HealthDay News — About 170 visitors and employees at Yosemite National Park have been hit by gastrointestinal illness, park officials say.
They said most of the cases occurred around the first week of January and the number of new cases has declined in the past several days, CNN reported. Two of the cases are confirmed as norovirus, and most of the others are consistent with the virus, according to the park officials.
The situation is being investigated by the park, which has improved sanitation measures to prevent further spread of the illness.
Norovirus is the most common cause of acute gastroenteritis in the United States, and causes about 21 million illnesses a year, according to the U.S. Centers for Disease Control and Prevention, CNN reported.