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Report: U.S. Plagued by 20-Year High in Measles Cases

Considered eliminated from the U.S. in 2000, measles has spiked this year.

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Shakeithia Roberts holds her son, Jermaine Roberts, as Dr. Amanda Porro administers a measles vaccination during a May 16 visit to the Miami Children's Hospital in Miami.

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Measles cases reached a 20-year high in the U.S. during the first five months of 2014, according to the Centers for Disease Control and Prevention.

The CDC said 288 measles cases were reported between Jan. 1 and May 23 of this year – the largest number reported during the first five months of any year since 1994. Between Jan. 1 and May 29, the number of reported cases totaled 307, CDC spokesman Jason McDonald tells U.S. News.

Many of 2014's reported cases were contracted by international travelers who were not vaccinated, said Dr. Anne Schuchat, assistant surgeon general and director of the CDC’s National Center for Immunizations and Respiratory Diseases.

“The current increase in measles cases is being driven by unvaccinated people, primarily U.S. residents, who got measles in other countries, brought the virus back to the United States and spread to others in communities where many people are not vaccinated,” Schuchat said in a statement. “Many of the clusters in the U.S. began following travel to the Philippines where a large outbreak has been occurring since October 2013.”

Ninety-seven percent of the 288 measles cases in the U.S. as of May 23 are believed to have been imported from international travel, according to the CDC. Ninety percent of the 288 cases occurred in people who were not vaccinated or had an unclear vaccination status. And 43 of the cases required hospitalization, Reuters reports.

[READ: U.S. Measles Cases at 20-Year High]

So few measles cases had been contracted in the U.S. that the disease was considered eliminated in the country in 2000. No more than 220 cases had been recorded by the CDC during the first five months of any calendar year between 2000 and 2013, McDonald says.

Schuchat said the rarity of the disease makes it difficult for general practitioners to diagnose and treat.

“Many U.S. health care providers have never seen or treated a patient with measles because of the nation’s robust vaccination efforts and our rapid response to outbreaks,” she said.

The American measles outbreak includes large clusters in some states, as reported by The Washington Post. The largest concentrations are in Ohio with 138 cases, California with 60 cases and New York with 26 cases, and officials said the Amish community in Ohio – with many unvaccinated residents – has been at the center of the country's biggest outbreak, according to the Post.

A 2013 outbreak in New York saw 58 cases of measles among a group of Orthodox Jews after an unvaccinated teenager returned from a trip to Britain, according to NPR. All of the 58 cases occurred in individuals who did not have vaccination documentation, according to the Jewish Telegraphic Agency.

“Measles vaccine [in the U.S.] is very safe and effective, and measles can be serious,” Schuchat said, according to the Post. “It’s very infectious."

[ALSO: Delaying Measles-Related Vaccines May Raise Seizure Risk: Study]

An estimated 20 million people around the world contract measles every year, according to the CDC, and about 122,000 cases are fatal.

Measles cases in the U.S. dropped 99 percent after a vaccine was introduced in 1963, according to Slate, and from 2000 to 2007, the U.S. on average only saw 63 cases of measles per year. This year's total has almost quintupled that number.

Common symptoms of measles include fever, rash, cough, runny nose and pink eye. Recent international travel should also be considered among those exhibiting measles symptoms, Schuchat said.

Infants and young adults are at high risk of contracting measles, according to the CDC. A measles, mumps, and rubella vaccine is recommended by the CDC for every U.S. citizen older than 12 months, or any citizen older than 6 months before international travel.

“This is a wake-up call for travelers and parents to make sure vaccinations are up to date,” Schuchat said.