Strangles
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
Isolate immediately when suspectedUse separate carers and equipment where possible. Clinical recovery alone does not establish that shedding has stopped.
Emergency presentation is possibleSevere airway obstruction and systemic complications require intensive veterinary care.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Strangles is a contagious infection caused by Streptococcus equi subspecies equi. The bacterium spreads in nasal discharge and material from abscesses, either directly or on contaminated water, equipment, clothing and hands. After entering the upper respiratory tract it travels to regional lymph nodes, where inflammation and abscesses develop. The incubation period is commonly several days but varies.
Horses typically develop fever, depression, reduced appetite, thick nasal discharge and painful enlargement of lymph nodes beneath the jaw or behind the throat. Abscesses may obstruct swallowing or breathing, producing the “strangling” appearance that gave the disease its name. Young horses often show classic disease, while partially immune animals can have milder or atypical signs.
Complications include guttural-pouch infection with inspissated pus or chondroids, which can create a long-term carrier. Metastatic or “bastard” strangles forms abscesses in distant organs. Purpura haemorrhagica is an immune-mediated vasculitis causing limb or head swelling, skin leakage and systemic illness, sometimes after infection or inappropriate vaccination timing. Severe upper-airway obstruction can require emergency tracheostomy.
Most uncomplicated horses recover, but shedding can continue for weeks and a minority remain carriers for months. Recovery therefore cannot be judged only by closure of external abscesses. Strangles demands disease-specific isolation, testing and guttural-pouch management. It should not share a generic respiratory release rule with influenza or asthma, because persistent S. equi in the guttural pouches is central to preventing recurrence.
After lymph nodes mature, abscesses may rupture externally or into guttural pouches, leaving persistent chondroids that support silent shedding. Metastatic “bastard strangles” can seed internal organs, while purpura haemorrhagica is an immune-mediated vasculitis after infection or vaccination. Recovered appearance therefore does not establish that a horse is no longer a carrier.
Early guttural-pouch assessment is particularly important when a property has repeated cases despite apparently complete recovery.
Screening & Early Detection
Any horse with fever and submandibular or retropharyngeal swelling should be isolated promptly. During an outbreak, horses are divided into affected, exposed and clean groups, with separate carers and equipment where possible. Twice-daily temperatures help identify newly febrile horses before obvious discharge. Movements, contacts and clinical dates should be recorded.
Samples are chosen by disease stage. Culture of aspirated abscess material is highly specific in a clinical case. Nasopharyngeal wash is more sensitive than a simple swab, while PCR increases detection. Early infection and intermittent carrier shedding can produce false negatives. Endoscopy and guttural-pouch wash provide the best assessment for empyema, chondroids and carrier status.
Carrier screening normally begins after clinical signs have resolved, using veterinarian-directed timing. A single bilateral guttural-pouch wash with endoscopic examination is highly sensitive; serial nasopharyngeal washes may be an alternative. Blood antibody testing has selected uses for complications and vaccination decisions but does not prove active shedding. Release from quarantine requires clinical recovery and appropriate testing, not simply a dry nose.
Treatment & Management
Treatment depends on stage and severity. Horses with mature lymph-node abscesses often receive supportive care, soft palatable feed, anti-inflammatory pain relief and warm compresses that encourage maturation. Once an abscess is ready, veterinary drainage and repeated cleaning reduce pressure and contamination. Personnel handling pus must prevent environmental spread.
Antimicrobial use is selective. Very early treatment may stop abscess development in some horses but can limit development of protective immunity, while established uncomplicated abscesses may not benefit. Penicillin or another susceptibility-informed drug is indicated for severe systemic illness, respiratory compromise, metastatic infection or other defined complications. Airway obstruction may require intensive care or tracheostomy.
Guttural-pouch empyema is treated with lavage; chondroids may need endoscopic or surgical removal plus local therapy. These cases are retested to confirm clearance. Isolation, cleaning and group management continue throughout recovery. Vaccination strategy is reviewed only after assessing recent exposure and antibody risk, because vaccinating a horse with very high titres can contribute to purpura. Prognosis is good for uncomplicated disease but guarded with metastatic abscesses, purpura, pneumonia or severe airway compromise.
Draining abscesses are kept covered from flies and their contaminated material is disposed of safely.
Breeds or species affected
Akhal-Teke
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Anglo-Arabian
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Arabian
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Barb
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Caspian
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Kathiawari
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Marwari
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Shagya Arabian
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Thoroughbred
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American Quarter Horse
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American Paint Horse
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Appaloosa
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Australian Stock Horse
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Brumby
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Waler
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Morgan
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Standardbred
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American Saddlebred
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Tennessee Walking Horse
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Missouri Fox Trotter
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Rocky Mountain Horse
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Peruvian Paso
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Criollo
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Mustang
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Canadian Horse
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Andalusian
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Lusitano
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Lipizzaner
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Friesian
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Dutch Warmblood
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Hanoverian
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Holsteiner
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Oldenburg
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Westphalian
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Trakehner
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Selle Français
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Belgian Warmblood
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Danish Warmblood
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Swedish Warmblood
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Swiss Warmblood
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Australian Warmblood
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Irish Sport Horse
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Cleveland Bay
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Württemberger
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Zangersheide
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Knabstrupper
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Orlov Trotter
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Camargue
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Icelandic Horse
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Pony of the Americas
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Quarter Pony
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Miniature Horse
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Clydesdale
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Shire
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Percheron
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Belgian Draft
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Suffolk Punch
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American Cream Draft
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Ardennes
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Breton
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Boulonnais
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Comtois
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Dutch Draft
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North Swedish Horse
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Norwegian Fjord
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Haflinger
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Gypsy Cob
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Irish Draught
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Welsh Pony and Cob
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Connemara Pony
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New Forest Pony
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Dartmoor Pony
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Exmoor Pony
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Shetland Pony
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Highland Pony
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Fell Pony
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Dales Pony
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Australian Pony
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Finnhorse
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Black Forest Horse
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