The discovery of the highly pathogenic H5N1 strain of avian influenza, or bird flu, at a commercial turkey farm in Co Carlow is "very worrying", the Irish Farmers' Association has said.
It is understood that the farm has a flock of around 500 turkeys.
A 3km protection zone and a 10km surveillance zone are in place around the site in Carlow.
It is the first outbreak of bird flu in a commercial poultry flock in Ireland since 2023, although the virus has been detected in more than 40 wild birds across the country this year.
Speaking on RTÉ's Morning Ireland, National Chair of the IFA's Poultry Committee Nigel Sweetman said the pattern of bird flu is changing and presents in a new form every year.
"It's a mutating disease and every year presents in a new form and new challenges. It arrived probably a month earlier than normal, and in different geographical locations, with two outbreaks in Cork, where we haven't seen it very much before.
"So it's all together, very, very worrying, and particularly for the farmer involved. It's his livelihood," Mr Sweetman said.
He said the turkeys in Co Carlow had become infected by wild birds and the flock will now have to be euthanised.
Mr Sweetman advised farmers to consult with their vets if they have concerns about their flock.
He said people who find dead birds on the ground should report it to a vet, because it is vitally important that "we keep track of where the disease is".
Mr Sweetman called for a housing order to be implemented, which would compel free-range farmers to keep birds indoors and restrict movement onto their sites, keeping unnecessary visits out of farms.
"Over the last five years, because bird flu is becoming such an issue, we have enhanced housing for birds. We've reduced stocking rates. We have the facilities now to keep birds indoors. It's basically avoiding trouble," he added.
No concern over fewer turkeys for Christmas
Chief Veterinary Officer Dr June Fanning at the Department of Agriculture said there is no concern, at this stage, that there will be fewer turkeys than usual for Christmas.
Speaking on the same programme, Dr Fanning said the flock in Co Carlow is a relatively small commercial operation and both the State and poultry sector have experience in dealing with commercial outbreaks and minimising their impacts.
"Industry have been really good at working with us in relation to biosecurity. It is highly contagious, so it is a threat, but we have measures in place, restriction zones - the three and 10km around the infected holding, they are all in place to prevent and minimise the spread of the disease," Dr Fanning said.
"Biosecurity is really, really important ... So this is simple things. Even if you've only one or two birds or a commercial poultry flock, it's, you know, changing dedicated footwear, changing clothes, before you interact with the birds.
"Feeding them away from wild birds, reducing that interaction between wild birds and kept birds, reducing the number of visitors onto a holding, cleaning and disinfecting vehicles. So very simple," Dr Fanning said.
Head of Communications and Development for Birdwatch Ireland Niall Hatch said he is very concerned about wild bird populations and "little heed" that has been paid to them.
Speaking on RTÉ's Today with Philip Boucher-Hayes, Mr Hatch called for "more joined-up thinking" and guidance as to how wild birds should be handled and buried.
"I think we do need more clarity as to what whose responsibility is to remove carcasses. I know that in public areas, the advice is that it's the local authority.
"But then when it's on private land, either a farm or a garden or school yard, which is something we encountered quite a bit, the advice is that it's the responsibility of the landowner, but the advice also is not to touch the bird, so there's there's a disconnect," he said.
Mr Hatch said scavenging animals remove dead birds and it spreads the disease further.
"It is very important that these carcasses are cleaned up and also to prevent spreading within those wild bird populations at times when they are congregating," he said.
Outbreaks of highly pathogenic bird flu have also been identified in poultry flocks in several European countries, as well as the United Kingdom, this year.
It comes after Fota Wildlife Park announced it will remain closed until at least the end of the month due to an "ongoing assessment of the national avian flu situation".
The UK is due to bring in a housing order for captive poultry flocks on Thursday that will include Northern Ireland, with the Irish Government expected to introduce a similar measure.
Although avian influenza can be very contagious between birds, the Health Protection Surveillance Centre (HPSC) and the European Centre for Disease Control (ECDC) advise that the risk to public health from the strain circulating is very low.
Members of the public are advised not to handle sick or dead wild birds and to report any episodes of sick or dead wild birds to their regional veterinary office or, if outside business hours, to contact the National Disease Emergency Hotline on 01 492 8026 or use the Department of Agriculture's 'Avian Check' app.
