Clamp down on spread of CSF, pig men urged
18 August 2000
Clamp down on spread of CSF, pig men urged
By James Garner
PIG producers are being urged to tighten biosecurity measures to prevent further spread of classical swine fever (CSF), despite hopes that recent outbreaks have been contained withing one BQP supply pyramid in East Anglia.
More sites from the same supply chain are expected to announce positive CSF test results as farmers weekly goes to press.
Suffolk pig vet Jake Waddilove of the Eastgate Vet Group, Bury St Edmunds, says CSF is currently confined within one production system. "But we dont know how long it had been in existence before it was detected. Some estimates suggest as long as eight weeks, so we mustnt be complacent."
Integra vet groups John Hayden of Thetford, Norfolk, reckons it will be two to three weeks before the outbreak can be classified as "under control".
He says there are similarities between CSF and porcine dermatitis nephropathy syndrome (PDNS) in its early stages.
"On the face of it they look similar, but nursery units suffer far more mortality with CSF – it can be as high as 30%. CSF also normally affects pigs as young as five to six-weeks-old, rather than 10 weeks plus with PDNS."
Any unit that has had PDNS for the last month or so and is yet to show signs of recovery should be tested for CSF, he warns.
Mr Waddilove says biosecurity is the key to control. A newly published study of the Dutch swine fever outbreak reveals that transmission between units was caused mainly by local spread within an area of 1km around infection sites.
"Local transmission accounted for 39% of spread, but of course the Dutch pig industry is much more densely populated than ours." Local transmission is not so much of a factor here, so other sources become more important.
Of these, transport is crucial. "This includes lorries of any type, whether feed wagons or knacker lorries," he says. These need to be disinfected and wheels and wheel arches sprayed immediately before they enter the farm.
But the milkman and postman travel between pig farms too, says Norfolk pig producer Richard Lilwall of Jordans Green Farm, Whitwell, Dereham.
"We have stopped any vehicles including the milkman and postman from coming on to the farm. Fortunately, we had a feed delivery before the outbreak, but when the next one is due we will make sure it is disinfected and its wheels sprayed."
Mr Waddilove reckons all feed should be delivered off-farm if possible, using farmer-owned blower hoses.
People are another area of concern. "They can transfer the disease through dirt under finger nails or on hands, boots and in hair.
"Ideally visitors should shower in. Where this is not possible they should change into unit clothes and its a good idea to provide disinfectant dips at access points around the unit."
Semen, previously thought to be fairly unimportant as a source of transfer, was found to cause 8% of dispersal in the Dutch outbreak after infection of an AI stud, says Mr Waddilove, which means it shouldnt be discounted.
"Only purchase semen from known CSF-free sources. Again be confident in your sources biosecurity and delivery systems." The same applies for units buying in any breeding stock and it is, he says, best to avoid buying pregnant sows.
Pigmeat and pigmeat products are another area of concern and all staff must be banned from having these products in their pack lunches.
Outdoor units are probably at greater risk from this means of transfer, particularly when they are by roadsides as passer-bys can throw pig meat products into pens. "Set them back from the perimeter of the field," he suggests.
Other measures include tightening up on rodent and pest control and avoiding sharing equipment with other pig farms.
CSFPRECAUTIONS
• Disinfect all vehicles.
• Staff and visitor hygiene.
• Breeding stock sources?
• No pigmeat products on-farm.
• Rodent and pest control.
• No sharing farm equipment.