Paul Farmer, _Infections and Inequalities: The Modern Plagues_, Berkeley: U of California P, 1999 Paul Farmer, MD, Ph.D Associate Professor of Social Medicine, Harvard University [Paul Farmer is a physician and anthropologist. In addition to his book, _Infections and Inequalities: The Modern Plagues_ Farmer is also co-editor of _Women, Poverty, and AIDS_, and author of _The Uses of Haiti_, and _AIDS and Accusation_. In 1993 he was awarded the MacArthur Foundation "genius award" for his work.] Chapter 2: Rethinking "Emerging infectious Diseases" However secure and well-regulated civilized life may become, bacteria, Protozoa, viruses, infected fleas, lice, ticks, mosquitoes, and bedbugs will always lurk in the shadows ready to pounce when neglect, poverty, famine, or war lets down the defenses. And even in normal times they prey on the weak, the very young and the very old, living along with us, in mysterious obscurity, waiting their opportunities. -- HANS ZINSSER, 1934 The microbe is nothing; the terrain, everything. -- LOUIS PASTEUR, 1822-1895 AIDS. Ebola. Flesh-eating bacteria. With newspaper and television reports rife with references to mysterious and lethal outbreaks caused by new (or newly virulent) pathogens, perhaps it's safe to conclude that we're living in a time of unprecedented popular interest in infectious diseases. Yet medical historians might be quick to discern, in this most recent wave of hysteria and genuine interest, but a small peak in the jagged line charting the course of popular concern with epidemic disease That's not to say that there's nothing new under the sun. This most cent surge of interest comes at a time when novel technologies can reveal a level of detail -- about both pathogens and hosts -- unimagined by our recent forebears. And this past decade has surely been one of the most eventful in the long history of the study of infectious diseases. There are multiple indices of these events, and also of the rate at which our knowledge base has grown. We have only to follow, for example, the sheer number of relevant publications to perceive the explosive growth in this knowledge base. We have developed new methods of monitoring antimicrobial resistance patterns. And we have new ways to promote rapid sharing of information (and also, unfortunately, speculation and misinformation) through means such as the Internet that barely existed even ten years ago. Then there are the microbes themselves. One of the most significant events of the past ten or fifteen years, and perhaps the most remarked upon, is the explosion of "emerging infectious diseases." Some of the disorders -- such as AIDS and Brazilian purpuric fever -- can be regarded as genuinely new. Others were clinically identified some time ago but have newly identified etiologic agents or have again burst onto the scene in dramatic fashion. For example, the syndromes caused by Hanta viruses have been known in Asia for centuries, but they now seem to spreading beyond that continent as a result of ecological and economic transformations that increase contact between humans and rodents. The phenomenology of neuroborreliosis had been tackled long before monikers "Lyme disease" and Borrelia burgdoferi were coined, and before suburban reforestation and golf courses complicated the equation by creating an environment agreeable to both ticks and affluent humans. Hemorrhagic fevers, including Ebola, were described long ago, and their ecologic agents were in many cases identified in previous decades. Still other diseases grouped under the "emerging" rubric are ancient and were known foes that have somehow changed, either in pathogenicity or distribution. Multidrug-resistant tuberculosis and invasive or necrotiz Group A streptococcal infection -- the "flesh-eating bacteria" of the popular press -- are cases in point. Popularizing the concept of "emerging infectious diseases" has helped to marshal a sense of urgency, notoriously difficult to arouse in large bureaucracies. Funds have been channeled, conferences convened, articles written, and a dedicated journal founded. The research and action programs elaborated in response to the perceived emergence of new infections have, by and large, been sound. But the concept also carries complex symbolic burdens -- as do some of the diseases most commonly associated with it. Such burdens have certainly complicated and, in some instances, hampered the laying down of new knowledge. If certain populations have long been afflicted by these disorders, why are the diseases considered "new" or "emerging"? Is it simply because they have come to affect more visible -- read, more "valuable" persons? This would seem to be an obvious question from the perspective of the Haitian or African poor. In the emerging literature on emerging infectious diseases, some questions are posed while others are not. A subtle and flexible understanding of emerging infections would be grounded in critical and reflexive study of how our knowledge develops. Units of analysis and key terms would be scrutinized and regularly redefined. These processes would include regular rethinking not only of methodologies and study design but also of the validity of causal inference, and they would allow reflection on the limits of human knowledge. The study of such processes, loosely known as epistemology, often happens in retrospect. To their credit, however, many of the chief contributors to the growing literature on emerging infectious diseases, accustomed to debate about microbial nomenclature, have shown exceptional self-awareness in examining the epistemologic issues surrounding their work. Many are also thoroughly familiar with the multifactorial nature of disease emergence. In a 1995 review, one of the prime movers in the field (a virologist) noted that the emergence of a newly recognized or novel disease is rarely a purely virological event without identifiable causative co-factors: "Responsible factors include ecological changes, such as those due to agricultural or economic development or to anomalies in the climate; human demographic changes and behavior; travel and commerce; technology and industry; microbial adaptation and change; and breakdown of public health measures."1 Similarly, the Institute of Medicine's influential report on emerging infections does not even categorize microbial threats by type of agent, but rather according to major factors held to be related to their emergence: "human demographics, behavior; technology and industry; economic development and land use; international travel and commerce; microbial adaptation and change; and breakdown of public health measures."2 Many students of emerging infectious diseases thus distinguish between a host of phenomena directly related to human actions -- ranging from improved laboratory techniques and scientific discovery to economic development, global warming, and failures of public health and another set of phenomena, much less common and deriving more directly from changes in the microbes themselves. Even in cases of microbial mutations, however, we often find signs that human actions have played a large role in enhancing pathogenicity or increasing resistance to antimicrobial agents. In one long list of emerging viral infections, for example, only the emergence of Rift Valley fever is attributed to a possible change in virulence or pathogenicity; and this cause is enumerated after other, social factors for which better evidence exists.3 No need, then, to launch a campaign calling for a heightened awareness of the sociogenesis, or "anthropogenesis," of disease emergence. Ironically, perhaps, some of the bench scientists involved in the field are both more likely to refer to a broad range of social factors and less likely to make immodest claims of causality about any one of them than are behavioral scientists who study infectious diseases. Yet a critical epistemology of emerging infectious diseases is still in early stages of development. A key task of this endeavor is to take our rating conceptual frameworks and ask, "What is obscured in this way of conceptualizing disease? What is brought into relief.?" For example, a first step in understanding the epistemologic dimension of disease emergence involves, as Eckardt argues, developing "a certain sensitivity to the terms we are used to."4 When we think of "tropical diseases," for instance, malaria comes quickly to mind. But not too long ago, malaria was a significant problem far from the tropics. Although there is imperfect overlap between malaria as currently defined and malaria of the mid-nineteenth century, some medical historians agree with contemporary assessments that this illness "was the most important disease in the United States at that time."5 In the Ohio River Valley, according to Daniel Drake's 1850 study, thousands died in seasonal epidemics. 6 A million-odd soldiers were afflicted with malaria during the U.S. Civil War.7 During the second decade of the twentieth century, when the population of twelve southern states was about twenty-five million, the region saw an estimated one million cases of malaria per year. Malaria's decline in this country was "due only in small part to measures aimed directly against it, but more to agricultural development and to other factors some of which are still not clear."8 One responsible factor that is clear enough, if little discussed in the literature, is the reduction of poverty, including the development of improved housing, land drainage, mosquito repellents, nets, and electric fans -- all of which have been (and remain) beyond the reach of those most at risk for malaria.9 In fact, many "tropical" diseases predominantly afflict the poor; the groups at risk for these diseases are often bounded more by socioeconomic status than by latitude. In Haiti, for example, my patients with malaria are almost exclusively those living in poverty. None have electricity; none take prophylaxis; many have lost kin to malaria. This aspect of disease emergence is thus obscured by an uncritical use of the term "tropical medicine," which implies a geographic rather than a social topography.10 Any modern practitioner dealing with infectious disease knows this well, even if he or she sits in a travel clinic in New England. Those who come in for malaria prophylaxis and to ask about appropriate vaccinations are students, professionals, and tourists. When practitioners are called into the emergency room for an imported case of malaria, however, we usually see a very different patient shuddering on a damp gurney. In Boston, at least, the patient with malaria is likely to have been born in an endemic region -- Haiti, say, or West Africa -- and to be working as a laborer in the U.S. service economy. And that patient is also likely to tell us the diagnosis, for it will not be the first time that he or she has had malaria. Similarly, the concept of "health transitions" is influential in what some have termed "the new public health" and also among sectors of the international financial institutions that so often control development efforts.11 The "health transitions" model suggests that nation-states, as they develop, go through predictable epidemiologic transformations; that infectious cause is gradually supplanted by death due to malignancies and complications of coronary artery disease; the latter deaths occur at a more advanced age, reflecting progress. Although it describes broad patterns now apparent throughout the world, the concept of national health transitions also masks other realities, including morbidity and mortal differentials within nationalities, which show that health conditions are often more tightly linked to local inequalities than to nationality. For example, much was made of the fact that noncommunicable pathologies such as coronary artery disease and malignancies caused the majority of all world deaths in 1990. A very different picture emerges, however, when we compare causes of death among the wealthiest fifth the world's population to the afflictions that kill the poorest fifth: though only 8 percent of deaths among the world's wealthiest were caused by infections or by maternal and perinatal mortality, fully 56 per cent of all deaths among the poorest were caused by these pathologies with infectious diseases at the head of the list.12 How do the variables of class and race fit into such paradigms? In Harlem, where age-specific mortality in several groups is higher than that in Bangladesh, lead causes of death are infectious diseases and violence.13 The units of analysis are similarly up for grabs. When Surgeon General David Satcher, writing of emerging infectious diseases, reminds us that "the health of the individual is best ensured by maintaining or improving the health of the entire community,"14 we should applaud his clear-sightedness. But we should also go on to ask, What constitutes "the entire community"? In a few instances -- the 1994 outbreak of cryptosporidiosos in Milwaukee, say -- the answer might be part of a city.15 In other instances, "community" may mean a village or a group of passengers on an airplane. But the most common unit of analysis referred to in public health, the nation-state, is not all that meaningful to organisms such as dengue virus, Vibrio cholera 0139, HIV, penicillinase-producing Neisseria gonorrhoeae, multidrug-resistant tuberculosis, and hepatitis B virus. Such organisms often proudly disregard political boundaries, even though a certain degree of "turbulence" in their dynamics may be introduced at national borders. The dynamics of disease emergence are not captured in nation-by-nation analyses any more than the diseases are contained by national boundaries, which are themselves emerging entities. (Most of the world's nations are, after all, twentieth-century creations, which might also give pause to those buying into the two-worlds myth.) The limitations of these three important ways of viewing the health of populations -- the concepts of tropical medicine, health transitions, and national health profile -- demonstrate that models and even assumptions about infectious diseases need to be dynamic, systemic, and critical. That is, models with explanatory power must be able to track rapidly changing clinical, even molecular, phenomena and link them to the large-scale (often transnational) social forces that shape the contours of disease emergence. I refer here to questions less on the order of how pig-duck agriculture might be related to the antigenic shifts central to influenza pandemics and more on the order of the following: Are World Bank policies related to the spread of HIV, as some have recently claimed?16 What is the connection between international shipping practices and the spread of cholera from Asia to South America and elsewhere in this hemisphere?17 How is genocide in Rwanda related to cholera in Zaire?18 The study of anything said to be "emerging" tends to be dynamic. But the very notion of emergence in heterogeneous populations poses analytic questions that are rarely tackled, even in modem epidemiology, which, as McMichael argues, "assigns a primary importance to studying interindividual variations in risk. By concentrating on these specific and presumed free-range individual behaviors, we thereby pay less attention to the underlying social-historical influences on behavioral choices, patterns, and population health."19 Systemic analyses of disease emergence are not hemmed in by political or administrative borders. New tools based on DNA analysis allow us to rethink comfortable conclusions regarding treatment for some but not for others. The notorious "W strain" of MDRTB, for example, spread quickly through New York City but then moved on to Atlanta, Miami, and Denver.20 New data suggests that the W strain's family tree has roots in Asia and Russia.21 If these are transnational pandemics, spread through sharing air, then surely responses must be transnational -- although, thus far, such responses have been hobbled by short-sighted parochialism. Genetic subtyping of HIV leads to the same conclusions. A critical (and self-critical) approach would ask how existing frameworks might limit our ability to discern trends that are related to the emergence of diseases. Not all social-production-of-disease theories are equally alive to the significance of how relative social and economic positioning inequality-affects the risk of infection. For example, neither poverty nor inequality appears as a "cause of emergence" in the self-described "catalog" of emerging infections compiled by the Institute of Medicine. Further, a critical approach would push the limits of existing academic politesse in order to ask more difficult and rarely raised questions, questions that still need to be answered if we are to better understand disease emergence. Examples might include issues such as these: By what mechanisms have international changes in agriculture shaped recent outbreaks of Argentine and Bolivian hemorrhagic fever, and how do the mechanisms derive from international trade agreements such as GA and NAFTA? How might institutional racism be related to both urban crime and the epidemics of multidrug-resistant tuberculosis registered New York prisons? Does privatization of health services buttress social inequalities, increasing risk for certain infections -- and poor outcomes -- among the poor of sub-Saharan Africa and Latin America? How do the colonial histories of Belgium and Germany, and the neocolonial history of France and the United States, tie in to genocide in Rwanda -- which is itself related to an epidemic of cholera? We can productively pose similar questions about many of the diseases now held to be emerging, as a few examples will suggest.... <http://HIVInSite.ucsf.edu/social/books/2098.438e.html> _______________________________________________ Crashlist website: http://website.lineone.net/~resource_base
