Influenza: A Century of Science and Public Health Response

Chapter 3:Breakthroughs

58 Spanish flu was arguably the worst pandemic in human history, but as the catastrophe receded from memory, few medical researchers worked on the agent responsible for the disaster. In the interwar years, the study of influenza was largely an individual pursuit rather than an organized research field. During World War II, however, and in the years following it, organizations for systematically tracking and studying the influenza virus began to emerge. One such organization, the World Health Organization, developed a surveillance system that both drew on previous health systems, such as the League of Nations Health Organization, and maintained a narrow focus on technical issues. Sustained, well-funded research on the influenza virus began to yield important breakthroughs. But the methods of studying and responding to it became increasingly technical. In some ways this technical focus helped break down the intense national interests in pursuit of science, but in other ways it created a sharp dichotomy between those who could engage in science and those who could not. Technical programs began to dominate public health efforts. Global public health began to develop in new ways. Exactly why the medical establishment and historians largely turned their back on unraveling influenza’s secrets in the years following the Spanish flu epidemic is a bit of a mystery. Perhaps it was, as Howard Phillips and David chapter 3 Breakthroughs • Breakthroughs 59 Killingray suggest, a matter of wounded pride: “As the Spanish flu amounted to an enormous rout in the war against disease for the medical profession, it was not a subject to hold much appeal for the triumphalist brand of medical history then in vogue, thanks to medicine’s stream of successes since Pasteur.”1 And perhaps the rout occurred because it is difficult to identify what you cannot see. By the end of the Spanish flu pandemic, the medical community had concluded that Pfeiffer’s bacillus was not the cause of influenza. As early as 1918, some researchers had begun claiming that influenza was caused by a filterpassing element called a virus (the Latin word virus means “poison”), but there was no consensus on the causative organism.2 Viruses had been a perplexing riddle for medical researchers. In the frenzied search for the germs that caused diseases, budding bacteriologists identified a host of organisms responsible for various afflictions, but they soon realized that some disease-causing entities resisted identification. Complicating matters, a set of experiments (the first run in 1876 on the tobacco mosaic disease) demonstrated that infectious matter of certain sorts can be passed through even the finest bacterial filters and still cause infection. By 1903 Pierre Roux, successor to Louis Pasteur as the director of the Pasteur Institute, codified this mysterious subgroup of disease-causing material. Roux proposed three characteristics common to the causative entities: they were filterable, invisible via light microscopy, and nonculturable (on known bacterial growth mediums). The nature of these “filterable viruses” would remain a mystery until the invention of the electron microscope in 1938 and the discovery of the double helix structure of DNA by James Watson and Francis Crick in 1953.3 To test the viral theory of influenza infection, scientists attempted to use very fine porcelain filters to screen out bacteria but still induce the infection in experimental animals and human volunteers. Probably because of sloppy techniques, none of the experiments were conclusive, and researchers wrongly concluded that the illness was not caused by a virus. Without a method to positively identify the causative agent, medical researchers were forced to rely on identifications based on symptoms. Unfortunately, influenza’s symptoms— fevers, cough, body aches, and exhaustion—are common, in various degrees, to numerous respiratory infections. Influenza was easy to see on the community level but difficult to identify in the individual. Compounding the difficulties of accurate diagnosis was the issue of immunity or resistance to influenza infection. A bout of influenza offered little or even no resistance to the disease in succeeding years. Researchers recognized that this phenomenon sometimes reflected merely an earlier misdiagnosis of influenza infection, but they suspected that something else was going on as well.4 Some scientists posited remarkably prescient hypotheses about in- 60 Breakthroughs fluenza despite their limited knowledge of the virus and its behavior. Edwin Oakes Jordan concluded: “It seems to me at least a plausible hypothesis that the coming into existence of a peculiar strain of influenza virus different from the strain or strains of...