Expert: More Virus Cases Likely To Be Identified Officials have begun tracking the swine flu virus to find out why the virus is affecting more people and spreading more freely in Mexico. Dr. William Schaffner, chair of the Department of Preventive Medicine at Vanderbilt University Medical Center, says it's unclear why the virus is so much worse in Mexico than it is in the United States.
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Expert: More Virus Cases Likely To Be Identified

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Expert: More Virus Cases Likely To Be Identified

Expert: More Virus Cases Likely To Be Identified

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ROBERT SIEGEL, host:

More now on swine flu from Professor William Schaffner, who is chairman of the Department of Preventive Medicine at Vanderbilt Medical School. And he was hospital epidemiologist at Vanderbilt University Hospital for nearly 30 years. Welcome to the program, Dr. Schaffner.

Dr. WILLIAM SCHAFFNER (Department of Preventative Medicine, Vanderbilt University Medical School): Good to be with you.

SIEGEL: The same virus is found to sicken people very badly in Mexico. It's suspected in more than 100 deaths there. But in this country, the confirmed cases are very mild. What does that say to you?

Dr. SCHAFFNER: Well, that's an enigma. We haven't really figured out why it's so much worse in Mexico than it is in the United States. We're grateful that we haven't had that problem in the U.S. It could just be that they've had so many more cases, that the viruses in Mexico found people who are frail, who have underlying heart disease or diabetes and such, and therefore has carried off more people.

We don't think it's a difference in the virus. The CDC tells us the virus is quite similar. So we need more information from an investigation in Mexico to answer that question.

SIEGEL: What does it say to you if an outbreak in a New York City school seems to affect a couple of dozen kids there, but it doesn't seem to extend to the neighborhood around the school or to the families of the students who have it?

Dr. SCHAFFNER: Yeah, that's very fortunate because it suggests that at least in our circumstances, the virus is not all that transmissible. But that leaves open the question: Why is it that it's apparently spreading so much more freely in Mexico? Once again, that's inexplicable on its face, and we need more information about that.

SIEGEL: And at this point, do we assume that people are trying to track the swine flu virus back to some point of origin in Mexico and to find the village, the farm, the individual who might've first contracted this?

Dr. SCHAFFNER: Well, that's always part of the intention of a complete public health investigation. I don't know whether that'll be possible in this circumstance. But it's always very interesting to try to determine how it is and where and when this virus apparently picked up the genetic capacity to go not just from swine to swine, but from human to human.

SIEGEL: And it somehow has gotten, we assume, from Mexico to New York City, a few other points in this country, to New Zealand and to Scotland. I mean, do we assume if it - this would perhaps be practically impossible, but at least in theory, one could draw dotted lines between individual people and connect them all together from Wellington to Edinburgh or wherever?

Dr. SCHAFFNER: Yeah. Actually, I think something like that is possible, except that all the dotted lines go back to Mexico. Because I believe in each of those circumstances, someone in that group that was affected had recently been in Mexico, gotten on an airplane, probably while they were still well, and shortly after they disembarked, became ill and were able to then spread the virus to a small cluster of acquaintances.

SIEGEL: The briefer from the CDC told people today to expect things to get worse in this country. Why? Why should one expect that an outbreak would be worse?

Dr. SCHAFFNER: Because we'll find out more cases. I don't know if that really means worse. And that's because we're all now looking intently. And the harder you look, the more you'll find. We're testing more and more patients who are coming to us, who we would, under normal clinical practices, not test.

SIEGEL: You mean patients who might've just been assumed to have the flu will now be examined more closely to see if it's this flu.

Dr. SCHAFFNER: Yes, exactly. People who are coming with an influenza-like illness to our hospitals and to many of our clinics now, particularly if they've had a provocative travel history, are going to get a specific test so that we can try to isolate the influenza virus from them and then further characterize the virus. And the CDC has asked us to do that. So with that much more intense surveillance, we call it, we'll surely find more cases. And that will help us define the extent of the infection in our country.

SIEGEL: Dr. Schaffner, thank you very much for talking with us.

Dr. SCHAFFNER: More than a pleasure. Anytime.

SIEGEL: That's Dr. William Schaffner, chairman of the Department of Preventive Medicine at Vanderbilt University Medical Center.

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