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In October 2006, the American Association of Swine Veterinarians developed a case definition1 to describe porcine circovirus-associated disease (PCVAD). The following summary was adapted from that case definition.
PCVAD is a broad categorization of multi-systemic diseases. PCVAD can be subclinical (no obvious clinical signs in the herd) or include one or more of the following signs concurrently:
- Multi-systemic disease with weight loss (formerly known as PMWS)
- High mortality: Doubling of historical mortality rate without introduction of a new known pathogen.
- Respiratory signs, including pneumonia
- Porcine dermatitis and nephropathy syndrome (kidneys are affected)
- Enteric signs including diarrhea and weight loss
- Reproductive disorders, including abortions, stillbirths and fetal mummification
PCVAD must be properly diagnosed by a veterinary diagnostic laboratory that will confirm the following histopathological (microscopic) changes in affected pigs:
- Depletion of lymphoid cells in lymphoid tissues of growing pigs
- Identification of disseminated granulomatous inflammation in one or more tissues (e.g., spleen, lymph nodes, lung, kidney, tonsil, etc.)
- Detecting PCV2 virus in lesions of growing pigs
- Reproductive disorders associated with PCVAD confirmed by demonstrating presence of PCV2 antigen in fetal myocarditis lesions
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