Deadly MERS Virus Traced to Bats in Saudi Arabia

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Marco Werman: A deadly mystery in the Middle East appears to be a step closer to being solved. In the past year and a half, more than forty people in that region have died from a new SARS-like virus. Scientists call it Middle East Respiratory Syndrome, MERS for short. The big question is where did the virus come from? Is it being spread to people from some sort of animal? A new study suggests the answer is yes. And those animals? Bats. Epidemiologist Ian Lipkin of Colombia University co-authored the study. And remind us first of all, Dr. Lipkin, what MERS is.

Ian Lipkin: Well, it's a syndrome that's caused by a virus that results in loss of your ability to oxygenate your blood to exchange carbon di oxide and essentially people go into respiratory failure. Some individuals also have renal failure, multi-system failure, but the primary side of the disease is in the lungs.

Werman: Right, and with sixty percent of the subjects so far in the Mid-East dying from it, does that scan with how lethal it is?

Lipkin: It does to the best of our knowledge, but the more we begin to look for evidence of mild cases of MERS or infection with the coronavirus that causes MERS, the more likely we've see that number drop. This is frequently the case when you identify a new infectious because the cases that come to attention are those where there is severe disease, and as you begin looking for evidence of infection you find that some people may actually be asymptomatic entirely or have only mild disease.

Werman: So just clear something up, the bats naturally carry the virus? Is that right?

Lipkin: Well, what's interesting about bats and infectious diseases is that they tend to have the ability to carry a large number of viruses without any apparent disease. So in this instance there was no evidence that this bat was ill.

Werman: You mean with no apparent disease or with no apparent symptoms?

Lipkin: That's right. In that the bats that we collected in Saudi Arabia appeared to be healthy bats

Werman: So this type of bat that the virus is associated with, the bat doesn't usually bite people. So how did the virus leap to humans?

Lipkin: Well, we don't know how the virus leapt to human and your point is well taken. Most bats are in fact insectivorous. So this was an insectivorous bat. Now, we don't know the link between the bats and humans. There are a number of possibilities. We know, for example, that there are instances where bats will excrete virus in their stool, in their guano, and as it dries up one can inhale it. There are examples where we've seen bats can contaminate food products, for example. But it's also possible that bats infect some intermediate animal which might be a rodent or a ferret or a domestic animal of some sort and then people then become infected as a result of being exposed to that second source, that vector that carries the virus.

Werman: Can it spread from human to human? Because I mean the Hajj is coming up in a few weeks and millions of travelers from around the world will be in Saudi Arabia, the center of this outbreak.

Lipkin: There has been some evidence of very limited human to human spread, but typically that's in individuals who are in very close contact with individuals who are sick. And, again, the majority of the people who get exposed to this virus may have either mild disease or no disease whatsoever. The individuals we've identified, "we" meaning the whole field of science and physicians that take care of these patients, not me personally, have been individuals who have had some sort of underlying illness. They've had renal failure, they've received transplants, they've had diabetes. There has been something in additional to MERS. It's MERS Plus. Now, your point is that when you have any situation where you large numbers of people congregating in closely-confined spaces there is an opportunity for spread. We saw this with SARS in 2003. But SARS appeared to spread much more aggressively from person to person. There is always the concern with any new agent that this virus might evolve and become more capable of spreading from person to person, but as yet there's no evidence that that has happened.

Werman: Ian Lipkin, professor of epidemiology at Columbia University. Thank you very much.

Lipkin: My pleasure.