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Health Woes Grow in Shrinking World

Health Woes Grow in Shrinking World TRAVEL IS broadening. Unfortunately, it may also be diarrhetic, emetic, toxic . . . that is to say, a vehicle for exposing the body to unfamiliar ills even as it opens up new vistas for the mind. As people who live in the industrialized countries of the world make more forays for pleasure or business into global areas that are less developed, many physicians in the voyagers' homelands are finding their diagnostic acumen challenged by diseases that have disappeared from, or were never common in, the places where they practice. Medical professionals in North America and Europe are also encountering patients who visit or migrate from their native countries, sometimes leaving behind everything but their endemic illnesses. At the same time, people who spend their lives in places where parasitic and other exotic diseases flourish are becoming increasingly eager to see the discoveries of modern science translated into cures for their ancient ills, and public health agencies throughout the world are concerned with the problem of emerging and reemerging infectious diseases. The confluence of these current streams has fed a flood of interest in the American Society of Tropical Medicine and Hygiene. Participants in a course held just before the group's annual meeting in Lake Buena Vista, Fla—including tropical medicine physicians, infectious disease specialists, epidemiologists, clinical microbiologists, graduate students, public health physicians, and medical educators—heard updates from experts on the control, management, and elimination of tropical diseases. Following are some highlights of their presentations. Infectious Disease in 2001 "As we enter the 21st century, we still see infectious diseases accounting for 33% of the mortality throughout the world," warned David L. Heymann, MD, PhD, a soft-spoken man who has become known (via the television special "The Coming Plague" based on the book by Laurie Garrett) as an "infectious disease cowboy" who strides out to lasso and dispatch lethal microbes. "There's really no reason for this in a world where the tools to combat or eliminate these diseases are available," he said in his keynote address. Heymann, who is director of the Geneva, Switzerland–based World Health Organization (WHO) Division of Emerging and Other Communicable Diseases Surveillance and Control, blamed the deterioration of the public health infrastructure worldwide, along with such well-known phenomena as population increase, overcrowding, and environmental change, for facilitating the emergence of previously unrecognized infectious diseases and the reemergence of known diseases. He listed a litany of global "failures," among them that of vaccination programs in eastern Europe, which contributed to epidemic diphtheria and polio; of vaccination for yellow fever in Latin American and sub-Saharan Africa, which led to outbreaks of the almost eliminated disease in those areas; and of surveillance for cholera, which allowed that disease to reappear in Peru in 1991 after a century's absence from South America. Mosquito control efforts in the 1950s and 1960s had nearly eliminated dengue from Latin America and Asia, he pointed out, but as those efforts slackened in the 1970s, the disease began to reappear. Now, he said, "Dengue is hyperepidemic in most of Latin America, with over 500000 cases reported in 1995 to 1996 of which over 13000 were the hemorrhagic form diagnosed in 25 countries." Antimicrobial resistance and dramatic increases in international travel amplify the emergence and reemergence of infectious diseases, Heymann reminded his listeners, alluding to ubiquitous penicillin-resistant Staphylococcus aureus and Neisseria gonorrhoeae, chloroquine-resistant Plasmodium falciparum, and other now-recalcitrant organisms. He cited a World Tourism Organization report that in 1995, for example, a half-billion people traveled by air, facilitating transmission of one region's resistant microorganisms to nearly anywhere in the world within hours. That air travel affects transmission patterns is exemplified, he said, by the finding that a clone of multiresistant Streptococcus pneumoniae first isolated in Spain in 1988 was identified shortly thereafter in Iceland, and a second clone of that organism, also first identified in Spain, was then found in the United States, Mexico, Portugal, France, Croatia, Republic of Korea, and South Africa. Add to this the problems of refugees and forced migration, and the containment of infectious diseases indeed appears a daunting task. Renewed efforts toward eradication, improved education, and revised regulations—such as the WHO–implemented International Health Regulations that provide a universal code of practice—will all help, Heymann said, but "we have to look at basic public health measures as the most important tool." He called for worldwide "rebuilding of the weakened public health infrastructure and strengthening of water and sanitary systems; minimizing the impact of natural and man-made changes of the environment; effectively communicating information about prevention of infectious diseases; and appropriately using antibiotics." To do all this, he said, while also providing additional resources for other emerging public health problems, such as those related to smoking and aging, will be the challenge in the 21st century. Leishmaniasis "Who besides ‘leishmaniacs' even cares about leishmaniasis?" asked Barbara L. Herwaldt, MD, MPH, a medical epidemiologist at the Centers for Disease Control and Prevention (CDC), Atlanta, Ga, rhetorically before plunging into an exhaustive exposition about this particularly difficult-to-treat tropical disease. The answer is an increasing number of physicians because of changing patterns of incidence. Although thought of as endemic in India, parts of Africa and the Middle East, and Brazil, the disease is now being seen in persons infected with HIV in Spain, Portugal, Italy, France, in other parts of Latin America, and elsewhere. In the southern Sudan, an ongoing epidemic is related to the migration of the population. Cases have occurred in US travelers, as well as in veterans of the Gulf War. The topic is all the more complex because of the number of leishmanial syndromes and species, the controversy about whether and how to treat the disease, and apparently so many—but in reality so few—therapeutic options, said Herwaldt. Her two major points were, first, that the pentovalent antimonial agent Pentostam (sodium stibogluconate), long considered the drug of choice, may soon be replaced—at least in some parts of the world and for infection with some species of Leishmania—by amphotericin B, which is more effective and better tolerated. Second, from a review of the literature, Herwaldt concluded that it is impossible to generalize about the treatment for leishmaniasis. Among the gamut of other therapies that have been tried, she said, some may be effective in a particular area with a particular species of parasite in a particular individual. The varying species respond differently to different drugs; none is uniformly effective and all must be used with caution. Studies that have been done have not been well controlled, and there have not been repeatedly confirmatory studies showing that the drugs work. Herwaldt offered several CDC telephone numbers physicians may call for assistance with treating leishmaniasis: for clinical consultation (770) 488-7760; for diagnostic assistance such as review of specimens or slides and serologic testing (770) 488-4474; and for the CDC Drug Service (404) 639-3670. New Treatment for Scabies Ten years ago, the corporate compassion of Merck & Company Inc, Whitehouse Station, NJ, in donating the drug Mectizan (ivermectin) for the treatment of onchocerciasis, or river blindness, in Africa was widely hailed. Last November at a Merck symposium that included the ministers of health of 30 African nations, the possibility was broached of eliminating the disease—which still infects some 18 million people and for which 126 million more are at risk in Central and South America and the Middle East, as well as Africa—as a major health problem in the next decade. This instance of hope was reported at the tropical diseases meeting by David R. Nalin, MD, Merck's director for Vaccine Scientific Affairs. Noting that ivermectin was approved for marketing in the United States only within the past year, Nalin suggested several further applications of the agent that may be of benefit in this country. It has been found effective against strongyloidiasis, a potentially fatal roundworm infection that occurs in the United States among immunocompromised patients, and as a single-dose topical agent against scabies. Topical application of ivermectin has also been effective, he said, in preliminary trials against head lice. New Concepts in Filariasis Alleviating the grotesque misery of elephantiasis—the swelling usually of the scrotum or legs resulting from infection with the parasite Wuchereria bancrofti—has been the lifelong work of Gerusa Dreyer, MD. Working in Recife, Brazil, at Centro de Pesquisas Aggeu Magalhaes–Fiocruz, she is credited with revolutionizing the treatment of filariasis after she showed by ultrasonography that diethylcarbamazine kills the parasite (Am J Trop Med Hyg. 1994;50:753-757). At the meeting in Florida, Dreyer countered the traditional idea that elephantiasis is caused by an obstruction in the lymphatic channels of the affected body part with her observation that, on the contrary, the channels become dilated, probably because of the parasite's release of some cytokine or toxin. The fact that the lymphatic channels are altered, but not obstructed, may have implications for therapy. Dreyer's other new contribution to the lives of people with this disease is demonstrating the importance of preventing secondary infection. She said that simply caring for the feet to prevent the superficial fungal infections that lead to cracks in the skin and the entry of bacteria prevents 93% of the episodes of lymphadenitis that are common in people with filariasis. And finally, Dreyer proposed that a single dose of diethylcarbamazine might well replace the usual 2 to 3 weeks of recommended therapy. She said that her observations led her to believe that, although not all the parasites are killed by one dose, increasing the dose level and duration added little to the efficacy of the drug. Ecology and Disease Mary E. Wilson, MD, chief of the Department of Infectious Diseases at Harvard-Mt Auburn Hospital in Cambridge, Mass, discussed the factors in the physicochemical environment that influence the burden of infectious diseases on humans. She spoke of "the unintended consequences of well-intended interventions," her illustrations making it clear that so-called improvements, meant to make life easier for people in undeveloped areas, often carry a high price in human suffering. With examples drawn from around the world, she demonstrated how dams on rivers in Senegal and China can lead to the importation of schistosomiasis, and roads across mountains in Brazil can open the way for mosquitoes as well as commerce. Even hospitals can sometimes hurt those they mean to help, she said, because in many countries "we are collecting the sickest of the sick in areas with very poor infection control." Wilson's suggestion for avoiding the more dire possibilities of drastic action was, "We need to use retrospective analyses prospectively." By systematically studying the consequences of our actions, perhaps we can learn ways to avoid repeating our mistakes. This prescription, it seems, might profitably be applied to many areas of human endeavor in addition to the study of tropical diseases. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png JAMA American Medical Association

Health Woes Grow in Shrinking World

JAMA , Volume 279 (8) – Feb 25, 1998

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Publisher
American Medical Association
Copyright
Copyright © 1998 American Medical Association. All Rights Reserved.
ISSN
0098-7484
eISSN
1538-3598
DOI
10.1001/jama.279.8.569
Publisher site
See Article on Publisher Site

Abstract

TRAVEL IS broadening. Unfortunately, it may also be diarrhetic, emetic, toxic . . . that is to say, a vehicle for exposing the body to unfamiliar ills even as it opens up new vistas for the mind. As people who live in the industrialized countries of the world make more forays for pleasure or business into global areas that are less developed, many physicians in the voyagers' homelands are finding their diagnostic acumen challenged by diseases that have disappeared from, or were never common in, the places where they practice. Medical professionals in North America and Europe are also encountering patients who visit or migrate from their native countries, sometimes leaving behind everything but their endemic illnesses. At the same time, people who spend their lives in places where parasitic and other exotic diseases flourish are becoming increasingly eager to see the discoveries of modern science translated into cures for their ancient ills, and public health agencies throughout the world are concerned with the problem of emerging and reemerging infectious diseases. The confluence of these current streams has fed a flood of interest in the American Society of Tropical Medicine and Hygiene. Participants in a course held just before the group's annual meeting in Lake Buena Vista, Fla—including tropical medicine physicians, infectious disease specialists, epidemiologists, clinical microbiologists, graduate students, public health physicians, and medical educators—heard updates from experts on the control, management, and elimination of tropical diseases. Following are some highlights of their presentations. Infectious Disease in 2001 "As we enter the 21st century, we still see infectious diseases accounting for 33% of the mortality throughout the world," warned David L. Heymann, MD, PhD, a soft-spoken man who has become known (via the television special "The Coming Plague" based on the book by Laurie Garrett) as an "infectious disease cowboy" who strides out to lasso and dispatch lethal microbes. "There's really no reason for this in a world where the tools to combat or eliminate these diseases are available," he said in his keynote address. Heymann, who is director of the Geneva, Switzerland–based World Health Organization (WHO) Division of Emerging and Other Communicable Diseases Surveillance and Control, blamed the deterioration of the public health infrastructure worldwide, along with such well-known phenomena as population increase, overcrowding, and environmental change, for facilitating the emergence of previously unrecognized infectious diseases and the reemergence of known diseases. He listed a litany of global "failures," among them that of vaccination programs in eastern Europe, which contributed to epidemic diphtheria and polio; of vaccination for yellow fever in Latin American and sub-Saharan Africa, which led to outbreaks of the almost eliminated disease in those areas; and of surveillance for cholera, which allowed that disease to reappear in Peru in 1991 after a century's absence from South America. Mosquito control efforts in the 1950s and 1960s had nearly eliminated dengue from Latin America and Asia, he pointed out, but as those efforts slackened in the 1970s, the disease began to reappear. Now, he said, "Dengue is hyperepidemic in most of Latin America, with over 500000 cases reported in 1995 to 1996 of which over 13000 were the hemorrhagic form diagnosed in 25 countries." Antimicrobial resistance and dramatic increases in international travel amplify the emergence and reemergence of infectious diseases, Heymann reminded his listeners, alluding to ubiquitous penicillin-resistant Staphylococcus aureus and Neisseria gonorrhoeae, chloroquine-resistant Plasmodium falciparum, and other now-recalcitrant organisms. He cited a World Tourism Organization report that in 1995, for example, a half-billion people traveled by air, facilitating transmission of one region's resistant microorganisms to nearly anywhere in the world within hours. That air travel affects transmission patterns is exemplified, he said, by the finding that a clone of multiresistant Streptococcus pneumoniae first isolated in Spain in 1988 was identified shortly thereafter in Iceland, and a second clone of that organism, also first identified in Spain, was then found in the United States, Mexico, Portugal, France, Croatia, Republic of Korea, and South Africa. Add to this the problems of refugees and forced migration, and the containment of infectious diseases indeed appears a daunting task. Renewed efforts toward eradication, improved education, and revised regulations—such as the WHO–implemented International Health Regulations that provide a universal code of practice—will all help, Heymann said, but "we have to look at basic public health measures as the most important tool." He called for worldwide "rebuilding of the weakened public health infrastructure and strengthening of water and sanitary systems; minimizing the impact of natural and man-made changes of the environment; effectively communicating information about prevention of infectious diseases; and appropriately using antibiotics." To do all this, he said, while also providing additional resources for other emerging public health problems, such as those related to smoking and aging, will be the challenge in the 21st century. Leishmaniasis "Who besides ‘leishmaniacs' even cares about leishmaniasis?" asked Barbara L. Herwaldt, MD, MPH, a medical epidemiologist at the Centers for Disease Control and Prevention (CDC), Atlanta, Ga, rhetorically before plunging into an exhaustive exposition about this particularly difficult-to-treat tropical disease. The answer is an increasing number of physicians because of changing patterns of incidence. Although thought of as endemic in India, parts of Africa and the Middle East, and Brazil, the disease is now being seen in persons infected with HIV in Spain, Portugal, Italy, France, in other parts of Latin America, and elsewhere. In the southern Sudan, an ongoing epidemic is related to the migration of the population. Cases have occurred in US travelers, as well as in veterans of the Gulf War. The topic is all the more complex because of the number of leishmanial syndromes and species, the controversy about whether and how to treat the disease, and apparently so many—but in reality so few—therapeutic options, said Herwaldt. Her two major points were, first, that the pentovalent antimonial agent Pentostam (sodium stibogluconate), long considered the drug of choice, may soon be replaced—at least in some parts of the world and for infection with some species of Leishmania—by amphotericin B, which is more effective and better tolerated. Second, from a review of the literature, Herwaldt concluded that it is impossible to generalize about the treatment for leishmaniasis. Among the gamut of other therapies that have been tried, she said, some may be effective in a particular area with a particular species of parasite in a particular individual. The varying species respond differently to different drugs; none is uniformly effective and all must be used with caution. Studies that have been done have not been well controlled, and there have not been repeatedly confirmatory studies showing that the drugs work. Herwaldt offered several CDC telephone numbers physicians may call for assistance with treating leishmaniasis: for clinical consultation (770) 488-7760; for diagnostic assistance such as review of specimens or slides and serologic testing (770) 488-4474; and for the CDC Drug Service (404) 639-3670. New Treatment for Scabies Ten years ago, the corporate compassion of Merck & Company Inc, Whitehouse Station, NJ, in donating the drug Mectizan (ivermectin) for the treatment of onchocerciasis, or river blindness, in Africa was widely hailed. Last November at a Merck symposium that included the ministers of health of 30 African nations, the possibility was broached of eliminating the disease—which still infects some 18 million people and for which 126 million more are at risk in Central and South America and the Middle East, as well as Africa—as a major health problem in the next decade. This instance of hope was reported at the tropical diseases meeting by David R. Nalin, MD, Merck's director for Vaccine Scientific Affairs. Noting that ivermectin was approved for marketing in the United States only within the past year, Nalin suggested several further applications of the agent that may be of benefit in this country. It has been found effective against strongyloidiasis, a potentially fatal roundworm infection that occurs in the United States among immunocompromised patients, and as a single-dose topical agent against scabies. Topical application of ivermectin has also been effective, he said, in preliminary trials against head lice. New Concepts in Filariasis Alleviating the grotesque misery of elephantiasis—the swelling usually of the scrotum or legs resulting from infection with the parasite Wuchereria bancrofti—has been the lifelong work of Gerusa Dreyer, MD. Working in Recife, Brazil, at Centro de Pesquisas Aggeu Magalhaes–Fiocruz, she is credited with revolutionizing the treatment of filariasis after she showed by ultrasonography that diethylcarbamazine kills the parasite (Am J Trop Med Hyg. 1994;50:753-757). At the meeting in Florida, Dreyer countered the traditional idea that elephantiasis is caused by an obstruction in the lymphatic channels of the affected body part with her observation that, on the contrary, the channels become dilated, probably because of the parasite's release of some cytokine or toxin. The fact that the lymphatic channels are altered, but not obstructed, may have implications for therapy. Dreyer's other new contribution to the lives of people with this disease is demonstrating the importance of preventing secondary infection. She said that simply caring for the feet to prevent the superficial fungal infections that lead to cracks in the skin and the entry of bacteria prevents 93% of the episodes of lymphadenitis that are common in people with filariasis. And finally, Dreyer proposed that a single dose of diethylcarbamazine might well replace the usual 2 to 3 weeks of recommended therapy. She said that her observations led her to believe that, although not all the parasites are killed by one dose, increasing the dose level and duration added little to the efficacy of the drug. Ecology and Disease Mary E. Wilson, MD, chief of the Department of Infectious Diseases at Harvard-Mt Auburn Hospital in Cambridge, Mass, discussed the factors in the physicochemical environment that influence the burden of infectious diseases on humans. She spoke of "the unintended consequences of well-intended interventions," her illustrations making it clear that so-called improvements, meant to make life easier for people in undeveloped areas, often carry a high price in human suffering. With examples drawn from around the world, she demonstrated how dams on rivers in Senegal and China can lead to the importation of schistosomiasis, and roads across mountains in Brazil can open the way for mosquitoes as well as commerce. Even hospitals can sometimes hurt those they mean to help, she said, because in many countries "we are collecting the sickest of the sick in areas with very poor infection control." Wilson's suggestion for avoiding the more dire possibilities of drastic action was, "We need to use retrospective analyses prospectively." By systematically studying the consequences of our actions, perhaps we can learn ways to avoid repeating our mistakes. This prescription, it seems, might profitably be applied to many areas of human endeavor in addition to the study of tropical diseases.

Journal

JAMAAmerican Medical Association

Published: Feb 25, 1998

Keywords: filariasis,leishmaniasis,scabies,communicable diseases,tropical disease,ecology

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