THE SCOTTISH GOVERNMENT
FOOT AND MOUTH DISEASE
Veterinary Risk Assessment (No.13)
Movement of Itinerant Embryo Transfer and Artificial Insemination Teams in Mainland Scotland
What are the current risks of causing new outbreaks of FMD by allowing itinerant embryo transfer and artificial insemination teams to operate between livestock farms in mainland Scotland?
SUMMARY OF THE RISK FACTORS
Movements of personnel and equipment between farms during an FMD outbreak increase the risk of spreading infection to premises that were previously uninfected. The risk is that undisclosed infection will be carried to new locations. The important risk factors are:-
- There may be undisclosed FMD at a farm (or at farms previously visited) because of "silent spread" of FMD by sheep, or the presence of susceptible livestock incubating disease. In 2001, sheep were the most significant "vectors" of FMD over long distances where disease went undetected.
- Subsequent mechanical spread of FMD virus - by people handling livestock (boots and clothing) and by vehicles/equipment used in connection with handling susceptible livestock.
The factors considered to be most responsible for increasing the risks are:
- Licensed movements of FMD susceptible animals between 3 August to 8 September (under the first national movement ban); movement of FMD susceptible animals between 8 September and 13 September 2007 (the period between the two recent national movement bans), and any illegal livestock movements since mid-July.
- Lack of awareness of appropriate biosecurity precautions on many farms throughout GB.
- Poor disease detection in sheep not frequently inspected/poor awareness of appropriate biosecurity precautions on many farms throughout GB.
Undetected or incubating disease arising from the Surrey outbreak cannot be ruled out in Scottish livestock because (a) we are now back within an incubation period of the last confirmed case in Surrey, so further previously undetected disease cannot be ruled out and (b) 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.
CURRENT POSITION
The Scottish Government reintroduced restriction zone measures across mainland Scotland on 12 September, following a confirmed case of foot and mouth disease in Surrey. The most recent confirmed case prior to that was on 3 August and the first national movement ban ran from that date to 8 September. There was therefore a short period between 8 September and 12 September where free movements of animals in GB were permitted.
The following factors are relevant when assessing the current risks of causing new outbreaks of FMD by allowing itinerant artificial insemination of embryo transfer teams to operate between farms in mainland Scotland:-
- As far as can be determined at the present time, there have been no direct movements of sheep or pigs from Surrey, or its surrounding counties to mainland Scotland since 1 August 2007. Work is currently underway to determine if there have been any direct or indirect cattle movements from those areas to mainland Scotland since 1 August.
- There have been no confirmed cases of foot and mouth disease outside Surrey during the current outbreak.
- This strain of FMD in cattle and pigs has proved relatively straightforward to detect clinically and the general media interest in FMD has raised farmer's awareness further.
- The latest available epidemiology report on the outbreak of foot and mouth disease in Surrey, published on 15 August, concluded that the risk of disease spread outside of the Surrey Protection and Surveillance Zones was now considered to be "very low".
- There are ongoing statutory controls to reduce the spread of undetected disease including the pre existing 6 day standstill period applying to all farms in England and Wales and the 13 day standstill periods in Scotland, introduced after the 2001 FMD epidemic.
- Biosecurity standards can reasonably be expected to be higher as a result of the publicity generated by the current outbreak in Surrey.
- Although extensively kept sheep are not always closely or frequently inspected, extensively kept sheep are less likely to come into contact with and propagate FMD virus.
Ovine artificial insemination/embryo transfer
Artificial insemination/embryo transfer of sheep involves the synchronisation of recipient ewes, usually using progesterone sponges and a subsequent surgical procedure, usually conducted on-farm, to inseminate or implant embryos. The latter procedure requires a surgical team, under the supervision of a veterinary surgeon, to travel between farms (up to three or four a day in the current peak season) and conduct surgically sterile procedures on recipient ewes.
Artificial insemination of cattle
An itinerant inseminator travels between roughly 20 farms a day, coming into direct contact with cattle.
RISK MANAGEMENT
Cattle inseminators have the potential to spread any virus faster than sheep inseminators/sheep AI, because they visit a significantly greater number of farms in a day. However, both sets of operatives come into direct contact with livestock and both teams travel between farms with their respective equipment.
- Visits to conduct artificial insemination or embryo transfer of sheep or cattle should only be permitted under general licence conditions. The frequency and exposure time between AI/ET operatives and sheep/cows that they handle, in different epidemiological groups, could be limited by restricting farm visits to one premise per day.
- However, effective cleansing and disinfection of AI/ET personnel and equipment between visits will minimise the "very low" risks of transferring previously undetected infection. All livestock attendance must wear clean protective clothing that must be cleansed and disinfected between visits, or else wear new protective clothing on each occasion.
- All equipment used must be cleansed and disinfected at the end of a farm visit with disinfectant approved for use against foot and mouth disease, and again before work starts up at new premises.
- The livestock to be handled on the premises must consist only of the female livestock to be subjected to artificial insemination/embryo transfer procedures.
PREMISES
- At arrival at any premises all trailers and vehicles must be first washed with disinfectant that is approved for use against foot and mouth disease and thoroughly washed and cleaned.
- A contract work book (eg a logbook) should be produced and maintained and signed by the owner of each flock/herd to confirm that disinfection has been conducted.
SUMMARY OF THE RECOMMENDED ACTION
Any risk of spreading FMD may be minimised further by restricting the number of visits to cases where the artificial insemination/embryo transfer procedures are considered essential for those sheep/cows at the current time.
The resumption of artificial insemination/embryo transfer work can be considered in the Restricted Zone on the basis of the veterinary risk assessment above and the conclusion that the risks of causing future outbreaks of FMD may be considered currently to be "very low".
Scottish Government
Rural Directorate
Veterinary Division
14 September 2007