India, May 30 -- A highly contagious stomach virus commonly known as the "vomit bug" is spreading throughout the majority of the United States, including Southern California, where hikers have recently reported experiencing symptoms, according to the Pacific Crest Trail Association (PCT).

A norovirus outbreak in the San Francisco Bay Area was also reported by Dr Linda Yancey, an infectious disease specialist at Memorial Hermann, to NBC on Friday.

The virus, which is the leading cause of foodborne illness in the US, has sparked concern because of its ability to spread quickly through contaminated food, water, surfaces, and close person-to-person contact.

The vomit bug, or Norovirus, is not a new disease, but periodic spikes in infection...