Horse owners, trainers and riders at PEI are once again taking extra precautions to prevent the spread of strangles. The last outbreak of the disease on the island was in 2020-2021.
The infectious disease of the upper respiratory tract is highly contagious and causes symptoms such as swollen lymph nodes, fever and lethargy.
It is caused by the Streptococcus equi equi Bacteria and can in some cases cause swelling so extreme that the lymph nodes cut off the horse’s airway, leading to the common name “choke”.
“It’s really a sore throat in horses,” said Dr. Ben Stoughton, a specialist in internal medicine for large animals and an assistant professor at Atlantic Veterinary College.
“Like humans, they can get strep throat.”
Stoughton said the bacteria spread “like wildfire” in barns, particularly through nose-to-nose contact.
“If a horse shares buckets of water or grooming supplies or is in the same stall or environment and it’s exposed to high levels of bacteria, it’s quite contagious,” he said.
The vet recommends quickly isolating and testing for the disease any horses showing symptoms.
“Preferably in a separate area or barn, separate tools, separate water, separate feed so there’s no cross-contamination with people or things in the area,” he said.
“Then they start monitoring the other horses in the stable – they check their temperatures and see if they have fevers.”
6 horses with symptoms
Six horses were diagnosed with symptoms suggestive of strangulation in late January and early February at Red Shores Racecourse in Charlottetown.
Red Shores general manager David MacKenzie said those horses were quickly taken off the premises in accordance with the circuit’s guidelines.
“Fortunately, the trainers were very accommodating and removed the horses from the property here,” he said.
While Red Shores would not technically need to report any illnesses until the horses return to the track, MacKenzie said there are no confirmed cases of choking at this time.
“We’re watching very closely,” he said.
dr Stoughton also said he hasn’t treated any cases of strangles at AVC recently, but added that it’s not a surprise as most cases are treated on-site by a local vet and only taken to AVC if there are complications.
He said that most horses, like humans, can fight the disease on their own after two or three weeks, and medication can be given if the horse has a high fever.
Increased cleaning
Meanwhile, Red Shores has also increased cleaning and biosecurity measures in its stables, particularly those where the symptomatic horses had been staying.
“Biosecurity includes things like increased temperature controls in horses. We know certain temperatures can be a symptom,” MacKenzie explained.
“Foot baths so people going in and out can clean their boots and don’t have to carry them from stall to stall. We sprayed disinfectant and in this case we took extra precautions and sprayed all the stalls these horses were in.”
This isn’t the first time Red Shores has improved cleaning efforts. In November 2020 there was a confirmed case of a stranglehold on a horse on the property. As of March 2021, a second horse has been infected and 200 horses have been tested for the disease.
“Thrush is an endemic disease, so it’s in the air — it’s everywhere,” MacKenzie said. “And we know it’s a reality and we looked at it a couple of years ago and we learned a great deal from it.”
MacKenzie said there are no plans to reduce biosecurity measures anytime soon, even though it’s the off-season. Staff are aware that Druse is “probably everywhere,” so it’s important to be aware at this point.
“The racing has just ended but the horses are still training hard and we just want to keep them healthy,” he said. “That’s our number one priority at Red Shores.”
dr Stoughton said the outbreak a few years ago could actually be helping horses today.
“Many of them have probably developed a robust immune response to this and then become immune,” he said.
“Three quarters of these horses will still be immune today.”
Still, Stoughton said it’s a good idea for all horse owners on the island to keep an eye out for symptoms.
“Any place where you find equidae, you will find geodes. It’s distributed all over the world, and it occurs on various sporadic occasions where we find outbreaks of it in the population,” he said.
“It has happened here before and it will probably happen here again.”
