Erysipelas in pigs
W R Webster, Animal & Plant Health Service, DPI&F Queensland
and M J Moore, Pig & Poultry Production Institute, South Australia
Erysipelas is a common pig disease sometimes called diamond skin disease. Affected pigs often have a fever, sudden deaths may occur and sows may abort, skin may redden and suffering from arthritis or heart disease may develop. Although the bacteria responsible are widespread, outbreaks of generalised illness are relatively rare. It is more likely to surface as chronic lameness or joint condemnations at slaughter, and protective vaccination is strongly recommended. The disease
The disease is caused by Erysipelothrix rhusiopathiae (formerly E insidiosa) a bacteria which is commonly present in an estimated 30-50% of tonsils in healthy pigs. Rodents and birds can introduce and maintain the organism within a piggery, and it can survive temporarily in soil, bedding and water. The bacterium is spread through faeces, saliva and nasal secretions.
Erysipelas can be an acute (rapidly developing), subacute (with mild and sometimes unnoticed symptoms) or chronic (slowly developing and long lasting) disease, and usually causes illness in pigs between 3 months and 3 years of age. Infected pigs may suffer from one or more of the five forms of the disease below. Acute-Fever
An acute form which may affect pigs of all ages. In older pigs sporadic cases can occur but with younger animals whole litters may be affected. Pigs may be fevered and ill for several days with temperatures exceeding 40°C. They may be reluctant to stand or walk, and if forced to do so, may squeal and move with a stiff, stilted gait, and will soon lie down again. They are often depressed but remain alert, and may partly or completely lose interest in their feed.
Death can occur at any stage of the illness and will often occur in untreated pigs within 24-48 hours of onset. Young pigs generally die earlier than others. Prompt treatment with an appropriate antibiotic will speed recovery and reduce the likelihood of later complications.
Pregnant sows may abort when affected by the fever rather than from a specific action of the bacteria on the uterus, placenta or unborn piglets (by comparison Leptospirosis does attack the pregnant uterus). Acute-Skin form
An acute form of the disease which may occur in fevered pigs, or as a mild form of the disease which only damages skin. Some affected pigs have red, diamond-shaped swellings appearing on the skin within 24-48 hours. The diamonds may be 100 mm or more across and can be felt by touch. Many photographs of these swellings have been published, but only a very small proportion of cases show such dramatic lesions, with most affected pigs more likely to develop welt-like red skin blotches, especially on the ears. On casual inspection, cases could be missed as the swellings are not always distinct.
If the skin lesions are light-pink to light purplish-red, they will usually slough off and disappear within 4-7 days unless they become infected. However, dark purplish-red lesions usually precede death.
