July 13 2009
Causes of swine dysentery spread in East Anglia
• Pig movement 44.8%
• Management 13%
• Local spread 10%
• Pig transport 10%
• Birds 7%
• Contractor 3%
• Dead pig transport 3%
• Feed lorry 3%
• Unknown 3%
When numerous East Anglia pig units went down with swine dysentery in 2006-2007, fewer than half the cases were caused by pig movements. Most of the outbreaks could have been avoided by good biosecurity, vet Jake Waddilove told Yorkshire and Humberside Health’s recent standing-room-only Good Health meeting at Malton.
To the extent that it can take months to develop and is almost impossible to detect in outdoor breeding herds, swine dysentery is the ‘invisible killer’.
So there is a danger that it may be out of sight, out of mind. But once scouring starts, it will cost more than £10 a pig and as these costs are ongoing they will bring a unit to its knees unless action is taken to eliminate the disease.
If you look closely at scours, it is possible to make out necrotic debris from pieces of intestinal lining. Pigs scouring like this will either die or their performance will be severely affected.
‘Medication doesn’t work as well as it used to. You need regional initiatives such as Yorkshire and Humberside Health to get rid of the disease,’ said Jake Waddilove.
Yorkshire and Humberside Health invited Jake Waddilove to address its Malton meeting because of current concern among Yorkshire producers that the county may be on the brink of a serious outbreak.
When the meeting came to choose which diseases should be targeted by Yorkshire and Humberside Health...
91 percent of producers said it was quite or very important to tackle swine dysentery.
88 percent said the same for PRRS.
86 percent said the same for enzootic pneumonia.
45 percent said the same for mange.
Jake Waddilove said the East Anglia outbreak started when 400 pigs were sent from Scotland in late summer 2006 for organic finishing outdoors in East Anglia.
Pigs broke down to mucoid haemorrhagic scours soon after arrival and some died. It was quickly established the cause was swine dysentery (brachyspira hyodysenteriae).
When a unit breaks down with swine dysentery it is essential the owner is prepared to quickly depopulate, for the regional good. If this doesn’t happen the effects can be profound, especially in East Anglia where pig movements constantly criss-cross the region.
Through late 2006 and into the following year, pig units in East Anglia fell like dominoes to the invisible killer.
Jake Waddilove’s talk exposed the complex interconnections between units and people in the East Anglia, which in turn highlights the need for much better biosecurity.
One infected finisher unit reported how its infestation of starlings had suddenly disappeared when the last of the pigs had gone. At the same time a nearby unit reported a sudden influx of starlings, just before the pigs started scouring. (Sea-gulls can also spread the disease.)
Another unit went down with scours as a result of a visit from a pig lorry that had collected pigs from an infected unit, taken them to the slaughterhouse, and then washed down and disinfected, but not thoroughly enough.
When two units some distance apart broke down with the disease the likely cause was managers moving between the two units.
Another unit may have got the disease because a contractor who had been carting straw went to an infected unit and then brought the disease back to his own unit.
One unit may have got the disease when a knacker lorry passed nearby. Another when infected muck was spread nearby.
Feed lorries have also been blamed for spreading infection. In one case it may have been a blower pipe that caused the spread. Having dragged it through the muck on one unit the driver would have washed it off before putting it back in its tube... but did he remember to wash the inside of the tube?
Jake Waddilove’s presentation demonstrated that on current form the humble bacteria brachyspira hyodysenteriae can easily outsmart humans. We have got to become more cute with our biosecurity if we wish to keep it at bay.