ROBERT SIEGEL, HOST:
The number of measles cases linked to a recent outbreak at Disneyland has now risen to at least 98. Even so, measles remains extremely rare in the United States. As NPR's Jason Beaubien reports, that's not the case in many other parts of the world.
JASON BEAUBIEN, BYLINE: Measles is a major public health problem across the developing world. The number of cases globally isn't as high as say, HIV or malaria, but in poor countries with less than ideal health care systems, measles is a killer. Last year of the roughly 250,000 cases around the world, half of them died. Measles causes an intense fever, coughing, watery eyes and a signature, full-body rash. It can also cause brain damage and permanent hearing loss. And once the virus starts spreading among kids who haven't been immunized, it's very difficult to stop.
STEVE COCHI: The measles virus is probably the most contagious infectious disease known to mankind.
BEAUBIEN: Steve Cochi is with the Centers for Disease Control and Prevention's Global Immunization Division. His team tracks flare-ups of measles around the world. Currently one of the biggest is in the Philippines, which generated almost 60,000 cases last year. Cochi says measles started spreading widely there after the country was battered by Typhoon Haiyan late in 2013.
COCHI: That virus incidentally from the Philippines has spread all over the world to the Middle East, to other parts of Asia, to the United States and to Europe.
BEAUBIEN: The CDC is still investigating the Disneyland outbreak and has not yet declared its exact source. From earlier U.S. cases however, Cochi says, surprisingly the source is usually not a foreign visitor.
COCHI: It's really traveling Americans who are unvaccinated then return to the United States with the measles virus that are causing most of the measles in the U.S., currently.
BEAUBIEN: There's a couple of issues here. First, travelers can be infected with measles and contagious before they feel sick. Second, there's measles just about everywhere in the world. Besides, the Philippines, China, Brazil, Ethiopia and Vietnam all had significant outbreaks last year. Even the European Union recorded several thousand cases. Part of the reason measles drives public health officials crazy is that it's a people problem. Humans are its only hosts. As long as the virus can find new, unvaccinated populations, it can reproduce, survive and spread some more.
COCHI: So if one can achieve high immunity throughout the world against measles, one can wipe out the disease.
BEAUBIEN: One of the groups working to achieve that high immunity around the globe is the International Medical Corps. Paul Robinson with the group says, actually, immunizing a child against measles is easy and cheap. Their biggest challenge is reaching children in post-disaster and war-torn countries, but Robinson believes it's very important that they do.
PAUL ROBINSON: The children under 5 are very vulnerable to measles. And it takes just a few days to get them to be vaccinated, but it also takes a very short time for the virus to kill them.
BEAUBIEN: Prior to the widespread use of measles vaccine in the 1980s, there were more than four million cases of the disease around the globe every year. That number has been cut significantly to roughly a quarter-of-a-million cases a year. But measles is still out there, and as Cochi at the CDC points out, the virus is just a plane ride away from the United States. Jason Beaubien, NPR News.