Two cases of measles have been confirmed in Ocean County, the New Jersey Department of Health reported Thursday.
State health officials classified the cases of the highly contagious illness as an outbreak.
The people infected are believed to have developed symptoms after they were exposed to a person in Ocean County who contracted measles while traveling internationally.
In that first case, the person developed symptoms earlier this month after having traveled to Israel, where there has been an increase in measles cases. The state told residents to look for symptoms if they visited the following Lakewood locations: Schul Satmar, 405 Forest Ave., from Oct. 13 to 21; Eat a Pita, 116 Clifton Ave., on Oct. 15; CHEMED Health Center, 1771 Madison Ave., on Oct. 17 or 18.
The two new cases are believed to have potentially exposed others in Ocean County to measles between Oct. 25 and 30. Two of the likely venues where others could have been infected were NPGS, a kosher supermarket located at 231 Main St. in Lakewood, on Oct. 25 and 29, and Pizza Plus at 241 Fourth St. in Lakewood on Oct. 28.
The Health Department did not release information about the patients' ages or whether they were up to date on vaccinations.
State health officials are working with Ocean County officials to identify and notify people who might have been infected.
Meanwhile, residents are urged to be vigilant for signs of measles. Symptoms include rash, high fever, cough, runny nose and red, watery eyes. Individuals who have been infected may not develop symptoms until as late as Nov. 20, officials said.
Measles can cause serious complications, such as pneumonia and encephalitis, or swelling of the brain. Measles during pregnancy can lead to miscarriage, premature delivery, or a low-birth-weight baby.
Anyone who may have been exposed is being asked to contact a health-care provider before going to a medical office or emergency room, to safeguard others from becoming infected.
People who have not been vaccinated or have not had the measles are potentially at risk. Health officials are urging people to ensure they are up to date on the measles/mumps/rubella (MMR) vaccines.
Two earlier cases of measles were identified last summer in Camden and Burlington Counties.
The Philadelphia region had an outbreak of mumps in March and April that affected more than two dozen people in Chester and Montgomery Counties and the state of Delaware.