Martha’s Vineyard is experiencing a sharp rise in lone star ticks, whose bites can trigger alpha-gal syndrome, an allergy to red meat and sometimes dairy. The spread is disrupting everyday life and local businesses, with residents taking greater precautions outdoors and restaurants adapting menus.

The tick, marked by a white spot on its back, has expanded north and west from the southern United States since the 1980s, with numbers rising markedly after 2011. Martha’s Vineyard Hospital conducted more than 1,600 alpha-gal tests last year, compared with nine in 2020; 44 per cent were positive, though the true total may be higher. Reactions vary widely, from digestive symptoms to anaphylaxis, while some bitten people develop no allergy.