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FOREWORD

     Get ready to explore the fascinating terrain of infectious diseases that includes The Hot Zone by Richard Preston (best seller on the Ebola outbreak), Strafford-Belmont Hotel in Philadelphia (Legionnaires disease outbreak), Jack-in-the Box fast-food restaurants (E Coli  0157), Lyme, Connecticut (tick-borne infection), Jim Hinson (famous puppeteer killed by streptococcal infection), the Four Corners region in the Western U.S. (Hanta virus), India and Bangladesh (Bengal cholera), the waterworks in Milwaukee (cryptosporidium), an animal facility in Reston, Virginia (Ebola Reston), Kitum Cave in Zaire (Ebola Zaire), Lake Barombi region, Cameroon (schistosomiasis), and the Centers for Disease Control and Prevention in Atlanta  (all of the above).

     Infectious diseases have always played a major role in defining our daily lives.  Empires have risen and fallen from events related to contagious diseases.  Human and animal populations have been devastated—and controlled—by the outbreak of epidemics of infectious diseases. The last century and a half has brought great understanding of the biology of microbial agents that affect human populations and the environment.  With this knowledge, we have had periods of extreme optimism regarding our ability to control and even conquer the pestilence affecting our health. However, this euphoria is often followed by periods of doubts of our dominion over the scourges of our planet.

     A little more than a decade ago, Harrison’s Principles of Internal Medicine proclaimed that “infectious diseases are more easily prevented and more easily cured than any major group of disorders…” A new disease called “acquired deficiency of cell-mediated immunity in young homosexual men” occupied less than a column of text.  Ten years later, cardiovascular disease mortality has declined, and much of the public knows that high cholesterol and blood pressure should be controlled.  Infectious disease mortality, meanwhile, has climbed to the third leading cause of death in the United States .

     As recently as twenty-five years ago, the threat of plague seemed old-fashioned, even medieval.  Death from infectious diseases was thought to be the result of poor hygiene and lack of good antibiotics and vaccines, problems that by the mid-1970’s had been largely overcome in the United States and most other industrialized nations.  Medical practitioners were confided that infectious diseases would eventually represent a small percentage of concern.   Their optimism seemed justified.  Smallpox had nearly been eradicated; tuberculosis and polio were on their way out and, with the exception of malaria, so were all of the other major infectious diseases.  Scientists anticipated the eradicated of infectious diseases.

     There were some skeptics.  Agents of disease ranging from bacteria to insects had started to show resistance to the drugs and chemicals that had once so successfully killed them.  Then came Lyme disease (1975), Legionnaires disease (1978), toxic-shock syndrome (1978) and, more recently, AIDS (1981), chronic-fatigue syndrome (1985), and Hanta virus (1993).  Malaria reemerged in regions where it had been eliminated.  Dengue and Yellow fever began spreading.  Cases of tuberculosis increased in countries previously reporting declines.  Diphtheria reemerged in the former Soviet Union.

     Today scientists are reluctant to predict eradication of human infectious diseases.  With the acceptance that infectious disease will always be part of the human experience, comes a new approach to understanding the patterns of disease evolution.  Complex interactions of social, epidemiological, ecological, and evolutionary forces must be studied.  Among such forces to be studied are population shifts, intercontinental travel, climate changes, floods and other natural disasters, rodent and insect vectors, deforestation, urbanization, antibiotic resistance, and vaccines.

     Public health professionals generally have been complacent regarding the erosion of infectious diseases surveillance, prevention, and control programs in the United States over the past two decades. As infectious diseases have emerged or reemerged, some crisis such as those posed by the emergence of the acquired immunodeficiency syndrome or resurgence of tuberculosis and measles have been addressed selectively.  However, a comprehensive approach to prevention is noticeably absent in the American public health model.  Health education is often forgotten as an effective tool in primary prevention.  Martin Ayim has attempted to address this issue in this textbook: Principles of Infectious Disease Epidemiology: An introduction and discussion of selected communicable diseases.    

     Students in health sciences will find this text to be an essential part of the curriculum, particularly the issues of prevention and control of infectious diseases.  The international flare of this text assures multicultural considerations in the study of infectious diseases.