Exhaustive tests have failed to find the source of anthrax that killed two cattle on a Welsh farm.
No evidence of the bacterial disease was found in samples of soil, sediments and water collected at Ynys Gau Farm, Gwaelod-y-Garth, near Cardiff.
Welsh Assembly scientists claimed the negative results indicated that any ongoing risk to animals was low, and that the likely source was spores from an outbreak on the farm 35 years ago.
In a statement they said that monitoring of remaining stock would continue, and the farmer would be advised on the actions to
take should further cases occur.
The public health implications were minimal.
There was no evidence of spores in the river, and any that were there would be diluted to such a degree that infection was extremely unlikely.
As anthrax in humans was usually caused by direct contact with diseased animals, the risk to users of public rights of ways crossing the land was also small, so the lifting of the ban on their use was being considered.
But veterinary officials emphasised that it was imperative that dogs were not allowed to roam when the public used any footpaths crossing farmland.
Gareth Vaughan, president of the Farmers Union of Wales, said he extended the sympathy of all his members to the farmer involved in the outbreak.
The negative test results would mean continuing uncertainty, extra vigilance and adopting specific targeted biosecurity advice.
“But the positive thing is that the Welsh Assembly can be congratulated on the speedy but calm way Christianne Glossop, the chief vet, and her staff reacted to ensure that the outbreak was contained and that the public were reassured,” Mr Vaughan claimed.
As a result of their actions, which included halting the sale of stock from the farm, and closing footpaths, there had not been a blip in consumer confidence in home-produced beef.
“It was particularly satisfying to see the animal health and public protection measures that are in place working well.”