MAFF WARNS FARMERS TO ENFORCE THE 'FIREWALLS'
by Steve Connor and Nigel Morris
Tuesday 10 April 2001, p. 6.
(First half of article then ...) Scientists at the American government's
Plum Island Animal Disease Center in New York state carried out airborne
transmission experiments on pigs and found that the virus could not be
transmitted between members of a swine herd by air currents alone. Fred
Brown, an authority on the virus at Plum Island, said the experiment was
repeated six times but failed to uncover any evidence for airborne
transmission between pigs.
In the American experiment, a group of pigs infected with foot-and-mouth
were put in the same barn with an uninfected group, separated by a barrier
to prevent physical contact. Although both herds breathed the same air, the
uninfected group remained free of the disease. Dr Brown said:"They did this
seven times but none of the uninfected pigs came down with foot-and-mouth."
Chris Bostock, director of the Institute of Animal Health, said there was
abundant experimental evidence to show that airborne transmission was a real
threat, especially when pigs and cattle were involved.
Epidemiologists, for instance, were able in 1981 to predict correctly than
an outbreak of foot-and-mouth among pigs in northern France posed a risk to
animals in Jersey and the Isle of Wight because of prevailing northerly
winds, Professor Bostock said.
However, Dr Brown is sceptical that wind was the transmission route. He
said: "I find it difficult to accept that the virus could have travelled 170
miles through the air. There is no direct, physical evidence for airborne
transmission of foot-and-mouth virus."