Understanding Streptococcus Equi Infection
Strangles is a highly contagious disease caused by the bacterium *Streptococcus equi
- subspecies equi. It is considered the most common infectious respiratory disease in horses globally. Unlike Equine Influenza, which is viral, Strangles is bacterial and focuses on the lymphatic system of the head and neck.
The Pathophysiology of Lymphadenopathy
Once the bacteria enter the horse's system, they migrate to the regional lymph nodes. The resulting immune response creates localized abscesses that can become massive, physically restricting the horse's ability to breathe or swallow. This distinguishes it from other respiratory infections like Equine Viral Arteritis, which often present with more generalized vasculitis and systemic signs.
Clinical Manifestations and Diagnostic Indicators
Primary Symptoms of Respiratory Distress
Early symptoms often include pyrexia (fever), depression, and a loss of appetite. As the disease progresses, owners will notice a mucoid or mucopurulent nasal discharge. The most distinctive sign is the swelling of the submandibular lymph nodes, which feel firm and hot to the touch before eventually softening as they mature into abscesses.
Identifying 'Bastard Strangles' and Complications
While the condition is usually confined to the head, hematogenous spread can lead to abscesses in the abdominal, thoracic, or internal organs. This is a severe complication and often fatal. Veterinarians diagnose these cases through clinical suspicion, physical exams, and confirmatory testing.
Veterinary Diagnostic Protocols
Microbiological Culture and PCR Testing
Diagnosis is confirmed by collecting samples via nasal swabs or washing the guttural pouches. PCR testing is the gold standard for identifying the bacterial DNA, even in carrier horses that appear healthy. Practitioners often differentiate this from Infectious Bovine Keratoconjunctivitis (Pink Eye) or other conditions like Blackleg by checking for specific respiratory and lymphatic markers.
Management, Treatment, and Long-Term Care
Supportive Therapy
Treatment focuses on palliative care, such as warm compresses to encourage abscess drainage and non-steroidal anti-inflammatory drugs (NSAIDs) to manage pain and fever. In some cases, veterinarians may perform surgical drainage of the lymph nodes to provide immediate relief from physical obstruction.
Eliminating Carrier Status
For horses that persist in shedding the bacteria, the treatment involves flushing the guttural pouches with medicated solutions to eradicate the bacterial colonies. This is crucial for breaking the cycle of transmission within a stable.
Biosecurity and Preventive Strategies
Preventing the introduction of *S. equi
- is superior to managing an outbreak. Strict quarantine protocols for all new arrivals—typically for 21 to 30 days—are essential. Additionally, vaccination programs, while not providing 100% immunity, can significantly reduce the severity of clinical signs in exposed populations.
