too little, too late? more intense culling campaign would have reduced the number of cases by 66%, according to a study.
To stop a catastrophic outbreak of foot-and-mouth disease (FMD), the British government has so far destroyed nearly 4 million pigs, sheep and cattle - a strategy some call overzealous and draconian. But new studies show that, if anything, the measures were not strict enough: A policy of more rigorous culling in the first phase of the epidemic could have saved millions of animals, researchers say
crude models. the same researchers helped guide policy earlier this year after the outbreak of foot caught Britain by surprise in February ( science NOW, April 17). Now, the same groups have built more elaborate models that paint a detailed picture of how the British countryside was ravaged by the virus of FMD, taking into account such things as each farm location, number estimated pigs, cattle and sheep farm each contained and comprehensive data on the spread of the disease and the slaughter process. One of the documents, by Roy Anderson and colleagues at Imperial College London, is published in Nature this week another, Bryan Grenfell and colleagues at the University of Cambridge and the University of Edinburgh, is published online by Science this week.
The groups also calculated a number of scenarios to show how the different measures could have turned the course of the epidemic. For example, if the government had managed to slaughter each infected farm within 24 hours and each adjacent farm within 48 hours, the number of cases was reduced by 66% and the number of 62% of farms reform, according Imperial College model (see chart); the other team puts these figures to 43% and 46%, respectively.
Other veterinary epidemiologists praise the accuracy of models to describe the epidemic. At the same time, some wish the studies would have offered more clues about exactly how the disease spreads. For example, the studies do not explain very well why the epidemic has a long tail, said Mart de Jong of Wageningen University in the Netherlands. De Jong hopes that further analysis of the data will give such ideas.
With three new cases last week, Britain is still waiting for the end of the epidemic smoldering. Both research teams caution against relaxing controls. If the current rules are strictly enforced, Edinburgh and Cambridge team predicts the disease will almost certainly be stamped by next spring.
Related Sites
Background story about foot-and mouth disease ( science , 23 March, p. 2298)
Information on FMD of the Department of Environment, Food and rural Affairs
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