Pennsylvania and, now, New Jersey have each reported suspected cases of measles in 2015, after the infectious disease was thought to be largely eradicated in the United States.

This undated U.S. Centers for Disease Control and Prevention photo shows the skin of a patient after three days of measles infection.

The New Jersey Department of Health on Thursday said it was investigating a suspected case in a 1-year-old baby in Jersey City who had not been vaccinated, nj.com reports.



The baby has recovered, a department spokeswoman said, but the potential for others to have been exposed to the virus remains, according to the report; the latest time a person could become ill due to exposure in this case is Saturday.



The Pennsylvania Department of Health on Jan. 28 advised the public of a measles case that may have led to potential exposure in Cumberland and Franklin counties.



While still a scourge in many corners of the world, measles has been all but eradicated in the U.S. since 2000 because of vaccinations. But the virus has made a comeback in recent years, in part because of people obtaining personal belief exemptions from rules that say children must get their shots to enroll in school.

Others have delayed getting their children vaccinated because they still believe now-discredited research linking the measles vaccine to autism.



The Pennsylvania and New Jersey cases surfaced as more than 100 measles cases in half a dozen states have been linked to people who visited or worked at Disneyland in December, or exposure to infected people who went there. California health officials on Wednesday reported 99 measles cases including six new infections with a Disneyland connection.

In addition to California, the U.S. Centers for Disease Control and Prevention say the cases linked to Disneyland have been in Utah, Washington, Oregon, Colorado, Nebraska and Arizona.

The CDC describes measles as:

... a highly contagious respiratory disease caused by a virus. It spreads through the air through coughing and sneezing. Measles starts with a fever, runny nose, cough, red eyes and sore throat, and is followed by a rash that spreads all over the body. About three out of 10 people who get measles will develop one or more complications including pneumonia, ear infections or diarrhea. Complications are more common in adults and young children.

Public health experts say success at containing the outbreak will largely depend on how many unvaccinated people get the measles shot.



"This was a wake-up call," said Dr. James Cherry, a pediatric infectious disease expert at the University of California, Los Angeles. "It could continue to smolder" if not enough people get vaccinated.



Still, it isn't the largest U.S. measles outbreak in recent history. That happened last year in Ohio's Amish country, where 383 people fell ill after unvaccinated Amish missionaries traveled to the Philippines and returned with the virus.



The Associated Press contributed to this report.