Yosemite National Park has received reports of approximately 170 people who have experienced a gastrointestinal illness. Affected individuals include park visitors and employees, and most of these individuals spent time in Yosemite Valley. As of today, there have been two confirmed cases of norovirus. Most of the cases occurred on and around the first week of January 2020 and there has been a significant decline of new cases reported over the past several days.

Yosemite National Park officials and medical professionals with the National Park Service Office of Public Health (OPH) are continuing to investigate the circumstances surrounding the illness and are continuing to conduct interviews with affected people. The overwhelming majority of the reported cases are consistent with norovirus.

Norovirus spreads very easily, including through direct contact with an infected person, touching a surface or object contaminated with norovirus, or eating food or drinking liquids contaminated with norovirus. Symptoms of norovirus usually begin 12–48 hours after exposure.

Yosemite National Park, OPH, and other public health agencies are working together, and in collaboration with park partners, to prevent additional illnesses. The Park continues to undertake extensive cleaning and enhanced sanitation protocols.