INFECTIOUS THREATS NOW: HYGIENIC IMPROVEMENTS AND AGAINST INFECTION IS THE USE OF ANTIMICROBIALS
The second great strategy is hygienic improvements. No other single intervention in the history of medicine has saved as many lives and reduced as much suffering as the provisioning of uncontaminated water, which is necessary to curb the great plagues of diarrheal disease. Before cities cleaned up their water supplies, about one out of every five residents would die of diarrheal diseases, particularly typhoid fever, dysentery, and cholera. Provisioning of clean water dropped this death toll virtually to zero. Hygienic improvements in hospitals during the same period transformed hospitals from institutions that served as the last stop for the living to places where people had a good chance of being cured, particularly after antibiotics were introduced. We can think of hygienic improvements as the strafing of enemy forces as they try to cross bridges, the point being that enemy forces are stopped by disinfecting, filtering, or washing them away while they are en route to their target. Those with a less militaristic disposition can equate hygienic improvements to the Marshall Plan, which rebuilt postwar Europe. Infrastructural improvements that encourage safe drinking water, sewage disposal, hand washing, disinfection of hospitals, and use of gloves allow people to improve their lives by reducing the ravages of microbial warfare. Whatever the metaphor, the overriding argument is that hygienic improvements work and are relatively inexpensive. We relax them at our own peril. The third great strategy against infection is the use of antimicrobials. When antibiotics were introduced, some hoped that they might put an end to bacterial diseases. The track record, as of the mid-1940s, bolstered this lofty expectation, at least for those who did not bother to consider evolution. Those who did, however, sounded an alarm almost from the beginning of the antibiotic era. The discoverer of penicillin, Alexander Fleming, warned in the late 1940s that antibiotics might soon lose their effectiveness through the evolution of antibiotic resistance. Another Nobel laureate, Joshua Lederberg, voiced a similar warning during the early 1950s. But the alarm went largely unheeded. Although antibiotics are a marvelous solution for the individual patient, they are a poor way to control disease in a population. Their flaw stems from an ethical dilemma: what is best for the individual patient may often be at odds with what is best in the long term for the society. The individual patient usually benefits by taking antibiotics. The society pays a price over the long term because the more antibiotics are used, the stronger are the selective forces favoring the evolution of antibiotic resistance. Societies might reduce this price if they were able to restrict antibiotic usage, but they have few options. If the restrictions are voluntary, a physician who does not treat a sick patient with an available drug will likely lose the patient—if not to death, then to another physician. If the restrictions are mandatory, their enforcement would undoubtedly lead to a black market in effective antibiotics. Even if societies had the power to enact such restrictions, ethical considerations might cause them to choose not to exert it. Should the possible long-term interests of the society as a whole restrict the access of individuals who need an antibiotic now? The antibiotic might not even be necessary in the future if other antibiotics were developed in the meantime. There is no easy way out of this dilemma. The best long-term solution is undoubtedly to reduce the need for antibiotics rather than to restrict their availability. But this solution requires clear and clever thinking about evolutionary processes, something that has been in short supply in the health sciences throughout the past two centuries. Still, for all the negative press antibiotics have received in the context of antibiotic resistance, they remain one of the three great achievements in the fight against infectious disease. Many of the difficulties that are encountered with antibiotics result from a failure to distinguish between purposes for which they are particularly suited and those for which they are not. Antibiotics are an excellent weapon for destroying the microbes that are on a rampage in a sick patient. They are a poor weapon for controlling the spread of infectious agents through a population—when they are put to this use, problems of antibiotic resistance are sure to be exacerbated. Hygienic improvements and vaccination are the better weapons for this goal. This rule of thumb sounds simple, but it is frequently violated. It is violated when hospital staff decide to treat wards prophylactically with antibiotics instead of maintaining the high hygienic standards that prevent infections. It is violated when antibiotics are offered to poor countries as a cheap solution to diarrheal diseases instead of making the more expensive improvements in water supply and sewage disposal. It is violated when tuberculosis control policies rely on seeking out and treating the infected individuals in a city rather than improving housing quality, airflow, and nutrition in the hotbeds of tuberculosis transmission.*27\225\2*
