Alexis Ohanian, the co-founder of Reddit and husband of the tennis star Serena Williams, was perplexed.

He was showing no symptoms of Lyme disease, and had not spent much time in the wilderness or northeastern US states where the ticks that carry it are most prevalent. And yet, after a “full battery of health scans”, his doctor had told him that he was infected.

Experts warn that celebrity tell-alls and rampant “pseudoscience” surrounding Lyme is fuelling misdiagnoses. “Lyme disease has been plagued with misinformation for decades,” said Andrea Love, the executive director of the American Lyme Disease Foundation. “Unfortunately, there are instances of celebrities bringing attention to Lyme when it is unlikely they actually were infected with this bacteria.”