This disease will be regularly updated as our knowledge base increases.
This disease is not new and has been recognised in most pig producing countries as a minor sporadic condition. In recent years bigger more severe outbreaks have occurred particularly in parts of Europe.
PDNS occurs mainly in growers and finishers but rarely in other age groups.
Clinical signs may occur in a herd in a few pigs sporadically and the disease may then go undiagnosed or they may occur in a bigger proportion of pigs and be economically damaging.
Mortality in affected pigs may be around 15%, death occurring within a few days of onset but mortality can rise much higher.
Pigs that recover are often permanently unthrifty.
Symptoms
Weaners & Growers
- Appearance of extensive greasy brown, purplish red slightly raised blotches of various sizes and shapes over the chest, abdomen, thighs and forelegs. The majority of pigs that develop extensive skin blotching die.
- Over time the blotches become covered with dark infected crusts (dermatitis) and then fade leaving scars.
- The pigs are depressed.
- May have a fever.
- They are usually reluctant to move.
- Lose weight
- Sometimes breath heavily.
- Mortality high.
- Loss appetite.
Piglets & Sows
- Rare
Causes / Contributing factors
- The cause is unknown.
- It is not known how the disease spreads between pigs or between herds or what triggers off a clinical outbreak. However sources of incoming pigs must come from herds with no history of disease.
Diagnosis
The clinical signs are strongly suggestive but not diagnostic. Gross and microscopic post mortem examinations are needed to make a firm diagnosis. At gross post mortem examination lymph nodes, particularly those at the rear of the abdomen which are not usually examined, are reddened and enlarged and there is often fluid in the abdomen. The most consistent lesions are in the kidneys which are swollen, pale and mottled with many small haemorrhages showing through the surface. Tests can be done for high urea and creatinine levels in the blood which indicates severe kidney damage. These tests may be negative if the kidneys are less severely affected. Microscopically, the lesions in the blood vessel walls are distinctive. Since the cause is unknown there are no specific diagnostic tests.
Similar diseases
Classical swine fever (CSF), (Hog cholera), or African swine fever (ASF). Other diseases which might be confused with PDNS include erysipelas and Actinobacillus suis. Other kidney conditions may also be confused with PDNS.