Deciding on Strangles vaccination for your horse depends on its individual risk of exposure. Factors like travel, contact with new horses, and boarding situations are key. A veterinarian can help you assess these risks and choose the best vaccine type and schedule to protect your horse effectively and safely, avoiding unnecessary vaccinations.

Understanding how to protect your horse from diseases can feel overwhelming. Strangles, a common and highly contagious bacterial infection, is often a major concern for horse owners. While vaccines exist, the decision to vaccinate isn’t always straightforward. Many owners wonder if their horse truly needs the vaccine, given its specific lifestyle. You’re in the right place to get clear, practical advice. We’ll walk through how to make smart, risk-based vaccination choices for your horse, ensuring their health and your peace of mind.

Strangles in Horses: Making Smart, Risk-Based Vaccination Decisions

Strangles is a well-known and often feared disease in the equine world. Caused by the bacterium Streptococcus equi subspecies equi, it’s highly contagious and can lead to significant illness, affecting not just individual horses but entire barns and communities. While it’s rarely fatal in adult horses, the complications can be severe, and the recovery process lengthy and costly. This article will delve into what Strangles is, how it spreads, and most importantly, how to make informed, risk-based decisions about vaccination for your horse.

What is Strangles in Horses?

Strangles is an acute, highly contagious upper respiratory tract infection of horses, donkeys, and mules. The name “Strangles” comes from the characteristic swelling of lymph nodes in the throat area, which can become so large they obstruct the horse’s airway, leading to a “strangled” appearance or difficulty breathing. While the disease is primarily known for these abscesses, it involves a range of symptoms and can have various outcomes.

The bacterium, Streptococcus equi subspecies equi, is unique to equids and does not affect other species. It primarily targets the lymphoid tissue of the upper respiratory tract, leading to inflammation, pus formation, and abscessation. Understanding the nature of this bacterium and its interaction with the horse’s immune system is crucial for effective prevention and management.

How Strangles Spreads

Strangles is notorious for its rapid spread within equine populations. It primarily transmits through direct contact with infected horses or indirect contact with contaminated surfaces. This includes:

• Direct Contact: Nose-to-nose contact between horses, especially during active infection or if one horse is a carrier.
• Indirect Contact: Sharing water troughs, feed buckets, tack, grooming tools, stalls, or even human hands and clothing that have come into contact with nasal discharge or pus from an infected horse.
• Environmental Contamination: The bacterium can survive in the environment for weeks or even months under ideal conditions (cool, moist environments), making contaminated pastures, stalls, and trailers significant sources of infection.
• Asymptomatic Carriers: A major challenge in controlling Strangles is the existence of “carrier” horses. These horses may have recovered from the acute illness but harbor the bacteria in their guttural pouches (air sacs connected to the throat). They can shed the bacteria intermittently for months or even years without showing any outward signs of illness, acting as a hidden source of infection for other horses.

The highly contagious nature of Strangles means that a single infected horse introduced into a new herd can quickly lead to an outbreak, impacting many animals and disrupting activities like showing, training, and breeding.

Symptoms of Strangles in Horses

The clinical signs of Strangles can vary in severity, but typically follow a predictable pattern. Recognizing these symptoms early is vital for containing an outbreak and initiating treatment. Common symptoms include:

• Fever: Often the first sign, with temperatures reaching 103-106°F (39.4-41.1°C).
• Nasal Discharge: Initially clear and watery, progressing to thick, yellow, and purulent (pus-filled).
• Depression and Lethargy: Horses may appear dull, lose appetite, and show reduced energy.
• Difficulty Swallowing (Dysphagia): Due to pain and swelling in the throat.
• Cough: A soft, moist cough may be present.
• Swollen Lymph Nodes: This is the hallmark sign. The lymph nodes under the jaw (submandibular) and in the throat latch area (retropharyngeal) become enlarged, hot, and painful. These swellings often develop into abscesses that eventually rupture, releasing thick, creamy pus.
• Inappetence: Due to fever and painful swallowing.

Less common but more severe forms of Strangles can occur, known as “Bastard Strangles.” In these cases, the abscesses form in other parts of the body, such as the abdomen, chest, or brain. This form is much more serious and can be life-threatening, often requiring extensive medical intervention and having a poorer prognosis.

Diagnosing Strangles

Accurate and timely diagnosis is crucial for managing Strangles. Clinical signs alone can be suggestive, but definitive diagnosis requires laboratory testing:

• Bacterial Culture: Swabs from nasal discharge, nasopharyngeal washes, or pus from ruptured abscesses can be cultured to identify Streptococcus equi subspecies equi. This is considered the gold standard.
• PCR (Polymerase Chain Reaction) Testing: PCR tests detect the genetic material of the bacteria and are highly sensitive, especially for identifying carriers or horses in the early stages of infection before significant shedding. Samples are typically taken from nasopharyngeal swabs or guttural pouch washes.
• Guttural Pouch Endoscopy: For suspected carrier horses, endoscopy of the guttural pouches is often performed. Pus or chondroids (dried pus concretions) can be found in the guttural pouches, and samples are taken for culture and PCR to confirm carrier status.
• Blood Tests: While not diagnostic for active infection, a blood test for antibodies to Streptococcus equi subspecies equi (Strangles M protein ELISA) can indicate previous exposure or infection. It’s useful for screening horses that may be carriers or for determining herd exposure levels.

A combination of these diagnostic methods is often used, especially in outbreak situations or when screening new horses.

Treatment for Strangles

Treatment for Strangles primarily focuses on supportive care, allowing the disease to run its course. Antibiotic use is a debated topic and generally not recommended for uncomplicated cases once abscesses have formed, as it can prolong the disease, interfere with the development of natural immunity, and potentially increase the risk of carrier status or Bastard Strangles. However, antibiotics may be indicated in specific situations:

• Early Stages: If caught very early, before abscess formation, antibiotics (like penicillin) might prevent the development of clinical signs.
• Severe Respiratory Distress: To alleviate life-threatening airway obstruction.
• Bastard Strangles: When abscesses form internally, antibiotics are often necessary.
• Complications: For secondary bacterial infections or severe systemic illness.

Supportive care includes:

• Isolation: Strict isolation of infected horses is paramount to prevent spread.
• Warm Compresses: Applying warm compresses to swollen lymph nodes can encourage abscess maturation and rupture.
• Drainage: Once mature, abscesses should be lanced and drained by a veterinarian, and the pus collected and disposed of safely.
• Pain Relief: Non-steroidal anti-inflammatory drugs (NSAIDs) can help reduce fever, pain, and swelling.
• Soft Feed: To ease swallowing difficulties.
• Clean, Dry Environment: Essential for recovery.

Recovery from Strangles usually confers a strong, but not always lifelong, immunity. However, as mentioned, some horses can become asymptomatic carriers.

Why Risk-Based Vaccination?

The decision to vaccinate for Strangles should not be a blanket choice for every horse. Instead, it should be a thoughtful, risk-based decision made in consultation with your veterinarian. This approach aligns with modern veterinary recommendations, such as those from the American Association of Equine Practitioners (AAEP), which advocate for tailoring vaccination protocols to the individual horse’s lifestyle, environment, and exposure risk.

Why is a risk-based approach so important for Strangles?

• Vaccine Efficacy and Type: Strangles vaccines are not 100% effective, and their efficacy can vary depending on the type of vaccine and the specific strain of bacteria. Some vaccines are better suited for certain risk profiles than others.
• Potential Side Effects: Like any medical intervention, vaccines carry a small risk of side effects. While generally mild, these can include local swelling, fever, or in rare cases, more severe reactions. The intranasal vaccine, while effective, carries a very small risk of causing abscesses if administered improperly or if the horse is a carrier.
• Cost-Benefit Analysis: Vaccinating horses with minimal exposure risk may not provide enough benefit to outweigh the costs and potential side effects. Conversely, not vaccinating a high-risk horse leaves them vulnerable to a debilitating disease.
• Existing Immunity: Horses that have recently recovered from Strangles typically have robust natural immunity for several years. Vaccinating these horses immediately after recovery is usually unnecessary and potentially counterproductive.
• Biosecurity as a Primary Defense: For many horses, especially those in closed herds with limited external contact, stringent biosecurity measures are often the most effective and primary defense against Strangles. Vaccination complements, but does not replace, good biosecurity.

A risk-based approach ensures that vaccination resources are used wisely, targeting the horses most likely to benefit, while minimizing unnecessary interventions for those at low risk. This approach also promotes responsible antibiotic use and helps maintain herd health on a broader scale.

Factors Influencing Strangles Vaccination Decisions

When considering Strangles vaccination, several factors come into play. A thorough assessment of these elements, ideally with your veterinarian, will guide your decision.

Horse’s Lifestyle and Exposure

• Travel: Horses that frequently travel to shows, competitions, trail rides, or clinics are at a significantly higher risk of exposure. They come into contact with horses from diverse backgrounds, potentially including carriers or those from areas with active outbreaks.
• Boarding Facility: Horses in large boarding facilities, especially those with high turnover of horses, frequent visitors, or active lesson programs, face a higher risk. Private, closed barns with stable populations generally have lower risk.
• New Horse Introductions: If new horses are regularly introduced to your property or barn without proper quarantine and screening, the risk of Strangles introduction increases.
• Breeding Operations: Broodmares and foals are particularly vulnerable. Foals can get Strangles from their mothers or other horses.

Geographic Location

• Regional Prevalence: Some geographic areas or regions may have a higher prevalence of Strangles outbreaks. Your veterinarian will have local knowledge of current disease activity.
• Endemic Areas: If you live in an area where Strangles is considered endemic (regularly present), the background risk for all horses is higher.

Herd Immunity and Management

• Open vs. Closed Herd: A “closed herd” where no new horses enter and no horses leave is at the lowest risk. An “open herd” with frequent movement of horses is at much higher risk.
• Biosecurity Practices: The level of biosecurity implemented at your facility significantly impacts risk. Strict quarantine for new arrivals, proper hygiene, and disinfection protocols reduce risk, even for high-traffic barns.
• Vaccination Status of Other Horses: While vaccination doesn’t prevent shedding in all cases, a highly vaccinated herd can reduce the overall disease burden and spread.

Individual Horse Health

• Age: Young horses (foals and weanlings) are generally more susceptible to Strangles and tend to experience more severe symptoms. Older horses or those with compromised immune systems may also be at higher risk.
• Immune Status: Horses that are immunocompromised due to other illnesses, stress, or certain medications may be more vulnerable.
• Previous Infection: Horses that have recovered from a confirmed Strangles infection usually develop natural immunity that can last for several years. Vaccinating these horses immediately after recovery is generally not recommended.
• Carrier Status: If a horse is a known Strangles carrier, vaccination is not appropriate and can potentially cause adverse reactions or exacerbate shedding.

Types of Strangles Vaccines

Currently, there are two main types of Strangles vaccines available, each with different mechanisms of action, administration routes, and considerations:

Intramuscular (IM) Vaccine

• Type: This is a killed (inactivated) whole-cell vaccine. It contains dead Streptococcus equi bacteria, which stimulate an immune response without causing the disease.
• Administration: Given by injection into the muscle.
• Immunity: Primarily stimulates systemic immunity (antibodies in the bloodstream).
• Pros: Generally well-tolerated with fewer local reactions than the intranasal vaccine. Cannot cause the disease.
• Cons: Provides less robust mucosal immunity (protection at the site of infection in the respiratory tract) compared to the intranasal vaccine. Requires multiple initial doses and regular boosters. Efficacy can be variable.
• Usage: Often considered for horses at lower to moderate risk, or as part of a broader vaccination program.

Intranasal (IN) Vaccine

• Type: This is a modified live (attenuated) vaccine. It contains a weakened, live strain of Streptococcus equi that can replicate in the horse’s upper respiratory tract but is unable to cause the full-blown disease.
• Administration: Administered as a spray into the horse’s nostril. This is crucial as it mimics the natural route of infection and stimulates local immunity.
• Immunity: Primarily stimulates mucosal immunity in the upper respiratory tract, which is critical for preventing the bacteria from establishing infection. It also provides some systemic immunity.
• Pros: Generally considered to provide superior protection due to the mucosal immune response. Often provides faster and longer-lasting immunity than the IM vaccine.
• Cons: Can cause mild, transient nasal discharge or swelling of lymph nodes in some horses. There is a very small risk of abscess formation if the vaccine is inadvertently injected or contaminates an injection site. It is critical to avoid accidental contamination of injection sites or contact with other horses that are about to receive other injectable vaccines, as the live bacteria could potentially cause problems. It should not be given to horses receiving antibiotic treatment or to those with a compromised immune system.
• Usage: Often recommended for horses at higher risk of exposure, especially those that travel or are in open herds.

Here’s a comparison table summarizing the key differences:

Feature	Intramuscular (IM) Vaccine	Intranasal (IN) Vaccine
Type	Killed (inactivated) bacteria	Modified live (attenuated) bacteria
Administration Route	Injection into muscle	Spray into nostril
Primary Immunity	Systemic (bloodstream antibodies)	Mucosal (local in respiratory tract)
Onset of Immunity	Slower (weeks)	Faster (days to weeks)
Duration of Immunity	Generally shorter (6-12 months)	Generally longer (12 months or more)
Potential Side Effects	Local swelling, muscle soreness, mild fever	Mild nasal discharge, lymph node swelling, rare abscesses if improperly administered
Risk of Causing Disease	None	Extremely low (attenuated live bacteria)
Recommendations	Lower to moderate risk horses, general protection	Higher risk horses, provides stronger local immunity

Developing a Risk-Based Strangles Vaccination Plan

Creating an effective Strangles vaccination plan requires a systematic approach. This isn’t a one-size-fits-all solution but a tailored strategy for your horse.

Step 1: Assess Your Horse’s Risk Profile

Review the factors discussed above: travel, boarding situation, contact with new horses, geographic location, and your horse’s age and health status. Be honest and thorough. For example, a retired horse living alone in a private pasture has a vastly different risk profile than a show jumper that travels weekly to events.

Step 2: Consult Your Veterinarian

This is the most crucial step. Your veterinarian has the expertise, local knowledge of disease prevalence, and understanding of your horse’s individual health history. They can help you accurately assess risk, discuss the pros and cons of each vaccine type for your specific situation, and advise on the most appropriate vaccination schedule. They can also perform necessary diagnostic tests (e.g., guttural pouch washes for carrier status) if there’s a history of exposure or illness.

Step 3: Understand Vaccine Types and Schedules

Based on the risk assessment, your veterinarian will recommend either the IM or IN vaccine, or potentially no vaccine at all. They will also outline the initial series of doses (e.g., two or three doses for primary vaccination) and subsequent booster schedule (typically annually, but can vary based on risk and vaccine type).

Step 4: Implement Biosecurity Measures

Vaccination is a tool, not a complete shield. Strong biosecurity practices are your primary defense against Strangles, even for vaccinated horses. This includes:

• Quarantine: Isolate all new horses for at least 3-4 weeks. Monitor them for signs of illness and consider testing for Strangles carriers.
• Hygiene: Regularly clean and disinfect stalls, water buckets, feed tubs, and equipment.
• Dedicated Equipment: Avoid sharing tack, grooming tools, and feed/water buckets between horses, especially if there’s any suspicion of illness.
• Handwashing: Wash hands thoroughly after handling different horses, especially those showing signs of illness.
• Traffic Control: Limit unnecessary visitors to the barn and ensure they follow hygiene protocols.

Step 5: Monitor and Adjust

Your horse’s risk profile can change over time. If you plan to start traveling more, move to a new boarding facility, or introduce new horses, revisit your vaccination plan with your veterinarian. Stay informed about Strangles outbreaks in your area. Regular communication with your vet ensures your plan remains optimal for your horse’s ongoing health.

Biosecurity Measures: Your First Line of Defense Against Strangles

While vaccination plays a role in protecting horses from Strangles, robust biosecurity measures are arguably the most critical component of disease prevention. No vaccine offers 100% protection, and many horses, particularly those in closed herds, may not even require vaccination if biosecurity is meticulously maintained. Think of biosecurity as your first and strongest line of defense.

Key biosecurity practices for preventing Strangles include:

• Strict Quarantine for New Arrivals: This is paramount. Any new horse introduced to a property should be isolated for a minimum of 3-4 weeks, ideally in a separate barn or distant paddock. During this period, monitor them daily for signs of illness (fever, nasal discharge, swollen lymph nodes). Consider diagnostic testing (nasal swabs, guttural pouch washes, or serology) for Strangles during quarantine, especially if the horse’s history is unknown or if they come from a high-risk environment.
• Separate Equipment: Use dedicated feed buckets, water buckets, grooming tools, tack, and cleaning supplies for each horse, or at least for quarantined horses. If sharing is unavoidable, thoroughly clean and disinfect items between uses.
• Isolation of Sick Horses: Immediately isolate any horse showing signs of Strangles or other contagious diseases. This means separate stalls, paddocks, and dedicated equipment. Handle sick horses last, after all healthy horses have been attended to, and wear protective clothing (gloves, disposable overalls) that can be removed and disinfected.
• Hand Hygiene: Wash hands thoroughly with soap and water, or use an alcohol-based hand sanitizer, between handling different horses, especially after touching a sick or quarantined animal.
• Footwear and Clothing Hygiene: Change clothes and disinfect footwear (or use disposable boot covers) after being in contact with sick or quarantined horses. Avoid wearing barn clothes to other equine facilities.
• Environmental Cleaning and Disinfection: Regularly clean and disinfect stalls, trailers, and common areas. Streptococcus equi can survive in the environment, so thorough cleaning with appropriate disinfectants (e.g., diluted bleach, quaternary ammonium compounds) is essential.
• Water Source Management: Avoid communal water troughs if possible, especially in high-traffic areas. Individual buckets are preferred and should be cleaned daily.
• Pasture Management: Rotate pastures and allow them to rest. Contaminated pastures can harbor the bacteria.
• Control of Human and Animal Traffic: Limit non-essential visitors to the barn. If visitors must enter, ensure they adhere to hygiene protocols. Keep barn dogs, cats, or other animals away from areas where horses are housed, as they can inadvertently carry the bacteria on their paws or fur.
• Testing and Removal of Carriers: If an outbreak occurs, work with your veterinarian to identify and treat carrier horses. These asymptomatic carriers are often the source of recurrent outbreaks and must be managed effectively to break the disease cycle.

Implementing these biosecurity measures diligently can significantly reduce the risk of Strangles entering your herd and limit its spread if an infection does occur. They are the cornerstone of any effective disease prevention strategy.

The Role of Testing in Vaccination Decisions

Testing plays a critical role in making informed Strangles vaccination decisions, especially in situations where a horse’s history is unknown, or there’s a concern about previous exposure or carrier status. Blindly vaccinating can be ineffective or, in some cases, even detrimental.

• Identifying Carriers: Perhaps the most crucial use of testing is to identify asymptomatic carriers. Horses that have recovered from Strangles can harbor the bacteria in their guttural pouches for months or years, shedding it intermittently and acting as a silent source of infection. Vaccinating a carrier horse with the intranasal vaccine is contraindicated as it can lead to adverse reactions or even exacerbation of shedding. Guttural pouch endoscopy with subsequent PCR and culture of guttural pouch washes is the gold standard for identifying carriers.
• Assessing Previous Exposure/Immunity: A blood test (Strangles M protein ELISA) can detect antibodies to Streptococcus equi. A positive result indicates the horse has been exposed to the bacteria at some point. This can be useful for:
  • Screening new horses to assess their prior exposure status.
  • Determining if a horse that experienced a mild, undiagnosed illness might have had Strangles and therefore possess natural immunity.
  • Guiding vaccination decisions: If a horse has high antibody titers from recent natural infection, vaccination may be unnecessary or delayed.

  It’s important to note that a positive ELISA only indicates exposure, not necessarily active infection or carrier status. Further testing (PCR/culture) is needed for definitive diagnosis of active shedding.

• Guiding Outbreak Management: During an outbreak, PCR testing of nasal swabs or nasopharyngeal washes helps confirm active cases and monitor the resolution of infection. This information guides isolation protocols and helps determine when it’s safe to move horses or introduce new ones.
• Pre-Purchase Exams: For high-value horses or those entering high-risk environments, pre-purchase Strangles testing (including guttural pouch washes for carriers) is increasingly recommended to prevent introducing disease into a new herd.

By incorporating testing into your management strategy, you gain valuable information that allows for more precise, safe, and effective vaccination and biosecurity protocols.

To help you assess your horse’s individual risk, here is a helpful checklist:

Risk Factor	Low Risk (Vaccination Less Critical)	Moderate Risk (Consider Vaccination)	High Risk (Vaccination Strongly Recommended)
Boarding Environment	Private, closed herd, stable population, no new horses.	Small boarding facility, occasional new horses, limited turnover.	Large boarding facility, high turnover, active lesson program, frequent new horses.
Travel/Competition	Horse never leaves the property.	Occasional local trail rides, small local shows.	Frequent travel to shows, clinics, trail heads, or events with horses from other barns/regions.
Introduction of New Horses	No new horses introduced.	New horses introduced with strict 3-4 week quarantine and monitoring.	New horses introduced without proper quarantine or screening.
Geographic Prevalence	Area with historically low Strangles incidence.	Area with occasional Strangles cases.	Area with frequent or ongoing Strangles outbreaks.
Horse’s Age/Health	Healthy adult horse (3-15 years), good immune system.	Young horse (weanling/yearling), older horse, or horse with mild underlying health issues.	Foal, immunocompromised horse, horse recovering from other illness.
Previous Strangles Infection	Confirmed infection within the last 2-5 years (likely strong natural immunity).	Confirmed infection >5 years ago, or suspected mild infection.	No history of Strangles infection.
Biosecurity Practices	Excellent (strict quarantine, no shared equipment, high hygiene standards).	Good (some quarantine, general hygiene).	Poor (no quarantine, shared equipment, lax hygiene).

Common Misconceptions About Strangles Vaccination

Despite the advancements in veterinary medicine, several myths and misunderstandings persist regarding Strangles vaccination. Addressing these is crucial for making informed decisions.

• “The vaccine causes Strangles.” This is largely untrue. The intramuscular (IM) vaccine contains killed bacteria and cannot cause the disease. The intranasal (IN) vaccine contains a modified live (attenuated) strain of the bacteria, which means it’s weakened and designed not to cause full-blown disease. While it can cause mild, transient nasal discharge or swelling of lymph nodes, and in very rare cases, abscesses if administered improperly (e.g., accidentally injected), it does not cause clinical Strangles in the way a natural infection would. The benefits of the IN vaccine’s superior mucosal immunity generally outweigh this minimal risk for high-risk horses.
• “Vaccination guarantees 100% protection.” No vaccine offers absolute protection, and Strangles vaccines are no exception. They significantly reduce the risk of infection and, more importantly, often lessen the severity and duration of clinical signs if a vaccinated horse does become infected. They can also help reduce shedding, thereby limiting environmental contamination and spread. However, a vaccinated horse can still contract Strangles, especially if exposed to a very high dose of bacteria or a particularly virulent strain, or if its immune response is suboptimal.
• “All horses need to be vaccinated for Strangles.” This is a key misconception that risk-based vaccination aims to correct. Horses in closed herds with minimal external contact and excellent biosecurity may not require vaccination. The decision should always be tailored to the individual horse’s risk profile, as discussed throughout this article.
• “Once vaccinated, a horse is immune for life.” Immunity from Strangles vaccination is not lifelong. Both IM and IN vaccines require initial series and regular boosters (typically annually) to maintain adequate protection. Natural immunity from prior infection is often more robust and longer-lasting, but even that can wane over time.
• “Vaccination is a substitute for good biosecurity.” Absolutely not. Vaccination is a valuable tool in Strangles prevention, but it complements, rather than replaces, stringent biosecurity measures. Quarantine of new horses, hygiene, and isolation of sick animals are paramount, regardless of vaccination status.
• “If my horse has been exposed, I should vaccinate immediately.” This is generally not recommended. If a horse has been recently exposed or is already showing signs of Strangles, vaccinating (especially with the live IN vaccine) can potentially exacerbate the disease or cause adverse reactions. In such cases, testing for active infection or carrier status and implementing strict biosecurity is the priority.

When NOT to Vaccinate for Strangles

Just as important as knowing when to vaccinate is understanding when vaccination is contraindicated or ill-advised. Administering the Strangles vaccine in certain situations can be ineffective, cause adverse reactions, or even worsen a horse’s condition.

• During an Active Infection: If a horse is already showing clinical signs of Strangles (fever, nasal discharge, swollen lymph nodes), vaccination is contraindicated. The horse’s immune system is already battling the infection, and adding a vaccine can overwhelm it or lead to more severe reactions.
• Known or Suspected Carrier Status: Horses that are known or suspected to be asymptomatic carriers of Streptococcus equi (i.e., they harbor the bacteria in their guttural pouches) should not be vaccinated with the intranasal vaccine. This can trigger a local reaction, potentially leading to guttural pouch empyema or even Bastard Strangles. Such horses should be treated to clear the carrier state before any vaccination is considered.
• Horses with Recent Natural Infection: Horses that have recently recovered from a confirmed Strangles infection typically develop strong natural immunity that can last for several years. Vaccinating these horses within a few months to a year of recovery is usually unnecessary and may increase the risk of adverse reactions due to existing high antibody levels. Your veterinarian can advise on the appropriate interval.
• Immunocompromised Horses: Horses with compromised immune systems due to illness (e.g., Cushing’s disease, equine metabolic syndrome), stress, or certain medications (e.g., high doses of corticosteroids) may not mount an effective immune response to the vaccine or could be at higher risk for adverse reactions, especially with modified live vaccines.
• Pregnant Mares: While some Strangles vaccines are approved for use in pregnant mares, it’s crucial to check the product label and consult your veterinarian. Generally, it’s best to avoid vaccinating pregnant mares unless they are at very high risk, and then only with products specifically labeled as safe for pregnancy.
• Horses Receiving Antibiotics: The live attenuated intranasal vaccine should not be given to horses currently on antibiotic therapy, as the antibiotics could kill the vaccine bacteria, rendering the vaccine ineffective.
• Close Proximity to Other Injections (for IN vaccine): When administering the intranasal vaccine, extreme care must be taken to avoid contaminating other injection sites. The live attenuated bacteria, if inadvertently injected, can cause abscesses. Therefore, the IN vaccine should ideally be given on a separate day from other injectable vaccines, or at least with meticulous attention to hygiene and site separation.

Always discuss your horse’s full health history and current status with your veterinarian before any vaccination. They can provide the best guidance based on the specific vaccine product and your horse’s individual needs.

For more general information on vaccination schedules, you might find this article helpful: Dog Vaccines & Boosters: How Often Does Your Dog Need Shots?

Conclusion

Protecting your horse from Strangles is a critical aspect of responsible horse ownership. However, the decision to vaccinate should be a nuanced one, moving away from a universal approach to a personalized, risk-based strategy. By carefully evaluating your horse’s lifestyle, exposure risks, and individual health, in close consultation with your veterinarian, you can determine the most appropriate course of action.

Remember that vaccination is just one tool in your arsenal against Strangles. Robust biosecurity measures – including strict quarantine for new horses, meticulous hygiene, and prompt isolation of sick animals – remain the cornerstone of effective disease prevention. Understanding the different vaccine types, their benefits, and their limitations, alongside the crucial role of diagnostic testing, empowers you to make truly informed decisions for your horse’s well-being.

Ultimately, a proactive, well-researched approach, guided by expert veterinary advice, is your best defense against Strangles, ensuring your horse stays healthy, happy, and safe for years to come.

Frequently Asked Questions (FAQ) About Strangles Vaccination

1. What exactly is Strangles in horses?