British authorities were testing for a new outbreak of foot and mouth disease (FMD) Friday, after cattle in a herd grazing several miles away from an initial cluster of cases were suspected of falling ill, raising fears that the virus is spreading.

(Horses cannot be infected by FMD, but can carry the virus on their hooves, skin, hair, and possibly in their nasal passages.)

The chief veterinary officer, Debby Reynolds, BVSc, PhD, MRCVS, said cows in a second area of the southern England county of Surrey had shown “mild clinical signs of infections” and announced that a new 1.8-mile, or about three-kilometer, zone had been set up around a farm that was previously unlinked to the outbreak.

Although the case is unconfirmed, Reynolds said the outbreak was a “developing disease situation,” renewing worries of a repeat of scenes in 2001, when seven million animals were killed and incinerated on pyres. Britain’s agriculture and rural tourism industries were devastated.

The new suspected case is about nine miles from two farms where cases have been confirmed and a third plot where cattle have been killed as a precaution.

If the latest tests prove positive, it would suggest the initial outbreak was not contained and increase the prospect of the virus’s infecting herds across southern England.

“The containment and eradication of foot and mouth disease remains our priority,” Reynolds said in a statement late Thursday. “This is why we have moved swiftly to put in place a temporary control zone while we investigate this development.”

FMD does not typically infect humans, but its appearance among farm animals can have a swift and possibly far-reaching economic impact–several countries have banned imports of British livestock and Britain has voluntarily suspended exports of livestock, meat and milk products and destroyed more than 570 cows since the