Both Australia and the US have recorded the first known deaths from red meat allergy that developed following tick bites.
The death of teenager in NSW, Australia in 2022 and a man from New Jersey in 2024 have both recently been confirmed as being caused by an allergic reaction to eating red meat (alpha-gal allergy). The development of alpha-gal allergy is caused by tick bites, with the main culprit in Australia being the paralysis tick (Ixodes holocyclus) and in the US the common culprit being the lone star tick (Amblyomma americanum).
Alpha-gal syndrome (AGS) or mammalian meat allergy (MMA) as it is often called in Australia, is an allergic reaction to galactose-alpha-1,3-galactose, a sugar found in mammalian meat and dairy products. It can develop after being bitten by certain species of ticks. The NSW teenager was reportedly bitten numerous times while camping during childhood and the New Jersey man had been bitten by numerous lone star ‘seed ticks’ (tick nymphs) on a family camping trip prior to his allergic reaction.
Symptoms start to occur 2-6 hours after eating mammalian meat or dairy products. The severity of symptoms depends on the sensitivity of the patient and can vary from hives and itching through to stomach pain, vomiting and diarrhoea, and in severe cases impact the respiratory system. Occasionally symptoms extend to anaphylaxis and death.
It is not clear how common this allergy is. In the US, AGS is only a reportable diagnosis in three states. The US Center for Disease Control and Prevention estimates that 450,000 Americans may have the allergy. In Australia, the prevalence is 113 per 100,000 people, but is as high as 700 cases per 100,000 people in hot spots such as the northern beaches of Sydney and northern NSW. However, many people with the allergy don’t always show symptoms or only develop mild symptoms, and since they occur several hours after eating the meat or dairy products, the two events are often not connected. In addition, medical attention is often only sought in cases of severe allergic reactions.
Apart from protecting yourself from tick bites, and offering clients tick treatments for their yard, pest managers can help make sure their customers are aware of mammalian red meat allergy. CSIRO reports that nationally, reported cases have been increasing by approximately 40% per year since 2020, indicating that it could be a growing health problem.
