|Dates: 23 July-8 August Time in Tokyo: BST +8|
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Swiss sprinter Alex Wilson is out of the Olympics after his provisional doping suspension was reinstated despite his claims the banned substance came from eating contaminated beef.
The Court of Arbitration for Sport (Cas) has reinstated the 30-year-old's suspension with immediate effect.
He had successfully appealed a ban from Anti-Doping Switzerland after testing positive for the steroid trenbolone.
Wilson was due to contest both the 100m and 200m in Tokyo.
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Wilson tested positive in March but Swiss Olympic, the umbrella organisation for Swiss sports and the national Olympic committee, lifted the ban in early July - a decision which was appealed to Cas by governing body World Athletics.
The Jamaican-born athlete, who won European 200m bronze in 2018, claimed the presence of the substance was due to consumption of contaminated beef he had eaten in a Jamaican restaurant in the United States.
Cas said: "The panel concluded that the provisional suspension imposed should not have been lifted by the disciplinary chamber of Swiss Olympic.
"It follows that the decision of the disciplinary chamber of Swiss Olympic dated 2 July 2021 is set aside and the provisional suspension shall be reinstated with immediate effect."
In its response, Swiss Olympic said: "Swiss Olympic very much regrets this case and would be very disappointed if the offense was confirmed.
"Swiss Olympic is convinced that the fight against doping must be conducted with all consistency."
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