'If only people knew what a tick could do' - the deadly meat allergy caused by tick bites

When Myfanwy Webb looks back at her birthday party five years ago, she is overcome with regret - remembering what she now sees as a missed opportunity to save her son's life.

Hours after a celebratory lunch at a restaurant Jeremy began having difficulty breathing. His parents called an ambulance, and the then-15-year-old began vomiting.

At the hospital, doctors noted that Jeremy had a suspected meat allergy, but ultimately blamed the episode on his asthma, which he'd had since he was a toddler. He was sent home the next day.

"I made the wrong decision," Webb says, wishing she had asked for more testing. If she had, doctors might have established that Jeremy had actually been suffering from anaphylaxis, and sent him home with an EpiPen.

​​Just over a year later, in June 2022, Jeremy died after eating a beef sausage on a camping trip with friends at a beach north of Sydney.

The cause of death was initially recorded simply as asthma. But in February, after an inquest pushed for by his family, a coroner ruled that the asthma attack and resulting fatal anaphylaxis was triggered by tick-induced mammalian meat allergy (MMA).

His death is the first in the world known to have been caused by MMA, also known as alpha-gal syndrome.

Diagnosed cases of MMA have steadily escalated since 2007, when an Australian doctor first discovered the allergy was linked to tick bites. Now, scientists and campaigners are warning that the condition, though easily prevented, can be unexpectedly triggered - and could pose a deadly threat.

Webb had long suspected that her son had a meat allergy, but it was never formally diagnosed and the family had no idea it could be fatal.

"When I looked up the research about it, there wasn't at that time anything to suggest it was more than a food intolerance."

In retrospect, she says, it was "like a ticking time bomb."

Symptoms of the allergy can range from mild to severe including skin rashes, swelling, stomach cramps, vomiting and anaphylaxis, which can be life-threatening.

From around the age of 10 Jeremy had suffered nausea after eating meat, or even occasionally after inhaling the fumes from roast meat – which Webb believes may have set off the episode after her birthday party. On another occasion he had been hospitalised after eating marshmallows, which usually contain gelatin derived from animal parts.

What makes an MMA hotspot?

It was Prof Sheryl van Nunen who discovered the link between MMA and ticks almost 20 years ago, after noticing a correlation in patients at her Sydney allergy clinic.

Working on Australia's east coast, she inadvertently found herself in one of the world's two MMA hotspots. The other is in the US - although cases of the allergy have since been noted on all six continents where ticks live.

In Australia, MMA is caused by the bite of the eastern paralysis tick. After two tick bites 50% of people will develop antibodies to alpha-gal, a sugar molecule found in the tick's saliva, van Nunen explains. After that, they have a 15 to 20% chance of becoming allergic to meat.

"If only people knew what a tick could do," she says.

Jeremy, who grew up surrounded by dense bushland at his family home north of Sydney had been bitten by ticks since he was a small boy.

It's not clear why the east coast, particularly areas north of Sydney, is an MMA hotspot - in some areas there are more than 700 sufferers per 100,000 people. But there are several hypotheses, says Dr Alex Gofton, a tick expert who led a recent study into the allergy.

One is that more people are coming into contact with ticks there.

"The population in those tick endemic areas over the last 20, 30 years has increased dramatically," Gofton says.

The years between 2020 and 2023 were also rainy La Nina years - conditions in which ticks thrive - and around the same time the Covid pandemic was pushing even more people to move out of cities and into the bush, he adds.

The high rate of diagnosis - there has been a 22% increase in cases every year since 2020 - may also be fuelled by increased awareness and testing, Gofton says. Using lab data, he has concluded there are more than 5,000 suspected MMA cases in Australia - although he believes this is an under representation of the true figures.

An 'anytime not every time' allergy

Despite increasing awareness, diagnosing a meat allergy can be difficult.

Symptoms often develop at night, hours after people have eaten their evening meal, and for those suffering asthma, the two can often be confused.