An outbreak of the measles that originated in California's Disney parks has grown to 95 confirmed cases, with officials in Arizona monitoring 1,000 people, including 200 children, who could have been exposed to the disease at a Phoenix-area medical center. 

Arizona health officials have asked those who were exposed to the disease and have not been vaccinated to stay home for 21 days, or wear masks if they have to go out in public. State health officials said its possible, but unlikely that the number of cases in Arizona can be contained to seven. 

"To stay in your house for 21 days is hard," State Health Services director Will Humble said. "But we need people to follow those recommendations, because all it takes is a quick trip to the Costco before you're ill and, 'bam,' you've just exposed a few hundred people. We're at a real critical juncture with the outbreak."

Health officials do not know the number of how many children were vaccinated for measles or their age ranges, and are working to contact the families of children who visited the medical center from Jan. 20-21.Children under a year cannot receive the vaccination for measles, mumps or rubella, but can get an immunity booster.

Arizona is second in the number of cases traced to Disney parks last month, next to California. The California Department of Public Health told the Los Angeles Times Wednesday that 79 confirmed cases are in California, and 52 can be directly linked to Disney Parks. There have also been cases confirmed in Utah, Washington, Colorado, Oregon, Nebraska and Mexico. Most of those infected were not vaccinated, and health officials have urged people to get the measles shot. 

In Southern California, 66 unvaccinated students are being told to stay home through the end of next week due to possible exposure. Mary Perry, spokeswoman for the Desert Sands Unified School District, said the students were released from class at Palm Desert High School Wednesday and will not be allowed back until Feb. 9, or until they are medically cleared through proof of immunity. 

The Arizona woman whose case was confirmed Tuesday in Maricopa County came into contact with a Pinal County family that traveled to Disneyland, but did not have telltale signs of measles like a rash when she visited the Phoenix Children's East Valley Center. Maricopa County health director Bob England declined to say whether she'd had the measles vaccine, which isn't 100 percent effective in stemming the spread of the disease.

"Unfortunately, she came down with the disease and by the time it was recognized had already exposed a large number of children at the facility," he said.

Masks are being placed outside health care facilities and signs went up outside placed in Kearny warning customers and employees that they could have been exposed to measles.

Gila County health officials say they are tracking 17 people who were at a hospital in Globe in the same time frame as a person confirmed to have measles. 

The U.S. experienced a record number of measles cases last year, with 644 infections from 27 states despite it being largely eliminated in 2000. 

The Associated Press contributed to this report.