Rare illness spreading across US that causes meat allergy has sparked warning from officials

A rare illness that's started spreading across the US has sparked a warning from experts.

Sufferers experience a range of symptoms, including itching, swelling and stomach pain, after eating animal products.

Presenting like a food allergy, the symptoms can occur in people who have eaten meat all their lives, but are triggered by the bite of a specific insect - a tick.

Ticks are parasites that feed on the blood of birds and mammals, including humans.

They vary in size and species and although the bites usually aren't painful, they can have lasting consequences in some cases.

For example, in the US, the bite of a lone star tick has been known to leave people with the illness - known as 'alpha-gal syndrome' or 'red meat allergy'.

Alpha-gal syndrome is also referred to as 'red meat allergy' (Getty Stock Image)

This happens due to a process which occurs once the tick has bitten a human.

The Centers for Disease Control and Prevention (CDC) explains: "Alpha-gal is a molecule (galactose-α-1,3-galactose) that is naturally produced in the bodies of most mammals but not in people. It is also found in the saliva (spit) of some ticks.

"When a tick bites, it can transfer alpha-gal from its saliva into a person's blood. The body's natural defences, or immune system, can identify alpha-gal as a threat and trigger an allergic reaction."

Some people could even have the condition and be unaware.

The bite of a lone star tick has been known to leave people with alpha gal syndrome (Getty Stock Image)

It seems that the illness is on the rise, with the CDC explaining that as many as 450,000 Americans could be affected since 2010.

What are the symptoms of alpha-gal syndrome?

Symptoms of alpha-gal syndrome include:

• Hives and itching
• Swelling of the lips, face, throat or eyelids
• Wheezing or shortness of breath
• Stomach pain, diarrhoea, nausea or vomiting

Symptoms usually appear up to six hours after eating an alpha-gal product.

Symptoms include hives and itching (Getty Stock Image)

What have experts said about alpha-gal syndrome?

Experts have shared warnings over the increase in cases, with Brandon Hollingsworth of the University of Carolina telling the Guardian: "We thought this thing was relatively rare 10 years ago but it’s become more and more common and it’s something I expect to continue to grow very rapidly.

"We’ve seen an explosive increase in these ticks, which is a concern. I imagine alpha-gal will soon include the entire range of the tick, which could become the entire eastern half of the US as there’s not much to stop them. It seems like an oddity now but we could end up with millions of people with an allergy to meat."

Meanwhile, in Martha's Vineyard, in the US, many people have turned to animal-free diets due to the increase in the allergy.

"Alpha-gal cases are skyrocketing across the island," Patrick Roden-Reynolds, a biologist in charge of the tick safety programs on Martha’s Vineyard and Nantucket, told the New York Times.

"There are a lot of angry people, a lot of stressed-out people and a lot of fearful people."

While researchers believe that alpha-gal syndrome can improve over time, it can also be worsened by any further tick bites.