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Building Blocks Associated With Porcine Circovirus-Associated Disease1,2
Several "building blocks" contribute to the development of PCVAD. The disease is best managed by controlling as many blocks as possible.
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Diagram courtesy of Pat Halbur, DVM, PhD, Iowa State University, Ames, IA
Key building blocks to bring under control:
- Porcine circovirus type 2 (can now be controlled with vaccination)
- Differences in virulence between PCV2 isolates (can now be controlled with some vaccines)
- Infectious cofactors (control with vaccines, treatment and management)
- Trigger factors that induce immune stimulation (control with management changes and mycoplasma vaccine timing or selection changes)
- Good production practices to minimize host susceptibility (management changes to reduce pig stress, improve hygiene and reduce overall disease challenge)
A summary of control measures1 for PCVAD
- Work closely with your veterinarian to:
- Confirm presence of PCVAD by using correct diagnostics (clinical signs, microscopic and demonstration of virus)
- Identify farm-, site- or system-specific concurrent infections
- Eliminate or minimize the effects of PRRSV co-infection, if present
- Eliminate or minimize the effects of swine influenza virus (SIV) coinfection in the breeding herd and, if needed, in piglets
- Identify if porcine parvovirus (PPV) is present as a co-infection at the time of PCV2 infection and implement PPV vaccination if recommended
- Design a program to minimize the effect of mycoplasma pneumonia (if present) using vaccination and/or medication
- Treat specific bacterial coinfections as needed
- If herd evidence suggests an association between vaccination practices and PCVAD, your veterinarian will re-evaluate the necessity and timing of products. It may be necessary to change vaccine brands or alter vaccination timing.
- Consider the use of increased levels of vitamin E and selenium in diets of pigs experiencing PCVAD
- Consider the use of enhanced diets (increased protein, etc) in pigs that are slow to respond
- Remove pigs that don't respond to treatment
- Adhere to all-in/all-out pig flow rules
- Minimize mixing and moving of pigs where possible
- Decrease pig density
- Use disinfectants with proven efficacy against PCV2 in buildings and on transport vehicles
- Consider changing pig source/pig genetics if the problem occurs repeatedly
Consider using segregated early weaning practices and strict biosecurity measures to derive and maintain PCV2-free herds or pig flows. Consult your herd veterinarian for the building blocks that may be contributing to PCVAD in your herd and steps you can take to bring them under control.
References
1. Halbur P. The building blocks of PMWS: Co-factors, host susceptibility, strain
characterization and immune modulation. Proceedings, AASV Preconference Seminar #12:
PCV2/PMWS: Understanding Factors That Impact Disease Expression and Control;
2006 Mar 5; Kansas City, MO. p. 31-8.
2. Halbur P. Practical Management of PWMS: The American experience. Proceedings,
AASV Preconference Seminar #12: PCV2/PMWS: Understanding Factors That Impact
Disease Expression and Control; 2006 Mar 5; Kansas City, MO. p. 65-71.
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