Nigeria women's 4x400 metres relay team have lost their place at the Olympic Games here after a member of their team positive for banned drugs for the second in her career, it has been reported.

According to media in Nigeria, 400m runner Tosin Adeloye has been banned for eight-years following the the second positive drugs test of her career.

Adeloye served a two-year ban after failing for anabolic steroid metenolone in 2012, only to reportedly fail again last year when competing at the Confederation of African Athletics (CAA) Super Grand Prix/Warri Relays.

She has been stripped of all results achieved in the last year, as well as being suspended, it has been reported.

Adeloye was a member of the Nigerian team that finished fourth at last year's International Association of Athletics Federations (IAAF) World Championships, meaning the team will be disqualified and no longer have a qualifying time for Rio 2016.

This has been confirmed by the IAAF, who said that Cuba have been called up to replace the African nation in the 4x400m relay.

While Patience Okon-George, Margaret Bamgbose and Omolara Omotosho will still compete for Nigeria in the individual 400m, Regina George will no longer be able to compete as she had only been selected for the relay event.

This is especially sad as George had successfully raised money to finance her qualification bid through the crowd-funding platform Gofundme.

Youssef Masrahi, the Asian Games 400m champion who clocked a continental record 43.93sec in his heat at the World Championships in Beijing, has been dropped from the Saudi Arabia Olympic team following a positive drugs test.

He tested positive during a training session in June, the Saudi Arabian Olympic Committee announced, although it is not yet clear exactly what he failed for.

"So as to maintain the principle of transparency, the Anti-Doping Committee of the Athletics Federation has decided to exclude Youssef Masrahi," they said in a statement.

Masrahi denies any wrongdoing and is now due to face a disciplinary hearing on August 7.

Other doping cases have been confirmed by the IAAF in their monthly newsletter.

These include Dutch sprinter Brian Mariano, who has received a four-year ban after testing positive in February for an unspecified substance.

Mariano is from Curaçao and competed for the Netherlands Antilles until it was dissolved in 2010 and became a constituent country of the Kingdom of the Netherlands.

He then served as a member of The Netherlands' 4x100m relay team that won the gold medal at the 2012 European Championships in Helsinki.

Morocco's 2002 world junior 1500m champion Yassine Bensghir has also been handed a four-year ban backdated to 2014 following an Athlete Biological Passport case.

In a more bizarre case, Belgium's Rik Demuynck has also received a four-year ban for "possession".

The 52-year-old had won the weight throw events - an event only on athletics programmes at veterans level - at the 2013 World Masters Championships in Porto Alegre.

But the horticulturalist was arrested in February in connection with an underground cannabis plantation in Belgium.