The 2012 London Olympics 1500m Champion Taoufik Makhloufi of Algeria withdrew on Thursday from next month's world championships in Moscow, Russia.
The source says that the athlete has been suffering of a viral infection and the he was not able to practice normally for the past month.
Makloufis the latest big name to miss the world championships, which take place in Moscow from August 10-18.
Kenya's world and Olympic 800m champion David Rudisha announced last week that he will not participate at the world champs due to a knee injury. Reigning world 100m champion Yohan Blake of Jamaica has withdrawn from the championships with a hamstring problem.
Sprinters Tyson Gay and Asafa Powell have been removed from their teams after failing drug tests.