HORSES · Condition guide
Strangles in horses: real veterinary case reports
Strangles is the highly contagious bacterial respiratory disease caused by Streptococcus equi subsp. equi. It's one of the most commonly diagnosed infectious diseases in horses worldwide and remains a serious biosecurity problem for yards, sales, and competition centres. Classic signs are sudden fever, off feed, nasal discharge progressing from clear to thick yellow, and the characteristic enlargement and abscessation of the submandibular and retropharyngeal lymph nodes — which can rupture and drain pus.
Most healthy adult horses recover fully with supportive care alone; routine antibiotics are not recommended for typical uncomplicated cases. Two important complications: "bastard strangles" (metastatic abscessation in other body locations — much more serious), and purpura haemorrhagica (immune-mediated vasculitis). Up to 10% of recovered horses become long-term carriers via persistent infection in the guttural pouches (chondroids), and these silent shedders are how outbreaks restart at yards.
What vets typically check for
- Clinical signs + nasopharyngeal swab or wash for PCR (most sensitive) and culture.
- Endoscopy of guttural pouches and nasopharynx — identifies chondroids or empyema.
- Serology (SeM antibodies) — screens for prior exposure and identifies carriers.
- Supportive care: hot-pack abscesses, ensure soft palatable feed, isolate from other horses.
- Strict biosecurity protocol — three negative guttural pouch washes before release from isolation.
Not a replacement for veterinary care. Use this to walk into the conversation prepared, not to self-diagnose.
Real cases from the veterinary literature
Peer-reviewed reports our semantic search surfaces for Strangles in horses (Streptococcus equi). Click into any case for the full abstract — or run a personalised search with your pet's exact details.
- Primary distension of the guttural pouch lateral compartment secondary to empyema.
The Canadian veterinary journal = La revue veterinaire canadienne · 1999 · United States
A 6-year-old quarter horse gelding, weighing 420 kilograms, had been having trouble swallowing and breathing for two months. The veterinarians found that he had a condition called guttural pouch empyema, which is an infection that caused a buildup of pus and large, hard lumps in a part of his throat. To treat this, the horse needed two surgeries to remove all the lumps and clea
- Streptococcus equi subspecies equi infection (strangles) in horses.
Compendium (Yardley, PA) · 2011 · United States
Strangles is a highly contagious upper respiratory infection caused by a bacteria called Streptococcus equi subspecies equi, which affects horses. Horses can catch this infection by breathing in or coming into contact with discharge from an infected horse. Symptoms include fever, low energy, and swollen lymph nodes under the jaw and in the throat, which can make it hard for the
- Identification of carriers of Streptococcus equi in a naturally infected herd.
Journal of the American Veterinary Medical Association · 1983 · United States
In a group of research horses, an outbreak of strangles, a contagious disease caused by the bacteria Streptococcus equi, led to the discovery of four mares that were carriers of the bacteria. Three of these mares showed typical signs of strangles, like swollen lymph nodes, while the fourth mare had a runny nose but only mild swelling of her lymph nodes. Tests confirmed the pres
- Strangles in equines: An overview.
Microbial pathogenesis · 2023 · India
Strangles, caused by Streptococcus equi subspecies equi, is a highly infectious respiratory disease affecting horses and other equines. The disease is economically important and compromises the productivity of equine farm significantly. The disease is characterized by pyrexia, mucopurulent nasal discharge, and abscess formation in the lymph nodes of the head and neck of horse
- Eustachian tube diverticulum chondroids and neck abscessation in a case of Streptococcus equi subsp. equi.
Journal of the South African Veterinary Association · 2007 · United States
A 12-year-old grey crossbred pony mare had a painful swelling in her neck, which was stiff and tender when touched. X-rays and ultrasound showed a large area of infection near her second cervical vertebra, leading to the discovery of an abscess filled with pus. After draining the abscess, tests confirmed it was caused by a bacteria called Streptococcus equi subsp. equi. The pon
Frequently asked questions
- Should I give antibiotics?
- Counterintuitively, routine antibiotics are not recommended for typical cases — they don't shorten the course, may interfere with normal abscess maturation, and can predispose to bastard strangles. Antibiotics are indicated for severe cases, complications, and certain prophylactic situations under veterinary direction.
- How long is a horse contagious?
- Shedding usually begins 1-2 days after fever onset and continues 2-3 weeks after clinical recovery. Up to 10% of recovered horses become silent carriers via the guttural pouches and can shed intermittently for months or years — three negative guttural pouch washes are the gold standard before declaring a horse non-infectious.
- Will the vaccine prevent it?
- Available vaccines (intramuscular and intranasal modified-live) reduce severity but do not reliably prevent infection. Strict biosecurity — quarantine of new arrivals, isolation of febrile horses, dedicated equipment, footbaths — is the most effective control on most yards.