Ellesha Gosling, Mr Gosling’s daughter-in-law, said he had first noticed that several of the ducks had become ill shortly before Christmas.

Mrs Gosling, from Cranbrook, Devon, said: “The past couple of weeks have been hell for this family. He saw all of his ducks killed, and they were like his closest friends. He is often on the phone to us, asking what the doctors have said, but we can’t answer questions we don’t know the answers to.”

The flock of ducks originally lived in a public area near Mr Gosling’s home, but after feeding them for a number of years he brought them to his house, where he kept 20 indoors.

The family said he had been tested several times, one of which had come back as the H5N1 strain, although the UK Health and Security Agency (UKHSA) said his infection had not been confirmed. Contacts of Mr Gosling have been traced, and none have tested positive for the disease.

The UKHSA has notified the World Health Organisation and urged members of the public not to touch sick or dead birds.

British outbreaks on the rise

The UK has recently seen a large number of outbreaks and incidents of avian influenza of the H5N1 strain in birds across the country, with 36 confirmed cases last year leading to a cull of 500,000 birds.

Christine Middlemiss, the UK’s chief veterinary officer, said: “While avian influenza is highly contagious in birds, this is a very rare event and is very specific to the circumstances on this premises.

“We took swift action to limit the spread of the disease at the site in question, all infected birds have been humanely culled, and cleansing and disinfection of the premises is under way. This is a reminder that stringent cleanliness when keeping animals is important.”

Mike Tildesley, a professor of infectious disease modelling at the University of Warwick, said members of the public who do not spend long periods with birds had no need to worry.

“This is clearly going to be big news, but the key thing is that human infections with H5N1 are really rare and they almost always occur as a result of direct, long-term contact with poultry,” he said. “There has never been any evidence of sustained human-to-human transmission of H5N1, so at present I wouldn’t consider this to be a significant public health risk.”

Experts also said there was no risk to food. Prof Ian Jones, a virologist at the University of Reading, said: “Despite the current heightened concern around viruses, there is no risk to chicken meat or eggs, and no need for public alarm.”

Prof Isabel Oliver, the chief scientific officer – transition lead at UKHSA, said: “While the risk of avian flu to the general public is very low, we know that some strains do have the potential to spread to humans and that’s why we have robust systems in place to detect these early and take action.”