Experts have cast doubts on claims a British tennis player was deliberately poisoned at Wimbledon last month.
Gabriella Taylor, 18, spent four days in intensive care after doctors diagnosed her with a rare strain of leptospirosis, known as Weil's disease.
Police are investigating whether she was deliberately poisoned.
But Dr Anna Checkley, from the Hospital for Tropical Diseases, said had "never heard of it being used as a poisoning agent".
Ms Taylor, from Southampton, was admitted to hospital after becoming unwell during her girls' quarter-final match, last month.
She was later diagnosed with a rare strain of leptospirosis - a bacteria which can be transmitted through rat urine.