Agricultural workers who recently arrived in California were previously exposed to measles during an outbreak in Arizona, public health officials said.

A group of 140 workers in Fresno, Madera and Merced counties who relocated from Arizona is being actively monitored for symptoms. No cases of measles have been confirmed in any of the workers at this time.

More exposed workers from Arizona could arrive in the state in the next few days, according to the California Department of Public Health.

Local health departments and the Arizona Department of Health Services are tracking the workers who transferred during the ongoing outbreak. The three California counties affected have coordinated preparedness measures to prevent potential spread of the disease, a release from the counties said.

The risk to the general public remains low, the release said.

Individuals who develop symptoms of measles, including fever, cough, runny nose or a rash, should call their healthcare provider before arriving for care in person.

The most effective protection against measles is two doses of the measles-mumps-rubella vaccine, health officials said.

The Centers for Disease Control and Prevention reported Thursday that there were 2,371 confirmed measles cases nationwide this year, marking the highest incidence of cases since 1991.

As of June, there have been three localized measles outbreaks in California this year, all of which have been resolved. The most recent data collected through July 27 show 53 confirmed measles cases in the state.