A research laboratory at the centre of an investigation into an outbreak of foot and mouth disease in southern Britain said today it had complete confidence in its biosecurity measures.
Investigators say there is a "strong probability" the disease, which has prompted a cull of cattle and an international ban on British livestock and related products, came from labs in Surrey close to farms where cattle were infected.
A preliminary report into the outbreak, confirmed five days ago, said there was a real possibility it involved "human movement" from the laboratories.
The state-run Institute for Animal Health (IAH); and Merial Animal Health, owned by US firm Merck and French firm Sanofi-Aventis; occupy the same site in Pirbright, about 5 miles from the affected farms.
Merial rejected the report's suggestions, saying that intensive internal investigations had "not been able to establish any evidence that the virus may have been transported out of our centre by humans".
But the possibility that outbreak was caused by sabotage is being investigated.
The preliminary report also concluded there were various potential routes for "accidental or deliberate transfer of material from the site".
It said: "We have investigated site management systems and records and spoken to a number of employees. As a result we are pursuing lines of inquiry.
"Release by human movement must also be considered a real possibility. Further investigation of the above issues is required and is being urgently pursued."
Environment Secretary Hilary Benn has admitted the British government must consider the possibility of deliberate human contamination.
Speaking after the publication of the report, he said: "The truth is, we don't know. We're all very, very anxious."
Both laboratories, which conduct research and develop vaccines against foot and mouth, handle the exact, rare strain of the virus - isolated by British scientists 40 years ago - that struck the herd.
Lead investigator Paul Logan said his team was carrying out further tests on the drainage system at the Merial lab to see if it was the method by which the virus spread. Results could be available later today.
Britain's livestock industry, whose meat exports are worth more than €725 million a year, is under threat from the outbreak, which has stirred memories of the 2001 crisis that cost Britain around stg£8.5 billion (€12.3bn).
The investigators' report drew no definitive conclusions but said there was a limited possibility it was borne on the air, its most common form of dispersion.
Agencies