The Washington Post quotes state GOP Chairman Jim Brutle as saying the staffers, who arrived in Cleveland last week ahead of California’s delegation, apparently brought the virus with them from home.

So far, none of the state's 550 delegates appear to have caught the virus and they have been advised to frequently wash their hands and avoid shaking hands or sharing food.

The virus, which causes intestinal distress, can spread quickly in closed places such as cruise ships, schools and nursing homes, according to the Centers for Disease Control and Prevention.