Diagnosing the disease
Most pig herds will be serologically positive for porcine circovirus type 2 (PCV2), so serology is of little value for diagnosis of disease. Serology can, however, be used for monitoring and vaccination purposes.
The clinical syndrome (stunting, pallor, dyspnea, jaundice, diarrhea and mortality) suggests Porcine Circovirus Diseases (PCVD), but confirmation is based on the pathological findings and demonstration of the virus in tissues. As post-mortem lesions are variable, it is often necessary to necropsy several pigs.
- Emaciated, pale or jaundiced carcass
- Very enlarged lymph nodes and spleen (the lymph nodes are white on cut surface)
- Swollen kidneys: white spots may be visible on the cut surface
- Sometimes enlarged or atrophied liver
- Rubbery, mottled lungs
- Changes in the stomach include ulcers in the pars esophagea
- There may be edema around the pancreas and in the intestines
- The small intestine is thin-walled, the contents are watery, and the cecum is distended and may also have reddening of the cecal wall
Oedematous kidney with white spots visible on the cut surface×
Hemorrhages in the gastric mucosa×
Diagnosis is based upon the presence of PCV2 histological lesions in affected organs. Immunohistochemistry is used to demonstrate PCV2 in tissues. Microscopically, these lesions are characteristic and diagnostic, particularly if circovirus is demonstrated in them.