The United States team at the swimming world championships in Singapore is battling a case of “acute gastroenteritis” that compromised performances on the opening day of eight days of competition in the pool.

Summer McIntosh is set to compete in five individual events at the world swimming championships in Singapore.

Yu Zidi of China is only 12 years old and has qualified for the world swimming championships in Singapore.

Four-time Olympic medalist Simone Manuel was listed as the anchor leg of the U.S. 4x100m freestyle relay team after speculation of whether she would be involved in the event at all.