Other names

Diamonds, Diamond skin disease, Measles,

Causal agent

A bacteria – Erysipelothrix rhusiopathiae.  There are over 25 serotypes, however types 1 and 2 are the most common

Age group

The disease can affect any age group.  However, most weaners below 12 weeks of age are protected from colostrum antibodies passed on from their mother

Clinical signs


There are five phases of the disease recognized:


Pig found dead with no clinical signs


The disease starts with a sudden onset. 

The classic diamond lesions of erysipelas

The animals present with a high temperature (40-42C).  The infected pig is often separated from the rest of the group and may appear chilled and cold (typical of a high fever).  The pig is generally found lying down.  When the pig is encouraged to rise, it will rapidly lie down again.  The pig appears to have a sore abdomen, walks stiffly and tucked up.  The pig generally appears very dejected.  The pigs are often off their feed and may be constipated (although young animals may have diarrhoea). Sows may abort with the high temperature. 

Boars may become infertile, which may be permanent or last 6 weeks.

2 to 3 days after initially becoming infected pigs develop diamond skin lesions, which can be pink to dark purple. The lesions are not visible in the early stage of the disease. 

The diamond lesions are generally raised, which may be the only way to diagnose the disease in black pigs. 

Pigs untreated may die or start to recover in 4 to 7 days. The skin lesions may go necrotic in the centre.  The more severe the diamond lesions indicate a poorer prognosis.


The pig presents with diamond lesions with few other clinical signs including no loss of appetite.


Two forms: arthritis and endocarditis affecting the heart


3 weeks after infection the pig may present with a chronic lameness in one or two joints.  It can affect the vertebrae and thus the pig has a sore back and difficult painful walking.



The pig develops breathlessness and poor circulation especially after exertion.  This can result in sudden death, especially after mating for instance.  The pig’s ears and tails may go purple with the poor circulation.


Some 20 to 50% of pigs may carry the organism on their tonsils without exhibiting any clinical signs







Many pigs carry the organism on their tonsils without any clinical signs

Soil, bedding, feces and drinking water can become contaminated

Stressed pigs are more likely to show clinical signs, cases are more likely after pigs have become stressed - sudden changes in diet, sudden changes in temperature or introduction of other disease such as Swine Influenza

The organism can cause problems in turkeys which can then cross-infect pigs

The organism also lives in fish and fish meal – which can be an source of infection

Poor vaccination may also result in unvaccinated pigs

Post-mortem Lesions

May have very few lesions. Possibly an enlarge spleen


The skin lesions may be seen or felt. The spleen is generally very enlarged


The endocarditis is seen a cauliflower lesions growing on the heart valves.

The heart may be enlarged associated with the poor circulation

               - arthritis

Severe arthritis in one or more joints.

Pathogenesis (how diseases occur)


The organism can gain access by many routes.  Classically most infections are via the mouth from contaminated feed and water.

In acute cases the disease enters the blood stream via the pharynx and infects the blood vessels hence the widespread clinical signs.  The diamond lesions are actually an immune response.  The circulation to the skin diamond lesions can be so compromised that the centre may die and become necrotic.

In the chronic form arthritis can take months to develop and therefore diagnosis can be difficult as the lesions are sterile at the time of clinical examination.



Clinical signs

Response to penicillin in suspected pigs.  With penicillin the pig should response within 24 hours.

Bacterial culture can be done on acutely infected pigs

In chronic cases the organism can be difficult to isolate and serology may be useful.



Penicillin based medicines are very effective in the treatment of erysipelas.


There is no practical treatment excluding treatment with painkillers in the arthritic form. 

Arthritis is generally permanent. Note vaccination is not protective against the arthritis form.


Vaccination is a cheap and effective control measure

Vaccination lasts about 6 months, therefore the following programme is recommended:  Pigs over 3 months vaccinated once and again 3 weeks later

Sows vaccinated either pre or post farrowing or every 6 months

Boars vaccinated every 6 months, the boar is often forgotten

Common differentials


Swine Fever.  Salmonellosis. Anthrax.  Other causes of sudden death.  Food allergic responses


Arthritis – Mycoplasma arthritis.  Endocarditis - Streptococcus

Zoonotic – human infections


Erysipelas can infect humans and infection usually only results in a skin infection; however, the condition can be more severe.