15 September 2000

Vets identify link between diseases identified

ALTHOUGH PMWS and PDNS are usually mentioned in the same breath, PDNS has in fact been recognised by vets for longer. However, there appears to be a connection between the two and PDNS often occurs on a unit at or soon after the start of a PMWS outbreak.

"PDNS was first described in 1987 and we used to see it rarely before PMWS occurred. It used to only affect the odd pig but now epidemics occur with 1-2% of pigs on a PMWS infected unit succumbing," says Norfolk vet John Hayden.

Although the cause of PDNS is unknown, the connection may be that PMWS compromises a pigs ability to fight pathogens, making it more susceptible to PDNS.

Pigs usually show signs of PDNS infection at eight to 14 weeks old and symptoms include blotchiness, a high temperature, stiffness and weight loss. "Some pigs may die of kidney failure but the disease isnt always fatal."

Because PDNS symptoms are similar to those of swine fever, the latter may be overlooked, warns Mr Hayden. "When you suspect an outbreak of PDNS, contact your vet to confirm that it isnt swine fever." &#42