Causative agent
- Escherichia coli (Enterotoxigenic E. coli : ETEC)
- Most common serotype :
  Neonatal diarrhea: O8,O9,O101,O141,O149,O157
  Weaning diarrhea: O8, O138, O141, O149, 0157
  Edema disease:     O138, O139,O141


Differential diagnosis
- Transmissible Gastroenteritis
- Porcine endemic diarrhea
- Porcine rotavirus infection
- Salmonellosis - Streptococcosis
- Coccidiosis     - Necrotic enteritis


1. History taking
- Neonatal septicemia: in non-immune piglets (no
  colostrum consumption or colostrum lacks specific
  antibody) the organism is present in dirty farrowing
  unit or in intestinal flora of the sow
- Neonatal diarrhea: favored by the same factors
  with predisposing stressed and complicated by
  other agents such as rotavirus, post-weaning
  enteritis, results from change of environment and
  contact dirty pens or drainage from pens at
  weaning and the loss of maternal immune
  protection
- Most likely in young sows farrowing for the first
  time


2. Clinical examination
- Septicemia is common in neonatal and
  accompanied with diarrhea, often within 12-48 hr
  after birth, most common in 1-10 days of age
- Death without clinical signs, high mortality (up to
  90%)
- Carcass with no clinical signs in early stage
- Anorexia, yellow to brownish and pasty to watery
  diarrhea, and dehydration, depression, death
  within 24 hr after showing clinical signs
- Post weaning diarrhea, occur within 10 days after
  weaning or 4-5 days of change of diet, anorexia
  and depress, watery diarrhea, death from
  dehydration

3. Necropsy
- No gross lesions in septicemic cases
- Neonatal and weaning diarrhea : dehydrated
  carcass, sunken eyes, dilated flaccid and
  congested small intestine, contents can be seen
  through the thin wall, and villi are intact


4. Histopathological observation
- Very mild epithelial degeneration
- Occasional segmental villous atrophy
- Secondary septicemia usually lacks of lesions


5. Bacterial isolation
Specimen : only fresh carcass and fresh rectal swab
before treatment, a piece of each site of
small intestine should be placed in
individual jar, separated from major
organs
Medium    : blood (TS) agar and MacConkey agar,
contents of duodenum or jejunum and
rectal swab need a quantitative culture
(more than 10⁶CFU/ml in contents and
10⁸CFU/g in swabs)
- Identification : biochemical characters
- Pathogenic E. coli is usually shown β-hemolytic and
  mucoid type except neonatal septicemia strains.
  (serotyping using O and K antiserum, detection of
  Pili antigen, and /or ST and LT of ETEC, if possible)


6. Toxin genes detection
- PCR technique


7. Serotyping


Control
- Husbandry improvement
- Medication by antimicrobial drugs
- Vaccination of the sow or piglet
- Treatment with long acting and broad spectrum
  antibiotic (IP or per os)