FOOT AND MOUTH DISEASE
Veterinary Risk Assessment (No.10)
What is the risk of causing new outbreaks of FMD by allowing gatherings of cattle and sheep for sale or show?
Summary of the risk factors
The Scottish Executive veterinary risk assessment "What are the risks of causing new outbreaks of FMD by lifting the current control measures that provide for a national ban on livestock movements, while retaining temporary movement controls where livestock pass through markets and shows?" stated that:
"It can be concluded that the current risk of there being a case of undetected or incubating disease in susceptible livestock in Scotland is now "very low" - defined by EFSA as "very rare if present, but cannot be excluded". The veterinary consensus is that the risk of having a case of FMD in Scotland now approaches the background level of persistent risk that is ever present between relatively infrequent epidemics.
Undetected or incubating disease arising from the Surrey outbreak cannot be ruled out however, because it is not possible to quantify and eliminate all the possible risk factors. For example, there are no available data on the frequency of movements of people and vehicles from Surrey to Scotland and the very small unquantifiable risk of further cases cannot therefore be entirely eliminated.
The remaining very low risk of new cases of FMD in Scotland is not negligible for the reasons stated. The consequences of missing a case of FMD would be greatest, if undetected affected livestock moved through a livestock market or an agricultural show, thereby negating the rapid and successful control of this outbreak to date."
Gathering livestock from different farms during an FMD outbreak increases the risk of spreading infection to premises which were previously uninfected. The risk is that there might be an undetected pocket of infection on one of the farms sending sheep or cattle to a gathering. At the gathering infected animals might spread the infection to the others. There is also a risk that unregulated contact with livestock at a gathering by persons delivering animals could spread the virus to other farms visited by farmers or drovers after the gathering.
The vehicles used to transport animals could carry the virus to other farms. The site used for a gathering could remain infected from one day to another multiplying the risk of the virus being spread by contaminated vehicles or people, and/or by these or other means (such as wind) onto livestock premises neighbouring the collection centre.
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Summary of risk reducing factors
There are many statutory controls which act to reduce risks. These include the pre-existing 6 day standstill periods applying to all farms in England & Wales and 13 day standstill periods in Scotland, introduced after the 2001 FMD epidemic. Pig premises are subject to different, more rigorous controls which restrict movements to within breeding pyramids and impose longer standstill period for movements which have taken place from outside the pyramid.
As soon as disease was suspected in Surrey on 2 August there were immediate restrictions on the movement of livestock from farms close to the original infected farm.
One of the most significant risk reduction measures has been the rapid introduction of the Restricted Zone measures which have prevented almost all movements of susceptible animals since the evening of Friday 3 August 2007.
The resulting publicity raised the awareness of the farming community, as evidenced by the 79 reports from England & Wales and Scotland of suspected disease - all of which were subsequently cleared by Animal Health.
The epidemiological report submitted to the European Commission dated 8 August 2007 indicated that the risk of silent spread out of Surrey through the movements of sheep during the risk period was very low.
The slaughter of animals recommenced in Scotland on 8 August. Since then, most abattoirs have been close to normal capacity and the 100,000 animals slaughtered have been subjected to ante and post mortem inspection at abattoirs without cases of FMD being confirmed.
Movements of animals for a number of welfare related reasons have been licensed after veterinary inspections. Since 3 August, 310 inspections have been carried out without suspicious findings being reported.
Risk management
before transport
• livestock should only be moved if the farm has not received any livestock from another premises in the preceding 20 days
• farmers/stockmen should regularly check their stock for disease, especially before being moved
• livestock must be transported in cleaned vehicles
at the sale or show
• animal gatherings must be licensed
• all livestock must be inspected by a veterinary surgeon
• the identification of livestock at must be accurate
• the reporting of movements into and out of a sale must be accurate and rapid
• at a sale, livestock transport vehicles should be cleaned and disinfected between loads of animals and the process recorded
• drivers (and any companions) should wear washable footwear and protective clothing and clean and disinfect themselves, particularly their hands, between each consignment
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structure
• markets should be required to provide livestock transport vehicle cleansing and disinfection facilities and facilities for the disposal of used bedding
• cleansing and disinfection of a market site should be completed at the end of the sale, and dung, bedding and used feedingstuffs should be disposed of in a safe manner
• dung, bedding and used feedingstuffs may be licensed from the market to an approved site where it does not come into contact with any livestock
• gravel and grass sites should be left empty for 27 days after a sale, any reduction in this time period gradually increases the risk of a carry-over of infection
• gatherings should not be held in places which cannot be adequately cleansed and disinfected until 27 days have elapsed
sales frequency and length
• each livestock 'sale' should have defined start and end points to allow site depopulation, cleansing and disinfection
• the market site should operate an 'all in - all out' policy with the site depopulated at the end of the sale
• exceptionally, longer sales may need to be licensed but only if the livestock are considered, by veterinary assessment, to present a low disease risk e.g. pedigree shows and sales, seasonal consignments from remote areas
market fields
• markets should not carry over stock from one sale to the next, particularly in market fields
• markets should not have any resident or semi-permanent stock on site
• market fields and gravelled areas should be left empty for 27 days after use as FMD virus can survive for this time period
• exceptionally, following veterinary assessment, low risk consignments may be collected in market fields before a seasonal sale and return there after the sale before despatch; the market fields should then be rested for 27 days
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people in markets
• cleansing and disinfection facilities for footwear, leggings and hands should be provided, particularly at the lairage exit points
• every person entering the animal holding areas and passageways should wear washable footwear and should use the cleansing and disinfection facilities when leaving the lairage
• access to livestock areas should be restricted to authorised persons
• all drovers and any person handling livestock should additionally wear washable protective clothing
• any person handling stock should clean and disinfect themselves, particularly their hands, between each consignment examined
• market biosecurity officers should ensure that these conditions are observed
premises contiguous to a market
• a 50 metre stock separation should be required
at destination or return home
• farmers/stockmen should check animals soon after arrival
• any vehicles or trailers belonging to the purchaser used to transport animals to the farm must be cleansed and disinfected within 24 hours of arrival and in any event before transporting any further livestock
• a 20 day stand still period on the whole farm after the arrival of new stock would reduce the risk of infection being spread to other farms.
SUMMARY OF THE RECOMMENDED ACTION
Shows with susceptible livestock may be held provided the conditions listed above under
• before transport
• at the sale or show
• at destination or return home
are complied with.
Sales with cattle and sheep may be held provided the conditions listed above under
• before transport
• at the sale or show
• structure
• sales frequency and length
• market fields
• people in markets
• premises contiguous to a market
• at destination or return home
Veterinary Division
Scottish Executive
22 August 2007
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