FOOT AND MOUTH
Although the origins of the current foot and mouth disease epidemic in the United Kingdom are not yet, and may never be, known, its subsequent spread raises issues about the management and control of infectious diseases in livestock, both specific to FMD and more generally, say Professor Mark Woolhouse and Dr Alex Donaldson in a Commentary in this week's Nature (Vol. 410, No. 6828, 29 Mar 2001). Professor Woolhouse is a scientific adviser to the British Government. Dr Donaldson is head of the Pirbright Laboratory of the UK's Institute for Animal Health, which is also the World Reference Laboratory for animal vaccines. We must acknowledge that we are living on a "global farm", not just a "global village", the authors say .
The course and scale of the current UK foot-and-mouth disease epidemic differs from those of its recent predecessors, and the elimination of the disease will be a formidable challenge. The epidemic is still ‘out of control’ in the sense that each outbreak (infection on a single holding) is generating an average of more than one subsequent outbreak, the duo argue. The immediate aim of a control programme must be to reduce R, the ‘case reproduction ratio’, to less than one so that the epidemic goes into decline. Even then, the infection may not be eradicated for some time, as diminishing chains of infection result in a long ‘tail’ to the epidemic.
Some demographic information for UK livestock populations is provided by annual MAFF (Ministry of Agriculture, Fisheries and Food) census data. But the fine detail of the spatial distribution of livestock holdings is not in the public domain, which is a major barrier to epidemiological research, say Woolhouse and Donaldson. Similarly, information on the age structure of livestock populations is either not available or is not in the public domain - absence of this information for UK cattle handicapped research on the epidemiology of BSE. In the rest of Europe, information is now collected on movements of cattle and pigs (less so for sheep), but these essential data can be equally difficult to obtain for non-government scientists.
Mark Woolhouse is at the Centre for Tropical Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK. Alex Donaldson is at the Institute for Animal Health, Ash Road, Pirbright, Woking, Surrey GU24 ONF, UK.
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Commentary articles in Nature are expert opinions on topical scientific issues of public importance. They are not works of new research -- in this case no new data are reported. The authors of this particular Commentary article are presenting the scientific options for dealing with the current foot-and-mouth disease epidemic in the UK, partly by reviewing published data and partly by recommending specific lines of research that need to be undertaken to combat this disease, both now and in future.
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