A rare but potentially deadly allergic reaction to mammalian meat, triggered by tick bites, has come under the spotlight following a coroner's ruling in Australia. The condition, known as mammalian meat allergy (MMA) or alpha-gal syndrome, was confirmed as the cause of death for Jeremy Webb, a 16-year-old who died in June 2022 after eating a beef sausage. His death marks the first known fatality globally attributed to MMA, prompting warnings from scientists and campaigners about the unexpected dangers of the condition.
Jeremy had experienced nausea after consuming meat from the age of 10, and had been hospitalised on at least one occasion. Despite these episodes, his family were unaware of the potential severity of his allergy, which was never formally diagnosed as MMA. His mother, Myfanwy Webb, expressed regret over not pushing for more extensive testing after a severe reaction five years ago, which might have led to a diagnosis and an EpiPen prescription. The family's persistence led to an inquest that ultimately linked Jeremy's fatal anaphylaxis to tick-induced MMA.
The link between tick bites and MMA was first identified by Professor Sheryl van Nunen in Australia nearly two decades ago. She observed a correlation in patients at her Sydney allergy clinic, located in one of the world's two known MMA hotspots – the other being in the United States. Cases of the allergy have since been reported on all six continents where ticks are found. In Australia, the eastern paralysis tick is responsible, with studies showing that after two bites, 50% of individuals develop antibodies to alpha-gal, a sugar molecule in the tick's saliva, leading to a 15-20% chance of developing a meat allergy.
Symptoms of MMA can vary widely, from mild skin rashes, swelling, and stomach cramps to severe and life-threatening anaphylaxis. Dr Alex Gofton, a tick expert, suggests that the increasing incidence in areas like Australia's east coast, where over 700 per 100,000 people are affected in some regions, could be due to increased human-tick interaction. Factors such as population growth in tick-endemic areas, coupled with recent rainy La Niña years that favour tick proliferation, and a shift of people from urban centres to bushland during the Covid-19 pandemic, are believed to contribute to this trend.
While this particular tick species is not native to the UK, other tick species are prevalent, and the broader implications of tick-borne illnesses are a concern for UK public health. The NHS advises on tick bite prevention, particularly when spending time outdoors in grassy or wooded areas, to reduce the risk of diseases like Lyme disease. Although MMA cases linked to UK ticks are not widely reported, the Australian experience highlights the need for vigilance regarding unusual allergic reactions following tick exposure.