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E. coli - Scour (Diarrhoea)

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Of all the diseases in the sucking piglet, diarrhoea is the most common and the most important. In some outbreaks it is responsible for high morbidity and mortality. In a well run herd there should be less than 3% of litters at any one time requiring treatment and piglet mortality from diarrhoea should be less than 0.5%. In severe outbreaks mortality can rise to over 7% and in individual untreated litters up to 100%.

E. coli diarrhoea, clostridial diarrhoea, coccidiosis, TGE and PED all cause diarrhoea in the piglet. E. coli is the most important.

At birth the intestinal tract is micro-biologically sterile and it has little immunity to disease producing organisms. Organisms begin to colonise the tract quickly after birth, among them potentially pathogenic strains of E. coli and Clostridium perfringens. Immunity is initially provided by the high levels of antibodies in colostrum (IgG, IgM, IgA). After the colostral antibodies have been absorbed into the blood stream, the immunity is maintained by the antibody (IgA) which is present in milk. IgA is absorbed into the mucous lining of the intestines. It is essential that the newborn piglet drinks sufficient colostrum soon after birth to prevent potentially pathogenic organisms multiplying against the intestinal wall and causing diarrhoea. It is also essential that the piglet continues to drink milk regularly after the colostrum has gone so that its intestines continue to be lined by protective antibodies.

The antibodies acquired passively from the colostrum and milk are finite and can be overwhelmed by large doses of bacteria present in the environment. The higher the number of organisms taken in, the greater the risk of disease. Environmental stress such as chilling also plays a role because it lowers the piglets resistance. There is thus a delicate balance between the antibody level on the one hand and the weight of infection and stress on the other.

Scour in the piglet can occur at any age during sucking but there are often two peak periods, before 5 days and between 7 and 14 days.

Sudden outbreaks of scour involving large numbers of litters with acute diarrhoea and high mortality suggest TGE, epidemic diarrhoea or PRRS. Rotavirus diarrhoea appears in waves in individual litters or groups of litters and normally in the second half of lactation. Coccidiosis is usually involved in diarrhoea from 7 to 14 days of age. At less than 5 days of age the most common cause is E. coli with acute diarrhoea particularly in gilts' litters. Clostridial infections also occur at this age.

At weaning the loss of sow's milk and secretory IgA allows the E. coli to attach to the villi of the small intestines, the toxins produced then cause acute diarrhoea, usually within five days of weaning.

Symptoms (E.coli)

Sows / Growers
  • Uncommon.
  • Usually occur with viral infection.

In acute disease:

  • The only sign may be a previously good pig found dead.
  • Huddle together shivering or lie in a corner.
  • The skin around the rectum and tail is wet.
  • Watery to salad cream consistency scour - distinctive smell.
  • Vomiting.
As the diarrhoea progresses:
  • Dehydrated.
  • Sunken eyes.
  • Leathery skin.
  • The scour often sticks to the skin of other piglets giving them an orange to white colour.
  • Prior to death piglets may be found on their sides paddling and frothing at the mouth.
In sub-acute disease:
  • Signs are similar but the effects on the piglet are less dramatic, more prolonged and mortality tends to be lower.
  • This type of scour is often seen between 7 to 14 days of age.
  • Watery to salad cream consistency diarrhoea, often white to yellow in colour.
  • The first signs are often slight loss of condition, dehydration and a watery diarrhoea.
  • In some cases blood or black tarry faeces may be seen or they may be like paste with a wide range of colour: grey, white, yellow and green. The colour is not significant.
  • Poor pigs - wasting, hairy.
  • Sloppy faeces and often dirty wet pens.
  • Sunken eyes.
  • Dehydration results in rapid loss of weight.
  • Pigs may be found dead with sunken eyes and slight blueing of the extremities.
  • Good pigs may also be just found dead with no external symptoms.
  • Occasional vomiting.

Causes / Contributing factors

Sows & Piglets
  • Poor pen floors.
  • Poor pen hygiene associated with bad drainage.
  • Poor hygiene procedures, between pens.
  • Environmental contamination from one pen to another i.e. boots, brushes, shovels clothing etc.
  • Continual use of pens.
  • Moisture, warmth, waste food and faeces are ideal for bacterial multiplication.
  • Draughts.
  • Routine use of milk replacers, particularly if they are allowed to get stale or contaminated, may increase the incidence.
  • Scour is more common in large litters. This can be due to:
      - Insufficient colostrum.
      - Poor teat access.
      - Poor crate design.
      - Agalactia in the sow.

Weaners & Growers


Are the weaning problems mainly in gilt litters? If so consider E. coli vaccination in gilts:

    - Creep feeding. Consider the type, frequency and age of introduction.
    - Stop creep feeding before weaning and assess the effects.
At weaning consider:

    - Stress.
    - Stocking density - group sizes.
    - House temperatures and temperature fluctuations.
    - Poor house hygiene.
    - Continually populated houses.
    - Water shortage.
    - Feed type: Meal or pellets, wet or dry.
    - Feeding practices.
    - Quality of nutrition.
After weaning consider the effects of:
    - Air flow - chilling.
    - Temperature fluctuations.
    - High ventilation and humidity.
    - Creep feed management.
    - Assess the response to different creep diets.
    - Consider other diseases present.
    - Age and weight at weaning.
    - Floor surfaces - provide comfort boards.
    - Asses rate and evenness of growth.
A diarrhoea problem in growing pigs is likely to be associated with one or more of the following diseases (Most common *):
  • Classical swine fever (in those countries where it is still endemic).
  • Coliform infections. *
  • Colitis (non specific). *
  • Parasites.
  • Porcine epidemic diarrhoea (PED). *
  • Porcine enteropathy including PIA, NE and RI. *
  • Rotavirus infection.
  • Salmonellosis. *
  • Spirochaetal diarrhoea.
  • Swine dysentery. *
  • TGE (rare in Europe now but still common in some other countries).


This is based on the clinical examination, the response to treatment (viral diseases do not respond to treatment) and laboratory examination of the scour.

Submit a rectal swab and faecal sample of a recently dead pig or a live pig to the laboratory for cultural examinations and antibiotic sensitivity tests.

A simple test to differentiate between virus causes and E. coli diarrhoea involves the use of litmus paper to determine whether the scour has an alkaline or an acid consistency. Soak the paper in the scour, E. coli diarrhoea is alkaline (blue colour change) whereas viral infections are acid (red colour change).

It is not possible to eliminate organisms such as rotavirus, E. coli and coccidiosis from the herd and most if not all pigs will be infected with them. Herds can be maintained free of TGE, PED and PRRS. All herds carry clostridia but other factors are required to cause disease.

Further Reading

Click on the links below to find out more about this disease, including treatment, management control and prevention information. The top link is the main article on this disease.