Clostridia are large gram-positive spore-bearing bacteria that are present in the large intestine of all pigs. There are several species. They multiply rapidly and produce toxins that rapidly kill the host. Such diseases can be a major problem in outdoor breeding pigs (C. novyi). The organisms may enter the body through damage to the skin and underlying tissues and muscles. Bacterial spores also get carried from their normal habitat, the gut, to the liver where they may lie latent and inactive for long periods. The course of the disease is extremely short and often the only sign is a dead pig.
The most common disease in sows is associated with C. novyi which causes sudden death. Whenever total sow mortality rises above 4%, this disease should be considered.
The species, C. perfringens, types A, B or C, can under certain conditions produce a severe diarrhoea with very high mortality in piglets. Type C is by far the most important and if it gets into the small intestine and becomes established before colostrum is taken in, disease can result. Piglets are normally infected under 7 days of age and more typically within the first 24 to 72 hours of life.
The disease caused by C. perfringens type A tends to be milder, less dramatic and more prolonged but it can look similar to that caused by type C.
Clostridial infections are relatively uncommon in growers, finishers and the sow during lactation.
Symptoms
Sows
- Sudden death.
- Gangrene, characterised by painful and discoloured swellings.
- Fluid and gas are often present in the tissues.
Piglets
- Rotten smelling watery diarrhoea often blood coloured with mucous.
- Diarrhoea 0-5 days of age.
- Diarrhoea 6-21 days of age
- The lining of the small intestine sloughs off (necrosis) and may be observed in the scour.
- Many piglets die.
- Bubble of gas in the small intestines.
Weaners & Growers
- Sudden death in well grown pigs.
- Haemorrhage – faeces.
- Diarrhoea.
- Painful and discoloured swellings over muscle masses.
- Gangrene.
Causes / Contributing factors
- High numbers of bacteria in the environment.
- Unknown factors.
- Trauma to muscles.
- Immuno suppressive diseases e.g. PRRS, fungal poisoning.
- Damage to the skin allowing bacteria to enter.
Diagnosis
In acute cases diagnosis is by the clinical signs and post-mortem lesions, which are diagnostic. It is necessary to submit preferably a live or very recently dead pig to the laboratory (within 3 to 4 hours) because the causal organisms multiply after death and cause rapid post-mortem changes. If the abdomen of a dead pig is cut open the middle portion of the small intestine is often claret wine coloured. A characteristic feature is the very rapid post-mortem change particularly in the liver, which is full of gas and turns a chocolate colour. Confirmation of the diagnosis must be carried out in a laboratory by a fluorescent antibody test to identify the bacterium.
Anthrax should also be considered as a possibility.