THE British government seems unconcerned about the possibility that foot and
mouth disease has spread to wild animals. It isn鈥檛 planning systematic testing
of deer for the disease鈥攄espite pleas from deer experts.
FMD did not persist in the deer population after Britain鈥檚 last big outbreak
in 1967. But the situation today is different. There has been a tenfold increase
in deer numbers to around 2 million. And the population of wild boar, which can
also spread the disease, has grown to unknown proportions since they were
accidentally reintroduced to Britain in the 1980s.
The worry is that the populations of deer especially are now dense enough for
the disease to persist in the wild. All five of Britain鈥檚 deer species can catch
FMD, and infected animals could sporadically reinfect livestock. Germany already
has this problem with swine fever, which is endemic in its wild boar population
and occasionally spreads to pigs.
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In Britain, deer hunting was banned in March, for fear that hunters might
spread FMD. Since then, a dozen roe deer shot on farmland and four sika from a
deer farm in the heavily infected district of Cumbria have shown clinical signs
of FMD, although all tested negative.
鈥淏ut it must have entered the wild population,鈥� says Simon Booth of the Deer
Initiative, an association of public and private agencies that manages England鈥檚
deer. From this week, hunters in Britain will be allowed to shoot a small number
of deer in infected areas. 鈥淏ut the government won鈥檛 give us money to test them
for FMD,鈥� says Booth. Instead, he plans to ask Brussels for help.
Chris Bostock, head of the Institute for Animal Health, Britain鈥檚 main
veterinary lab, doubts any FMD infection in deer would persist long enough to
threaten livestock. 鈥淲e think any infection would burn itself out,鈥� says
Bostock. Infected deer should die or recover before passing the virus on.
But this is impossible to predict without information on infection among
wildlife, say epidemiologists. Especially at risk are the large herds in heavily
infected areas such as Devon and Cumbria. What鈥檚 more, the hunting restrictions
mean deer numbers will rise this summer in precisely those areas, says Hugh Rose
of the British Deer Society.
Infection would be most likely to persist among red, fallow and sika deer,
because they form herds, get only mild symptoms and can carry the virus for four
months, although they aren鈥檛 infectious for that long, says Paul Gibbs of the
University of Florida at Gainesville.
Unlike Britain, the US鈥檚 emergency plans for FMD include the monitoring of
deer. During an outbreak in California in 1924, 22,000 mule deer in a national
park were killed as a precaution. Of these, 2300 were found to have symptoms of
FMD. The infection died out. 鈥淲e were very, very lucky,鈥� says Juan Lubroth of
the US Department of Agriculture鈥檚 FMD lab on Plum Island, New York.