Spanish officials have been forced to declare a national emergency after 13 cases of swine flu were detected, posing a threat to the country’s valuable pork exports.

The disease, which causes fatal internal bleeding in animals, has been confirmed in wild boar in Spain during the latest flu season, sparking fears that it will spread to other animals.

Experts have been deployed to 39 pig farms in a 12-mile area around the initial Catalonia outbreak zone, with a high-security lab that has been undergoing maintenance, the Centre for Research in Animal Health (CReSA) in the Bellaterra area of Barcelona province, reportedly being blamed.

While authorities have yet to detect a trace of the disease in any other animals, El País newspaper reported that in late November, a wild boar died of the disease just a few hundred metres away from the centre where the virus is being studied.

The Spanish newspaper contacted the CReSA to ask whether construction could weaken security protocols, but did not receive a response.

Salvador Illa, Catalonia’s regional president, said on Saturday (December 6) that he had ordered the autonomous community’s agrifood research institute to conduct an audit of the unnamed facilities.

He said: “The regional government isn’t ruling out any possibilities when it comes to the origin of the outbreak of African swine fever, but neither is it confirming any. All hypotheses remain open. First and foremost, we need to know what happened.”