"The athletics world governing body IAAF has started the investigation after being informed by the anti-doping laboratory in Lausanne that Kotova tested positive for a prohibitive substance at the 2005 world championships in Helsinki," RUSADA said.
"In January 2013, the IAAF handed this case to RUSADA."
Kotova, 36, won a third consecutive world silver medal in Helinski and also won Olympic bronze medals in the 2000 Sydney Games and again in Athens four years later.
She did not qualify for the Russian Olympic team for laat year's London Olympics after finishing sixth at the national championships.
Kotova's case has been the latest in a series of recent doping offences by Russian athletes.
European indoor 3,000 metres silver medallist Olesya Syreva was banned for two years last week for infringing anti-doping regulations.
In December, 2012 Olympic discus silver medallist Darya Pishchalnikova and Russian hammer champion Kirill Ikonnikov, who finished fifth at the London Games, were temporarily suspended while Olympic 2004 hammer champion Olga Kuzenkova was placed under investigation by the IAAF for failing drugs tests.
Also in December, the IAAF stripped shot putter Svetlana Krivelyova of her bronze medal from the 2004 Athens Games.
Krivelyova, 43 and long retired from the sport, tested positive for anabolic steroids after her samples from eight years ago were re-tested.
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