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By Mitch Phillips
ZURICH, Nov 30 (Reuters) - Russian sprinter Yulia Gushchina, who has previously been stripped of three relay medals won in the 2008 and 2012 Olympics after team mates were banned for doping, has also been disqualified from the London Games after testing positive, the International Olympic Committee said on Thursday.
Re-analysis of Gushchina's samples from London resulted in a positive test for banned substances dehydrochlormethyltestosterone and stanozolol, the IOC said in a statement, the latest sanction as it re-tests samples from Russian athletes.
Gushchina, who failed to make the final in the individual 400m in London, helped Russia to a silver medal in the 4x400m relay but the quartet were stripped of the honour after Antonina Krivoshapka was banned retrospectively earlier this year.
In Beijing four years earlier she won gold in the 4x100 and silver in the 4x400 but had those results annulled after positive tests for team mates. The IOC also said on Thursday that Russian long jumper Anna Nazarova had failed a retrospective test from 2012, where she finished fifth.
Thursday's announcements were the latest in a stream of recent doping positives from the summer and winter Olympics, the vast majority of them Russians.
Russia's athletics federation is currently banned from the sport as is its Paralympic Committee and anti-doping organisation in the wake of widespread doping offences and cover-ups.
The IOC has said it will decide during its executive board meeting next month on the participation of Russian competitors at the Pyeongchang Winter Olympics in South Korea in February. (Reporting by Michael Shields/Mitch Phillips; Editing by Toby Davis)