Updated Fri, Apr 25, 2014 3:45 pm
UPDATE 3:42 p.m. Sixteen cases of measles have been confirmed among Amish in the Knox County area of north-central Ohio.
The Department of Health says the outbreak of the highly contagious respiratory disease began with unvaccinated travelers who returned to Ohio after visiting the Philippines. A recent measles epidemic there has caused at least 20,000 illnesses.
Local agencies offered two free vaccination clinics Friday in Knox County and neighboring Holmes County in an effort to limit the outbreak. A Department of Health spokeswoman says it appeared the clinics were "well-attended."
Measles symptoms appear one to three weeks after a person is exposed to the virus. Symptoms include fevers, coughs, rashes and pink eye.
U.S. measles outbreaks so far have caused more illnesses than at the same point of any year since 1996.
Health officials say measles is up - again - in the United States, and they're investigating a new cluster of suspected cases in Ohio.
The nation has seen more cases of the highly contagious disease so far this year than at the same point of any year since 1996.
Authorities say 129 cases in 13 states were reported by mid-April.
Most were in California and New York City.
Most were triggered by travelers who caught the virus abroad and spread it in the United States among unvaccinated people.
The national tally already may be outdated.
Ohio officials on Thursday announced a new cluster of 13 suspected cases in rural Knox County.
At least three recently traveled to the Philippines, where a recent measles epidemic has caused 20,000 illnesses.