Saturday, 4 August 2007

Foot and Mouth: Deja-vu?

Here we go again? An outbreak of Foot and Mouth disease has been confirmed in beef cattle (the easiest domestic animals in which to see the symptoms) on a farm in Wanborough (near Guilford, Surrey). This is the first UK sighting of this highly infectious (to animals) viral agent since the devastating epidemic of 2001 that involved the mass slaughter of farm animals with 'funeral pyres' in parts of the country and involvement of the army. It also led to debates about how to effectively handle such emergencies and the potential role of vaccination in controlling such outbreaks. A farmer was eventually prosecuted for not reporting the initial outbreak of Foot and Mouth in his pigs. Information on many aspects relating to the 2001 event has been collected on a BBC site (http://news.bbc.co.uk/1/hi/in_depth/uk/2001/foot_and_mouth/default.stm). The event also caused serious financial problems for many visitor locations that involve animals such as Longleat and WWT because movement restrictions prevented paying customers arriving. There was also a discussion at this time into the potential involvement of wild mammals as potential transport agents and victims (deer are particularly vulnerable) of Foot and Mouth.
First reports suggest that the Government Agencies are more firmly 'on top' of the problem this time (http://www.defra.gov.uk/footandmouth/ ). COBRA are meeting (but I am not sure whether much is actually achieved by the Prime minister rushing back from his holiday in Dorset where he could have been seeing the delights of 'Monkey World' , perhaps reminding him of Camp David?). The authorities have put in place a 3 km radius Protection zone around the farm. There is also a 10 km radius Surveillance zone outside that (where farm animals will be checked for symptoms). The whole of the rest of GB is a Restriction zone with a banning of the movement of cattle, sheep and pigs (some minor deviations can be licenced such as the necessary moving cattle along roads for milking). The potential role of vaccination has been raised again but this entirely depends on the strain of the virus (yet to be identified in this case) and vaccine stocks. The main problems for the Authorities are identifying where the infection came from and what other animals might have been exposed to the agent (this was a severe problem in 2001 because of the extraordinary, largely unregulated movement of animals sometimes over long distances). The incubation period for Foot and Mouth can be as little as 3 and as much as 14 days. To be on the safe side, the vet detectives must try to locate every animal that could have been in contact with the Wanborough cattle within the last fortnight (and animals, in turn, that have been in contact with them). There will be a lot of anxious surveillance over at least the next month or so.
STOP PRESS
It has been confirmed that the strain of virus is one (of the 7 or so) that was being worked on for vaccine production at Pirbright (two laboratories essentially sharing the site- one the Government Institute of Animal Health and the other an American-French commercial company Merial). This suggests that the cattle may have been infected by the aerial route (although there is a suggestion that recent floods and sewage treatment may be implicated) and is potentially good news in terms of potential GB wide transmission but I wonder how long it will be before the first bioterrorism conspiracy hypothesis? Speculation in the newspapers about a 'senior scientist' with an allotment adjoining the farm where the outbreak occurred using containers from the laboratory as planting pots. Also claims about a plumbing contractor (who caught Legionnaire's disease) roaming the complex with minimal security checking.
STOP STOP PRESS
Another potential cluster was reported (9th August) outside the initial Surveillance zone in Dorking (still in Surrey). Fortunately, this was a false alarm. On the 15th August two more suspicious events were reported, one at Chessington's children's zoo and the other a farm in St Mary in the Marsh (Romney marshes, Kent) leading to the setting up of 2 more temporary 3 Km exclusion zones. Tests on both also proved negative. These developments illustrate that controlling this disease is both difficult and not an exact science. The obvious 'take home message' about such confusing events is that interest will ebb and flow with 'new' information of varied quality before (hopefully) petering out.
STOP STOP STOP PRESS
The decision to remove EU restrictions on the export of meat. livestock and milk from the UK on the 23rd August , effectively signalled the end of this event (except for the 2 farms initially involved where conditions still apply).

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