infections should be vaccinated prior to foaling.