As almost half a million cases emerge of a rare red meat allergy in the US, experts are urging Australians to be aware of the its link to a common risk Down Under — tick bites.
The warning comes as we enter the warmer months, with research indicating some may be at risk of developing the possibly life-threatening reaction to several types of meat or animal products.
Researchers say the condition may have already impacted as many as 450,000 people in the US. New data released by the Centers for Disease Control and Prevention (CDC) on Thursday shows a steep increase in cases of the illness.
Tick season in Australia started in July and will continue through the summer — increasing the risk of tick-borne illnesses. One illness, in particular, can even cause a regular person to develop a potentially fatal red meat allergy.
Mammalian Meat Allergy (MMA) has a number of symptoms, including gastrointestinal issues, which can emerge four to six hours after consuming mammalian meat such as beef, lamb, pork, kangaroo, and rabbit. Researchers are warning that mammalian milk products and animal-derived gelatin can also trigger MMA symptoms.
Dr David Langley of the Garvan Institute of Medical Research told news.com.au the delayed onset of the symptoms set MMA apart from most immediate tick allergies.
He explained the allergen responsible for MMA is a sugar molecule called alpha-galactose (alpha-gal), found in all mammalian meat apart from humans and apes. As we don’t produce the alpha-gal sugar, we have a natural low-level response against it when consumed in a meal, which is ordinarily of no concern.
However, our normally benign response to alpha-gal can be triggered towards a more serious immune response if we become sensitised after a tick bite, leading to severe reactions upon subsequent red meat consumption.
For those unlucky enough to develop MMA, red meat should obviously be avoided although chicken and fish are still on the menu as, unlike most mammals, neither produce the alpha-gal sugar. In most cases, the severity of the MMA will diminish over a course of several years.
“It is a bit of a mystery as to why alpha-gal sensitisation happens,” he told news.com.au. “But there is a high correlation between tick bites and this allergy.
“We’re not sure if it’s related to what the tick has been feeding on prior to biting the human, typically other mammals such as dogs, kangaroos, possums or bandicoots, which also contain alpha-gal, or whether there is something intrinsic to the tick bite that results in sensitisation.”
Dr Langley warned not to try and simply scratch or pull the tick off once discovered.
“As ticks become firmly attached and difficult to remove, if you aggressively scratch it off you risk spilling its guts into the bite wound,” he said, adding that he recommends a freezing agent like Tick-Off, or Wart-Off to locally freeze the minuscule arachnids before gently brushing them off or carefully removing them with tweezers.
The most high-risk areas lie on Australia’s east coast, “wherever there is moisture and warmth”, but also the east coast of the US.
Dr Langley advised to wear long loose clothing when trekking in the bush, and to always check yourself when you come in, particularly around sweaty areas and sometimes in your scalp.
Those who really immerse themselves in the bush (bush-care volunteers, for instance), will also tuck trousers into socks and apply insect repellent to their clothing. Wearing a hat is also advised.
In the US, more than 110,000 cases have been detected since 2010, the CDC says. From 2017 to 2021 the number of cases increased by around 15,000 per year.
Due to difficulties with diagnosis, the CDC says that up to 450,000 Americans in total may have developed meat allergies due to alpha-gal.
While there is no established treatment for MMA, research is underway to develop potential ways to deal with the issue.
Tick Induced Allergies Research & Awareness (TiARA) notes varying immune susceptibility, estimating the prevalence of MMA in Australia at around 113 per 100,000.
The Australian paralysis tick (Ixodes holocyclus) is responsible for most tick bites and related allergies, potentially leading to fatal outcomes.