How can a tick bite cause a deadly meat allergy? An expert explains
- Written by The Conversation
An Australian teenager who died after eating beef sausages on a camping trip has been confirmed as the nation’s first death from a tick-induced meat allergy.
New South Wales Deputy State Coroner Carmel Forbes today ruled Jeremy Webb died in 2022 from an anaphylactic reaction, which triggered an asthma attack.
This makes the teenager only the second person in the world confirmed to have died from “mammalian meat allergy”, after the 2024 fatal case of a man in the United States.
Here’s what you need to know about how tick bites can lead to a meat allergy.
How can ticks cause this?
In Australia, it’s mainly the bite of the eastern paralysis tick (Ixodes holocyclus) that causes mammalian meat allergy.
The tick’s saliva naturally contains a sugar molecule called alpha-gal, short for galactose-α-1,3-galactose, a sugar not normally present in humans.
So when a tick bites, alpha-gal enters the blood stream and in some people prompts the body to produce molecules associated with an allergic response (known as IgE antibodies). So their body is “primed” for an allergic reaction, but doesn’t have one straight away.
But when a person later eats substances containing alpha-gal – meat, products containing gelatine such as lollies, or certain medicines – this can trigger an allergic response hours later.
This can range from hives, gut symptoms (such as cramping and diarrhoea), to a severe anaphylactic reaction that affects the respiratory and cardiovascular systems.
Who’s at risk? Are cases rising?
While this latest Australian case involved a teenager, mammalian meat allergy typically occurs in older age groups.
In research that colleagues and I have just concluded and will be submitting for publication shortly, we’ve found that mammalian meat allergy peaks in Australians aged 45–75.
Females are at increased risk, accounting for about 60% of cases, but we don’t know what’s driving that.
Our analysis of 11 years of data to 2025 also showed that annual case numbers remained relatively stable until 2020, but have since grown rapidly, on average 22% year on year.
By 2024, we saw 787 people nationwide testing positive to alpha-gal antibodies.
But most (we estimate about 90%) of that increase is down to greater awareness and more testing for mammalian meat allergy.
Only about 10% is due to a real increase in disease prevalence. We don’t exactly know why this is happening. But hypotheses include a run of mild summmers/wet winters leading to higher tick numbers, or greater exposure to ticks as people move to the bush or urban fringes.
In our study we saw cases from every state and territory, although 96% of cases occurred within Ixodes holocyclus endemic regions along the east coast.
What was remarkable, though, was the extreme geographical clustering of cases in specific high-risk regions.
Hinterland regions of south-east Queensland and northern NSW, the northern beaches regions of Sydney, and NSW south coast in particular had disproportionately high case numbers.
Not just allergies
Exposure to alpha-gal may have other effects, other than triggering an allergic reaction from eating meat.
We are among a group of researchers exploring possible links with cardiovascular (heart) disease.
We’re working with Australian Red Cross Lifeblood to analyse blood from 5,000 donors, including from high-risk communities. We’re aiming to see if exposure to alpha-gal from tick bites might put certain people at higher risk of cardiovascular disease later in life.
The hypothesis is that exposure to the alpha-gal allergen leads to low-level inflammation of the plaques associated with coronary artery disease.
But we haven’t started analysing those samples, so it’s early days yet.
Prevention is best
There is no cure for mammalian meat allergy. So preventing tick bites is best:
wear long-sleeved shirts and long pants when walking or working in areas where there are ticks
tuck pants into long socks
wear a wide-brimmed hat
wear light-coloured clothing
use insect repellent, particularly ones containing DEET.
And if you are bitten by a tick, don’t use household tweezers to remove it. Use the methods described in this video instead.
