Salmonellosis

Salmonellosis is an important bacterial disease in swine for its capacity to produce food intoxication in humans. Clinically, Salmonellosis appears as diarrhea, systemic disease or pneumonia.

Alternative names: salmonellosis

Information

Salmonella is widely extended in humans and animals. From all the Salmonella serotypes (more than 2400), the more important ones causing clinical disease in pigs are Salmonella Choleraesuis and Salmonella Typhimurium. S. Choleraesuis is the specific serotype adapted to swine, and can produce a severe disease widespread in sows (fever, depression, septicemia, pneumonia, meningitis, arthritis and diarrhea), but does commonly not affect humans. The most commonly found serotype in pigs, however, is Salmonella Typhimurium which sometimes is associated with diarrhea in young pigs, and is a common source of food intoxication in humans. Pigs can be subclinical carriers of S. Choleraesuis for long periods of time because the organism survives in the mesenteric lymph nodes, located in the intestine. Many of these carriers do not excrete the bacteria in feces, unless they are under stressing conditions. Some pigs might excrete the organism in feces in a continuous or intermittent way. The disease depends on the strain and the dosage, meaning there is a need for a relatively high number of organisms to produce clinical signs.

Salmonella might occur at any age, but is more frequent in growing pigs 8 weeks or older. The salmonella present in the pig’s gut can contaminate the carcass during slaughter, which is a potential risk for human health.
 

Symptoms

Sows

  • High temperature.
  • Depression.
  • Loss of appetite
  • Ears, nose and tail congestion (septicemia).
  • Pneumonia.
  • Coughing.
  • Nervous signs (rare).
  • Smelly diarrhea, which sometimes can have blood and mucus.
  • Might die in the acute phase of the disease.


Lactating piglets

  • The disease is not frequent in piglets due to the passive immunity of colostrum.

Weaners and growers

  • Same clinical signs than sows.

 

Causes / Contributing Factors

  • Poor hygiene.
  • Crowding.
  • Stress produced when moving and mixing animals.
  • Barns used continuously.
  • Contaminated boots and clothes.
  • Mechanical transmission through feces and movement of contaminated material.
  • Worms and flies.
  • Feed contamination made by birds, rats and mice.
  • Contamination of feed ingredients (especially animal fat). 

 

Diagnosis

  • Clinical signs (may be similar classical swine fever or other septecemias).
  • Necropsy (Interstadial edema, congested liver, spleen, and gastrohepatic lymph nodes).
  • Bacterial culture (organs, feces, blood).
  • PCR.
  • Serology.
  • Serotyping isolate is important.

Control/Prevention

  • Improve hygiene by ensuring proper cleaning and disinfection (disease is dose dependent).
  • All-in-all-out pig flow.
  • Purchase animals (including breeding stock replacements) from known negative sources.
  • Vaccines can be very effective (do have some cross protection between S. Choleraesuis and Typhimurium).
  • Antibiotics can control disease but will not eliminate the pathogen.
  • Do not use animal fat in diets.
  • Control rodents.