Players in 13 National Basketball Association teams were infected with norovirus in late 2010, a new study finds, noting that tight schedules and close interactions between the staff contributed to a higher risk of infection.

The research was published in the journal Clinical Infectious Diseases.

The norovirus is a highly contagious illness causing gastroenteritis; inflammation of the stomach and intestines, with symptoms of diarrhea, vomiting, and stomach pain. Norovirus is highly contagious due to ease of transmission, from touching contaminated objects, surfaces then placing the hand in the mouth. There were 21 million cases each year according to the Centers for Disease Control and Prevention.

Dr. Rishi Desai, MD, MPH and colleagues at the CDC found that up to 13 NBA teams were affected by norovirus outbreaks in November and December of 2010.

"We confirmed that norovirus spread within at least one team and possibly from one team to another,” Desai said

Researchers pointed out that tight schedules and close interactions between players and staff contributed to increased risk for norovirus infection. Norovirus can spread quickly in such spaces. Infected individual can shed millions of virus particles through air, objects and surfaces where the infection can lay wait for days or weeks. The virus is resistant to most common disinfectants.

The study suggests limiting exposure by keeping sick athletes off the court during games and practice; avoiding contact with players and staff up to 24 hours post recovery. Strict adherence to personal hygiene, washing hands with soap, disinfecting common spaces and early reporting are critical.

Preventing norovirus is important for a healthy team.

"Overall, 21 players and three staff from 13 teams were affected, said Dr. Desai.