By Nick Butler

Ekaterina Iourieva has announced her retirement after recording a second positive test last month ©AFP/Getty ImagesFebruary 28 - Russia's disgraced biathlete Ekaterina Iourieva is retiring from the sport rather than face a life ban after recording the second positive test of her career last month.

The 30-year-old won a gold, a silver and a bronze medal at the 2008 World Championships in Östersund, but was banned for two years the following year after being one of three high profile Russian biathletes to test positive for erythropoietin (EPO).

After making her comeback she enjoyed success on the World Cup circuit earlier this season but, after failing in her bid to be selected for the Russian Olympic team in Sochi, was reportedly one of three biathletes - two from Russia and one from Lithuania - to test positive again last month for a still unnamed substance.

Furthermore, a German coach working for the Russian team, Wolfgang Pichler, has since admitted that he "was sure something was wrong," and that he "did not trust Ekaterina Iourieva" after her unexpectedly strong World Cup results.

But, in a message announcing her retirement posted in Russian on her personal blog, Iourieva made not the slightest reference to doping as a reason for her decision. .

Instead, she explained that in recent weeks she has experienced a very difficult period due to serious health problems of the mother, adding that once she had failed in her goal of participating in the Olympic Games, she had no more incentives to continue her career. 

Starykh was removed from the Russian Olympic team after her positive test was revealed at the same time as Ekaterina Iourieva's last month ©AFP/Getty ImagesAnother of the biathletes to have been confirmed as failing a test last month was Irina Starykh  - who was removed from the Russian Olympic team after her test was confirmed
©AFP/Getty Images

The emergence of the two positive tests just two weeks before the Opening Ceremony in Sochi appeared to set the scene for a multitude of other drug test failures by Russian athletes. 

But, although there was a late flurry of failed tests affecting athletes from six different European countries across four sports, none of those implicated were Russian as the host nation finished top of the medals table with 13 gold, 11 silver and nine bronze medals. 

Allegations did however surface yesterday that the Russian team had used xenon gas during the Olympics, which is said to increase the levels of EPO in the body, and these claims will now be investigated by the World Anti-Doping Agency (WADA).