THE PCV2 VIRUS
Since the 1990's, the world has seen a dramatic increase in the porcine circovirus type 2 (PCV2) virus loads in pigs. This prolific virus impairs the immune system and leaves pigs susceptible to other swine diseases. Pneumonia, PMWS, enteritis, respiratory disease, porcine dermatitis and nephropathy syndrome… those are just some of the diseases caused by PCV2 that can affect pigs suddenly and with devastating results:
- Dramatic increase in mortality
- Increased cull rates
- Substantial weight loss
- Increased number of lights
- Reduced profits
The hardy and environmentally stable circovirus can be transmitted:
- Vertically in uterus or during lactation
- Horizontally through nasal and fecal secretions
And although replication stimuli are not completely understood, it is believed there is slow replication prior to “stimulus.”
Multiple cofactors may increase viral load:
- Infectious cofactors: viral infections like PRRS, Influenza A Virus (IAV), SIV and Porcine Parvovirus and bacterial infections like Salmonella and Mycoplasma hyopneumoniae
- Non-infectious cofactors like some vaccine adjuvants, especially those with mineral oil, and “stressors” (management, environment, etc).
In addition, viral load can be influenced by PCV2 virus isolate, age, and genetic factors.
CLINICAL PCVAD SYMPTOMS
The clinical signs of PCVAD can mimic many diseases, which is why an accurate diagnosis is critical for appropriate control measures. Veterinary diagnostic laboratories can confirm PCVAD cases with testing.
Common signs include:
- Weight loss
- Jaundice, stressed appearance
- Diarrhea, enteritis
- Respiratory distress, pneumonia
- Porcine dermatitis and nephropathy syndrome
- Enlarged, depleted lymph nodes (which look pale on cut surface) Increased mortality and cull rates
- Reproductive disorders (abortions, stillbirths, mummies)
Clinical signs typically appear in pigs 9 to 12 days post-infection, with mortality beginning 10 to 21 days. Pigs are viremic for 21 days (3 weeks) or more and secondary infections and symptoms can persist for up to 42 days (6 weeks).
1. Cline, G., Wilt, V., Diaz, E., Efficacy of Ingelvac CircoFLEX in pigs vaccinated at 3 and 6 weeks of age in a PRRS and Mycoplasma hyopneumoniae-negative production system, Leman Conference 2007.