Bird flu has been found in a small flock in a backyard in North Yorkshire, the UK’s chief veterinary officer said, warning that people who kept chickens and ducks in their gardens needed to be vigilant.

A 3km protection zone and a 10km surveillance zone have been put in place around the infected premises, near Settle, to limit the risk of the disease spreading. The remaining live birds in the small flock of chickens and ducks are being humanely culled, the Department for Environment, Food and Rural Affairs (Defra) said.

The same H5N8 strain of avian flu has been confirmed at a poultry farm in Lincolnshire and at a premises in Carmarthenshire, Wales. It has also been found in wild birds in England, Scotland and Wales.

The advice from Public Health England is that the risk to public health from the virus is very low. The Food Standards Agency has made clear that bird flu does not pose a food safety risk for UK consumers.

The chief veterinary officer, Nigel Gibbens, said: “We have taken swift action to limit the risk of the disease spreading. Restrictions are now in place around the affected premises and a full investigation is under way to determine the source of the infection.

“This finding in a backyard flock shows how essential it is for all poultry owners, even those who just keep a few birds as pets, to do everything they can to keep them separate from wild birds and minimise the risk of them catching avian flu via the environment.

“This means keeping birds in a suitable building where possible, and taking precautions such as putting up netting, keeping food and water inside and disinfecting footwear and equipment after contact with birds.”

An avian influenza prevention zone that has been in place since 6 December will be extended until 28 February to help protect poultry and captive birds from avian flu, Gibbens said.

The zone requires keepers of poultry and other captive birds to continue to keep their birds indoors, or take appropriate practical steps to keep them separate from wild birds.

It covers England and similar declarations have been made in Scotland and Wales. There is also a Britain-wide ban on poultry shows and gatherings.