Print this page    •   Back to Web version of article

CDC Briefing on Public Health Investigation of Human Cases of Swine Influenza

April 23, 2009

Operator: Good afternoon and thank you all for holding. At this time your lines have been placed on listen-only until we open up for questions and answers. Please be advised today's conference is being recorded. If you have any objections you may disconnect at this time.

I would now like to turn the conference over to Mr. Glen Nowak, please go ahead, sir.

Glen Nowak: Thank you and thank you all for joining us this afternoon. I'm Glen Nowak, I am Director of Media Relations here at the Centers for Disease Control and Prevention. And this afternoon we're here to have a media update on human swine influenza cases that we have documented in the United States and CDC's efforts with respect to those cases.

We have two people available to speak this afternoon. With me is Dr. Anne Schuchat. She is Director of CDC's National Center for Influenza and Respiratory Diseases. Her last name is spelled S-C-H-U-C-H-A-T. And joining us also is Dr. Nancy Cox. Dr. Cox is Director of CDCs Influenza Division.

The way we'll do this, this afternoon is Dr. Schuchat will provide some opening remarks and then we will open up the phone lines for questions. So I will turn it over to Dr. Anne Schuchat.

Anne Schuchat, M.D., Interim Deputy Director for Science: Oh great, I am just going to correct my title for those of you who are taking notes. I am the Director for the National Center for Immunization and Respiratory Diseases. Sometimes it feels like the National Center for Influenza but it's actually Immunization.

You know, I appreciate the chance to update you today about a situation we're exploring related to swine influenza in people. On Tuesday we reported the detection of two children with swine influenza in California and today we want to update you about some new developments, new findings and actions that we're taking in close collaboration with the California Health Department and Texas Health Department and Public Health throughout the country.

Tuesday we reported that we had confirmed two cases of influenza that were swine flu in children in California and we intensified surveillance to look for additional cases. Not surprisingly we have now confirmed several additional cases of humans with swine influenza. The total right now is seven confirmed swine influenza cases.

There are a total of five human swine influenza cases in the state of California. Three of these were confirmed here at CDC yesterday in our laboratory. We have two confirmed cases in the state of Texas near San Antonio. These cases were confirmed at CDC very early this morning.

Both of those were in 16-year-old boys. All seven cases were detected through surveillance for seasonal influenza with tests that were sent then on to the laboratories where untypable influenza was detected. The specimens then get forwarded here to CDC where we found them to be of swine origin.

The good news is that all seven of these patients have recovered. One of them required hospitalization but has been discharged. And so far this is not looking like very, very severe influenza. Seven patients all recovered. The cases range in age from nine to 54 and there are three girls and four males in the group.

And so far the illnesses have presented with flu like illnesses, respiratory symptoms and sometimes with nausea and vomiting as well and diarrhea. But at this point we really don't know the extent of the spread of this particular strain of human influenza derived from swine. And we're in the process of an intensive investigation with partners.

I want to tell you a little bit about what the laboratory has found from exploring this particular strain. CDC has conducted testing on all seven samples and we've determined that they are swine influenza A, H1N1. These are human infections with swine influenza viruses. These are viruses that usually infect pigs but in this case we're finding the illness in people.

Preliminary testing of viruses from the first two patients shows that they are very similar. Additional testing is ongoing with the newer isolettes. We know so far that the viruses contain genetic pieces from four different virus sources. This is unusual. The first is our North American swine influenza viruses. North American avian influenza viruses, human influenza viruses and swine influenza viruses found in Asia and Europe.

That particular genetic combination of swine influenza virus segments has not been recognized before in the U.S. or elsewhere. Of course, we are doing more testing now and looking more aggressively for unusual influenza strains. So we haven't seen this strain before but we haven't been looking as intensively as we are these days.

The viruses are resistant to amantadine and rimantadine anti-viral drugs but they are sensitive or susceptible to oseltamivir and zanamivir, the newer anti-viral drugs for flu. And at this time we don't know exactly how people got the virus. None of the patients have had direct contact with pigs.

You can get swine influenza without direct contact but it's a bit more unusual. And we believe at this point that human-to-human spread is occurring. That's unusual. We don't know yet how widely it's spreading and we certainly don't know the extent of the problem. We're taking active steps to learn more and to make sure that we're on top of the situation. We're working closely with health officials in California and in Texas and we're working with the U.S. Department of Agriculture exploring illness in pigs and other animals.

We're also working with international partners to understand what may be occurring in other parts of the world. And we particularly want to get the messages to clinicians today. It's important as we are in this discovery stage of this investigation that clinicians have a heightened concern when they're seeing people with respiratory illness who are -- have had direct contact with pigs.

Or who have exposure to San Diego or Imperial County in Southern California or to San Antonio area. What we'd like clinicians who are treating people with respiratory illness in those circumstances to do is to get a specimen to test for influenza and to work with their state health laboratories to look for the typing of the influenza.

We also are asking laboratories to help, state laboratories now are fully equipped to test for influenza types and when they find influenza strains that are not typable we urge them to forward those isolettes on here to CDC where we can check to see whether this particular strain is circulating.

As a precautionary step we're also taking a number of other more forward-looking measures. We are working with this virus to prepare it as a vaccine seed strain should the situation evolve and we actually need to make a vaccine against this particular virus. And we're working with partners across the government to understand the virus as well.

So, there is quite a lot of work going on. I want to say that we are committed at CDC and with our public health partners to let you know what we find out when we find out it. And today we're providing availability to the press. But what we plan to do is to provide regular updates on our Web site and so at 3:00 p.m. each day, yes 3:00 p.m. each day we hope to be updating the Web site. That's www.cdc.gov to share the additional findings.

You know, in this stage of an investigation when we're really heightening our concern for clinicians, for laboratories, for others we're likely to find more cases. So that's not going to be surprising. At this point we really are making extra efforts here at CDC and with public health partners to understand the situation.

We don't think this is time for major concern around the country but we want you to know what we're doing and what we're learning from what we're doing. I think that there are probably a couple of questions that everybody has that I'd like to answer before we go to the general question and answer period.

You know, when you hear the word swine influenza you think about swine and many people wonder can you get this from eating pork? The answer is no you can't get swine flu from eating pork or from eating pork products. So that's not something that you need to worry about.

It's also important to know that some of the measures that we're taking as part of our investigation as we contact people who have come down with this illness and talked to their colleagues or their family members or their friends we may be doing extra efforts to understand the situation that would not be routine. That would not be what we would recommend everywhere.

So, in the parts of the country where the investigation is intensifying there may be active efforts to understand the spread of the virus. I also want to say something about regular influenza and regular respiratory illness because there is a lot of it. It's important when you have respiratory illness with fever that you wash your hands, that you stay home from work, or you don't travel and you try to protect others from spreading that infection.

And those are good rules when you're worrying about regular seasonal influenza and also at a time like this. So, just the importance of good hygiene, hand washing and keeping your coworkers and your classmates well. CDC is continuing to work actively with the local and state health departments in the affected states. And to connect with our clinical counterparts around the country.

We really want to make sure that information we have is available and at this point I'd like to answer questions that anyone may have.

Operator: Thank you and at this time if you would like to ask a question please press star one on your touchtone phone. Thank you, our first question comes from Helen Branswell, Canadian Press. Please go ahead.

Helen Branswell, Canadian Press: Hi, Thank you very much for doing this and for taking my question. Could somebody please tell me if there are links between these seven cases that you found or do you have suspect cases around these seven cases. Are there people who have been ill but like in the first two but were not tested in the active stage of disease.

Are any of these people actively sick? Another question, is there discussion under way about whether or not alert level needs to be changed at this time?

Schuchat: Thank you so much for those questions. There are two cases in Texas that were attended the same school. So there is contact between those two boys. And there is a father/daughter pair in California.

We don't right now have direct links between California and Texas. There's active investigation going on to understand what the source of infection may have been in people as well as to explore further the possibility of the animal exposure.

So we don't have a history of direct contact with pigs in the patient that we detected. So there are doubles and then others that are just the geographic ditch of two counties in California. Imperial County and San Diego are neighbors. And the patients there are about 130 miles apart from each other.

But this is a very active phase of the investigation and it's important for us to know that may change. You also asked about suspect cases and I can say that when you're in the very active phase of an investigation for something like respiratory illness or fever, it's very common to find people who have suspect symptoms.

So, we're very actively looking into those at this point understanding that information may change. We'll be updating daily the numbers of confirmed cases of swine humanus influenza but we won't be trying to keep on top of the suspect cases in a daily report.

I think you also asked about the pandemic phases. And what I can say is that we're in regular contact with the World Health Organization, with Pan American Health Organization, with counterparts in Washington. We have not changed anything.

Do we have another question?

Operator: Thank you. Our next question comes from Daniel Dunoon (ph), WebMD. Please go ahead.

Daniel Dunoon, WebMD: Thanks for taking my question. I understand that CDC is looking at antibody levels to see if other people have possibly been infected with this rather than active infection.

Has the investigation uncovered other infections and what have you learned from your ring of surveillance?

Schuchat: You know we're in an active phase right now. We are planning to update the investigation details in the NNWR and I would look for more details there. So far we are looking at contact cases to identify whether there are symptoms and whether among those who are symptomatic there are any, there's any evidence of laboratory findings consistent with this particular strain.

That can be done through the PCR test to look at the actual virus or antigen and it's also that we're also looking through serology. But those results aren't available at this point.

Next question?

Operator: Thank you. Our next question comes from Mike Stobbe, The Associated Press.

Mike Stobbe, The Assoicated Press: Hi, Thank you for taking a question. On Tuesday you all discussed the 10-year-old boy from San Diego County and he had gone to Dallas to visit relatives.

Now we have two cases in San Antonio. Did the boy go to San Antonio? Was any travel from any of these cases to San Antonio? I'm just wondering why San Antonio?

Schuchat: That's a great question. We're also wondering why San Antonio. I can say that we've been testing strains from Dallas and they have not shown to be this strain. So you are right that's one of the patients involved did travel from California to Texas but not to San Antonio.

Again, there is an active phase of the investigation and it's possible that links will come up as we continue to learn more about the individuals. But so far we don't have any direct links between people who have the infection in California and the two boys in San Antonio.

Next question?

Operator: Thank you. Our next question comes from Rob Stein, Washington Post. Please go ahead.

Rob Stein, Washington Post: Hi, thanks for taking my question. You might have addressed this in an earlier question but when you said earlier that you have evidence of human-to-human contact spread. Is that between those two pairs you just mentioned?

Schuchat: Well certainly between the father and daughter and the boys in the same school. We are suspicious of human-to-human spread but we actually think the pattern that we're seeing is likely to be from human to human spread primarily because we haven't been able to identify direct animal exposure.

You know, I think we mentioned in the MMWR and on Tuesday in the briefing that we have found swine influenza in people over the past several years. We've been finding more of it recently with our more intensive laboratory surveillance but the majority of swine flu cases that we've seen in the past many years have, do have the direct animal exposure.

We've seen the cases without direct animal exposure but they tend to be rarer because we haven't yet under covered anyone with direct recent pig exposure and because we have these family clusters or school clusters. We really think the pattern is much more consistent with human-to-human spread.

And that's one of the issues we're exploring further in the active investigation.
Next question?

Operator: Thank you. Our next question comes from Maggie Fox, Reuters. Please go ahead.

Maggie Fox, Reuters: Can you tell us a little bit more about the genetic characterization of this virus. What virus it resembles? I also wondered whether you found this just because we're looking more intensely now or whether you think this is a newly occurring virus?

Schuchat: Thank you so much for that question. At this point we really cannot differentiate the idea that this is something completely that we were -- from something that we found out about because we have much better surveillance.

We really strengthened our effort to track influenza during the season. We've strengthened laboratory capacities at the state health department and we've initiated reporting that is notifiable for detection of any untypable influenza strain.

So the Public Health system really knows that we want to know about these unusual occurrences. Ten years ago we were not doing that so we may be seeing something and actively investigating something that has happened many times before.

On the other hand the reason we've strengthened all these surveillance systems was to really be able to detect new problems early. And I think that it's very possible that this something new that hasn't been happening before.

In terms of the genetic characteristics, I would like to have Dr. Nancy Cox address those in more detail from what I've already said.

Cox: Thank you very much. The virus that has caused these infections is viruses are actually very interesting. They contain genetic segments as Dr. Schuchat said from four different virus sources.

So we have some gene segments that are North American swine influenza viruses. Some gene segments North American avian influenza viruses. One gene segment from a human influenza virus and two gene segments that are normally found from swine influenza viruses in Asia and in Europe.

We actually have complete genomic sequencing done for the first influenza viruses that were isolated from the ten-year-old and the nine-year-old. Those two viruses are very similar but not identical to each other. Now we have partial gene sequences for two additional cases from California.

We've found that the gene sequences from the viruses causing infection in those individuals are very, very similar to those in the initial two cases. So, we're seeing basically a virus that appears to be spreading from person to person in humans and viruses have very similar genetic characteristics to each other.

Are there any other questions about the viruses?

Operator: Thank you. Our next question comes from Mary Brophy Marcus, USA Today. Please go ahead.

Mary Brophy Marcus, USA Today: Hi, I actually have two questions the first; do we have any idea about the infectious window for this particular strain of influenza?

Schuchat: You know, it's usually within a few days but can be as long as nine days at this point. So, we are looking at the, you know, a spectrum. Some of the cases that we are reporting occurred quite a while ago. But have now made it through the laboratory system.

And some of the cases occurred in the more recent past couple of weeks.

Marcus: Thank you and my other question is, I don't know if this really off base, but since there is no indication that there is a link with pigs to human spread currently and since this is a time of year when a lot of parents take their children to petting zoos and farms, I'm just wondering if there is any need for concern for families, you know, for visiting rural areas or agricultural fairs or petting zoos.

Schuchat: Thank you for that question. You know, petting zoos are very popular and they are also in a place where it's possible to catch infections, not necessarily swine influenza, but other infections.

So very good hand washing and other precautions is an important thing for parents to know about when they are out visiting such venues. In this investigation we are asking quite a few questions about agricultural fairs, petting zoos and the like.

I think that CDCs Web site does actually have guidance about petting zoos in general because we've had some other kind of outbreaks associated with them. We're not telling parents to change their behavior in terms of the petting zoos or agricultural fairs at this point.

Next question.

Operator: Thank you. Our next question comes from Keith Garza, San Diego Union Tribune. Please go ahead.

Keith Garza, San Diego Union Tribune: Yes, thanks. I'm interested in the additional cases particular in California, the three new cases. Are they located in either San Diego or Imperial County?

Schuchat: Yes. Thank you. I neglected to mention that. Two of the cases are in San Diego County and those are the father/daughter pair. One of the cases is in Imperial County. So the same two counties where we had the original two reports.

Of course, those are places where we're very actively looking so specimens that were available from those places were expedited in terms of our testing. We really do want state laboratories that if they have untypable influenza strains they should send them on here so that we can verify their origin.

We've had terrific cooperation with the California and with San Diego and Imperial Counties. Next question.

Operator: Thank you. Our next question comes from Elizabeth Allen, San Antonio Express News. Please go ahead.

Elizabeth Allen, San Antonio Express News: Good afternoon, the -- you mentioned that you are working with numerous agencies and organizations on this and you talked about working with state labs. Are you also working directly with cities, such as the Metropolitan Health District in San Antonio or are they working with state labs, which are in turn communicating with you?

Schuchat: You know, we work through the states to work with locals such as cities and we're -- our primary contact would be the Texas Health -- the Texas State Health Department who would be actively working with cities and counties.

There are also our other, you know, hospital connections within the state. But our CDC direct link with the state. Next question.

Operator: Thank you, our next question is from Caleb Hellerman from CNN please go ahead.

Caleb Hellerman: Oh, hi, thanks so much for holding this briefing, it's very interesting. Actually, I had two quick questions. One was, if you could elaborate a little bit on the surveillance that initially picked up the initial two cases?

As I understand, there was some sort of pilot program where or testing that is not usually done and sort of wanted to find out more about that, actually that is my main question.

Schuchat: Thank you, yes the first two cases that were detected came from special surveillance activities. One was at a naval research facility where a special diagnostic test was being detected or was being studied. And one was at CDCs collaboration with -- it's called the Border Infectious Disease Surveillance or Bids.

Where we are really actively working U.S. and Mexico studying or evaluating infectious diseases along the border, in that setting we have been not just looking for influenza like illness but actually, actively testing to see whether influenza like illness is truly from one of the influenza viruses.

And it was in those two contexts with actually more diagnostic testing then would happen in a routine clinic or office that the first two cases emerged. Next question.

Operator: Thank you, our next question comes from Yronna Ricco (ph) LaOpinion, please go ahead.

Yronna Ricco (ph): Yes, hi, how can someone that has flu might know -- if it's infected -- what are the differences between this kind of flu and the regular flu?

Schuchat: That is a great question, thank you for asking that. It's important for people who are ill to take special precautions not to spread their illness and of course, to seek medical care when their more severely ill.

What is important is that your doctor or nurse knows that you have exposure in question here. The syndrome -- the presenting symptoms may look just exactly like regular flu. There may be a little bit more diarrhea or vomiting then in regular flu. But the principal symptoms are fever, cough, sore throat, and occasionally now we are seeing diarrhea or vomiting.

So the doctors really need to take a special test to look for influenza and then the laboratories need to do special activities to detect this particular kind. So this isn't something that a person could tell by themselves at home. You would need to get a diagnostic test.

At this point, we're not asking people to change their, you know, to go to the doctor when they have a cold or flu were basically saying if your ill and would seek care please let your doctor know that you have had contact with someone else who is ill or that you had contact with pigs or if you are in the San Diego or Imperial County area or the San Antonio area we're really alerting the clinicians in that area to be thinking about this and to collect respiratory specimen that are needed to detect it. Next question, please.

Operator: Thank you, our next question comes from Lisa Schnerring (ph), Sid Rap News (ph), please go ahead.

Lisa Schnerring (ph): Thanks so much for all the great information today. I have two quick questions. One, does the H1N1 component of this year's flu vaccine protect against this flu? And the other question I had is there any involvement that you know of, of illnesses across the borders, Canada, or Mexico?

Schuchat: Great, you know, at this point, we don't know yet about cross protection between this particular H1N1 strain and previous human H1N1 infections or the vaccine itself. There are active studies going on to understand possible cross protection just as you mentioned. It is a very important issue that we are looking into.

Of course, we think that getting the season flu vaccine is a good idea regardless of concerns about this particular swine infection. But at this point, we really don't know anything about that cross protection.

The second question you asked about was illness along the borders either with Mexico or Canada. And that is something that we're actively investigating. We are in regular contact with our counterparts in those countries. And, of course, interested in that particularly with the southern part of the U.S. cases and Mexico. Next question, please.

Operator: Thank you, our next question comes from Meredith Wadman with Nature Magazine, please go ahead.

Meredith Wadman: Hi, thanks for taking my question. I actually have two the first is in the five new cases you've described to us today at the Web site now is there a level of detail that I see in the MMWR case reports on the first two cases and if not can you go through the five. Obviously, you can't give that level of detail but give us the basics, the date of onset, the severity of the symptoms, the age, the sex, and so on.

Schuchat: The level of -- there will be an MMWR with more information whether it will have as much detail about these five additional cases as we had for the first two I can't say.

The age ranges for the seven cases are from 9 years of age to 54. And the -- and I guess the other information I don't have. So I think that would be something to look for, you know, the times I can give you are that it was yesterday when the three additional cases from California were confirmed as swine influenza with our laboratory testing here at CDC and it was very early this morning when the two cases from Texas we're confirmed here in our laboratory.

So additional details, you know, case by case I don't have. And I'm not actually sure they'll be in the MMWR.

Nowak: This is Glenn Nowak. We believe that MMWR probably will be posted later today. So look for those details.

Schuchat: And I think, you know, it's -- as I did say earlier, I think it's important for people to realize that we do expect to find more cases given the way we're very intensively looking and the nature of the cases that we have found so far.

We are fully expecting in the next several days at least, to find a number of additional cases. And so whether we share all of the details that we did with the first two in every update I'm not sure we'll be able to focus on that. Next question, please.

Operator: Thank you, our next question comes from Donald McNeil, The New York Times, please go ahead.

Donald Mcneil: Hi, thank you. These cases we're all spread out along the Mexican border. Are you in the -- there has been reports that the Mexican authorities informed the Canadian authorities that they we're having a particularly bad flu season this year with a high case fatality rate. Can you tell us more about what you are doing? Are you typing cases from Mexico? Are these cases all among Mexican Americans or unusual number of them or anything more about a Mexican connection?

Schuchat: You know, that question about New Mexico is interesting and important. We're actively discussing our situation and the Mexico situation with Mexico and with the Pan America Health Organization.

At this point, we do not have any confirmations of swine influenza in Mexico. We are working with them in terms of understanding what their seeing clinically as well as the virus characteristics of what they are seeing.

The -- and I -- the other question was about Mexican American. At this point, those details I don't have all though I am -- I think it is important to say that we are -- there are some reasons why cases along the border might have come to our attention more readily than elsewhere, partly because we have this border infectious disease surveillance system, which found one of the two original cases. And partly, because in San Diego the naval facility there has been doing special active surveillance for influenza like illness in the outpatient setting.

So that type of intensive type surveillance is not happening everywhere in the country. On the other hand, we are in close contact with Mexico to understand their situation and to share information that we have. And as we learn, more we'll share it, next question.

Operator: Thank you are next question comes from Amy Burkholder, CBS Evening News.

Amy Burkholder: Yes, hi, thank you very much. CDC said yesterday, that a flight crew was being tested after exposure to somebody with this swine flu. Can you give us any results on those tests? Have any members of the crew tested positive?

Schuchat: You know, I've shared with you all of the positive results that we have right now. The seven cases that we have do not include any flight crewmembers. We are in an active investigation mode so that each individual case with confirmed swine influenza prompts a contact tracing investigation that is much more aggressive than we would do with a routine season influenza patient.

So we are in the process of identifying contacts and trying to understand whether or not they were ill and whether or not there is any evidence of history -- laboratory evidence of swine influenza in them. We have no results that I am aware of suggesting crewmembers having swine influenza at this point.

But as I said, we're in an active phase and we'll be sharing results as we get them. Next question.

Operator: Thank you, are next question comes from Richard Knox, National Public Radio, please go ahead.

Richard Knox: Hi, thanks very much, I appreciate it. Two different kinds of questions. One, is can you tell us anything more about what the aviance (ph) sequence has been found in any of these viruses and what that might imply? And whether you've ever seen before such a desperate mixing from four different strains in a single virus as well?

Schuchat: Yes, let me actually answer that and then offer that we could get you more information in follow-up. I think it's -- the virus -- what we have is unusual the reassortant (ph) with these four genetic sequences is unusual. The avian (ph) lineage I don't have that information and if it's available we can try to get it for you later.

But I would say this is unusual and I like to preference that by saying, we're looking a lot more intensively and so we may be finding more unusual things and we are really trying to have a balance of taking this very seriously. Actively investigating, sharing information as we have it, and trying to convey the idea that we really can't differentiate whether this is truly new versus that we have a better situational awareness now. Next question.

Operator: Thank you, our next question comes from Martin Enserink, Science Magazine, please go ahead.

Martin Enserink: Hello, and thank you. You mentioned that your -- you are preparing this strain as a (seat) for a vaccine. I wonder if you could tell me a little bit more about that? And also if you are taking additional steps for the preparation of a vaccine? And so have you been in contact already with vaccine producers and ask them what it would take to switch to the production of these vaccines, for instance.

Schuchat: I didn't actually catch too much of that but I think you were asking about us preparing a vaccine strain and whether we could talk a little bit more about that. Is that what your question was? If that's your question would you like to -- we'll let Dr. Cox give you sort of a very high-level description of what's going on even though you're science -- OK.

Cox: Thank you for that question. I'd like to really place our activities to produce a vaccine candidate strain within the context of our normal activities. Whenever we find a virus that is different, that is to say it's anagenically (ph) directed from the seasonal strains that have been circulating previously.

Or, in the case of H5, whenever we see a virus that's different from the candidate vaccine viruses that we've already produced, we go ahead and make a candidate vaccine virus for this new virus. So this is within the context of what we normally do. This is actually standard operating procedure for us.

In terms of a timeline, of course, it takes us several weeks to produce a candidate vaccine virus and have it tested and so on. And certainly a candidate vaccine virus can be used in a variety of different ways, in the laboratory, as a reagent and so on. So it would be very useful to have this and we consider this to be in our library of candidate vaccine viruses should we need to use it.

Thank you very much.

Nowak: Thank you. We have time for two more questions.

Operator: Thank you. Our next question comes from Judy Silverman, NBC News.

Judy Silverman: I'd like to know the timeline when these cases occurred, these seven cases, from when to when?

Cox: Yes. The details that I have are that the earliest onset was March 28 and that the more recent ones are, I believe, April 19. That may not be accurate and on our Web site we will have the accurate information. But these are, you know, ranging from that early, that late March time line to quite a bit more recently.

So the last question? So the last question if there is one?

Operator: Thank you. Our final question comes from Collen Zachary-Chuck (ph), Infectious Disease. Please go ahead.

Collen Zachary-Chuck (ph): Hi, thanks for doing this. I just wanted to double check; do you guys think that this seems kind of like a late presentation for these flu -- for the flu to be presenting? Is that typical for California or do you think it's probably due to some of the vaccine maybe having (frost protection) affect? Can you guess on that?

Cox: Let me clarify. This is very late for seasonal influenza. The routine kind of influenza strains that we see every year. That's declining. The regular season is in its pale really. What we're seeing now is different. It's not seasonal influenza, it's what we call Swine Influenza. Has different characteristics and we don't really see enough of it in people to have a seasonality.

These are quite unusual cases. It's in fact a little bit easier that it's occurring now in the end of the influenza season because we don't have so much noise or so much background influenza to look through. But it is, you know, initially we want to take very special measures to make sure this really was a different strain because sometimes towards the end of a season it can be harder to take the strains that are just regular flu. So this is not routine seasonal flu it's just occurring at the tail end of the seasonal -- of the season of regular influenza.

So thank you for your questions and look to our Web site for more information.

Nowak: One of the things we hope to do yet today is publish the (MMWR) dispatch that will be made available at CDCs Web site. We will also be posting tomorrow morning the transcripts from this teleconference. If reporters have additional questions the CBC press office is available at 404-639-3286. And again, I thank you for your time and participation this afternoon and look for, as I mentioned, updates on our Web sites, including 3:00 every day. Thank you.




This article was provided by U.S. Centers for Disease Control and Prevention. You can find this article online by typing this address into your Web browser:
http://www.thebody.com/content/art51477.html

General Disclaimer: TheBody.com is designed for educational purposes only and is not engaged in rendering medical advice or professional services. The information provided through TheBody.com should not be used for diagnosing or treating a health problem or a disease. It is not a substitute for professional care. If you have or suspect you may have a health problem, consult your health care provider.