Alpha-gal syndrome, a tick-borne illness that can cause a life-threatening allergy to red meat, is spreading across the United States. Researchers estimate that up to 450,000 Americans may be living with the condition, many unaware until they experience sudden allergic reactions after eating meat they have consumed for years.
There is no cure for the syndrome, and reactions can be fatal. Two deaths have been reported, including a 47-year-old New Jersey pilot who died after being bitten by an infected tick and later eating meat at a barbecue. Experts fear the syndrome is underdiagnosed, with potentially more deaths going unrecognised.
Warmer weather linked to climate change is expanding tick habitats. While the lone star tick was previously thought to be the only culprit, researchers have identified western black-legged ticks and deer ticks as carriers. Cases have surged beyond the Southeast into the Northeast and Midwest.
Dr Vinay Jahagirdar and colleagues found a 100-fold increase in positive tests for alpha-gal antibodies from tick bites between 2013 and 2024. Over 110,000 suspected cases were identified from 2010 to 2022, according to the US Centers for Disease Control and Prevention.
Symptoms, which appear two to six hours after eating red meat, include nausea, vomiting, diarrhoea, difficulty breathing, and rash. Some people have no symptoms. Doctors may prescribe epinephrine auto-injectors for severe reactions.
