Horses contract strangles by inhaling or ingesting Streptococcus equi bacteria from infected animals or surfaces. Isolate symptomatic horses immediately to prevent herd spread. Look for thick, yellow nasal discharge or swollen, hot lymph nodes under the jaw. Contact your veterinarian for a formal diagnosis, as early action limits risk and ensures proper care.
How horses show signs of strangles
You can identify the early stages of this bacterial infection by watching for changes in your horse’s behavior and physical health. The following table outlines the common indicators and the first steps you should take if you notice them.
| What you notice | What it usually means | What to do first |
|---|---|---|
| Thick yellow nasal discharge | Active bacterial shedding | Isolate horse immediately |
| Swollen jaw lymph nodes | Developing abscesses | Check temperature twice daily |
| Rectal temp over 101.5°F | Early fever onset | Call your veterinarian |
| Difficulty swallowing food | Severe throat pain | Provide soft, moist feed |
| Dull or depressed attitude | Systemic illness | Monitor for lethargy |
| Coughing or nasal noise | Upper airway irritation | Keep in dust-free area |
| Burst abscess under jaw | Drainage of infection | Clean with saline solution |
A common mistake is waiting for a cough to appear before taking action. Many horses remain silent carriers for forty-eight hours before respiratory symptoms manifest. If your horse stops eating grain but continues to graze, it’s likely experiencing throat pain rather than a loss of appetite.
Use this decision rule: if the rectal temperature exceeds 102.5°F, treat it as an emergency and contact your vet before the horse stops drinking. If the temperature remains between 101.5°F and 102°F, isolate the animal and consult your veterinarian regarding a quarantine period based on clinical signs.
Distinguish between a simple allergy and infection by checking the eyes. Clear, watery discharge suggests environmental allergens, while cloudy or thick ocular discharge indicates a systemic infection. Always wear disposable gloves when handling discharge to prevent cross-contamination. If you have multiple horses, treat the one with symptoms as if it’s already contagious to the entire herd. Move it to a separate facility or a secure isolation area with a dedicated air gap and no shared drainage or equipment.
Direct contact with infected horses
Horses most commonly contract this bacteria through direct nose-to-nose contact with another horse that’s currently shedding the pathogen. Even if the other horse seems healthy, they may be a “carrier” who harbors the bacteria in their guttural pouches and sheds it during periods of stress. If you introduce a new animal to your property, you should keep them in a separate paddock for at least three weeks to monitor for any signs of illness before they mix with your existing group.
The primary check for this is to observe the interaction between horses; if you see a new arrival coughing or showing nasal discharge, move them away instantly. The bacteria survives in the environment for several weeks, especially in moist or cool conditions. If your horse has been in contact with an infected animal, you must watch their temperature closely. If the temperature exceeds 101.5°F, notify your vet immediately, as this is often the first sign before the visible swelling appears.
One common mistake is sharing water troughs or grooming kits between horses during an outbreak. This costs owners thousands in extra veterinary bills because the bacteria travels easily on brushes, buckets, and even the clothes of the people handling the sick animals. If you suspect an infection, you must dedicate specific equipment to that horse alone. If you have two horses, treat the one that’s sick as if they’re in a different building. If the healthy horse shows no signs after a period determined by your veterinarian, you may consider the risk reduced.
To determine if your horse is at high risk, evaluate your barn’s traffic. If you board at a facility where horses frequently arrive from sales or shows, your risk level is significantly higher than at a private, closed herd. In high-traffic environments, assume every new horse is a carrier regardless of their appearance.
If a horse has a fever, isolate them immediately and contact your veterinarian for diagnostic testing. If they develop a thick, yellow nasal discharge, you must initiate a full quarantine protocol immediately. Don’t wait for a formal diagnosis to restrict movement. Every hour of delay increases the likelihood that the bacteria will contaminate your barn’s common water source or shared aisleways, turning a single case into a facility-wide crisis.
Contaminated environment and equipment
Horses pick up bacteria from shared environments, including fence posts, water troughs, or stall walls where an infected animal has rubbed its nose. These pathogens can survive on surfaces for extended periods, necessitating thorough disinfection. This duration makes rigorous sanitation of high-touch zones mandatory during an active outbreak.
You should assume environmental contamination if your horse occupies a space previously used by a sick horse until that space has been properly disinfected. A common mistake is wiping surfaces down without removing organic debris first. If you leave behind dried crust or mucus, the disinfectant can’t reach the bacteria underneath. This oversight often leads to a false sense of security and continued spread.
To sanitize effectively, scrub surfaces with a veterinary-grade disinfectant and allow them to air dry completely. Inspect the edges of water buckets and horizontal fence rails for dried discharge. If you spot residue, assume the equipment is contaminated.
Distinguishing between environmental spread and direct contact requires tracking your horse’s recent movement. If the horse has moved to a new stall or shared a communal area, the environment is the likely culprit. Conversely, if your horse has remained in a locked stall with no visitors or shared equipment, look for a silent carrier or a breach in biosecurity protocols.
When managing an outbreak, follow this decision rule: if you must handle a sick horse, treat your clothing and hands as vectors. Change your outer layers and wash your hands thoroughly before approaching healthy animals. If you have limited help, always tend to the healthy horses first. Save the sick or potentially exposed animals for the end of your shift to prevent cross-contamination. Treating the environment as a living threat is the only way to break the cycle of infection when direct contact is absent.
Inadequate biosecurity protocols
The third cause involves the transfer of bacteria by human handlers who move between sick and healthy animals without changing gear. This is the least obvious path because the horse may not have touched another horse or a shared object directly. You can tell this is the cause if you’re the only person working with the horses and you notice symptoms appearing in a healthy horse shortly after you have cared for a sick one.
A common mistake is assuming that a quick rinse of your hands is sufficient. Pathogens like Streptococcus equi can survive on fabric for hours, meaning your jacket or belt can act as a vector even if your skin is clean. If you notice a new infection in a stable that has been otherwise closed off, look at your own clothing. If you wore the same sweater while treating a feverish horse and then grooming a healthy one, you have likely breached your own biosecurity.
To confirm this, review your daily routine for any moments where you touched the sick horse and then immediately handled the healthy one. The fix is to establish a “clean” and “dirty” zone. Always care for the healthy horses first and the sick horses last. You must wear dedicated boots and overalls for the sick animal and leave them in the isolation area.
Use a simple decision rule: if you have entered the isolation stall, you are “dirty” until you have fully changed your outer layer. If you follow this strict separation, the risk of human-mediated spread drops to nearly zero. Never assume you can sanitize your way out of the problem while wearing the same gear.
When to seek professional help
You must stop all home management and call a licensed veterinarian if you notice these specific danger signs. A professional must handle these situations because they require specialized medical equipment or prescription medications that you can’t safely administer yourself.
- Respiratory distress: If the horse has trouble breathing or makes a loud roaring sound while resting, this indicates the airway is closing, which is a life-threatening emergency.
- High fever that persists: A temperature that stays above 103°F for more than 24 hours suggests the infection is spreading to the blood or lungs.
- Refusal to eat or drink: If the horse stops drinking water for more than 12 hours, they risk dehydration and kidney stress, which requires intravenous fluids.
- Abscesses in unusual places: If you see swellings in the chest or abdomen, this is a sign of “bastard strangles,” where the infection has moved into the internal organs, requiring aggressive, long-term antibiotic treatment.
If you attempt to treat these complex cases at home, you risk voiding your insurance coverage and may cause permanent damage to the horse’s throat or lungs. Only a veterinarian has the training to perform a guttural pouch endoscopy or collect the correct samples for a culture test to confirm if the horse is still shedding the bacteria. Always defer to your vet’s clinical judgment once these symptoms appear.
How long does strangles last?
It typically lasts between three and six weeks for the average horse, provided they receive proper care and isolation. You’ll know the horse is recovering when the fever breaks and the nasal discharge stops completely. However, some horses continue to shed the bacteria for several months after they seem healthy, which is why a veterinarian must perform a follow-up swab test before you end the isolation period.
Is it safe to ride a horse with strangles?
No, it’s never safe to ride a horse showing any symptoms of this illness. Physical exertion can worsen the swelling in the throat and put unnecessary strain on the horse’s heart and lungs while they’re fighting a systemic infection. You should keep the horse quiet and comfortable in a clean, dust-free environment until your veterinarian confirms the horse is no longer shedding the bacteria and is fully recovered.
How do I disinfect a stall after strangles?
You should start by removing all bedding, manure, and leftover feed, then scrub all surfaces including walls, buckets, and fence rails with a veterinary-grade disinfectant. It’s essential to let these surfaces dry completely before letting a healthy horse back into the area. You must also wash all grooming tools and blankets in hot water with soap. Check the label on your disinfectant to ensure it’s effective against Streptococcus equi and is safe for use around horses.
Can humans get strangles from horses?
No, humans can’t get this specific bacterial infection from horses. Streptococcus equi is highly host-specific to equines, meaning it doesn’t cause illness in people. However, you should still practice good hygiene by washing your hands and changing your clothes after handling a sick horse to ensure you don’t carry the bacteria on your skin or gear to other horses in your herd.
What happens if I ignore the symptoms?
If you ignore the symptoms, the infection can lead to severe complications like internal abscesses, pneumonia, or permanent damage to the horse’s respiratory system. The horse may also become a long-term carrier, unknowingly spreading the bacteria to every other horse they meet for months or even years. This negligence often forces you to quarantine your entire property for a much longer time, which increases your total costs and risks the health of all animals in your care.
How often should I check the temperature?
You should check your horse’s temperature twice daily, once in the morning and once in the evening, during any suspected outbreak. This consistent monitoring is the only way to catch a fever before the horse starts shedding bacteria or develops visible lumps. Use a digital thermometer designed for animals and keep a written log of the readings so you can show your veterinarian the exact trend if the temperature starts to climb.
Horses strangles, in short
Recovery takes time, but your horse will likely bounce back with plenty of rest and clean surroundings. Keep a close eye on their progress, and don’t hesitate to reach out to your vet if you’re worried about their breathing. You’re doing a great job helping them get back on their feet.