Researching viruses in farm animals is essential rather than glamorous work, and The Pirbright Institute in Surrey excels at it. But recently they've been getting some very unwanted attention.

For months they've been unwittingly drawn into the orbit of conspiracy theorists, including those who accuse Bill Gates of planning the coronavirus pandemic. It's led to hate mail and threatening phone calls.

"We'd never experienced anything quite like that. Some of the commentary was quite vicious. Calling us murderers, that type of thing", says Teresa Maughan, head of communications.

Teresa remembers one particular phone call. The person had rung up before, leaving a colleague in tears after shouting down the phone accusing them of creating coronavirus and using it as a bioweapon.

"He then called me pretending to be Mrs Doubtfire, so it was pretty obvious it was somebody putting on a voice. He said something sexually abusive to me and I obviously put the phone down."It all started in January with misleading social media posts about a patent.

Jordan Sather, a YouTuber who promotes the pro-Trump QAnon conspiracy in the United States, posted a series of tweets linking The Pirbright Institute to a patent "for the coronavirus" granted in 2018.

Coronaviruses are a large family of viruses known to cause a range of illnesses in both animals and humans. The novel coronavirus that causes Covid-19 only emerged at the end of 2019, so the suggestion being made was that the institute had identified this virus much earlier and lodged a "patent" for it.

The institute does hold a patent, but it's linked to research into a vaccine for a previously known coronavirus that affects chickensMr Sather also wrote that Bill and Melinda Gates were major funders of this Pirbright project, later speculating: "Was the release of this disease planned?"

The connection to Bill Gates has drawn the institute into a much bigger global conspiracy theory - tapping into the unfounded notion that sinister forces led by Mr Gates have orchestrated the whole pandemic to eventually make huge profits from a Covid-19 vaccine.

The Gates Foundation is one of the world's largest supporters of global health projects, and The Pirbright is quite open about its funding from there for research linked to vaccines. However, that funding isn't related to any work for which a patent has been taken out.

At the end of March, long after the attacks began on social media, The Pirbright started working with Oxford University and Public Health England to test a potential Covid-19 vaccine on pigs, a necessary stage before a vaccine can be tested on humans.

We tried to contact Mr Sather about his comments but have been unable to get a response. In a later tweet he says he didn't claim The Pirbright patent was specifically for the "novel coronavirus" (the virus which causes Covid-19)..A search for The Pirbright Institute on CrowdTangle, a social media monitoring tool, returned 191,000 results between 16 January 2020 and 16 June. There were just 711 in the previous six months.

All manner of false accusations were levelled at them: that they had a patent for the virus or a vaccine for it; that they were actually based in Wuhan; that they were owned by Bill Gates.Online abuse was hurled at staff. An email to Dr Erica Bickerton, an expert in molecular virology, read:

"You know the composition of this Virus so you know how to destroy it...SO PLEASE I REQUEST YOU NOT LET MY FAMILY DIE AND TELL ME THE ANTIDOTE."

"Personally I found the misinformation spreading quite difficult", says Dr Bickerton,"because the work we're trying to do is to help livestock and other animals and understand this virus."

Someone even went to the trouble of setting up a fake "Pirbright" website offering to sell a coronavirus bioweapon.

BBCnews