Written by Ed Doornenbal, DVM, Professional Services Veterinarian,
Wyeth Animal Health

Typically, signs of PCVAD appear in pigs at 5 to 12 weeks of age. On occasion, new cases are reported in the late grower or finisher pig. In the original description of clinical disease typical of PMWS (postweaning multisystemic wasting syndrome), John Harding, DVM, MSc, noted six fundamental features frequently found in affected pigs and helped to form the basis of clinical diagnosis:

• Wasting and/or unthriftiness that is usually progressive
• Lymph node enlargement, a consistent feature that is often missed by the producer
• Dyspnea (difficulty breathing) is frequently observed; this ranges in severity from mild to life-threatening
• Pallor or anemia, often non-regenerative (pig does not recover)
• Diarrhea that is typically profuse, homogenous brown in color and often accompanied by dehydration. The etiology of this diarrhea often involves other pathogens, such as Salmonella, E. coli and Brachyspira.
• Jaundice/icterus is a less frequent, but dramatic, sign reported by most farms with PMWS

Pigs with PCVAD
Photo compliments of John Harding, DVM, MSc, Western College of Veterinary Medicine, Saskatoon, Canada

In addition to these features, reproductive problems have recently been described. It has also been reported there is an association between PCV2 and porcine dermatitis and nephropathy syndrome (PDNS). It is characterized by the appearance of red spots of different sizes on the skin. The kidneys are enlarged and easily damaged.

At the herd level, PMWS usually results in low-grade, but persistent, losses. However, the severity can vary, with severe epidemics resulting in a three to four-fold increase in post-weaning mortality. Morbidity can vary from 4 to 20 percent with a mortality of 70 to 90 percent in affected pigs.