Foot and mouth disease has spread to a second herd of cattle in southern Britain, as experts narrow down the possible source and step up efforts at containment.  VOA's Sonja Pace reports from London.

Officials are expressing concern over the possible spread of the highly contagious foot and mouth disease after a second herd of cattle was found to have contracted the virus.

"The tests that were done overnight on the samples taken from the animals culled does confirm foot and mouth," explained British Environment Secretary Hilary Benn.

Two farms in southern England have been hit.  The herds have been culled and authorities have cordoned off the farms as well as a nearby site where an animal research laboratory is located.

Roger Pride's family farm in Surrey, southwest of London, was where the first outbreak was discovered last Friday.  Speaking to reporters, Pride said he was devastated when he found something wrong with his herd of cattle.

"They were drooling, lots of saliva running out either side of the mouth," Pride said. "There was no lameness at that point.  They were very lethargic, walking around very slowly, which obviously to a farmer you can tell there is something drastically wrong."

Excessive saliva, lameness, blisters around the mouth and hooves, raised temperature and lethargy are the main symptoms of the virus.  The disease affects cloven-hoofed animals such as cattle, sheep, goats and pigs and is spread mostly through direct contact from one infected animal to another or through contaminated feed.

The virus is rarely fatal, but spreads rapidly and is generally dealt with through extensive culling.  The disease does not usually affect humans.

Authorities are investigating a nearby animal research laboratory, shared by a British government institute and a private pharmaceutical company as a possible source. The lab produces a vaccine using the same rare strain of the virus.  The lab says none of its safety procedures have been breached, but there is concern last month's heavy rains may have resulted in sewer backups or seepage from the lab site into the surrounding fields.

Spokesman for the National Farmers' Union, Anthony Gibson, told reporters that despite major efforts there is no assurance the disease can be contained quickly.

"I think everything that could have been done has been done," Gibson said. "The lessons have so far been learned from what went wrong in the 2001 outbreak, but foot and mouth is a hugely virulent disease and the virus can spread quickly and it can spread very long distances."

Britain was hit by a major foot and mouth outbreak in 2001 with more than 2,000 cases spread across the country.  More than six million animals were culled and the cost to the industry was estimated in the millions of dollars.