WASHINGTON -- After declaring in 2000 that measles had been eliminated from the United States through a successful vaccination program, government officials now say the number of confirmed cases has reached a 20-year high, as people who get the disease abroad bring it back to this country.
Unvaccinated Americans and foreign visitors who traveled to the Philippines, Europe, Africa and Asia are the main culprits in a growing spike of U.S. measles cases that began several years ago and exploded this year.
As of May 23, 288 cases have been reported in 18 states, the highest year-to-date total since 1994, when 963 cases were reported by year's end. Ninety-seven percent -- 280 -- of the 2014 U.S. cases were imported from other countries. Forty-three people have been hospitalized nationally, but no deaths have been reported.
"Measles is coming in on airplanes from places where the disease still circulates or where large outbreaks are occurring," said Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases at the U.S. Centers for Disease Control and Prevention and assistant surgeon general for the U.S. Public Health Service.
A highly contagious viral respiratory disease that grows in cells at the back of the throat and lungs, measles is spread through the air by coughing, sneezing and even breathing. It can cause fever and coldlike symptoms, along with a stubborn rash.
Ohio's 138 cases have been linked to Amish communities in which several members had traveled to the Philippines, which is experiencing its own measles outbreak, with more than 32,000 cases and 41 deaths this year, Dr. Schuchat said. Low vaccination rates in Amish communities have been a long-standing health issue.
Ninety percent of reported U.S. measles cases are among people who haven't been vaccinated for the disease, or who didn't know their vaccination status.
Of 195 unvaccinated U.S. residents with measles, 165, or 85 percent, chose to go without vaccinations for personal, religious or philosophical reasons, "not because they were too young or had medical reasons that they couldn't be vaccinated," Dr. Schuchat said. "Unfortunately, when we have larger communities of unimmunized people, it's more likely that bigger outbreaks will occur, making it much more difficult to control the spread of disease and making us vulnerable to have the virus re-establish itself in our country again."
Health officials are urging people to get vaccinated for measles, especially before international travel.
Fifteen measles outbreaks, involving three or more related cases, have occurred in places such as New York City and in California, where six outbreaks were reported in six counties.
Allegheny County, which had seen no cases of measles since 2009, reported a case in February, then two more in May -- the latest reported over the weekend. The three Allegheny County people who contracted the disease had been vaccinated, county health director Karen Hacker said Thursday.
"There's always going to be some people who don't mount a response to a vaccine," she said.
At this point, Dr. Hacker said, there is no evidence that the county's three cases are related. But she attributed the region's high rate of vaccination to preventing outbreak among more residents.
If people have immunity, she said, "the vast majority of people are going to be fine and are going to be protected. And that's the reason that we haven't seen this thing spread like wildfire."
Pennsylvania's Department of Health reported just two confirmed measles cases statewide, but communications director Aimee Tysarczyk warned that its statistics aren't broken down to specific counties when there are fewer than five cases in any one, and that this year's data is apt to change.
About 164,000 people around the world die from measles each year. Measles can also cause women to miscarry or give birth prematurely.
Before the U.S. measles-vaccination program, which began in 1963, 3 million to 4 million people in the U.S. developed measles each year, leading to 48,000 hospitalizations and 400 to 500 deaths.
Post-Gazette staff writers Kaitlynn Riely and Jill Daly contributed.