ThePigSite Pig Health
Oedema Disease (OD) - Bowel Oedema
(436) This is also called bowel disease or gut oedema. It is caused by certain serotypes of E. coli bacteria that produce a powerful toxin (verotoxin). These toxins damage the walls of small blood vessels including those in the brain and cause fluid or oedema to accumulate in the tissues of the stomach and the large bowel. Damage to the blood vessels in the brain results in some of the characteristic signs. The specific E. coli are described as O138, O139 and O141. Disease is generally seen 1 to 4 weeks after weaning, the peak being at 10 days. It was very common when pigs were weaned at 5 to 8 weeks of age. Since weaning ages have reduced to 17 to 26 days and starter diets have been improved the disease in its classical form is rarely seen. The E. coli bacteria attach themselves to the finger-like villi in the anterior small intestine and produce the toxins. This mechanism is similar to that which occurs in post-weaning diarrhoea associated with different strains of E. coli. During sucking the secretory IgA immunoglobulin component in milk prevents the bacteria adhering. After weaning when the IgA has disappeared the pigs becomes susceptible to disease.Clinical signs
Acute disease
Diagnosis
This is made from the typical clinical signs, the sudden appearance of disease after weaning, post-mortem examinations showing oedema of the greater curvature of the stomach wall, coiled colon, and eyelids and isolation of the haemolytic E. coli serotypes from the duodenum (anterior small intestine).
Treatment
By the time the clinical signs are seen it is often too late and most pigs die. Treatment routines are aimed at preventing the organism establishing itself and also reducing the weight of infection. The general principles of controlling coliform infections and post-weaning diarrhoea should be followed. Management control and prevention
Sometimes the only sign is a good pig found dead 1 to 4 weeks post weaning. A typical live affected pig will show a staggering gate, puffy eyelids giving a sleepy appearance and an abnormal high pitched squeak. Pigs stop eating and in the later stages become partially paralysed and go off their legs, sometimes with nervous symptoms. Diarrhoea is not a consistent feature but breathing difficulties become evident. The damage to the brain is irreversible and most pigs die. Recovery in the few pigs that do not die takes up to 2 to 3 weeks. Certain breeds of pigs may be associated with disease suggesting a genetic predisposition. The temperature is usually normal.
It must be admitted however that the disease is most difficult to deal with and often preventative medication and treatment are unsuccessful.
