Gabriella Taylor spent four days in intensive care after becoming unwell during her girls' quarter final.
Doctors diagnosed the 18-year-old with a rare strain of leptospirosis - also known as Weil's disease - a bacteria which can be transmitted through rat urine.
Her mother, Milena Taylor, said her daughter had nearly died as a result of the mystery illness and reported it to police last week.
"Gabriella is very, very disappointed. It is going to take her a very long time to recover from this physically and mentally. She almost died," her mother said.
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One theory being explored is that Taylor may have been targeted by an organised crime betting syndicate, a 'Daily Telegraph' report claims.
A Scotland Yard statement said: "Merton police are investigating an allegation of poisoning with intent to endanger life. The allegation was received by officers on August 5 with the incident alleged to have taken place at an address in Wimbledon between July 1-10. There have been no arrests and enquiries continue."
She returned to training this week.
"It was such an awful experience, probably the worst time of my life. It started the day before as a stomach bug and I managed to overcome it by winning my match that day. But, the day of the quarter-final, I woke up and felt 10 times worse.
"I couldn't believe it was happening to me in one of the most important tournaments of my life," she told BBC.