Emerging Infectious Disease
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H5N1 is one of many new human viruses arising from the animal world in recent years. In 1948, the U.S. Secretary of State pronounced that the conquest of all infectious diseases was imminent.697 Twenty years later, victory was declared by the U.S. Surgeon General: “The war against diseases has been won.” But as the chair of Medical Microbiology at the University of Edinburgh wrote in retrospect, “He was spectacularly wrong.”698
The Institute of Medicine calls the post-WWII period the “era of complacency.”699 The overconfidence of the time was understandable. We had conquered polio, nearly eradicated smallpox, developed childhood vaccinations, and assembled an arsenal of more than 25,000 different “miracle drug” antibiotic preparations.700 Even Nobel Laureates were seduced into the heady optimism. To write about infectious disease, one Nobel-winning virologist wrote in the 1962 text Natural History of Infectious Disease, “is almost to write of something that has passed into history.” “[T]he most likely forecast about the future of infectious disease,” he pronounced, “is that it will be very dull.”701
The year smallpox was declared history, a virus called human immunodeficiency virus began its colonization of Africa and the world with HIV/AIDS.702 In some countries, the prevalence of HIV now exceeds 25% of the adult population.703 The global efforts sparked by the WHO decision to “eliminate all malaria on the planet”704 succeeded, as another Nobel Laureate put it, “in eradicating malariologists, but not malaria.” The malaria parasites are now antibiotic-resistant, and the mosquitoes carrying them are insecticide-resistant as well.705 “Even the diseases once thought subdued,” the WHO finally had to concede, “are fighting back with renewed ferocity.”706 Infectious disease remains the number-one killer of children worldwide.707
It’s getting worse.708 “We claimed victory too soon,” said the co-chair of Yale University’s committee on emerging infections. “The danger posed by infectious diseases has not gone away. It’s worsening.”709 After decades of declining infectious disease mortality in the United States, the trend has reversed over the last 30 years.710 The number of Americans dying from infectious diseases started going back up.711 A bitter pill of a joke circulates among infectious disease specialists: “The 19th century was followed by the 20th century, which was followed by the…19th century.”712
The vice chair of the U.S. National Foundation for Infectious Diseases was asked, “Are we having more plagues?” “The answer is an unequivocal yes,” he replied. “These plagues are coming back with greater fury and in much greater profusion because they’re killing more people than they did in centuries gone by.”713
The concept of “emerging infectious diseases” has changed from a mere curiosity in the field of medicine to an entire discipline.714 As recorded by the U.S. National Library of Medicine, in excess of five times more medical journal articles have been written on emerging infectious diseases in the last four years than in the previous century.715 Within recent years, emerging diseases have been moving to center stage in human medicine.716
Since about 1975,717 previously unknown diseases have surfaced at a pace unheard of in the annals of medicine718 —more than 30 new diseases in 30 years, most of them newly discovered viruses.719 What is going on? Why is it getting worse? To answer that question, we first have to consider where these diseases are coming from, since they have to come from somewhere. In other words, from where do emerging diseases emerge? An increasingly broad consensus of infectious disease specialists have concluded that “nearly all” of the increasingly frequent emergent disease episodes in the United States and elsewhere over the past few years have come to us from the animal world.720