LONDON - The outbreak of foot and mouth disease in southern England could effectively be over by the end of the week if no new cases emerge, but farmers must stay vigilant, one of Britain's top microbiologists says.
The highly infectious disease was found in livestock on two farms in Surrey, southern England, but tests on two other properties proved negative.
"If there's nothing more by the end of this coming week I think we can be pretty certain we are in the clear," Hugh Pennington, a bacteriology professor and one of Britain's leading food safety experts, told the BBC.
John Oxford, one of the country's leading virologists, also told the broadcaster the outbreak was in effect "over".
Pennington, however, said it was important not to relax protection and surveillance measures.
As a result of the outbreak, more than 570 animals have been destroyed and the European Union and individual countries have banned British meat and dairy exports.
Farmers say the trade curbs are costing them 1.8 million pounds ($4.9 million) a day.
A severe outbreak of foot and mouth disease in 2001 forced the slaughter of six million animals and inflicted billions of dollars of losses on farmers and the tourism industry, as much of the countryside was closed to visitors.
Inspectors are continuing to trace the potential source of the disease, with a research facility at Pirbright in Surrey that was developing foot and mouth disease seen as the probable source of the outbreak.
The centre is close to the two infected farms.
Chief veterinary officer Debby Reynolds has said all lines of inquiry were being pursued, including the possibility of deliberate contamination.
The Pirbright facility houses a government-run laboratory and a second lab Merial, owned by US firm Merck and French firm Sanofi-Aventis SA.
Results of a number of inquiries into the possible source of the disease, including tests to check whether it leaked through Merial's draining system, are expected in the coming days.
Pennington said there was "no other logical explanation" for the disease escaping other than from Pirbright.