FOOT AND MOUTH DISEASE
Veterinary Risk Assessment (no.15)
What is the risk of causing new outbreaks of FMD by allowing (1) the movement of susceptible livestock between premises in Scotland and (2) the resumption of itinerant livestock services?
Summary of the risk factors
During an outbreak of foot and mouth disease, movement of livestock increases the risk of spreading infection to uninfected parts of premises and to other premises and holdings. Animals that have become infected but are not yet ill (i.e. incubating disease) will carry the virus with them and will start spreading virus shortly before they show symptoms. This period of time varies depending on the strain of virus and the dose of infection, amongst other factors.
Moving livestock during an FMD outbreak increases the risk of spreading infection to premises which were previously uninfected. The risk is that undisclosed infection will be carried to new locations. The important risk factors are:-
- infection might have been brought to Scotland by direct or indirect movements of animals from infected farms
- undisclosed FMD at the premises of departure in Scotland or the premises from which the transport was despatched.
- spread by susceptible livestock incubating disease or with unrecognised lesions.
- observations on infected premises in the present outbreak have shown that FMD has gone unreported for 10 days in the first infected premises and was only detected on another premises by routine veterinary surveillance visits.
Infection is easily spread by mechanical transmission between premises in the same ownership when the same personnel are caring for the livestock on the different premises.
Moving animals between premises under different ownership increases the risk of spreading disease.
Moving susceptible animals over long distances carries the additional risk of transferring the infection to a distant location.
Pigs are capable of generating large quantities of virus which can spread to neighbouring premises as an aerosol.
Summary of risk reducing factors
Prior to confirmation of FMD at the beginning of August, livestock movements were subject to a 13 day standstill at destination premises/holdings in Scotland (6 day standstill period in England and Wales), following arrival. In early September this was increased to 20 days for ruminants and again reduced to 13 (and 6 days) when there was no remaining evidence of FMD being present in GB. Pigs are similarly subject to a 20-day standstill period.
Rapid introduction of a Temporary Control Zone (TCZ) on suspicion of disease and subsequent declaration of Protection and Surveillance Zones after confirmation of disease on the first infected premises, have been implemented on 12 September. Rapid introduction of a movement ban for livestock and a ban on animal gatherings in the Great Britain Restricted Zone (RZ) outside the SZ on 12 September 2007.
Shortly after the imposition of the movement bans in August and again in September movements of animals to slaughter and for welfare reasons has been permitted. Each of these movements was an opportunity for latent or unrecognised disease to be detected.
An examination of the movement databases for cattle, sheep, pigs and goats has been completed for any direct imports into Scotland from 50 km around the infected premises in Surrey since 15 July. The CTS database shows that 72 cattle were moved to a total of three premises in Scotland. The sheep, goat and pig databases show that no animals moved directly to farms in Scotland. Animal Health have completed clinical inspections of all susceptible species on the farms of destination with negative results.
The EPIC team have examined data from the same sources for evidence of indirect contact between premises within 50 km of the infected premises and farms in Scotland. Animal Health have completed clinical inspections of all susceptible species on the farms of destination with negative results.
Communication to the public and industry has created a heightened awareness of the disease risk and continued vigilance. Reporting of suspected disease for veterinary investigation has taken place on 128 premises without confirmation of disease outside the existing surveillance zone.
Inspection of pigs by a veterinary surgeon before movements would allow detection of any disease present but would not show recent infection which had not yet produced clinical signs.
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Risk Management
(a) For movements susceptible animals, other than pigs, between farms
The stockman is to check the animals before movement to ensure no clinical signs suggestive of FMD are present in the stock to be moved or in any others on the premises. Any clinical signs of foot and mouth disease must be reported to the local Divisional Veterinary Manager without delay and the planned movement cancelled until an official inspection has been completed.
Only direct movements between premises in Scotland, without multiple pickups or drop offs, can be permitted. Movements to the Scottish islands are not permitted.
Vehicles used to transport livestock, including any trailers, must be leak proof and must be effectively cleansed and disinfected before and after use.
Movements must be reported to SAMU and CTS (as appropriate) without delay.
No susceptible livestock should be moved from the destination premises for a period of 20 days, except for movements directly to slaughter, veterinary treatment or research.
(b) For movements of pigs between farms within a farm business up to 8km
All the above conditions in (a) above apply.
(c) For movements of pigs between farms further than 8 km apart
All the above conditions in (a) above apply with the additional requirement for a pre-movement veterinary inspection within 6 hours of the proposed move to confirm no animals on the farm of departure are showing signs of FMD.
(d) For the resumption of itinerant livestock services
All livestock attendants must wear clean protective clothing that can be cleansed and disinfected in between visits to different premises, or else wear new protective clothing on each occasion.
Any equipment used must either be thoroughly cleansed and disinfected before use on another premises, enclosed in a protective cover or discarded after a single use.
SUMMARY OF THE RECOMMENDED ACTION
(a) For movements susceptible animals, other than pigs, between farms
(b) For movements of pigs between farms within a farm business up to 8km
- the animals must be checked before movement to ensure no clinical signs suggestive of FMD are present in the stock to be moved or in any others on the premises. Any clinical signs of foot and mouth disease must be reported to the local Divisional Veterinary Manager without delay and the planned movement cancelled until an official inspection has been completed
- movements to the Scottish islands are not permitted.
- vehicles used to transport livestock, including any trailers, must be leak proof and must be effectively cleansed and disinfected before and after use, in accordance with the provisions of the Transport of Animals (Cleansing and Disinfection) Regulations (Scotland) 2004.
- no susceptible livestock can be removed from the destination premises for a period of 20 days, except for movements directly to slaughter.
- movements must be reported to SAMU and CTS (as appropriate) without delay.
(c) For movements of pigs between farms further than 8 km apart
- the animals must be inspected by a veterinary surgeon before movement to ensure no clinical signs suggestive of FMD are present in the stock to be moved or in any others on the premises. Any clinical signs of foot and mouth disease must be reported to the local Divisional Veterinary Manager without delay and the planned movement cancelled until an official inspection has been completed.
- the veterinary surgeon must provide a certificate to confirm that an inspection has been carried out.
- movements to the Scottish islands are not permitted.
- vehicles used to transport livestock, including any trailers, must be leak proof and must be effectively cleansed and disinfected before and after use, in accordance with the provisions of the Transport of Animals (Cleansing and Disinfection) Regulations (Scotland) 2004.
- no susceptible livestock can be removed from the destination premises for a period of 20 days, except for movements directly to slaughter.
- movements must be reported to SAMU and CTS (as appropriate) without delay.
(d) For the resumption of itinerant livestock services
- all livestock attendants must wear clean protective clothing that can be cleansed and disinfected in between visits to different premises, or else wear new protective clothing on each occasion.
- any equipment used must either be thoroughly cleansed and disinfected before use on another premises, enclosed in a protective cover or discarded after a single use.
Veterinary Division
Rural Directorate
Scottish Government
23 September 2007
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