Dr Andrew Tucker, CS vet
What is Exudative Epidermitis?
Commonly known on farm as Greasy Pig Disease, Exudative Epidermitis is a bacterial disease caused by the bacteria Staphylococcus hyicus. Greasy Pig Disease is widespread, being commonly seen on pig farms worldwide and South Africa is no exception to this.
Infection with S.hyicus is via abrasions on the skin. These abrasions are often due to piglets fighting, or scratches from sawdust, rough flooring etc. S.hyicus bacteria then produce toxins which do damage to the epidermis (outer skin layer). The outer skin layer is then exfoliated which causes inflammation and sebaceous secretion.
How do you know if it’s on your farm?
Greasy Pig is most commonly seen in piglets between 7 and 35 days old. The first signs are usually just an unenergetic piglet. This is followed by a dulling of the skin and the appearance of pale brown flecks on the skin. Scabs on the cheeks (due to fighting) and knees (kneeling on a rough floor to drink) are often also seen on affected piglets. Over a three to five day period the lesion skin lesions then start spreading. The sebaceous secretion mentioned above gives the skin a greasy texture and bacterial multiplication as well as dirt caught on this greasy surface soon give the skin a dark brown to black appearance.
Severe and untreated cases can lead to the piglet losing a lot of weight, having a thickened wrinkled skin and dying, normally due to dehydration. This happens five to ten days post infection.
Greasy Pig is normally only seen in a few litters on the farm and does not necessarily affect all the piglets in the litter. Greasy Pig can be seen in older pigs as well, as 1 – 2cm localised lesions (brown scabs) and has also been identified in ear necrosis problems.
The diagnosis is often made on the basis of the clinical signs – typical skin lesions, but post mortem findings as well as various lab tests can confirm the diagnosis.
How do you treat or prevent it?
Proper washing and disinfecting of pens can stop the disease from remaining present in the pen and spreading to the next group of pigs to come in to the pen. All-in all-out systems also help to reduce the risk of the disease persisting within a pen or house.
By reducing skin abrasions the risk of Greasy Pig will also reduce. This can be done for example by fostering litters correctly so as to reduce fighting when suckling. Inadequate ventilation with a resulting humid building creates an ideal environment for S.hyicus and therefore increases the risk.
Treatment is usually effective if the disease is noticed early enough. Various antibiotics are effective against S.hyicus and appropriate disinfectants can also work well if sprayed onto the skin. Segregation of infected animals is necessary to reduce the risk of the bacteria infecting in contact pigs.
Pig Diseases – D.J. Taylor; Diseases of Swine – Straw, Zimmerman, D’Allaire, Taylor