Quantitative estimates of the risk of new outbreaks of foot-and-mouth disease as a result of burning pyres.

The risk of dispersing foot-and-mouth disease virus into the atmosphere, and spreading it to susceptible holdings as a result of burning large numbers of carcases together on open pyres, has been estimated for six selected pyres burned during the 2001 outbreak in the UK. The probability of an animal or holding becoming infected was dependent on the estimated level of exposure to the virus predicted from the concentrations of virus calculated by the Met Office, Bracknell. In general, the probability of infection per animal and per holding decreased as their distance from the pyre increased. In the case of two of the pyres, a holding under the pyre plumes became infected on a date consistent with when the pyre was lit. However, by calculating their estimated probability of infection from the pyres it was concluded that it was unlikely that in either case the pyre was the source of infection.