All entries for Monday 06 August 2007
August 06, 2007
I’ve just got back from the Society for Mathematical Biology annual meeting in San Jose; my colleagues and I were a little concerned to hear of a confirmed outbreak of foot and mouth disease (FMD) on a farm in Surrey last Friday.
It’s too early to say for definite how this outbreak will pan out, but a few things can be noted now. Firstly, the government moved quickly – following initial reports, a temporary restriction zone (1km) was put in place at around noon on Friday, and by 9pm FMD had been confirmed, and movements of susceptible cattle halted nation-wide. This is marked contrast to previous epidemics in 1951,1967, and 2001, when (as noted by the enquiries that followed each outbreak) movement restrictions were not put in place rapidly enough, which made those outbreaks considerably worse than they might otherwise have been.
There is no sign as yet of secondary cases, which is positive (although given a normal latent period of 3-6 days, we cannot be sure that there won’t be some still to come); we don’t have much live data to go on as yet, but given movement data from previous years and the local geography, spread outside the current 10km Surveillance Zone seems unlikely. I hope I don’t end up eating my words…!
The strain isolated from the culled animals is very similar to the 1967 epidemic’s strain, which isn’t thought to be currently “at large”, raising the question of where it came from. The nearby laboratory site at Pirbright seems a likely candidate, althought that has yet to be confirmed. The Institute for Animal Health, the world reference laboratory for FMD (amongst other things!) is on that site, as is Merial’s FMD vaccine manufacture plant. Both have 1967-strain FMDV, the latter in rather larger quantities than the former. Both have strict biosecurity controls; it will be interesting to see the results of the HSE’s investigation, due tomorrow.
In the mean time, we can just wait and see what unfolds. Interesting times…