Minnesota’s measles outbreak has grown to 44 cases after three new infections were announced Friday by state health officials.

All three of the new cases were detected in unvaccinated children living in Hennepin County, which has been the center of the outbreak so far. Two cases are in Ramsey County and one in Crow Wing County.

Officials at the Minnesota Health Department said Thursday they expect the number of cases to continue rising and that the outbreak could spread further in parts of the state beyond the Twin Cities area.

They are monitoring the Crow Wing County case, which involved an unvaccinated child who was exposed during a trip to Hennepin County, for any sign of new infections in that area.

All infections so far have been in children under age 11, except for an adult health care worker who, despite being vaccinated, developed measles after being exposed to several patients with the disease.

The outbreak has mainly affected the state’s Somali community — with 38 cases so far — where measles immunization rates are less than half the rate for all Minnesotans.

Measles is a highly contagious disease that is easily spread within unvaccinated populations. Most of the exposures have been in child care centers, health care settings and households.

Symptoms include fever, runny nose, cough, watery eyes and a rash that spreads to the entire body. In severe cases, measles can lead to pneumonia and swelling of the brain.