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The World Health Organization says doctors everywhere should suspect a new disease called MERS when they see cases of unexplained pneumonia. The WHO issued a statement today. It says the MERS virus can spread from infected people to close contacts, including health workers. But it's still not clear how people are getting infected in the first place. MERS is one of three deadly viruses that public health officials are watching closely.
NPR's Richard Knox says any one of them could turn into a global problem and possibly a pandemic.
RICHARD KNOX, BYLINE: Today's warning about MERS, Middle Eastern Respiratory Syndrome, comes at the end of a six-day WHO investigation in Saudi Arabia. That's where most of the reported 55 cases of the respiratory disease have occurred. Sixty percent of the victims have died.
WHO director-general Margaret Chan called MERS her greatest global health concern when she closed the annual World Health Assembly two weeks ago.
MARGARET CHAN: We understand too little, too little about this virus when viewed against the magnitude of its potential threat.
KNOX: The past week's investigation produced no new information on how people are getting MERS - from what animal source or by what route.
ANTHONY MOUNTS: That's the number one priority question right now.
KNOX: That's Dr. Anthony Mounts of the WHO.
MOUNTS: Where is it coming from and how are people getting it? If we can find that out, then it would really help a lot in knowing what's causing it to accelerate.
KNOX: He says it's possible MERS could morph into another SARS, the respiratory virus that struck 8,000 people around the world in 2003 and killed nearly 800.
MOUNTS: The lesson from SARS was that we do need to watch for that sort of thing. SARS didn't seem so transmissible under normal circumstances. But then you saw these events in which it spread really crazy fast, you know, from person to person.
KNOX: Officials worry about the risk that MERS may spread among pilgrims who visit holy sites in Saudi Arabia next month during Ramadan, or the millions more expected in October for the annual Hajj to Mecca. Mounts also worries that MERS could sneak out of the region in the lungs of guest workers.
MOUNTS: Pakistan, India, Indonesia, the Philippines all have large populations in the Middle East and travel back and forth quite a bit.
KNOX: But global health specialists don't have the luxury right now of worrying about just one potential pandemic virus at a time. There's new evidence two flu viruses that came from birds are close to becoming more contagious in humans. Both are deadly among people infected so far. The H5N1 bird flu virus that emerged a decade ago is only one or two tiny mutations away from being able to easily infect cells in the human respiratory tract, according to a team at MIT.
Their report is in the journal Cell. Author Ram Sasisekharan of MIT says recent samples of another bird flu virus discovered in China this spring called H7N9 may also be getting close to spreading efficiently in humans.
RAM SASISEKHARAN: Some of them are one amino acid away to achieve the necessary strength or affinity to latch onto human receptors. That's a key step.
KNOX: Dr. Anthony Fauci of the National Institutes of Health says that's important evidence.
ANTHONY FAUCI: However, that is not the entire story, at all, of how viruses evolve in a way to have sustained transmission.
KNOX: He says what makes animal flu viruses highly contagious among people is complex and poorly understood.
FAUCI: In fact, I'm not even sure what the extent of the complexity is.
KNOX: But he points out one possibly reassuring fact - there's never been a flu pandemic involving the kind of H5 or H7 bird viruses that are causing occasional infections and deaths among humans. But MERS comes from a family of viruses scientists understand even less than flu.
FAUCI: We take MERS very seriously.
KNOX: He says MERS is not likely to become what he calls a doomsday virus.
FAUCI: But does it have the potential to evolve into something that really has a much greater impact than it's having now? Oh, absolutely.
KNOX: Fauci says one thing about the current situation is certain.
FAUCI: I've been doing emerging infections for a very long period of time and we usually have one on the radar screen and occasionally two. But to have three on the radar screen, at least in my experience, is pretty unique.
KNOX: All over the world, from officials at WHO to scientists in labs to doctors in hospitals, it's keeping a lot of people on their toes. Richard Knox, NPR News.