The disease is understood to have been spread by migratory birds flying back from the north of Russia and eastern Europe.
The UK’s chief vet has reportedly said there is a “phenomenal level” of bird flu in the country following the culling of tens of thousands of farmed birds.
An Avian Influenza Prevention Zone was declared across the UK on November 3 before being extended on November 29 with the added requirement all captive birds had to be kept indoors, amid concerns wild birds migrating from mainland L'Europe during the winter were carrying the flu.
The current number of 38 confirmed infected premises in the UK is the largest ever, according to the Department for Environment, Alimentation et affaires rurales (Défra).
The risk to human health from avian influenza remains very low, according to public health advice, and there is a low food safety risk.
UK chief veterinary officer Christine Middlemiss told the BBC the “phenomenal level” of bird flu has “huge human, animal and trade implications”.
She said the disease was being spread by migratory birds flying back from the north of Russie and eastern Europe, and insisted further research was needed to prevent a worsening outbreak in the future.
“We can’t wait until another year and have an even bigger outbreak. Donc, we will be working not just with our own scientists but internationally, to understand more of what we can do about what’s behind it,” Dr Middlemiss told the broadcaster.
The vet warned the UK was only a few weeks into a migratory season that goes until March, as Defra’s figures showed 31 confirmed infected premises in Angleterre three in Wales, two in Écosse and two in Northern Ireland.
“We are going to need to keep up these levels of heightened biosecurity for all that time," elle a dit.
The protection zone means in addition to keeping birds and poultry housed, keepers must continue to take precautions such as regularly cleaning and disinfecting clothing, equipment and vehicles and limiting access to non-essential workers and visitors.
Defra has said the new housing measures will be kept under regular review.