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University at Albany Center for Public Health Preparedness

Epidemiology and Surveillance of Emerging Infections

Original Satellite Broadcast: 06/08/06

Moderator: Good Morning and welcome to the University at Albany Center for Public Health Grand Round Series. I'm Peter Slocum and I'll be your moderator today. Before we begin, I would like to remind you to take a moment after the broadcast to fill out your evaluations. Your feedback is very important and helpful in the development of future programs. Continuing education credits are available. We'll be taking your questions later in the program. The toll-free number is 800-452-0662. You may also send your questions by fax to 518-426-0696 anytime during the program. Today's program is on Epidemiology and Surveillance of Emerging Infections. Our guest, Dr. Morse from the Mailman School of Public Health at Columbia University edited the 1993 publication, “Emerging Viruses” from Oxford Press, and is an expert in what has come to be known as emerging infectious diseases. Thank you for joining us today Dr. Morse.

Dr. Morse: Thank you very much. It's my pleasure to be here.

Moderator: We look forward to quite a full conversation and I want to start by referring to the obvious interest right now in Avian Flu, the general public is certainly aware of this emerging infection, but there have been many others throughout history. I thought you might want to start by covering some of that history for us.

 Dr. Morse: Thank you. The impact of infectious diseases throughout history has been tremendous. The Black Death, the Plague of the 14th Century, killed one-third of the population of Europe and wiped out many villages and actually caused tremendous changes in society. Smallpox, which it is estimated to have killed more people than all the wars in history combined.  And the possibility exists that people from Europe coming to the new world may have brought smallpox with them and actually contributed to the death of many of the native people - many ofthe people who were already in North America. Some people—some historians think that Montezuma's empire was destroyed in part because of the smallpox that broke out, was accidentally introduced. Some people think, in return, syphilis came from the new world back to the old, but that's still controversial.

Moderator: Referred to as the Columbian exchange.

Dr. Morse: Yes, because of Columbus, of course and people think of Columbus as a sailor. Cholera was a very big deal in the 19th century, when steamships came along, and is one of the first examples of rural epidemiological at work. Before we even knew about the microorganism that caused it (which was discovered a few years later), John Snow and others were able to work out how it was transmitted through the water, the fecal-oral route as we indelicately call it. And the 1918 influenza, the Spanish flu, one of the greatest disasters in history, probably killed 50 million people all over the world in its two-year course.

Moderator: Since that time, of the influenza epidemic, we don't tend in this country to think of infectious diseases as a fatal phenomenon, but that's not true in the rest of the world.

Dr. Morse: Well, in fact, in most of the world, we're still living with the situation where infectious diseases are responsible for much death. They're major causes of illness and death, especially in children. Things that we take for granted, like diarrheal disease, kill many children. Diseases like measles, which we have almost forgotten about, still kill people in developing countries. And they are only sort of pushed down into the margins of our own civilization. We have controlled them, but we really haven't eliminated them. With the exception of smallpox, which has been eradicated as a natural disease, no infectious disease has as yet been eradicated from nature.

Moderator: We'll come back to avian flu in more detail, but how do you define emerging infection at this point in our epidemiological history?

Dr. Morse: Well, informally, you can think of emerging infections as things that inspire books like "The Andromeda Strain," a famous book by Michael Creighton about a deadly virus that fell from space. Of course that's not where they come from. I like to jokingly say emerging infection are the ones that are the incidents that push the really important news like, let's say the latest movie or the latest trial off the front pages for a few days. But in epidemiological terms, they are those infections that are rapidly increasing in incidence, the number of new cases, or in geographic range. Many of these are novel, previously unrecognized-Ebola when we first saw it in Africa; HIV/AIDS when we first saw it. Interestingly enough, in many cases, human beings do things inadvertently that cause these infections to appear and spread.

Moderator: Right. Let's look a little more closely at the graph that you have that describes the dramatic impact of HIV/AIDS in this country.

Dr. Morse: I think the perfect example, and it was one of the examples that really forced us to realize that infectious diseases are not a thing of the past, even in the most industrialized countries where we've largely forgotten about them. HIV/AIDS was unknown to western medicine in the early 1980s. When you look at this graph, that white line shooting up like a rocket-- I mean it really goes all the way across all these other more established causes of disease to become, in a mere decade, the leading cause of death in healthy, young people in the United States. It's better now. If we extended that, it's largely better because we have drugs to treat it, but that's a golden age that may end when the virus, as it has already, starts to develop serious resistance, and we're seeing the same pattern being played out all over the word. When I came to Columbia University, in the early 1990s, AIDS was almost unknown in South Africa at the time. Now AIDS is one of the most serious problems in South Africa, as well as being one of the places where the disease and the virus are most rapidly increasing.

Moderator: And the speed, in some ways, is what is so extraordinary. The rocket projectory of that graph is amazing. I remember the governor of New York gave an inaugural address in 1980 and the word "AIDS" never occurred to us to put in the address. Several years later, it was occupying our attention entirely.

Dr. Morse: I agree. We didn't even know about it. But the amazing thing is after thousands of years with all our experience with infectious diseases that a disease that is not only new and unknown to us, but the mechanism by which it kills people was unknown to medical science before that. A whole new mechanism of causing disease, after all these years of seeing all these disease mechanisms, is absolutely remarkable and makes you wonder what else is out there. Indeed there are many other things out there, as we know.

Moderator: Let's talk about what some of those other things that are less well known than HIV and avian flu, in other countries in the developing world.

Dr. Morse: There are a lot of examples. This map, for example, which comes from Dr. Tony Fauci at the National Institute of Allergy and Infectious Diseases at NIH, just shows a number of the outbreaks that have occurred, diseases that are appearing in new places or infections that are new to western medicine. And that includes things like outbreaks of what we call Nepa virus, which occurred first in Malaysia in 1998 as an agricultural problem. But people got it and many died. Ebola, of course, was one of the first examples, but there were some before that. HIV/AIDS, I have already mentioned. The Hanta Pulmonary Syndrome, the mysterious disease that started out in the four corners region of the southwestern US in 1993, started out with people getting a flu-like illness. These always start out as flu-like illnesses for some reason, and then rapidly people would develop respiratory failure, and about 60% of the people who had this disease actually died, despite intensive medical support. And when people went out to investigate this, the CDC did a lot of testing, it turned out to be a virus distantly related to one in Asia which is very widely proliferating, and it occurs largely in association with rice farming. It's carried by rodents. But we didn't know we had one like that in the United States that could cause this kind of disease. SARS, of course, is another example.

Moderator: Right. How do infectious diseases emerge into our population and consciousness?

Dr. Morse: Well, you know, that was the issue I was first concerned about: where do they come from? Is it the Andromeda Strain? It only seems like the Andromeda Strain. The answer is obvious, in fact. They come from nature. They already, in many cases, exist in other species or in the environment, and what's required, obviously, is for them to be introduced into the human population. I sometimes like to refer to this as the two-step process. First the introduction from some other source that already has an infection of its own or some environmental source, and then the ability of this infection to establish itself in the human population and spread is dependent on a lot of factors which may include things like the evolution of the infectious agent, the opportunities we may give the disease, the infection, as we did with HIV/AIDS to spread through the human population, even if it isn't yet well adapted to humans. The introduction step, that first step, was the one that always seemed the most mysterious, you know: Where did they come from? In fact, many of these are zoonotic. Zoonotic diseases are diseases that are naturally transmissible from other animals to humans and what I like to call the zoonotic pool. All the biodiversity of organisms out there is a rich source of emerging pathogens. Most of them are really not human pathogens. There are many we probably stumble on from time to time and don't get infected, but there's also a great variety of them. So every so often we do stumble upon one, for example Ebola, Hanta viruses -- and do get infected. It's hard, but it does happen. And changes in the environment may increase the frequency by which this happens simply because we get into the environment and we have more opportunities now to stumble on some of that biodiversity. And food animals are another route by which other infections may get into the human population. I think there's a slide that flashed briefly about emerging infections and their natural hosts. One of the most striking things is that some of these were mysterious, but we now know that Ebola and Marburg, a closely related virus, Nepa virus, which infects pigs and many other species, also dogs, and humans with high fatality rates, that is killing a large proportion of those that are infected, turns out their natural hosts are various species of bats, including fruit bats. With HIV, I think the evidence is getting stronger now that chimpanzees were probably the original source of the ancestor of HIV 1, the main AIDS virus, and another monkey for HIV 2.

Moderator: It was reported in the last week or so.

Dr. Morse: Exactly, from Beatrice Han and her collaborators, and that makes the link much clearer. It's always been speculated, but I think we now have better evidence. Influenza, where does it really exist when it's not infecting people? We're just accidental hosts for influenza. Most of the time it's out there in wild waterfowl and other birds -which as one of my colleagues, Rob Webster, likes to say is the library of influenza viruses in nature. And then SARS, though it came to us from another food animal, the civet in China-widely prized as food especially during the winter, is actually the natural host, the original source of infection, the species that actually carries the virus that later adapted and evolved to become the SARS virus as we know it today from bats.

Moderator: Bats again.

Dr. Morse: So rodents and bats and birds come into this a lot. Why? Because there's a great biodiversity and those are some of the species we come in contact within places like agricultural settings and other opportunities that bring changes to ecology. Sometimes things we do, like agriculture--

Moderator: We create opportunities for this to break loose sometimes by changes in the environment that are man-made, right?

Dr. Morse: Absolutely. And sometimes it happens through completely natural means. Hanta virus pulmonary syndrome outbreak had actually been there for a long time, but increased because of rodent population explosion, due to climate changes over several years. But most of the time, its things like agriculture. Why agriculture? It's one of the ways in which we change the environment in major ways and then we're right there in that environment. So if you plough or if you cut down the fields and put in rice, a particular rodent that carries a virus called Hantaan, the first-known Hanta virus disease related distantly to the one here in the four corners, that causes a fever with kidney problems, hemorrhagic fever with renal syndrome.And that's carried by a mouse, a field mouse very common in that area that particularly thrives in these rice fields. The mice come in and harvest the rice and the people follow and some of them may inhale some virus left behind in mouse droppings and become infected. A pattern we have seen over and over again, food-handling practices. Obviously as we saw with SARS, with avian influenza and with many other examples, have had a lot to do with it, maybe even HIV through what we call the bush meat trail. Protein is very valued and people find any source--

Moderator: Especially chimpanzee meat.

Dr. Morse: Chimpanzees or other animals, chimpanzees probably. We certainly have examples of Ebola that people have picked up from eating or butchering infected chimpanzees. Chimpanzees are accidental hosts for Ebola, just as we are. But then, of course, if you eat a sick or dead chimpanzee that died of Ebola, you can get it, too. And that probably happened with HIV. We also know with dams, changes in water systems, mosquito-borne diseases can suddenly pop up and increase. In Africa, we saw increases in diseases like yellow fever in places where we didn't even know it existed, probably had been there at a very low level, but when dams were put in, suddenly there was an increase in the mosquito population and people now had much greater opportunity to become infected and we started seeing many more human cases. And that's been true over and over again.

Moderator: I remember the urban legend when we lived in Maine. The story was after they cleaned up a lot of rivers which were subject to massive industrial pollution - then the black flies came back in much more ferocious numbers. And people said that was the downside of cleaning up the environment, the black fly population.

Dr. Morse: It is interesting, you know. The environment is something that has a lot of interconnections in many ways. Just as microbes in a sense, are interconnected, partly through our activities and our ability to carry them throughout the world over history. But we do things that have unintended consequences, sometimes for very good reasons:more food, more water, being able to grow things better and irrigate the fields, but unfortunately the unintended consequences sometimes come back to bite us. In the case you were speaking of, quite literally.

Moderator: Once a new disease is introduced, what's step two? The dissemination stage, I gather.

Dr. Morse: Of course, we're lucky in that none of us would be here today to talk about it if that second step was really an easy one. It isn't. There are lots of candidates out there that may be able to infect humans with some difficulty, but relatively few.  HIV has been one of the real—I hate to say success stories - but not from our point of view, but from the point of view of the virus. Luckily that's fairly rare, but there are a lot of opportunities that increase the ability of what I call microbial traffic, the ability of an infection to get into the human population and then to spread and possibly evolve so that it could establish itself more efficiently in the human population. And some of these things include, you know, very simple things like rural to urban migration occurring all over the developing world. And there, what you see is someone may have picked up the precursor to HIV. Somewhere in a rather remote place where they had contact with, maybe eaten or butchered a chimpanzee. And it may have been localized, happening several times in the past without any success. We know this happened with Ebola where it had probably been going on at a low level. As people then move into the cities, especially young men in search of work, you find that obviously there are now opportunities for a once very obscure disease, very localized to a remote place, now to get connected to the rest of the world. And there are fewer and fewer remote places now that's one of the problems. It's good for the world, good for cultural interchange and the ability for all of us to trade, but also, unfortunately, the microbes get to trade, too.

Moderator: They travel-- travel has become a vector for the dissemination of these diseases.

Dr. Morse: Indeed. Luc Montagnais, the co-discoverer of the virus HIV that causes AIDS, once referred to the 747 - that big wide-bodied jet - as the vector of HIV, the way a mosquito might carry a disease. It did, indeed, around the world because there's a tremendous amount of travel all over the world.And more and more of it as trade opens up, and that's a good thing, but it has its risks also.

Moderator: And also medical technologies change and lead to spread, right?

Dr. Morse: Medical technologies, you know, that's again one of the unintended consequences of good things. So we have to be on our guard. Ebola is a disease that doesn't spread well from person to person and it kills very quickly. In the old days, probably few people would get it, maybe a family taking care of the sick person. The original cases of Ebola we saw in the 1970s in Africa were actually amplified because these original patients, the index cases as epidemiologists very dryly call them, went to local clinics or hospitals, which were under resourced. One of these hospitals had only five sets of injection equipment, which they used for everybody, and so they were drawing blood or giving injections of antibiotics to the Ebola patient. At the same time, the same syringes were used on the other patients and so you had an outbreak of 200 cases, mostly spread in the hospital, because of lack of resources for infection control. That's certainly true of HIV, which is spread through the blood supply as well as, of course, the more famous actual contact and intravenous drug use. Now the blood supply has been cleaned up in the United States, but in many countries that have high rates HIV, Africa for example, there isn't the money to do that. So the blood supply still can give HIV to other people and there are many other ways to do it. So hospitals need to have good infection control. That's very important.

Moderator: I think we have a good slide of a map of the travel vector phenomenon here that I want to make sure we get a look at. This is since 1993, correct?

Dr. Morse: Yes. It's an old slide but I like it because it's so graphic. The amazing thing is that this slide probably would show numbers one and a half times what you see here being done today because travel has been increasing year by year, on the average, about 20% or so. But this kind of travel represents less than 1% of international travel. So when you think about all the tremendous opportunities for microbes that may have once been very isolated, to go from some far away place to our own doorstep. We saw that with SARS, for example. Those opportunities are increasing, and they really obviously are a concern. SARS is a very dramatic example. One doctor, a physician who had treated a patient with an unusual pneumonia in South China went to Hong Kong for a family event. I think it was a wedding. And he got sick. He went to his local hospital. He was staying at a hotel, now known as-- it's shown as Hotel "M" on the slide from WHO and CDC, but it's now known as the Metropol Hotel, a four-star hotel, not a cheap place. And he came down with pneumonia, an unusual one. He went to a hospital in Hong Kong, told his caregivers that he had been treating a patient with this unusual pneumonia and that several of his colleagues had also been getting sick from this, and he thought this was something strange and transmissible and he warned the people taking care of him in the hospital to take special precautions. Unfortunately, somehow the word didn't get out to others. While he was staying at that hotel, a dozen other people became infected. That's sort of a big bang, and you can see how it spread throughout the world. Some of the others got sick right away, went to other Hong Kong hospitals where it spread to health care workers. Others went to Vietnam and other countries, very famously Canada, where there was an outbreak in Toronto. All from that one initial patient and all within a matter of weeks to months. So it's really important to be able to not only be watchful, but to get the information out quickly and reliably.  

Moderator: Right. And that's why, of course, the great example of how a hospital becomes a multiplier, in effect, of the infection.

Dr. Morse: I think good infection control is very important. SARS reminds us that even in the industrialized world, infection control is still an important thing. Not only that, but it has to be paid careful attention to because it's very easy to slip up. Since HIV/AIDS is in most of the industrialized world, we have what we call standard precautions, used to be called universal precautions. That's helped a lot in terms of making infection control easier to practice and preventing things, I think in many cases that could have been bad. But we also have to recognize from the example in Toronto, that we can't be complacent and maybe that's the bottom line of everything about emerging infections. We can't afford to be complacent. We have to continue to be watchful.

Moderator: We have talked about the others. We have a slide here that indicates a number of the diseases we talk about and Lassa fever has the same sort of track record.

Dr. Morse: Lassa fever was, in fact, the example -- it's a hemorrhagic fever with effects on the blood vessels. You get weakness and often shock, and many of the infected people die. It was identified for the first time by Western medicine in Africa in the late-1960s, and that's what inspired the “Andromeda Strain.” People think Ebola now, but this was pre-Ebola. It also wiped out an entire mission hospital in Nigeria. By interesting coincidence, one of the surviving patients, a nurse, was medivacced to Presbyterian Hospital in New York City, and actually survived, probably as much because of her own good immune system or good immune response, because it didn't overreact in her case, as well as the good medical support. But this was amazing because it just ripped through hospitals when people would go in with it and would just kill many of the health care providers. We saw that with SARS and Ebola, as well. So it's a caution, something to be cautious about for all of us who work in health care. Not to scare people, but just remind us that infection control really does count.

Moderator: Let's jump next to the main area, and that is surveillance, and talk about the different kinds of surveillance. And first, what kinds of tools do we have to find out about these spreading infections and do we have a network that actually works?

Dr. Morse: I think the answer is we have had a number of traditional tools and now some newer ones. I think we're still building that infective medical intelligence network, but I think we have more pieces and more pieces coordinated than we did, say, ten years ago - when a group of colleagues and myself started an organization called Pro-MED.Pro-MED is a program for monitoring diseases, which came completely out of the concern that we did not have an effective system of global surveillance as pointed out by D.A. Henderson, well-known as one of the people who really deserves tremendous credit for spearheading the smallpox eradication, and many other people. But traditionally, we work on case reports and sometimes when laboratories are available, especially in this country and other countries, we can get laboratory confirmation. It's very important to do that. The problem with traditional surveillance is it's usually disease-specific. We go one at a time, and that means very often it's siloed or stove piped, meaning that the person is interested in one disease and is throwing out data that may be tremendously important to the person in the office next door dealing with a different disease. And unless they happen to talk in the hallway, they may never see that there's a real connection. So the fragmentation has been a real problem. Surveillance systems, of course, have inherent defects. Most of them are passive. We depend on the astute clinician and others to tell health authorities that something is going on.

Moderator: They come across something and decide they should report it.

Dr. Morse: Exactly.

Moderator: Rather than the active surveillance model is an aggressive seeking of reports, right?

Dr. Morse: Although active surveillance is far more effective, it's also far more expensive, and there are only a certain number of things that anybody can keep in mind at any given time. Even here, we have a tremendously long list of reportable infections. I couldn't recite it from memory and I'm sure most clinicians can't, but they have a notion. And it really depends a lot on people having that sort of index of suspicion. We used to say when you hear hoof beats in Central Park, think horses not zebras. But we have a zoo in Central Park, so it very well could be a zebra. You have to think horses and zebras. But when we think about the traditional surveillance, one of the best examples is influenza surveillance. I'll talk about that later, because that's many of the traditional pieces in place. So all of these things may be good for known diseases, but we're concerned about the unknown and unexpected, as HIV/AIDS was when it first appeared. For that, you obviously need other kinds of tools and other ways of looking at them.

Moderator: How do we spot these unknown diseases?

Dr. Morse: That's really tricky. That was one of the reasons, in fact, that Pro-MED was formed in the first place, and there are ways to do it. One of them is so-called, what was then called syndromic surveillance. It has many different meanings to many different people. In the '90s, when we started Pro-MED and there were other historic examples, syndromic surveillance meant looking for sort of clusters of disease manifestations, signs and symptoms of disease, and there were a few traditional examples of that. Or you could look for unexplained deaths in the hospital, which I think is quite an interesting possibility if you focus your case definitions so that you don't pick up too many things to track down because our capacity to do that is limited. I can give you a few examples of the so-called, old-fashioned syndromic surveillance, if you like. Definitions vary. In the past, it meant looking for clinically recognizable disease syndromes. Now often it's thought of as being something you do with data from a computer that's automated, but that's a somewhat different idea. Let me give you an example of a few classic infectious disease syndromic surveillance systems, because we have used them in the past--

Moderator: And successfully.

Dr. Morse: Very successful. They were successful in eradication or helping perform the eradication of smallpox. What people look for is rash and fever. A lot of those were chickenpox or measles.But if you trace down carefully every one of those cases -- that was really the trick -- you could rule out the cases of chickenpox and measles and find the real cases of smallpox and work to immunize in that area through a process known as surveillance and containment or wean vaccination. That strategy was originally developed by Bill Fagey and implemented by D.A. Henderson - real heroes of public health. It made it possible to eradicate smallpox, but we came upon a number of other diseases that we didn't know existed because they also caused rash and fever, as well as other things. Polio, which is targeted for eradication, is using a similar strategy. It takes awhile to identify these in the laboratories, so what we look for is a certain type of paralysis, again often with fever. Many are not caused by polio, but a lot of them also are. So you have some idea that you can go out there and find the polio cases if you were looking carefully. With smallpox, it was very successful to use the rash and fever. With polio, it's working well; the problem there being the political will and ability to do the follow-up actions. For various reasons, some countries are uncomfortable. And there have been, unfortunately, some rumors, that have been spread about the immunization, which is safe and effective. Unfortunately, sometimes people have suspicions -- which worries me. In the old days, public health was seen as beneficial, and indeed it is; working for all our benefit. That's why it was possible, even in war-torn countries, to get people to sign on to universal smallpox immunization and immunizing intensively in areas where there was still smallpox or indications of smallpox.

Moderator:  Right. Now, would most people recognize smallpox, do you think?

Dr. Morse: I think most people would not recognize it today. If you flash that picture-- this is an actual case of a child with smallpox. We haven't seen the natural disease since the late-'70s. It was officially eradicated in 1980. The last case was a laboratory accident in 1978 and the last natural case occurred in Africa in 1997. Most physicians are not trained on smallpox today. Luckily a few people are still alive who would know how to differentiate and we do have laboratory tests.

Moderator: Now, we'll go into more detail about Pro-MED and tracking, but we're running short on time, so we may have to cut some of it short. But I want to make sure we get into the surveillance issues in some detail, talking about the way to collect the data that comes from all around the world.

Dr. Morse: So the original idea with the program for monitoring emerging diseases was to build-- and this was a suggestion that had been made by a number of people, many of whom were involved with our steering committee, D.A. Henderson, for example and many others. In fact, we had a paper on health policy in 1996 that describes the idea of building a worldwide network of centers that could be regionally responsible for three things:  identifying clinical cases of particularly unusual diseases in certain categories that were fairly recognizable; being able to do at least some sort of minimal lab identification, and many of these laboratories had capabilities there; and to do the epidemiological follow-up, because those are the three things you need. And then share information, obviously very important. And then the idea was if they couldn't identify something in their own laboratory, it perhaps was something unusual, they could rule out the most common things. They would need the capability to do that, and then they could bump it up the chain to a larger laboratory -- and eventually keep going in that way until we could either identify it, get it to a lab with very specialized, broad capabilities that could identify it or recognize that it was something new and now-- new to us and as yet previously undescribed. A lot of that involved setting some minimal capabilities for laboratory and other types of centers of excellence round the world that would then form a network to share information. One of the things that came from that was, in fact, an information-sharing network called Pro-MED-mail on the internet which started as a way of getting all these labs around the world and all these scientists and public health officials around the world to communicate, but eventually became a prototype for disease reporting system. That's one of the pieces of the medical intelligence system, and it was actually the very first, although obviously the internet has evolved quite a bit since then, and we have much better capabilities. We can be grateful for that.

Moderator: Sort of a mini-example of that sort of operation right in New York City, right?

Dr. Morse: Indeed. New York City and a number of other places have been pioneers in trying new methods for what we call syndromic surveillance today, which in addition to looking at the traditional signs and symptoms I have talked about, looks for things like emergency calls for ambulances. There are a variety of call types that get coded when an ambulance is called in. You know, they ask a few questions before they send out the ambulance. Does it seem like a heart attack? Do you think the person looks like they're having shortness of breath? So something with fever and shortness of breath or headache or diarrhea, all are very suggestive and might suggest an infectious disease. Similarly, New York City and a number of other places are doing programs in emergency departments to find out about people who have similar types of diseases who are coming in with their chief complaint as a fever and something else suggesting it could be an infectious disease. For example, pharmacies looking at the over-the-counter sales -- because often it's an indication that the whole population -- such as in Milwaukee with cryptosporidium in the water supply causing diarrhea. This can be a terrible thing for HIV patients. But often people buy an anti-diarrheal, this may be the first indication that something is happening of a serious nature.

Moderator: We have a slide of the reporting points in New York City from the emergency rooms and it shows the kind of coverage you get.

Dr. Morse: Exactly. So they have covered, you know, a fairly wide range of emergency departments all over the city. And as an example, the next slide simply shows the kind of data you get, which has to be looked at very carefully, but can give you some indications when there's an increase in something like respiratory disease, which could be an influenza outbreak about to hit and increase.

Moderator: Okay. What are some examples of the things that Pro-MED is able to cover in picking up around the world?

Dr. Morse: Well, Pro-MED-mail, which is really available to anyone on the internet, is moderated by scientists, is free to all, and has a lot of subscribers all over the world. It covers things like SARS. One of the first descriptions of an atypical pneumonia came over the Pro-MED network. Ebola in 1995 came over Pro-MED, and a number of others. Of course there are other aspects to the global alert network. The World Health Organization has, in recent years been building that network of networks, as they like to call it, as a global alert and response network, including many networks all over the world that pick up various diseases. There are, of course, many possibilities. This map shows some of the pieces of that network, with the idea being to share information and make it more effective for sharing information and getting it out rapidly to the world health community and public health community and scientific community. There are obviously a lot of improvements that can be made, including hot spots that could be identified so we would know where to focus our effort, more intensively looking at the human/animal interfaces, bringing in veterinarians who know a lot about these things, looking at transportation hubs, and perhaps training local people in developing countries to do what we expect physicians and clinicians to do here, but could also be done in developing countries that have fewer clinicians by a sort of outreach and training mechanism. So I think there's a lot that still can be done, but at least we're getting there, we are making more progress.

Moderator: What are the components of the influenza surveillance?

Dr. Morse: That's an example of a very strong system that has a lot of components, although it's still not perfect. The World Health Organization has a number of national influenza laboratories in 83 countries. The US has its own very extensive system of laboratories that collaborate. Some of those are state public health labs, some are in hospitals and clinics, and they can test for influenza and do some additional testing in the laboratory and report it. In the 122 major cities reporting so-called pneumonia influenza mortality, if that seems to go up, it's a good indication that there's a bad influenza season coming.And physicians who are looking for influenza-like illnesses among their own patients have agreed to collect samples and send them for testing. And finally, the epidemiologists coordinate a program with all the state epidemiologists who report what they're hearing from their own health department and what the health departments are hearing from their own clinicians about influenza-like illnesses popping up in their states.

Moderator: I see. Back to the global perspective, for a moment. Are there laboratory facilities in every country in the world?

Dr. Morse: Unfortunately, not every country. Some countries have more extensive facilities: Australia, for example, the United States, Canada. Others have one or two - parts of South America, for example.Parts of Asia and Southeast Asia and Africa have only one, and some parts have none at all. In Africa especially and some parts of Asia, they have none. We would obviously like to see improvements there. You can also recognize these clinically, you know, just looking for influenza-like illnesses. And there's a case definition in the next slide which shows what the epidemiologists and the sentinel physicians are looking for to collect the samples that then can get tested in our own laboratories in the United States. What you end up with each influenza season, on the next slide, for example, is a map of, you know, where there seem to be a lot of influenza. This was last January, and you can see sort of a color-coded man of where the influenza hot spots are, and of course, as the season progresses, there's more red and less yellow and green.

Moderator: Right. And these are all based on local and regional reports.

Dr. Morse: These are all based on local and regional reports and obviously information sharing and that astute clinician, where it all starts, are very important things. And public health is at the leading edge of this, the first line of defense.

Moderator: Right. Maybe we could talk a little bit about a few things that might happen with avian influenza based on the travel patterns we talked about and our experience with the SARS outbreak.

Dr. Morse: Well, we don't know whether avian influenza is going to be the next pandemic or not. Right now it's a serious problem for agriculture. It's likely to get to the United States. We have had other outbreaks that do not transmit readily to humans in the past, so I think it's very likely we will be seeing it here. Whether it's going to transmit efficiently to humans-- it doesn't do it very efficiently right now, so the risk for humans is relatively low. No consolation for those people who have unfortunately gotten it, largely through close exposure. But luckily for us, so far, it hasn't spread well from person-to-person and that's the thing we look for before a pandemic happens. It has to spread really well from person-to-person, like the traditional influenza, as well as being novel. So it meets the criterion of novelty. It could be a problem for agriculture. There are actually USDA precautions in place right now and will ramp up if it's found in the United States. As a human health concern right now, the risk is low, but we don't know where the next pandemic influenza will come from. We don't know whether it's H-5 or probably something else. But we also know it's likely in our lifetime we'll see at least one and probably more.

Moderator: And it could be something we haven't seen, as you said, like dengue fever, probably coming to our shores as well?

Dr. Morse: Other things can come. Dengue fever has been traveling throughout the tropics. There are four types of dengue fever, four viruses closely related. They used to be geographically isolated, but now they're mixed together in many areas. And diseases we have forgotten about, like yellow fever. As recently as 1905 there was an outbreak in New Orleans. Luckily for us, there are ways to control it in the United States, but all of these diseases are forgotten but not gone.

Moderator: Right. What would you say are the most important lessons concerning emerging infections and the role of public health in this 21st-century environment?

Dr. Morse: I think it's essential that we not get complacent. Just because we've had some successes, and that's a wonderful thing, doesn't mean we're finished. We can't give up vigilance and surveillance with vigilance. Communication is very important because as with all public health, that's always the key thing. And the fragmentation of knowledge, delays in reporting have been major problems. Of course, many countries don't like to talk about the problems they have. We saw that with SARS in China, and we can't afford to be embarrassed about these things. For the benefit of the world, it's important to be truthful, and then that establishes trust and credibility. We have to be very good about how we communicate this information and do it in an honest and credible way. I think obviously we have to support public health worldwide at the local level, and this remains very under resourced. A frontline defense is absolutely essential, and we have to expect the unexpected because that happens and continues to happen.

Moderator: Let me pause for a moment and tell our audience that we are ready to take calls now and the toll-free number is 800-452-0662. You may also fax 518-426-0696. We already have some questions and we'll get to those in a moment. Here's one from West Virginia: How can syndromic surveillance be effective when various diseases' symptoms often resemble each other so closely?

Dr. Morse: That's very true and it's been a real issue. The answer is you have to find indicators that cast a broad enough net to pick up what you want but are narrow enough that you also don't pick up a lot of other things. In the Pro-MED proposal, we focused on a couple of diseases, for example, encephalitis with fever in adults. In Africa, that could very often be malaria, but the fact that it was adults meant that the probability was lower, although probably 80% of it or more would be malaria. We also focused on acute respiratory distress in adults, again with fever lasting more than a couple of days, because those are comparatively unusual. Even if other common diseases can cause them, you can rule them out fairly quickly if you have the laboratory capability and then also identify the unknown. A lot of the trick is having some laboratory capacity that can be networked and also making good case definitions, but you have to begin with asking the question could this be unusual? That's obviously the first thing:raising awareness. There's a trick to making good case definitions; we all know that. There are dangers to making them too broad.

Moderator: I see. All right. Here's another question and this goes back to the zoonotic factor we were talking about before. How important is the role of veterinarians in detecting these diseases and are there mechanisms that exist for them to report into the Pro-MED system or some other system?

Dr. Morse: They do report on Pro-MED-mail. It includes veterinarians, plant experts. We include both human and animal diseases in the main Pro-MED and emerging disease reports on Pro-MED-mail simply because we feel that those two communities need to be brought together on a frequent and regular basis. And because zoonotic diseases, some of our major concerns-- even some bioterrorist concerns like anthrax, and veterinarians often have the capability to diagnose them and the knowledge and laboratories. But the system is too fragmented, so we really need to build better bridges and linkages between the veterinary side of the house and the human medicine side of the house, as well as a number of other linkages. I think it's getting done, but it's essential.

Moderator: All right. We have a caller on the line, I believe from Michigan. Go ahead, please.

Caller: Hi. We had a question about pandemic flu. We were wondering why has it taken up until now for it to come into human contact? If it originated in birds, do they have an origin of it from a longer time ago?

Dr. Morse: Excellent question. And by the way, one of the experts in influenza epidemiology, Arnold Monteau, is in Michigan also. The answer is luckily for us, although there are lots of influenza viruses in birds, most of them do not infect humans very readily at all. It's a rare one that does. H-5 is one of the exceptions and it doesn't infect humans very well. It's difficult. The other one may have been the 1918 influenza. Those are the rare exceptions. Usually they have to go through another mammal first, and so as a result they luckily are relatively few in number. But the opportunities for us to come in contact and for mixing in other mammals, like pigs for example have been suggested. In South China, they have an agriculture system that puts pigs and ducks close together with the human farmer and may have helped to allow some other pandemics of the past. We don't know - that's a hypothesis - but that sort of intermediary may be very important. That's why we don't see pandemics all the time, luckily for us, because although there are lots of influenza viruses out there, few of them get into people and even fewer of them have evolved or can evolve easily, as far as we know, to be spread well from person-to-person.

Moderator: We have time for one quick call from the Hudson Valley of New York, I think. We have one minute to go. Go ahead, please. From Dutchess County. Are you there?

Caller: Yes. This is Rhonda Alley. I appreciate you taking my call, Dr. Morse. This session was extremely informative and very useful to all of us. The question I had was regarding syndromic surveillance, which considers the chief complaint as the main indicators that you're using to look for outbreaks. Would the advent of electronic billing, I think the ICD-9 codes are available to use... Is this a concentration that Pro-MED has in mind to use that rather than chief complaint?

Moderator: We have 15 seconds, I'm afraid.

Dr. Morse: Pro-MED uses reports from scientists and health people. This kind of surveillance you are talking about has a lot of interesting possibilities and the short answer is yes, it is possible, but unfortunately a lot of ICDE codes go by system rather than disease, so influenza may go as a respiratory lung problem rather than infectious disease. They're working on that with the coding system and that's improved.

Moderator: Thank you very much, Dr. Morse. It's been an informative hour.

Dr. Morse: My pleasure.

Moderator: We would like to thank you for joining us and ask you to fill out your evaluations. Your comments are very important to us in developing future programs. Continuing education credits, including nursing contact hours are available free of charge to those who fill out the evaluation and post-test. Visit our website for more details and an archive collection of past broadcasts. Join us July 13 for "Risky Business, Communication during Crisis," with Kristine Smith, Director of Public Health Risk Communication at the Office of Science and Public Health at the New York State Department of Health. I'm Peter Slocum. See you next time on the University at Albany Center for Public Health Preparedness grand round series. Thank you very much.

Dr. Morse: A pleasure.

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