The new cases confirmed Monday by the California Department of Public Health brings the total to 26 people in four states.
Officials say 22 of the cases are in California and two are in Utah, with one apiece in Colorado and Washington.
Most of the patients visited Disneyland or Disney California Adventure between Dec. 15 and Dec. 20, but some may have contracted the illness from others who visited.
The new cases include three reported Monday in Southern California, including two in San Bernardino County and one in Long Beach.
Disney officials have said they are working with public health authorities to provide any necessary assistance.