It is “almost inevitable” that an outbreak of avian influenza (AI) will occur in the NI poultry industry, DAERA’s chief vet Robert Huey has said.
“We know it’s out there in wild birds. So far, they have only been found up the River Bann as far as Kilrea and in Lough Beg, but you can be sure it’s virtually everywhere,” Huey said.
The highly pathogenic H5N8 strain of bird flu is circulating in western Europe and has led to outbreaks in commercial poultry flocks across Britain, as well as in a free-range Turkey unit in Co Wicklow.
A compulsory housing order came into effect in NI on Wednesday (23 December) which makes it a legal requirement for all poultry to be kept indoors full-time.
However, Huey warned that the housing order does not remove the threat of an AI outbreak occurring in commercial poultry units.
“A housing order is not a panacea. It doesn’t cure all ills. It does not replace good biosecurity,” the chief vet said.
“Time and time again, when there are outbreaks, it’s the weakest link that has let people down. It’s not rocket science, it’s something very simple that has gone wrong and has resulted in the flock getting infected,” he added.
A compulsory housing order can lead to issues for free range producers, as products are no longer classified as free range if birds have been housed for a continuous period of sixteen weeks.
However, the legislation has changed since the last housing order in NI, implemented during the winter of 2016/17. Back then, poultry products were no longer free range after 12 weeks of full-time housing.
The current housing order in NI is likely to remain in place well into the spring.
“The only time [avian influenza] risk [status] will go back to low again is when migratory birds return back north which is around the end of April or so,” Fraser Menzies from DAERA said.
Six months to re-stock after outbreak
It could take up to six months before a poultry unit can re-stock after an avian influenza (AI) outbreak, according to Ignatius McKeown from DAERA.
If AI is suspect on a unit, a local DAERA vet takes samples from the house and sends them to the Agri Food and Biosciences Institute (AFBI) for testing.
“We get the results fairly quickly, generally within 24 hours. If it is positive, the next thing that happens is the flock is valued and culling takes place. The birds are disposed of by rendering. We then start a process of cleansing and disinfection,” McKeown said.
The manure also has to be disposed of, but it may have to remain on the unit until the material is no longer deemed a source of the AI virus.
“Depending on the circumstances, it may be that the manure has to be left on the farm, so potentially it could end up that it is six months before it is possible to put poultry back on your farm again,” McKeown said.
As well as maintaining high levels of biosecurity on poultry units, a key message from the DAERA webinar was to be vigilant for any early signs of bird flu in poultry.
“The sooner that we get in, the sooner we get them culled, the less chance there is of it spreading to other farms,” McKeown explained.
Ian Stewart from Parklands Veterinary Group said that one of the first signs of an AI outbreak is the birds go quiet and stop eating.
“It’s a very severe infection that makes the birds have a high temperature. They quickly become dull and reluctant to move about. They will be sleepy looking with their eyes partially closed and very often their beak and head will be tucked in under their feathers,” Stewart said.
Other possible signs include a discharge of fluid or blood from the beak, the head becomes swollen, bruising appears on the legs and diarrhoea is seen below the tail.
“Not all those signs may show up in an outbreak. It is important that if you see anything abnormal, you alert your vet straight away,” Stewart said.
Avian influenza vaccine is a non-starter
Developing a vaccine for avian influenza (AI) is not a long-term solution for the poultry industry, viewers on DAERA’s webinar were told.
“The main stumbling block is AI viruses have a great ability to change. To get a vaccine that will actually work, and to have it ready each year for the new strains of virus that come along, it would be a great challenge,” said Ian Stewart from Parklands Veterinary Group.
Also, if a vaccine was available, its use would likely lead to restrictions on the international trade of poultry products, particularly by countries that do not use the vaccine.
“Vaccinated birds can still shed the virus and it’s very hard to prove what birds have been vaccinated and what birds actually have avian influenza,” explained DAERA vet Gemma Daly.
Ignatius McKeown from DAERA added that the use of an AI vaccine would create the opportunity for further mutation of the virus, especially if the strain from the vaccine entered the wild bird population.
“Flu viruses can basically join together, and you can get completely different strains of flu virus coming out of it. There are many complications with the use of a vaccine,” he maintained.