Health authorities in Arizona are trying to curb a measles outbreak at risk of increasing dramatically in size, The Associated Press reported. The state is the second-most affected, with respect to 95 cases of measles that originated at California's Disney parks. Though only seven individuals are confirmed to have contracted the disease, up to 1,000 Arizonians may have been exposed.

Among those at risk are nearly 200 children, and officials are asking those who have not been vaccinated against the disease to stay inside for 21 days or wear masks if they do go out in public. According to the AP, this is "standard health practice."

"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 suspect a Phoenix-area woman diagnosed with measles may have exposed as many as 195 children to the disease on Jan. 20 and 21 during a visit to Phoenix Children's East Valley Center, according to the Arizona Republic.

Humble said officials have a list of individuals who were at the hospital but do not know whether those exposed have had contact with others or traveled to other parts of the state. He added that symptoms do not usually appear until about one week after exposure, though the disease is contagious before then.

Anyone who suspects they've contracted measles should call ahead before going to the hospital, Phoenix Children's spokeswoman Debra Stevens said. Knowing potential measles patients are on their way gives facilities time to take necessary precautions to keep the disease from spreading, Stevens said.

This is especially true for individuals who are not immunized, she added.

"If someone has chosen not to vaccinate their children -- or for some reason cannot vaccinate their children -- they face a higher responsibility now to let their health care provider know in advance," Stevens said.