A family of wild boars euthanised by wildlife personnel of the Department of Heritage amid fears they would spread a contagious and fatal disease to local pigs and pig farms were free of all disease, tests have confirmed.

Seven boars were spotted running wild in the Mount Eagle and Castleisland areas on 15 June. Six were isolated in a field where silage was being cut and shot by National Parks and Wildlife (NPWS) personnel.

They comprised two females and four piglets. A large male boar escaped and was tracked down some days later.

The shootings caused distress among animal rights activists and others who pointed out that place names from Kanturk in Cork to Muckross and Torc in Killarney were associated with the once native boar or "torc".

The Department of Housing, Local Government and Heritage, which worked with the Department of Agriculture on the issue, said boar were considered an alien species and it was policy to eradicate those released illegally.

"Such releases are not only illegal, but they also pose a very serious threat to the disease-free status of the national herd. There could be dire consequences if diseases such as blue tongue or African swine flu were to be present or if these highly contagious disease were unintentionally introduced," they said.

The dead animals were sent to the regional laboratory for analysis.

The Department of Agriculture confirmed at the weekend the tests were clear.

"African swine fever (ASF) is a viral disease currently affecting the wild boar and domestic pig population in many European countries which can kill up to 100% of animals affected," the Department of Agriculture said.

"Although, Ireland has never had an outbreak of ASF, the Department urges farmers to remain vigilant for signs of this devastating disease which can be spread for example through the illegal feeding of infected pig meat or the movement of infected animals," it said.

As part of early detection measures for ASF, the department carries out surveillance on feral pigs of unknown origin which have been removed from the environment by the Department of Housing, Local Government and Heritage and all test results to date, including the recent samples collected in Kerry, have returned negative results for ASF.