WELLINGTON COUNTY – Two county horses at two different facilities have tested positive for strangles.
That’s according to the Ontario Ministry of Agriculture, Food and Agribusiness (OMAFA), which issued alerts for both horses on April 10.
Strangles (streptococcus equi) is a respiratory disease that, while rarely fatal, can cause concerning symptoms such as high fever, lack of appetite, coughing, thick white nasal discharge and severely swollen lymph nodes in the head and neck.
It gets its name because the lymph nodes can swell so severely that they are said to “strangle” the horse, restricting breathing.
Strangles has been designated as an “immediately notifiable disease” under the Health Animal Act since February 2023, meaning all veterinary diagnostic laboratories in Ontario must report positive strangles test results to OMAFA.
It is a highly contagious and serious infection that is considered endemic in most horse populations, according to the government of Ontario.
One of the recent county cases is an 11-year-old gelding quarter horse at a boarding facility.
Another six horses have been exposed and are suspected to be positive for the disease.
“Two new horses arrived 10 days before clinical signs developed,” OMAFA officials state. “This horse developed copious nasal discharge.”
Strangles S. equi was confirmed on polymerase chain reaction (PCR) testing.
The other case involves a mare at a private facility, where 10 horses were exposed to the disease.
According to OMAFA officials, the mare that tested positive “was exposed briefly to a horse that temporarily stayed at the farm and that had come from a facility that had some respiratory illness.
“She developed signs of strangles and tested positive by PCR.”
OMAFA reported on the same day that a third horse, in Halton, also tested positive for strangles.
This seven-year-old quarter horse mare “was stalled next to a horse that arrived back from training at a facility that had a respiratory illness,” OMAFA officials state.
“She developed clinical signs of strangles and tested positive by PCR and culture.”
Owners at all three facilities have instituted voluntary animal movement restrictions and biosecurity protocols.
Strangles is transmitted through horse-to-horse contact and can be carried on people’s skin and clothing, as well as equipment.
In certain wet conditions, the disease can survive for up to six weeks without a host.
“It is imperative, therefore, when dealing with a horse diagnosed with strangles, or with horses of unknown health status … that shared water sources such as buckets and troughs not be used,” provincial officials state.
And during a strangles outbreak, all potentially contaminated equipment and surfaces should be cleaned with a foaming soap agent, rinsed and soaked in a liquid disinfectant.
“Staff working with infected horses should wear protective clothing (such as coveralls), boot/shoe coverings (or use a foot bath) and gloves,” Ontario officials state, and staff and equipment must not go back and forth between healthy and diseased animals.
Movement of horses on and off the farm should be stopped until the outbreak has cleared completely.
Identifying strangles as early as possible is key to reducing its spread. Temperatures often rise a day or two before the horse starts shedding the contagions, so isolating a horse as soon as its temperature rises can significantly slow the spread.
If a horse has a higher-than-usual temperature or any other signs of infection, it’s important to isolate the animal and call a veterinarian right away, experts advise.
Most horses stop transmitting the disease within six weeks of symptoms clearing.
However, according to provincial officials, about 10 per cent of infected horses go on to become long-term carriers if proper intervention and treatment is not administered.
Horses should therefore be tested after recovery, to ensure they have not become asymptomatic carriers, provincial officials recommend.
