Just as strep throat can run rampant in elementary schools, strangles, the "strep throat" of horses, caused by a different Streptococcus bacterium, is highly contagious. Veterinarians have an important role to play not only in treating the disease, but also in ensuring that infected horses are kept away from other animals until they have fully recovered from the illness.
In horses, lymph nodes in the head and neck region become swollen and develop abscesses, resulting in nasal discharge and drainage from the throat. Though rarely fatal, strangles cases can range from mild to severe, and complications that impair eating and breathing can arise in some instances. Altogether, it's a disease that horse owners want to keep far from their stables. In addition, recovery is not always clear cut, as many animals remain carriers of the bacteria even after they appear healthy.
To assist veterinarians, and owners, in understanding the most up-to-date clinical recommendations when it comes to treating strangles, Ashley Boyle, an associate professor of medicine at the University of Pennsylvania's School of Veterinary Medicine, took the lead in writing a new consensus statement, issued by the American College of Veterinary Internal Medicine, on treating, controlling, and preventing strangles in horses.
"From a practical standpoint, the consensus statement serves to advise all veterinarians on what we recommend as a way to treat and deal with the disease," Boyle says.
"An owner can start thinking about monitoring their horses' temperatures if they suspect an outbreak, and isolate horses when they first spike a fever," Boyle says. "That way they can catch it right at the beginning and spare any other horses from getting sick."
Although strangles is not typically deadly, it is a global problem and quite costly, as management protocols can be extensive.
"There are huge financial repercussions not only from dealing with the disease but from quarantining barns and screening potential carriers," Boyle says. "It's also a big problem in the population of rescued horses, as they often come from different locations and are housed in close quarters resulting in the spread of disease."
The publication lays out best practices for quarantine and examination to prevent the spread of disease, and biosecurity protocols to reduce transmission in facilities where infected horses have been housed.
It spells out treatment protocols, urging judicious use of antibiotics, and explains how to recognize, evaluate the risk for, and treat one of the more serious complications of strangles, an autoimmune reaction known as purpura hemorrhagica, which can be fatal.
It also explores the pros and cons of strangles vaccines,the use of different blood tests that can measure previous exposure to disease and determine when it is safe to give vaccines.
- A.G. Boyle, J.F. Timoney, J.R. Newton, M.T. Hines, A.S. Waller, B.R. Buchanan. Streptococcus equi Infections in Horses: Guidelines for Treatment, Control, and Prevention of Strangles-Revised Consensus Statement. Journal of Veterinary Internal Medicine, 2018; DOI: 10.1111/jvim.15043