Porcine Dermatitis and Nephropathy Syndrome (PDNS)

PDNS can be responsible for high mortalities in affected pig herds. It is also significant because of its similarities to African Swine Fever (ASF) and Classical Swine Fever (CSF). PDNS can complicate the diagnosis of these notifiable diseases. PDNS is usually seen in herds that are also affected by PMWS.

History

PDNS was fist described in the U.K. in 1993 as a sporadic condition affecting individual finisher pigs. It has since been described all over the world. It has caused increasing problems over the years and seems to be associated with or closely related to Porcine Multisystemic Wasting Syndrome (PMWS). Under these circumstances PDNS has become a significant condition affecting large numbers of pigs.

Age affected

PDNS is usually seen in grower and finisher pigs. The main age group affected are is pigs of 11-14 weeks of age.

Clinical Signs

• Slightly raised red-purple blotches on the skin.
• Skin lesions are most obvious on the hind legs, loin, scrotum and ears, but can extend over the abdomen, flanks and fore legs eventually covering the whole body.
• In the acute phase pigs have temperatures of up to 41°C.
• Pigs are lethargic and acute cases have swollen legs leading to lameness.
• Lesions become crusty and brown over a few days and if pigs survive the acute phase eventually fade.
• Pigs that survive acute disease usually become emaciated and eventually die.

Etiology

PCV-2 has been identified in many cases of PDNS and may act as a trigger for the disease complex. Management factors also play a role It has also been suggested that PDNS is an immune complex mediated disease associated with abnormal stimulation of the immune system. This implies antibody antigen reactions. It has been postulated that the condition could be initiated by factors such as medicines, vaccines, chemicals and infectious agents.

Diagnosis

Accurate diagnosis is important because of the similarities to ASF and CSF. Laboratory tests to rule out these diseases are essential.

Carcass of a pig with PDNS - extensive purplish red slightly raised blotches of various sizes and shapes on the skin.

Enlarged inguinal lymph node and typical blotchy skin lesions.

Swollen congested kidney with white foci.

Cut surface of the kidney with congestion and white foci.