A Comprehensive Guide to Swine Dysentery: Causes, Symptoms, and Treatment

A Comprehensive Guide to Swine Dysentery: Causes, Symptoms, and Treatment Swine dysentery is a significant health issue that affects pigs and can lead to severe economic losses for pig farmers. In this comprehensive guide, we’ll delve into the causes, symptoms, and treatment options for swine dysentery to help you better understand and manage this condition.

1. Overview of Swine Dysentery

Swine dysentery, also known as bloody scours or Brachyspira hyodysenteriae infection, is a highly contagious bacterial disease that primarily affects pigs. The condition is characterized by severe diarrhea, which can lead to dehydration, weight loss, and even death in severe cases. It is particularly dangerous for young pigs and can cause significant economic losses for pig farmers due to reduced growth rates and increased mortality.

2. Causes of Swine Dysentery

Brachyspira hyodysenteriae is the primary causative agent of swine dysentery. This bacterium is anaerobic, meaning it thrives in environments with low oxygen levels. It invades the pig’s large intestine and causes inflammation, leading to the production of mucus and blood in the feces.

Factors that contribute to the development and spread of swine dysentery include:

  • Poor hygiene and sanitation: Inadequate cleaning and disinfection practices can allow the bacterium to persist and spread among pigs.
  • High stocking densities: Overcrowding can promote the transmission of the disease.
  • Stress: Stressful conditions, such as extreme temperatures or transportation, can weaken the pig’s immune system, making them more susceptible to infection.
  • Introduction of infected pigs: Bringing new pigs onto a farm can introduce the bacterium if the incoming animals are carriers.

3. Symptoms and Diagnosis


Swine dysentery presents with the following clinical signs:

  • Diarrhea: The most common and noticeable symptom is watery, foul-smelling diarrhea that often contains blood and mucus.
  • Weight loss: Affected pigs may lose weight due to reduced feed intake and nutrient absorption.
  • Dehydration: Persistent diarrhea can lead to dehydration and electrolyte imbalances.
  • Lethargy: Pigs may become weak and lethargic as the disease progresses.
  • Increased mortality: In severe cases, swine dysentery can result in high mortality rates, particularly in young pigs.


Swine dysentery can be diagnosed through several methods:

  • Clinical signs: The presence of bloody diarrhea in pigs may raise suspicion of swine dysentery.
  • Laboratory tests: A definitive diagnosis can be made by isolating and identifying the Brachyspira hyodysenteriae bacterium from fecal samples.
  • Necropsy: In some cases, a post-mortem examination of the pig’s large intestine may reveal characteristic lesions indicative of swine dysentery.

4. Treatment Options

Once swine dysentery is diagnosed, prompt treatment is crucial to minimize losses and prevent the spread of the disease. The following treatment options are available:

  • Antibiotics: Administering appropriate antibiotics, such as tiamulin or lincomycin, can help control the infection. However, it’s essential to consult with a veterinarian for proper antibiotic selection and dosage, as some strains of Brachyspira hyodysenteriae have developed resistance to certain antibiotics.
  • Supportive care: Providing affected pigs with proper hydration and electrolyte balance is crucial to combat dehydration caused by diarrhea. Intravenous fluids may be necessary in severe cases.
  • Dietary management: Providing a highly digestible diet with adequate fiber can help reduce the severity of diarrhea and support the pig’s recovery.
  • Isolation: Infected pigs should be isolated from the rest of the herd to minimize disease spread.

5. Prevention and Control

Preventing swine dysentery is more cost-effective than treating it. Implementing the following preventive measures can help reduce the risk of infection:

  • Biosecurity: Establish and maintain strict biosecurity protocols, such as limiting access to pig facilities, using dedicated clothing and footwear, and quarantining new pigs before introducing them to the herd.
  • Hygiene and sanitation: Regular cleaning and disinfection of pig facilities can help eliminate the bacterium from the environment.
  • Proper pig management: Avoid overcrowding and minimize stress by providing adequate space, ventilation, and temperature control.
  • Vaccination: Although no commercial vaccine is currently available, some experimental vaccines have shown promising results in preventing swine dysentery. Consult with a veterinarian for the latest information on vaccine development.
  • Regular monitoring: Routinely monitoring your pigs for signs of swine dysentery can help detect the disease early and facilitate prompt treatment.

Swine dysentery is a significant health concern for pig farmers, causing severe economic losses due to reduced growth rates and increased mortality. Understanding the causes, symptoms, and treatment options for swine dysentery is crucial for effective disease management. By implementing stringent preventive measures and promptly treating infected animals, you can minimize the impact of this disease on your pig herd’s health and productivity.