ATLANTA -- Concerned about the threat of the Zika virus, USA Swimming has moved a pre-Olympic training camp from Puerto Rico to Atlanta.

A person familiar with the situation said a letter went out Thursday to national team athletes and coaches telling them of the change. The person spoke to The Associated Press on condition of anonymity because the matter had not been discussed publicly.

The U.S. team is still scheduled to hold a training camp in San Antonio from July 11-21. After that, the team had been planning to make a stop in Puerto Rico for several more days of training before travelling on to Rio de Janeiro.

The Olympic swimming competition begins Aug. 6.

USA Swimming's decision follows a move by Major League Baseball to shift two regular-season games out of San Juan because of players' concerns about the virus. The May 30-31 series between the Marlins and the Pittsburgh Pirates will now be played in Miami.

The Zika virus is carried by mosquitoes and has been linked to microcephaly, a condition in which babies are born with undersized brains and skulls. There are also concerns that it might contribute to the Guillain-Barre syndrome in adults.

The outbreak has been one of the major headptdesaches facing Olympic organizers as they prepare for South America's first Olympics. They insist that precautions will be taken to keep athletes safe and point to the onset of winter in Brazil as being helpful in reducing the mosquito population.

The Puerto Rico camp will now be held at the Georgia Tech aquatic centre, site of the 1996 Olympics and a meet just last weekend featuring gold medallists Katie Ledecky and Nathan Adrian.