Swine dysentery caused by the spirochete Brachyspira hyodysenteriae is one of the dangerous gastrointestinal diseases, causing bloody diarrhea, reduced weight gain, poor feed conversion and high treatment costs. This is a major concern for farmers, especially sows and piglets. With experience and reputable veterinary solutions,
Fivevet supports diagnosis, consults on treatment regimens and provides effective disease prevention measures, helping to minimize economic losses and protect healthy, high-yielding pig herds.
Swine dysentery Swine dysentery caused by a group of highly hemolytic spirochetes (β) called Brachyspira hyodysenteriae (formerly known as Serpulina or Treponema) is one of the important gastrointestinal infectious diseases of pigs, with the main symptoms being bloody and mucous diarrhea. The disease mainly occurs in gilts and adult pigs; severe cases often occur in sows and piglets.
1. Swine dysentery
a. Cause
Brachyspira hyodysenteriae (B. hyodysenteriae) is a species of bacteria in the Brachyspira family, with high diversity including many different strains and different gene structures. This is the main agent causing swine dysentery.
b. Resistance
B. hyodysenteriae bacteria can survive for quite a long time in the environment, especially in moist manure. Specifically, they can live up to 48 days in diluted feces at 0–10°C, 7 days at 25°C, but only less than 24 hours at 37°C. In addition, the bacteria survive for 10 days in soil at 10°C, 78 days in soil containing 10% pig manure and even up to 112 days in an environment containing only pig manure.
However, when infected pig manure is dried, the pathogen is quickly eliminated. Some disinfectants, such as phenol and sodium hypochlorite, are highly effective in killing this bacterium.
2. Epidemiology
a. Infected animals
Brachyspira hyodysenteriae can be naturally infected in domestic pigs, wild pigs and some poultry species such as ostriches, chickens, ducks and geese. On infected farms, the pathogen is also found in mice, rats, dogs and many wild birds, including seagulls. However, dysentery caused by B. hyodysenteriae only causes disease in pigs and is not transmitted to humans.
b. Transmission
- The disease is mainly transmitted through the digestive tract when pigs eat food or drink water containing feces containing pathogens.
- High risk when introducing infected pigs into the herd without careful quarantine. In addition, rats, wild birds, and even dogs in the farm can carry and spread the bacteria, causing the disease to spread rapidly in the herd.
c. Age of infection
The disease is common in gilts and adult pigs, but less common in weaned pigs.
The most likely time to develop the disease is a few weeks after separation from the mother, during the period when the pig's resistance is decreasing due to dietary changes.
Piglets born from gilts that have never been exposed to B. hyodysenteriae bacteria or piglets in newly infected herds can also get the disease.
3. Symptoms of swine dysentery
The incubation period varies widely, from 2 days to 3 months, but is most commonly 10–14 days after the pig is exposed to the pathogen. The disease spreads rapidly in the herd and symptoms in each individual may vary. Early stage: pig feces are slightly soft, yellow to gray; pigs have anorexia, mild fever (40–40.5°C).
Progression stage: after a few hours to a few days, mucus, flaky mucosa and blood patches begin to appear in the stool. Diarrhea becomes increasingly severe, with bright red blood, mucus and fibrinous mucosal secretions mixed in the stool. The stool is sticky around the anus and tail.
Impact on health: Most pigs can recover after a few weeks, but the rate of weight gain is significantly reduced. If diarrhea persists, pigs are susceptible to dehydration, weakness, and emaciation.
Morbidity rate: in an outbreak can be up to 90%, the mortality rate is usually 30% and can reach 50% if there is no timely treatment. In herds that have had chronic disease or have been treated, the symptoms are often not obvious.
Symptoms of swine dysentery4. Pathological lesions of swine dysentery
Acute form: Swelling of the large intestine and mesentery, swollen mesenteric lymph nodes. These lymph nodes are white; the central area is slightly raised due to the proliferation of mononuclear cells in the mucosa. The mucosa is often swollen due to the disappearance of characteristic folds, covered by mucus and fibrin mixed with blood. The intestinal contents are soft to watery and contain fluid.
As the disease progresses, the edema in the colon wall may decrease. Mucosal lesions become more severe with increased fibrin secretion and the formation of pseudomembranous colitis with fibrin and blood.
When the disease becomes chronic, the mucosal surface is covered by a thin layer of fluid, dense with inflammatory exudates containing fibrin - a manifestation of necrosis. Lesions can also be observed in pigs with healthy clinical signs, such as the appearance of discrete red patches on the mucosal surface, covered by a layer of mucus, but the contents of the colon remain normal.
Lesions - extent of damage:
- Lesions can vary between individuals: in some cases, the entire large intestine is affected, but in others, only a few segments of the intestine are damaged.
- As the disease progresses, the lesions often become more widespread.
- A few cases show signs of liver or epigastric obstruction, but this is not a typical lesion.
Lesions of swine dysentery5. Diagnosis of swine dysentery
a. Clinical diagnosis
Typical lesions when pigs die from swine dysentery:
- Dead pigs are often emaciated, thin due to dehydration, dry, upright hair, and the anal area is covered with feces.
- The most typical lesion is hemorrhagic enteritis - widespread mucous membrane, with many patches of blood and mucus in the intestine.
b. Differential diagnosis
When examining lesions, it is necessary to pay attention to distinguish swine dysentery from some other intestinal diseases in pigs with similar symptoms, including:
-
Intestinal hyperplasia caused by the bacteria
Lawsonia intracellularis.
-
Swine typhoid caused by
Salmonella.
-
Disease caused by whipworm (
Trichuris suis ) parasitizing the large intestine.
c. Paraclinical diagnosis
To diagnose swine dysentery, the specimen is usually the feces of pigs suspected of having the disease. Farmers can send directly to the testing center for testing, thereby receiving accurate results and promptly applying effective treatment and disease control solutions.
6. Preventing swine dysentery
a. Disease prevention and control
To effectively prevent swine dysentery, farmers need to combine many management and care measures:
- Implement the principle of "together in - together out", regularly clean and keep the barn clean.
- Isolate new pigs entering the farm for at least 15 days to monitor their health before entering the herd.
- Reduce stress for pigs by ensuring reasonable stocking density, adjusting temperature and humidity suitable for each age stage.
- Strictly control vehicles, people and tools entering and leaving the farm, and regularly exterminate rats and prevent wild birds from entering.
- Periodically spray disinfectants on barns with specialized products from
Fivevet, such as:
Five-Iodine, Five-BGF, Five-BKG, Five-Perkon 3S,... to effectively kill pathogens.
Some Fivevet antiseptic productsb. Vaccines
Currently, swine dysentery vaccines are still in the research process. Some multivalent vaccines are produced from bacterial strains isolated at the outbreak, but the effectiveness is not high, the price is expensive and difficult to commercialize. In addition, live attenuated vaccines, genetically modified vaccines, subunit vaccines, and recombinant vaccines are also being tested but are not yet popular in practice.
7. Treatment of swine dysentery
Rehydration and electrolytes
- Because pigs have diarrhea and lose a lot of water and minerals, the first step is to give them electrolytes to restore their physical condition.
- Can use:
Five-Lyte Oral , Five-No stress super, ...
Fivevet's rehydration and electrolyte productsFivevet's injectable antibiotic treatment products
Fivevet's powdered antibiotic treatment products
Some digestive enzyme products of Fivevet
Cleaning and disinfecting barns: Periodically spray disinfectants on the breeding area with products:
Five-Iodine, Five-BGF, Five-BKG, Five-Perkon 3S, etc.
Ensure a reasonable diet, supplement nutrition and create favorable feeding conditions to help pigs recover quickly.
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