As a physician epidemiologist, I practice the science of epidemiology and the art of public health at the Centers 
for Disease Control and Prevention in Atlanta. My work involves enteric bacterial infections transmitted though food and water, mostly food in this country and mostly water in the developing world. Since I took up this discipline, in 1983, it has rapidly evolved, as bacteria become more virulent and resistant to medicines, as they invade new ecological niches, and as we develop better methods to find and control them.

Though it may surprise some who think science and religion are separate or even incompatible, I find deep religious meaning in the works of anthropologist Loren Eiseley and paleontologist Stephen Jay Gould, as well as writings of and about Charles Darwin. From them I learned that, given spontaneous variation within a species, change and evolution result from the natural selection of those forms that survive best in their current environment. Many of the critical moments of evolution involve choice—as a hummingbird pauses over this or that flower, a creature chooses a mate, or a lungfish first strikes out cross-country on stubby fins in search of another pond.

The major influences in my religious thinking came from scientific ideas like these. While it’s hard to distill a complex of beliefs down to a few phrases, here are some essential elements. First, long-term change happens because of repeated selections and is not just random motion. Events are connected by chains of causation. Tracing these complex chains is difficult but possible, and it can help us understand and predict the consequences of events, which in turn can allow us to begin to control them.

Second, the scientific method is the best available tool we have to understand the processes around us and predict their outcomes. We can approximate the truth through empiric observation, creative rational thought, and experimental testing. I say “approximate” because, in our imperfect world, high probability combined with a strong explanatory story may be as close as we can get to truth.

Third, much of the world around us, natural and man-made, was shaped, as it is shaped now, by choices and the changes that resulted from them. Some of these are recent and recorded, such as a highway department’s choice to introduce kudzu as a low-maintenance ground cover for road cuts or the choice of some English Unitarians (including Charles Darwin’s grandfather) to hire an engineer named James Watt to design a new power source for pumping water, which led to the invention of the steam engine. Others are not so apparent, even as they shape our everyday life. For example, the room in which I write this was built as a screened sleeping porch. This once common feature of southern houses was designed for people who wanted to avoid tuberculosis by sleeping in fresh air every night but feared the risk of malaria from night-biting mosquitoes. Neither danger crosses the mind of many Atlanta homeowners today. Many other patterns of choice and change are only visible when we look across eons, such as the mutual selection between insects and plants for bright colors and pleasing aromas that fills our gardens with flowers and butterflies today.

Whatever the choices, they add up. Decisions small and large make a difference, and each of us affects the future, willingly or not. We all live upstream from generations to come, who will find it easier or harder to live, the world more or less beautiful, and life more or less meaningful as a result of decisions we make now.

Though this belief makes me responsible for shaping the future with my decisions, I still find it comforting. It satisfies my spirit to know that the living world has developed because of natural selection, that many varieties of creatures are generated by the mismatches and reassortments of the genetic code, that the myriad choices of habitats or mates or lunch by the great buzzing world of our ancestors are what got us here today. The thoughtful writings of Darwin, that observant Victorian scientist, and those who followed him—on the slow sinking of stones into a field as a result of the action of earthworms, on the small variations in birds’ beaks from one island of the Galapagos to the next, or even on the way animals and humans differently express apparently similar emotions—encourage me to keep pursuing meaning in the structure and tempo of change. 

I suspect my early UU training—my boyhood minister, an amateur astronomer, blended cosmological metaphors into his sermons and would sometimes invite the congregation out of an evening to witness a meteor shower or the rings of Saturn—and the subsequent development of my religious beliefs helped me choose preventive over curative medicine. In the office I joined and now lead, we try to understand transmission of infectious agents well enough to prevent it. This means using the epidemiologic method to trace out the events leading up to outbreaks or epidemics and to look for ways to prevent them in the future. While others try to develop better strategies for treating hemolytic uremic syndrome, we try to prevent it in the first place.

For example, when epidemic cholera struck Latin America in 1991, my colleagues and I went to learn why, and how to prevent it. In these countries most people haul drinking water from a public tap or well. In our investigations we repeatedly observed that the way people stored their drinking water varied dramatically between the households with cholera and those without. In cholera houses, families kept their drinking water in open buckets and scooped it out with a cup. The healthy families, by contrast, tended to keep their water in a covered, narrow-mouthed container and to pour it out or draw it from a spigot. Our key observation was that behaviors that prevented cholera were already present in the community. What we needed to do was foster them.

After investigations in several Latin American cities yielded these results, we hatched an intervention, developing an inexpensive water-storage vessel, putting it into commercial production in Latin America, and combining it with home chlorination to make safe water for all a practical reality. Last year, its first year of operation, our partner in Bolivia sold 60,000 water vessels and is now ramping up production for a national campaign. Several other companies now make a simple device that converts salt to chlorine water disinfectant, in a format suitable for village use, so that even though large-scale municipal water treatment and piping systems are still beyond the means of most of Latin America, a community can make its drinking water safe at a fraction of the cost. I hope this project offers an object lesson in social evolution. I recognize that some will rely on luck or a deity or intervening angel to protect them from hazards they feel unable to control. Part of the UU tradition is to respect the values and decisions of others as they face danger. But, given the option, people may choose health; they don’t have to accept their society as it is.

Closer to home, our investigations of outbreaks of E. coli O157:H7 infection showed they were often related to foods of bovine origin, and we showed there is a reservoir for this organism in cattle. We also showed that simple variations in food preparation could greatly affect the risk of disease. The ongoing improvements in slaughter hygiene and the safety instructions now printed on every package of raw meat all resulted from our work.

The story doesn’t end there, however. Microbes can evolve at an astounding rate. The bacteria that fill the world can exchange genes with each other, recombining and varying such that we can expect new challenges regularly. E. coli O157:H7 itself appears to have resulted from a relatively recent evolutionary event in which a rather ordinary E. coli acquired the ability to cause catastrophic disease when it became infected with a virus itself—a particular virus that carries the gene for a powerful toxin that damages blood vessels. What makes that virus spread? Intriguingly, recent work by colleagues in Boston suggests that E. coli exposed to low levels of antibiotic emit clouds of the virus, which spread out and infect other E. coli. Could the use of antibiotics as growth promoters in agriculture have fostered the appearance of E. coli O157:H7? Understanding the dynamics of those viruses may be critical in the future to making it less likely to happen again. 

E. coli O157:H7 is a good example of how new challenges can arise as bacteria acquire new properties and move into new ecological niches. Doubtless, new pathogens will arise in the future to threaten public health. Thus, the challenge will never end, the world will never attain perfection, and the lion will never lie down with the lamb. Progress means continual adaptation, then—not the construction of an unchanging and harmonious paradise.

One adaptation I would encourage is for everyday medical practitioners to take evolution into account. The rise of antibiotic resistance in the microbes that infect us is no mystery but rather the predictable result of our use of antibiotics. We in the medical community are the selective force in this case, not natural selection or chance variation. When we use an antibiotic, we hope to kill off the infecting organism, but at the same time we also select for any microbe that might already have a resistance gene to that antibiotic. This means we can slow down the increase in antibiotic resistance by decreasing the pressure on the bacterial populations, and we can do that by making sure each use of an antibiotic is worthwhile and prudent, even given the risk of developing resistance. Many hospitals, confronted with resistant pathogens in their ICUs and burn units, have already adopted this way of thinking, but it’s new on farms and feedlots, where over half of the nation’s antibiotic production is used.

On a more metaphysical level, natural selection and evolution provide a deep metaphor for the search for new solutions. My religious training impels me to continue the search for a meaningful way of living in my own life, looking for the choices that make life healthier for all. With patience, care, and responsibility, we can find good solutions, and the wonders of the natural world around us are grand evidence of this. 

Robert V. Tauxe is chief of the food-borne and diarrheal diseases branch of the Centers for Disease Control in Atlanta. The views he expresses in this article are his own and do not reflect the positon of the Centers for Disease Control.

A version of this article originally appeared in the Journal of the Medical Association of Georgia, Volume 87, Number 4, November 1998. Reprinted with permission from the Medical Association of Georgia.