Diarrhoea in newborns can pose a human risk, the causes of diarrhoea in this early stages of life are E. coli – Clostridial infection, TGE – epidemic diarrhoea, rotavirus – common disease in the small intestine. Within 48 hours of birth watery diarrhoea is noticeable it can stunt growth and if not treated loss of life can occur.
The gut of the newborn pig is sterile but is rapidly colonised by bacteria. Antibodies found in colostrum and later in milk protect against any damaging effects of these bacteria in normal piglets. Piglets which do not receive colostrum and those born from non-immune sows may develop disease. One of the first bacteria to colonise the neonatal piglet is Escherichia coli (E.coli). The strains of E. coli responsible for neonatal diarrhoea attach to the cells lining the small intestine by means of fimbriae (hair-like fibres) which secrete an enterotoxin (usually Heat Stable Toxin) which causes loss of chloride ions, the secretion of fluid followed by diarrhoea. Diarrhoea and loss of fluid are particularly important in neonatal piglets as water forms a large part of their body mass and the only source is sow’s milk. The next organisms to colonise are the clostridia, C. perfringens type A and type C and possibly, C. difficile. They may be followed by rotavirus, the viruses of Transmissible Gastroenteritis or Porcine Epidemic Diarrhoea and coccidia which multiply in the cells lining in the small intestine, destroy absorptive cells and produce atrophy of the intestinal wall (finger-like fibres) and give rise to diarrhoea.
Source of transmission
The sources of infection in neonatal diarrhoea are affected piglets, the piglet environment and the faeces of the sow. Each of the agents mentioned can occur in small numbers in the faeces of the sow, although adult animals are unaffected by the coccidia, rotavirus, E. coli and clostridial strains because of immunity. Piglet to piglet transmission is most common within a pen or house but the most important agents (E. coli and the clostridia) can also persist in the environment for months in the absence of thorough cleaning. New strains of all the agents can be introduced to a farm with carrier pigs.
Neonatal diarrhoea (scouring) occurs in piglets aged 0-4 days and can begin within 12 hours of birth. Affected piglets may suck but often stand with drooping tails, appear shrunken and have a dull skin with erect coat hairs. Dehydration results in sunken eyes and makes the hips and backbone more prominent. The diarrhoeic faeces may be difficult to see on casual inspection as it is often pale in colour. Dried crusts of diarrhoeic faeces may be seen on the thighs or perineum and there may also be scalding about the anus. Affected pigs may either enter a coma and die, or recover without subsequent loss of condition after 3-6 days or remain stunted. Blood-stained diarrhoea may occur after 36-48 hours when clostridia are involved. Outbreaks of neonatal diarrhoea occur in successive litters, particularly those of gilts or newly purchased sows. In some cases up to 70% of all piglets born may be affected. Seventy percent of piglets affected with diarrhoea in the first few days of life may die. Mortality rates from diarrhoea then decrease rapidly until less than 10% occurs in affected pigs over 2 weeks of age.
The presence of neonatal diarrhoea in piglets is confirmed by inspection of the piglets and the pen. Dehydrated piglets often have diarrhoea, but it may be necessary to examine piglets individually to confirm diarrhoea in very young litters and early cases in older piglets. Rectal temperatures are usually normal, and insertion of a thermometer or a swab often confirms the presence of diarrhoea.
Treatment and prevention
Neonatal diarrhoea can be treated by individual oral dosing with antimicrobial for 3-5 days. As most neonatal diarrhoea is caused by E. coli, ampicillin, amoxicillin, neomycin, apramycin, tetracyclines, trimethoprim sulphonamide, spectinomycin, fluoroquinolones, gentamicin and can all be used. Where treatment is ineffective, post-mortem examination and laboratory tests are required to confirm that E. coli is the sole cause and whether or not it is sensitive to the antimicrobial used. Penicillin, ampicillin and amoxicillin may be required for clostridial disease and the viral conditions do not respond. Electrolyte solutions with glucose: glycine should be available in all.
Neonatal diarrhoea caused by E. coli can be prevented by vaccinating the sow and ensuring that the litter receive colostrum. All-in, all-out management should be practised in farrowing houses with thorough disinfection between batches.