Members of Amish communities in Ohio traveled to the Philippines for heartfelt reasons: They were there on service projects to help less fortunate people. Unfortunately, they came home with unwelcome hitchhikers: measles viruses.

Those travelers hadn't been vaccinated against this highly contagious disease, the Centers for Disease Control and Prevention said Thursday. As a result, they have triggered an outbreak of more than 130 cases, primarily among their unvaccinated friends and relatives in Amish communities.

Add that to other cases and there have been 288 cases of measles in the United States so far this year, CDC officials said. And while that number is small compared with the hundreds of thousands of cases that swept the nation in the 1960s before vaccination campaigns succeeded, it's the largest number since the mid-1990s.

The cases reported to date are in 18 states. The CDC says 41 people have been hospitalized, but nobody has died so far.

There is a safe and effective measles vaccine (known as MMR), CDC officials note. But most cases these days are among people who have philosophical or religious objections to vaccination.

This outbreak has changed some hearts and minds, though. Melanie Amato at the Ohio Department of Health told Shots that more than 8,000 Amish people have lined up to be vaccinated for measles to help stem outbreaks in six Ohio counties.

Measles strikes more than 20 million people around the world each year. The Philippines is in the midst of an epidemic that has so far sickened 32,000 people, the CDC says. That's one major source of the current outbreaks in the United States, though the virus has been imported by travelers to more than a dozen different countries. So far all of the cases in the U.S. have been connected to foreign travel.

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