People who visited an ice cream shop in Cortez on the day before Thanksgiving should watch out for signs of measles, according to the state health department.

An unvaccinated child in Montezuma County recently tested positive for measles, according to the Colorado Department of Public Health and Environment. The child hadn't traveled out of state or visited any known exposure locations, suggesting the virus is spreading under the radar in the Cortez area, the department said.

So far this year, the state has 33 known cases, with five hospitalizations and no deaths. In a typical year, measles cases don't rise above the single digits.

People who visited Cold Stone Creamery, 215 S. Sligo St. in Cortez, between 3:30 and 6 p.m. Nov. 26 could have encountered the virus. Symptoms can take up to three weeks to appear, meaning people exposed during that window need to be vigilant through Dec. 17.

Measles can initially resemble other respiratory infections, with symptoms including a fever, cough, runny nose and red eyes. The rash usually appears three to five days after people become contagious, meaning they could spread it before realizing what they have.

People exposed to measles who develop symptoms should call a health care provider before coming in, so the hospital or clinic can take precautions to avoid further spread, the health department said.

Two doses of the vaccine are about 97% effective in preventing measles. Children typically receive their first dose at one year and their second before they start kindergarten.