A second positive test for bovine spongiform encephalopathy (BSE) on a 15-year-old cow reinforced suspicions that it had mad cow disease, the Norwegian Veterinary Institute said.

“We have a likely and strong suspicion of a possible variant of BSE,” Bjørn Røthe Knudtsen of the Food and Safety Authority told public broadcaster NRK.

The authorities however said there was a distinction between the type of BSE caused by cows eating meat-based feed — banned in Europe since 2001 after the British epidemic — and an atypical version which has sporadically appeared in older cows in several European countries in recent years.

A definitive diagnosis can only be made by a European reference laboratory in Britain.

“We take this seriously and we are handling it as if our suspicion were confirmed,” Food and Safety Authority official Solfrid Aamdal said in a statement.