The inappropriate use of antibiotics in animals poses a risk of the emergence of so-called "superbugs" - but the risk is less than previously believed, according to a leading Irish microbiologist.
Dr Robert Cunney, consultant microbiologist with the National Disease Surveillance Centre, was responding to a statement yesterday by the body representing the animal health industry in the Republic.
The Animal and Plant Health Association (APHA) claimed the "use of antibiotics in farm animals has little connection with the emergence of superbugs" - bacteria which are resistant to antibiotics.
It based its claim on a new study by the European Federation of Animal Health (FEDESA), which estimated farm animals consumed 35 per cent of all the antibiotics administered in the EU during 1999, while humans consumed 65 per cent. "Superbugs" are increasingly causing problems in Irish hospitals and add huge costs to treatment of infections.
This study "suggests that treating sick animals with modern medicine can only be a very small contributing factor to the problem of anti-microbial resistance, if it's a factor at all", said APHA director Mr Declan O'Brien. But this claim may be slightly overstated, Dr Cunney said. "There may not be as great a risk factor as previously thought, but the risk is still there," he said.
APHA also said "there is no evidence that the use of antibiotics in farm animals represents a risk to human health". However, Dr Cunney said scientific studies have found evidence showing the use of antibiotics does pose a risk to humans.
One study, published in the New England Journal of Medicine, reported an outbreak of antibiotic-resistant salmonella in humans in Denmark, which resulted in the deaths of two people and the hospitalisation of 11 others.
This linked antibiotics administered to pigs and the emergence of antibiotic-resistant salmonella in humans, which they developed by eating contaminated pork, Dr Cunney said. Another study, carried out by Dr Cunney and colleagues in the UK, found a link between a bacteria which causes a urinary system infection in humans and the administration of a veterinary antibiotic.
It has been suggested that the EU should limit the medications to treat sick cows, pigs, horses, sheep, goats, chickens, and rabbits as a way of stopping the spread of new bacteria. But APHA said "the new study undermines those arguments because it illustrates that farm animals consume far less antibiotics than people".
Of the antibiotics given to animals, 29 per cent of the total were administered to help sick animals recover from disease, while six per cent were given to farm animals, in their feed, as growth promoters, the FEDESA study found.
Dr Cunney said the use of antibiotics on animals meant animal diseases were "becoming more difficult to treat". The emergence of "superbugs" needed to be attacked through the appropriate use of antibiotics in hospitals and in animals.