PIRBRIGHT British animal health inspectors preparing to report new findings into the source of a foot and mouth outbreak interviewed staff at a nearby research laboratory on Thursday.
Farmers across England resumed sending livestock for slaughter after the government lifted a ban on movement imposed after the first case of the disease was confirmed on Friday in the county of Surrey.
A foot and mouth crisis in 2001 devastated farming and cost Britain about 8.5 billion pounds ($17 billion).
Foot and mouth has been confirmed on two farms and officials expect to say later on Thursday whether animals on a third farm had the disease.
They are also set to say if the drainage system at the private Merial Animal Health laboratory or a nearby vegetable garden owned by a Merial executive were linked to the outbreak.
Merial -- owned by U.S. firm Merck and French firm Sanofi-Aventis SA -- shares a site in Pirbright, about 5 miles from the affected farms, with the government-run Institute for Animal Health (IAH).
Both laboratories, which develop vaccines against foot and mouth, handle the same rare strain of the virus that has struck the Surrey herds.
"There are people on site, investigations are continuing, interviewing is still going on," said a spokeswoman for Defra.
Complicating the picture, officials said a suspected case of legionnaire's disease had been contracted by a person who had spent time at the IAH.
Health inspectors are checking the institute as part of a routine examination of locations visited by the patient, which include the patient's home and recent travel destinations.
Officials say there is no link between legionnaire's disease and foot and mouth.
The latter, which can travel on the wind and on farming equipment, causes high fevers and blisters in cloven-hoofed animals and often leads to death. It is very rarely transferred to humans and is not regarded as a public health threat.
STRICT SECURITY MEASURES
Outside a protection and surveillance zone in Surrey, relieved farmers sent their livestock to abattoirs after the movement ban was lifted at midnight although they were subject to strict measures to prevent the disease's spread.
Government inspectors have said there is a "strong probability" the disease originated in the research laboratories near the infected farms.
A preliminary report this week said there was a possibility "human movement" had released the virus. Merial has said it has total confidence in its health and safety measures.
The European Union decided on Wednesday to maintain a ban on all British fresh meat, milk and live animal exports because of the outbreak. They will review the ban on August 23.
National Farmers' Union president Peter Kendall welcomed the early review date. The NFU estimates export curbs are costing farmers 1.8 million pounds ($3.7 million) a day.
Britain's livestock industry has annual meat exports worth more than $1 billion and a long export ban would hit it hard.