But that's wrong. The real story behind the 2014 outbreak isn't on the West Coast. It's in Ohio Amish country, where a missionary returning from the Philippines turned an otherwise unremarkable year for this virus into one of the worst in recent history.

That's where Jacqueline Fletcher, the public health nursing director for Ohio's Knox County, got an harried call from a pay phone last April.

A member of the local Amish community was on the line. There was a potential measles outbreak in the town, the woman said, and the public health department should know.

Fletcher's first thought was, "Oh, shit." For a health worker, this was a nightmare scenario. She couldn't just call the woman back or ring up other potential victims; they didn't have phone numbers. This Amish community, like others in the United States, eschews the conveniences of modern technology.

"We don't have any internet or computer. We don't have a car," Ivan Miller, an Amish furniture store owner in the community struck by measles, explained. "It's not that we feel a car is wrong. It's our choice because we feel if we had a car, it would bring us to a lot more temptations in the world."

At the time, this Amish population was generally against vaccination. This, however, wasn't a matter of religious principle but one of health concerns.



In the 1990s, Miller explained, two Ohio kids allegedly got sick after they took the MMR shot, which protects against measles, mumps, and rubella. Rumors about vaccine safety spread through the Amish community like a virus. "That put a scare in us and we quit," Miller says. This made it incredibly easy for measles — the most contagious virus known to man — to move through this cluster of unvaccinated individuals.



Fletcher had been with the Knox health department for 29 years. And she'd never seen anything like what she found in some of the Amish households she visited, trying to get a sense of the outbreak's size — and stop its spread. "There was a household that had six adolescent teenage children with measles, all sitting in the dark," she says. They were covered in the spotty rash that's characteristic of the virus, miserable, and sick. It was a scene from the last century.

The outbreak that Fletcher spent months working to contain ultimately infected 382 Amish Ohioans by the time it was declared over in August of last year. Nobody died, but nine wound up in the hospital with more serious symptoms.

"We had never seen a case of measles before this," Fletcher says. "I just remember a man from the [Centers for Disease Control and Prevention] saying to me, 'You have got to get ahead of this.'"

Unvaccinated travelers drive measles outbreaks

Last summer, a team of researchers got together to try and understand an alarming trend: why had so many measles cases popped up recently?



In 2000, the federal government declared that the United States had eliminated the disease: enough people were immunized that outbreaks were uncommon, and deaths from measles were scarcely heard of.



But in the first half of 2014 alone, there were 288 cases. And nearly all of them, the CDC researchers wrote in findings published last June, stemmed from Americans traveling abroad and returning with the disease.

"Of the 288 cases, 280 (97 percent) were associated with importations from at least 18 countries," they wrote. Many of these travelers were coming back from the Philippines, which has been dealing with a massive outbreak since fall 2013.

"What we've seen — since the epidemic of measles was interrupted in 2000 — is that we are continually getting measles coming in from overseas," says Jane Seward, deputy director of the viral diseases division at the CDC. "More often than not, it's US residents who go overseas for a trip — to say, Europe, where they don't think they need to be vaccinated. They bring measles back."

"A perfect storm" in Ohio

In the Ohio case, "patient zero" had traveled to the Philippines on a missionary trip. (In case you were wondering, he took a plane. Miller explained, "Some Amish fly. Some don't.") At the time, the Philippines happened to be facing a massive measles outbreak, with tens of thousands of cases.



When he returned to Ohio, and fell ill, a doctor misdiagnosed him with Dengue fever, so he continued to pass his disease along to friends and neighbors, many of whom had refused the vaccine out of those concerns over adverse effects.



Fletcher describes it as a "perfect storm:" an unimmunized traveler going to a place with an outbreak and bringing an infectious disease back to an unprotected community.



Measles is one of the most contagious viruses ever discovered. In most cases, it's not deadly, but it's almost always debilitating, bringing on a weeks-long fever, rash, and painful, watery eyes. Up to forty percent of people experience serious complications, such as pneumonia and encephalitis (or swelling of the brain). One or two children in 1,000 die.



The most remarkable thing about the virus, however, is that it's incredibly indestructible. A person with measles can cough in a room, leave, and — if you were unvaccinated — hours later, you can catch the virus from the droplets in the air that they left behind. No other virus can do that. It also lives on surfaces for hours, finding new hosts in the unimmunized.

"Measles is very contagious, so once [the Ohio missionary] felt better, he went to church, and the church was in somebody's house," Fletcher says. "The majority of those first cases, we linked back to him. They had all attended church in that house."

"There was a household with six adolescent teenagers with measles, all sitting in the dark."

Then, there were obstacles specific to tracing a disease through an Amish community. Trying to reach everyone who might have been exposed to the disease and get them into quarantine so they couldn't spread the infection further required a level of gumshoeing nearly reminiscent of searching out Ebola victims in rural West Africa.

"Because the Amish don't have phones, we had to go out to their homes," she says. "We're a small health department in a rural area. It was a lot of work."

Fletcher and her team patiently went door to door, collecting specimens, educating people about vaccines, making sure the vulnerable — pregnant women and small babies too young to get vaccinated — were safe from harm. CDC officials even flew in to support the effort.

An Amish man travels to the Philippines...

The actual story of the 2014 outbreak complicates the narrative that has developed in the wake of the new outbreak of measles at Disneyland in early 2015: that a growing number of parents, led by Jenny McCarthy, have begun to opt their kids out of vaccinations, letting the disease spread easily.

Federal data shows no drop off in vaccination rates over the past decade

In fact, it's only about two percent of the population that refuses vaccines outright. All 50 states have had school immunization requirements since the early 1980s, though some now allow medical and philosophical exemptions. Even so, there hasn't been a drop off in vaccination rates in the past decade, the National Immunization Survey shows. Coverage for the MMR vaccine stands at 92 percent.



It's not actually a rising anti-vaxx tide or naturopathic, private school mothers driving a return of vaccine-preventable disease here. It's not even low-income folks who wind up getting sick, and it's especially not undocumented migrants bringing in viruses, the CDC's Seward says: "The people getting measles are those that travel abroad, come back, and live in a community among people who weren't vaccinated."



Some years, we get 40 "importations." Last year, there were about 65. "This is more than normal," she added, "and it reflects travel patterns and where measles is active globally."

The travelers spark outbreaks when they hit geographic clusters of unvaccinated people, like the one in Ohio. These infectious disease powder kegs exist all across the US, waiting to be sparked. Their low rates of vaccine coverage are hidden in the statistics about national averages, and they are by no means guided by a singular ideology. They may be the hesitant Amish of Ohio, vaccine-opposing Christian Scientists, or simply worried parents who delay immunizing their kids.



Last year, the Amish outbreak in the United States mirrored an uptick in Canadian cases. A population of Christian Dutch Reformers in British Columbia, which had refused vaccines out of concerns over safety, drove an outbreak of more than 400 measles cases. According to the World Health Organization, there were only 512 cases in Canada in total last year.

Miller, the Ohio furniture-store owner, says the measles episode in Knox changed his mind about the MMR vaccine. His wife got a bad case, and so did his son-in-law. "On their worst days, we were wondering if they're going to make it," he says.



"We all took the vaccine after that. I had one shot, and I still took the other one and we had all our kids vaccinated, too. After people saw how sick people got, they changed their minds."