The bird flu pandemic with the potential to be “100 times worse than COVID” may be on the horizon after a rare human case was discovered in Texas, experts have warned, the New York Post reported on Thursday.

The H5N1 avian flu has spread rapidly since a new strain was detected in 2020 affecting wild birds in every state, as well as in commercial poultry and backyard flocks.

But the recent cases detected in mammals, with cattle herds across four states becoming infected and on Monday, federal health officials announced that a dairy worker in Texas caught the virus.

“This virus [has been] on the top of the pandemic list for many, many years and probably decades,” Suresh Kuchipudi, a bird flu researcher from Pittsburgh, said at a recent panel discussing the issue, the New York Post reported citing the Daily Mail.

“And now we’re getting dangerously close to this virus potentially causing a pandemic.”

He noted that the H5N1 virus has already been detected in species throughout the world and “has shown the ability to infect a range of mammalian hosts, including humans.”

“So therefore, in my view, I think this is a virus that has the greatest pandemic threat [that is] playing out in plain sight and globally present,” Kuchipudi said.

John Fulton, a pharmaceutical industry consultant for vaccines and the founder of Canada-based BioNiagara who organized the meeting, also expressed his concerns, the Mail reports, the New York Post reported.

“This appears to be 100 times worse than COVID — or it could be if it mutates and maintains its high case fatality rate,” he said.

“Once it’s mutated to infect humans, we can only hope that the [fatality rate] drops.”

Around 52 per cent of humans who have contracted H5N1 since 2003 have died, according to the World Health Organization.

For comparison, COVID currently kills less than 0.1% of those it infects — though at the start of the pandemic, the fatality rate was around 20 per cent.

Symptoms of the bird flu are similar to those of other flus, including cough, body aches and fever, the New York Post reported.

Some people may not develop noticeable symptoms, but others can develop severe, life-threatening pneumonia.

The dairy worker in Texas who was infected has reported “eye redness (consistent with conjunctivitis)” as their only symptom, the Centers for Disease Control and Prevention noted.

“The patient was told to isolate and is being treated with an antiviral drug for [the] flu,” the CDC said.

The agency and “the whole US government is taking this situation very seriously,” CDC Director Mandy Cohen told the Washington Post.

She maintained that the virus does not pose much of a risk to the general public, noting that the dairy worker was in direct contact with infected cattle, and the US Department of Agriculture has said there are currently no changes that would make it more transmissible to humans.

“While cases among humans in direct contact with infected animals are possible, this indicates that the current risk to the public remains low,” the department said in a statement over the weekend.

But the fact that the virus has been found in cattle could mean it is starting to mutate, Cohen told the Washington Post.

“We had not seen avian flu in cattle prior to last week. That is new,” she said. “It is a reservoir for [the] virus to circulate and potentially change.”

If the virus does mutate enough to infect humans, it could spread rapidly, the European Food Safety Authority warned on Wednesday, according to Fox News.

“If avian A [H5N1] influenza viruses acquire the ability to spread efficiently among humans, large-scale transmission could occur due to the lack of immune defences against H5 viruses in humans,” the Food Safety Authority said.

To prevent any potential spread, the US is already testing components used to create a vaccine for the virus, and two candidate vaccine viruses appear to be well-matched to protect against H5N1, the Washington Post reports.

White House press secretary Karine Jean-Pierre also said the Biden administration is monitoring the threat.

“We take the health and safety of the American people seriously,” she said at her briefing on Wednesday. “It is very important to this president.

“Our top priority is to keep communities healthy, safe and informed.”