Ivory Coast and Liverpool defender Kolo Toure has contracted malaria.
The Ivory Coast team's head of medical staff Cyrille Dah said in a statement that Toure had likely contracted the illness on a trip to the Ivorian capital Abidjan before he joined up with the squad for their pre-World Cup training camp in Dallas.
Dah beleives Toure fell ill on a flight to the United States ahead of his country's friendly against Bosnia, which they went on to lose 2-1.
The head of medical said the 33-year-old central defender is undergoing treatment and 'will return next week'.
Yaya Toure also missed the friendly in St Louis with a muscle problem and is expected to join the Elephants' squad in America this week.
Toure has played over 100 games for Ivory Coast, who face Japan, Colombia and Greece in group games at the World Cup.