We are badly hit in Great Britain with postweaning multi-systemic wasting syndrome (PMWS). Estimates are 40% of older weaners are affected. The disease cost us $70 million in 2001.
For the British pig farmer, discovery of this latest disease complex may prove to be the final nail in the coffin following a litany of problems. That list includes welfare issues, poor prices, Classical Swine Fever, foot-and-mouth disease and now the PMWS/PDNS (Porcine Dermatitis and Nephropathy Syndrome) disease complex.
Management Means
Recently, we got together with other involved European pig producers to see what we can do to keep PMWS/PDNS out of our herds, and to mitigate the effects when they arrive.
Contrary to opinion that you cannot do much about this new plague, there is much to be done.
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Change your mindset. There is a lot you can do to keep PMWS out or lessen its impact.
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Reexamine the immune status of your breeding herd. The syndrome seems to flourish in the face of too-early breeding, coupled with too-rapid heat induction and a poorly planned disease challenge program. Talk to a specialist pig veterinarian.
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Use the new virus-specific disinfectants as a routine management practice. In an Iowa State University trial, the disinfectant (Virkon S) comfortably outperformed 10 others in its effect on the PCV2 (porcine circovirus type 2) organism.
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Use a preliminary, heavy-duty (fat) degreasing detergent as routine. Seek advice on dilution and coverage specifically for PCV2.
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Buy replacement stock. Consider junior gilts only from herds certified free of PMWS — sometimes not easy.
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The virus is often spread by vehicles. Tighten up security. Be a nuisance, demand proof of bio-hygiene. Ensure there is no unauthorized access to the pig unit.
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Quarantine new stock off-farm if possible. Review quarantine protocol.
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Control rodents and birds.
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Change to all-in/all-out pig flow in farrowing and nursery rooms.
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Ensure pits under slotted floors are cleaned/disinfected, too.
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PCV2 can survive in waterlines and in above-ceiling lofts. Find out how to sanitize these, too.
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Follow the routine biosecurity advice given above.
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Crossfostering and multi-suckling will spread diseases related to PMWS/PDNS.
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Moving piglets in feed barrows will also spread it. Think about this.
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Wean as late as you can. “Batching and matching” will spread it — best to keep litter groups separate as long as possible.
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PCV2 loves overstocking, complicated by a stuffy environment, closed up ventilation on cold nights, temperature fluctuations and drafts.
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It also loves feces (and mud). Don't allow nursery areas to get fouled up.
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Parvovirus, porcine reproductive and respiratory syndrome history and an ongoing respiratory infection from enzootic pneumonia lets it take hold. See your vet to advise on protection; there are signs that over-vaccination, especially of early weaned piglets, may “confuse” the animals' immune response to it.
Clinical Comments
British veterinarian Stanley Done, Central Veterinary Laboratory, Weybridge, Surrey, provided the following comments at the recent Iowa State University Swine Disease Conference for Swine Practitioners.
Actually, there are two disease syndromes associated with PMWS. There is PMWS itself and secondary Porcine Dermatitis and Nephropathy Syndrome (PDNS).
PDNS has been around in Britain since about 1976. This skin affliction produces purple to red discoloration, particularly common over the hind quarters, flanks and ears. Anorexia, depression, stiff gait, reluctance to move and edema are other symptoms.
In 1999, PMWS arrived on the scene with 10 recorded cases, following some outbreaks of PDNS. In 2000, there were 70 cases. PMWS strikes pigs 6-14 weeks old, causing diarrhea, depression, rough hair coat, loss of appetite, palpable lymph nodes and sudden death. Many PMWS cases are followed by problems with PDNS.
In short, PMWS and its associated problem PDNS, comprise one of the most significant sources of economic loss to the European pig industry. Its symptoms and economic consequences are quite variable and can persist from months to even years.
It's also important to note the apparent contribution of porcine circovirus type 2 (PCV2) to disease problems including PDNS, PMWS, congenital tremor, porcine necrotizing pneumonia, myocarditis and reproductive failure.
