Lecture 6: Hygiene: Cholera, Hookworm, & Sanitation

Adam Blatner, M.D.

 (This six-lecture series is part of Senior University Georgetown’s Winter-Spring 2009 session.)

This series is available as a two-DVD (double-level) set, which shows the pictures as well as has Dr. Blatner telling the stories with great animation. To order the series, email to Mr. Rohi Emran, who did the videography. The cost is $35 plus postage.
To read other lectures in this series: Click on:  1. Introduction and Beginnings of Germ Theory.   which also has, three supplements, which you can click on to link to related webpages:
            A. A very brief overview of the history of medicine. (pre-history to the Renaissance) (just to get you oriented)
            B. Further Overview to modern times.
            C. A further history of microscopy.
  Other lectures:       2: Contagion, Infection, Antisepsis ;   3: The Early History of Immunology  ;   4:  The Discovery of Anesthesia;  5:  Recognizing Nutritional Deficiencies ;     6: Hygiene: Cholera,  Hookworm, & Sanitation (This Present Webpage).   (Addendum: 6a: Dental Hygiene & Plaque Control)

(Re-Posted around  March 2, 2009)

Some diseases, like cholera, typhoid fever, and hookworm, may be prevented by sanitary measures. Cholera and typhoid fever are linked to contamination of food and water by the feces of those with those diseases, from flies, impure water, not washing hands in food preparation, and the like. Hookworm comes from walking barefoot near feces infected with the worm's eggs, or otherwise letting skin connect with moist ground. (This lecture also included a discussion of dental hygiene, which is presented now as a separate webpage.)


"An ounce of prevention is worth a pound of cure"--so goes an old proverb. Preventive approaches in medicine  have helped many more people

 than all the medical treatments ever given! My own career trajectory in the last decade has been in the direction of prevention, mainly through the vechicle of education, and partly that through these lectures at Senior University Georgetown. Prevention has always been recognized as an important dimension in medicine. The Greek god of healing, Aesculapius (right) had a daughter, Hygeia (image at far right is a Roman statue dated around 100 CE), and her hame then came to be applied to the general field of preventiive health---i.e., "hygiene."

Previous lectures have addressed not only treatment, but also prevention: Immunization and an understanding of the nature and prevention of nutritional deficiencies are significant elements. This lecture will be more related to sanitation. In dental hygiene, that deals with brushing and flossing---to be presented in the associated webpage.  This lecture will deal with two types of sanitation. Sanitation is an euphemism, a nice way to say that we're dealing with feces---also known, crudely, as "shit,"---a word that still seems a bit shocking. This shock is in turn associated with a tendency to avoid that which is disgusting. Freud made a point of noting that the avoidance of any thoughts dealing with feces can be neurotic, especially when it interferes with our thinking intelligently about how to dispose of our waste products. In other words, because of this avoidance, there has been a delay in

developing a rational, communal approach to sanitation, including the provision of clean water, water treatment plants, well-built sewers, fly control, and similar sanitary measures. Rose George recently wrote an important book about how we deal with---and mostly avoid dealing with---human feces; the book's title is The Big Necessity (now at the Georgetown Library) see cover picture on left.

The first disease to be mentioned has been around in Asia for millennia, being described more fully in China in the 9th century, and thereafter in the Middle East and India on several occasions. It hadn't really spread into Europe and the West until around the early 19th century, and then, for the next around 120 years, there were five or six waves of epidemics with a surpiring degree of virulence and rapidity of onset.

Cholera is a bacterial disease, and for the first two-thirds of the century the germ theory itself was not established. Just as people can catch a virus that invades and damages its cells, so too can bacteria, though much smaller, also be invaded and affected by viruses! It turns out that many of this general type of "vibrio" germ aren't so toxic, but some are, especially when infected by a virus that feeds on it, and makes it give off a toxin.

Cholera Vibrio (scanning electron microscope)
Cholera Vibrio (Transmission Electron Microscope)
This toxin, in turn, blocks the re-absorbtion of fluids from the intestine. In ordinary digestion, the body secretes a great deal of fluid, which dissolves the nutrients coming through, and almost all of this liquid and associated nutrients are then reabsorbed. If you block this reabsorption, all the fluid remains in the gut and the person develops a severe diarrhea, vomiting, and quite rapidly, severe dehydration. The blood gets thicker and begins to block up the arteries, oxygen can't get through, and the person often dies. If you give the patient enough fluid and the right balance of salts---because a lot of sodium, potassium and bicarbonate also is in that intestinal liquid secretion---then they may recover, because the body has a chance to mount an immune response. The key is getting that fluid and the right balance of salts (i.e., "oral rehydration therapy") in right away.

Cholera was a frightening disease, and theories as to why it happened were widespread. To the right below is a poster from a French magazine in the mid-19th century.

I cannot express the depth of fear that comes with an epidemic. The psychological consequences of living through several waves of one or several types should be recognized as generating a low-grade or more severe post-traumatic stress disorder—PTSD. There was a good deal of "blaming the victim," since it often occurred in areas where poor people lived, and poor people often were of a minority background. The political struggle was between the private businesses and people of moderate wealth who, like today, had reservations about their obligations to contribute to the common good through developing the infrastructure. At that point---and often, still today, in countries like India---it involves money to build adequate sewer systems, water filtration and treatment plants, toilet systems that kept the germs out of the drinking water,---and there were legal actions taken to block community efforts at sanitation.

The trend of more people moving from the country to the city to find work led to crowding, slums, and the city's lack of infra- structure (e.g., sewers). I spoke about the filth of cities in the second lecture---the almost hopelessness about trying to ensure cleanliness and the resultant spread of hospital based ("nosocomial") infections; and the darkness of smog and child labor that made rickets common also in the 19th century. As a result, an interesting movement happened in medicine that was sort of right but for the wrong reasons: There were many people who advocated what would be today thought of as intelligent efforts at cleaning things up, sanitation, but this was because disease didn't come from germs (so many thought then---hey, germs were just an unproven "hypothesis" for most of the century!) but rather from miasma, the toxic air that arose from unclean situations.
   (Briefly, to review:
First Pandemic:  1817-1823, India, Middle East, etc.
Second: 1829-1849, India, Russia, in 1831, England, in 1832, the Americas,
   – then again in England, Wales 1848
Third: 1852-1859, the most deadly, from India, devastated large swaths of
   Asia, Europe, North America and Africa.
Fourth: 1863-1879, Bengal, Mecca, Europe, North America
Fifth: 1881-1896, India, Russia, Japan, Europe
Sixth: Asia, Africa through 1923 (a little less virulent, different strain bacterium
Seventh, on and off in underdeveloped countries.)

Contagionists versus Miasmatists

There were two schools of thought about cholera: One, that it was caused by something noxious in the air, a miasma, associated with the air coming up from the moist earth and rotting or fecal material. This theory held sway during much of the previous 18th century and well into the 19th century. The contagionists thought that disease was caused by something that was catching, like smallpox or syphilis. Although it turned out the contagionists were right about cholera, they didn't understand the mode of contagion until halfway through the 19th century; and although the miasmatists were wrong, technically---there is no such thing as miasma, it turns out---their efforts at holistic prevention and sanitation were more in the right direction in the long run! This is one of the ironies and lessons of history! More about this conflict as we go on.

Certainly things were fiilthy.  Indeed, for a variety of ecological, economic, technical, and political reasons, the 17th through the 19th century in Europe became ever filthier. I should say by the words filth, or waste, or fecal, all these are euphemisms for the earthier word—excuse me—shit— and I say it for shock value, because that’s just the point: People don’t want to be confronted by it, by the reminder that part of their very real and necessary lives tends to be experienced as disgusting. Freud himself noted that this area of awareness tends to be repressed, taboo—and this essentially neurotic reaction has led to the whole problem of waste disposal, fecal disposal be labeled “sanitation”—again an euphemism—and one that far more often that is wise tends to be marginalized, pushed off into the corner, swept under the rug (ugh), and neglected until the complications of this neglect come back to haunt us—and this is the social and historical lesson of cholera.

 Not that newspapers weren’t calling attention to the contamination of the water: It was obviously polluted and full of bugs. The actual shape and size of the bugs–the bacteria—wouldn’t be known for another 40-plus years, though—requiring an advance in the technologies of microscopy and staining—we spoke about that in the first lecture.

In the earlier lectures on infection the main cause of disease was mysterious and had many theories. One of the theories that gained a lot of support was that there were “miasmas,” a word that refers to the smelly air—it fits our intuitive perceptions that there’s something wrong with the air, just as spoiled food tends to taste bad.  And as noted above, the stench of rotting garbage and open sewers was powerful.

The contagionists spoke mainly about quarantine, and burning or removing clothes, fumigating, isolating cases. In fact, for some diseases, this in part worked. But the miasmatists felt the contagionists neglected the miasma and the dirty conditions that caused it. In fact, they turned out to be right, but for the wrong reasons. It wasn’t the smelly air, it was the fecal contamination that goes with flies and open sewers and other stuff that gets into the water.

Interestingly, you won’t get sick from fecal contamination, as distasteful as that idea may seem—unless those feces contain germs or worm eggs or some other disease—in which case you will catch that disease. But there were a lot of those kinds of diseases—typhoid fever and dysentery were very common and have a story that is more low-grade, not so much epidemic as endemic—around a little all the time—but the battle for sanitation is relevant to all of these.

Max von Pettenkofer

This Munich physician became established in an era when seeking sanitation was already somewhat innovative. (This resonates with the lesson of the second lecture, in which the students doing autopsies were already enlightened compared to their parent's generation, so how could enlightened people be mistaken?)  Pettenkofer had become well-known as a pioneer, and in terms of the actual effectiveness of the work that needed to be done regarding creating an adequate sewage system and water purifying plants, the "miasmatists" were perhaps even more active than the "contagionists."  Pettenkofer also wanted to promote better nutrition, sunlight, adequate warmth in winter---indeed, he was the kind of  public-health minded holistic physician who Dicken's character, Ebenezer Scrooge (in A Christmas Carol), would have hated. Dr. Professor von Pettenkofer also had a good deal of status, doing research in several fields such as biochemistry and physiology, and in Munich would found a world-famous institute of hygiene.

In addition, there had been pressure from pioneers such Edward Chadwick—not a physician but a civil servant—who fought consitently for several decades with the entrenched interests in the parliament. In the third corner there were those who, liked Scrooge, only thought of themselves, and the poor could just fend for themselves. They hired lawyers to argue for the rights of their clients to pollute as much as they want on their own property—a bit of libertarianism versus the common good was a problem then as it is today!

So with all these edges, there needed to be a build-up of supporting evidence. What’s wrong with a little dirt, anyway? (Remember, this was a problem in the realm of surgery and infections, all this happening in hospitals around the same time!) Also, through the mid-19th century, no one had "seen" any bacteria---or not so that it would be believed. (Actually, Leeuwenhoek saw them over two centuries earlier!)

John Snow, M.D., and the Elucidation of the Cause of Cholera

Among the contagionists was . Dr. John Snow(1813-1858). (picture below), who has been generally credited for correctly identifying the idea that leakage of contaminated water can carry disease. Interestingly, we heard about Snow a few lectures ago, in connection with his being the one who used chloroform to alleviate the pain of childbirth for Queen Victoria (Sadly, he died unexpectedly from a stroke in 1858 at age 45, but his epidemiological work on cholera continued to be vindicated. He's now considered one of the earliest epidemiologists.) In the early 1840s,  Snow studied the problem and disagreed with the miasmatists, thinking that the disease might be due instead to a kind of contagion---but not direct; rather, through the water supply.

In 1848 Snow's researches into this subject was first published as a small booklet, On the mode of the communication of cholera, and he kept accumulating evidence. A major breakthrough came in a flare-up of cholera in London, in the Soho district. Snow constructed one of the first "spot maps" for noting the distribution of the deaths, and it became apparent that these centered on a water supply, the Broad Street Pump. (That is, while Semmelweis assessed numbers, Snow assessed frequency and location.)

Snow first took the handle off the pump and noted a decline in the incidence of the disease. Investigating further, Snow discovered that there had been an old cesspool not far from the well that served the pump! This was connected in turn to another cesspool in a house nearby, and a child with cholera had had his diapers washed into that cesspool.
Further research on comparing the water supplies of different parts of London confirmed his theory: People who obtained their water from upstream of the London Thames River water supply had a much lower incidence of cholera, while those who got their water from the Thames became sick nine times more often! Building on this and other evidence, Snow expanded his earlier writing and re-published it as a well-researched book in 1855. A decade later, in the 1866 third wave of cholera, another epidemiologist confirmed Snow's theory, but still the germ itself hadn't been identified. Indeed, for over twenty years the conflict between the miasmatists and contagionists continued---with residues continuing for yet another twenty years, even after the germ had been found. Honored more posthumously, he is now considered another early pioneer of epidemiology.

Nevertheless, Snows findings did not receive a positive reception. Those in power were torn between the miasmatists and the lawyers arguing that government had no right to tax private property-owners to build sewers. Government bureaucrats and members of Parliament were concerned that sewer systems were costly. Perhaps they could control the infection by increasing the quarantine measures. So, like Lister, he and those who came after him kept accumulating evidence. What was needed was to identify the causative agent, and this was done two decades later:.

Robert Koch

In the ensuing period of the 1860s and 1870s progress was made in the field of germ theory, as discussed in the first and second lecture. Let's move the time up then to 1870s, when Dr. Robert Koch finally was able to identify the cholera germ. (There are stories upon stories in all of these, but I’m trying to be selective.) He, too, was gaining status, as did Pasteur. The germ theory itself was gaining acceptance, but Pettenkofer didn’t give up that easily. At one point—here’s another story:

Pettenkofer offered to drink cholera germs. He maintained that the germs without the accompanying miasma and certain earth-influences wouldn’t make you sick!  And he did! And he didn’t get that sick! Proof to him. Koch didn’t even acknowledge this. The miasmatists were losing influence. Finally, Pettenkofer, in spite of many awards and honors, perhaps he realized he might have been wrong? – he shot himself.  Ah. Because, as I said, his efforts probably did more to influence the authorities to install water treatment and adequate sewage than the work of the contagionists. Right for the wrong reasons.

Koch, about whom I spoke three sessions ago in the lecture 2 on infection, a pioneer in bacteriology, continued to gain eminence in the 1880s. He confirmed the bacterium Vibrio comma as the etiologic or causative agent. Hamburg, 1892: Another wave of cholera. England had begun to install water purification plants and better sewers, as did many places. In Hamburg, struck by another epidemic, those in nearby suburb of Altona were spared. They had installed a water filtration plant. Hamburg’s governors chose to make that an option reserved to the private owners. Koch did some site epidemiology and instituted a variety of techniques: (1) Isolate the cases and destroy chemically their wastes—don’t let that stuff re-enter the water supply. (2) Disinfect homes so that residues of diarrhea aren’t picked up by flies. Clean up in general. And these techniques are seen in the pictures to the right---(near) a cholera hospital for the Hamburg epidemic; and a special disinfectant team.

Continuing Efforts

Alas, cholera  has a world-wide distribution and won't go away easily. The map on the left shows where it crops up every once in a while. Epidemics continue in areas that don't have strong sanitation infrastructures.  Many times during the 19th century  the pilgrimage (haj) to Mecca was disrupted by cholera epidemics.

But people were learning special techniques for working with the disease.
Typhoons (the Pacific name for a hurricaine) lead to flooding, and fecal material is washed out of cesspools, so cholera is a danger. (There was danger in Louisiana and Texas in the last few years, but it didnt't happen.) On the right techniques similar to what Koch suggested a century ago are being used in cholera epidemics: This in Dakha, Bangladesh, around 1971:

Another breakthrough is the use of rehydration therapy mentioned above. Here it is being used for an outbreak of cholera in Peru around 1991.
    And of course we have heard about the unfortunate events more recently in Zimbabwe when government mismanagement leads to a sanitary infrastructure breakdown----and by that I mean that feces come to contaminate wells.
 Medicine and Public Health.
The second aphorism of Hippocrates notes that the doctor should also..."make the externals cooperate," by which I think is meant that it is fitting for physicians to participate in advocacy for public policies for the common good. We must not assume that doctors have much actual power. The short period of high status in the 1950s was an anomaly, riding on the crest of a series of major breakthroughs. (Indeed, the doctor's authority was so esteemed that it was mis-used to sell cigarettes!) Because of the rise of managed care and third-party payors since the 1970s, though, doctors have had to struggle to get their message across. This was so in the first quarter of this century (as noted in the story of pellagra), and it is sadly so today, when doctors have been demoted to the category of providers by the corporations who run health insurance. Anyone who can receive payment---chiropractors, massage therapists, nurses---all are also "providers.").



28. Let’s move to another disease of sanitation, Hookworm, which is prevalent in over a billion people worldwide. It's like cholera in that it requires a degree of warmth as well as moisture—plus poor sanitation; but the germs aren't drunk in the water; rather, they enter as microscopic worm larvae that invade the bare skin of the feet as you walk on the ground. Although this condition has been around for probably centuries, but we've only really known about this tiny worm for a couple of centuries. The American hookworm probably came over with the slaves. There's also a European and Mediterranean hookworm, Ancyclostomata, which is only slightly different in some respects, but its life cycle and dynamics of contagion are the same.

 These worms are about a quarter-inch long, narrow,  the ones on the left enlarged about 12 times. They attach to the small and large intestine, and suck blood.

 As for their mouth-parts: Little vampires, they are.

And they embed themselves in the side of the intestines: Here's a microscopic side view of that right below:

There they feed, lay thousands of eggs a day, and co-exist. Interestingly, there is some evidence that a light infection of hookworm actually helps the body to be resilient, and researchers are exploring the idea of giving selected patients a light dose of hookworm as a treatment for certain intractible chronic inflammatory diseases like Crohn’s disease, ulcerative colitis, even asthma. So far there have been some promising results. (The use of less-than-disease infection  to prevent disease is a recognized but not widely used method, and another example is the application of otherwise sterile maggots---fly larvae---to eat any necrotic tissue in the treatment of  bedsores..

By accident, Arthur Loos in Germany spilled a solution of larvae on his arm and found he had a skin rash similar to what some folks call ground itch on their feet. He checked his stool in a few weeks and there were the eggs. He repeated this experiment, taking thymol to rid himself of the worms. Thus through serendipity, we benefited from the unexpected good fortune that Pasteur noted when he said, "Chance favors the prepared mind." Loos elucidated the life cycle: Hookworm isn't caused by drinking the feces-contaminated water (as in cholera) but through the skin, by walking on the ground. Part of this also was because by the end of the 19th century microscopes of sufficient power were coming into wider use.
So here's the life cycle:

The eggs hatch into tiny tiny worms, much smaller than the adult size, small enough to be effectively invisible and also to penetrate the skin without much effort. (The skin should be recognized as being a little porous—a sheet of cells that small critters can burrow through.) Depending on how many times one walks over larvae-infested moist earth with bare feet or porous or shabby shoes—they can get through those, too— a person may have a light or heavy infestation..
The micro-larvae, tiny roundworms, then penetrates the human skin, particularly between the toes of bare feet, and is transported through the capillaries into the venous system
       Then, (upper right picture) from the venous system, the micro-filiarae go into and out the right side of the heart through the pulmonary artery into the lungs. There the blood gives off carbon dioxide, picking up oxygen, with the help of the iron in the hemoglobin molecule.
 Meanwhile, the micro-worm-larva escapes into the air sacs or alveolae; and gets covered with mucus, carried up the bronchial tree as phlegm; where it is coughed up and swallowed, is carrie down into the intestines, burrows into the lining of the small intestine and matures. Then it cross-fertilizes and can lay up to 10,000 eggs a day!

The hookworm  causes illness primarily by ingestion of the host’s blood leading to chronic anemia, and chronic anemia generates its own secondary features. It’s an iron deficiency anemia, in part—as I spoke about in last week’s lecture. And there’s a leakage of serum, and the protein parts of serum. Note the blood cells portrayed on the left are quite pale---it's called "hypo-chromic," meaning low-color, meaning low levels of hemoglobin, due to the chonic loss of iron. If a person eats a diet rich in iron, this isn't so pronounced. But the condition is made much worse if there are alos other types of malnutrition, again described in last week’s lecture—such as pellagra, low-grade scurvy, or other deficiencies. Hookworm was called “the germ of laziness,” as it became apparent that the lazy, shiftless "white trash" and negro slave wasn't in fact lazy so much as genuinely fatigued, and that in turn was due to severe anemia. That would make anyone seem lazy! Chronic anemia is also bad for the heart because that organ has to beat harder to try to get oxygen to the tissues. People with anemia not only feel tired very quickly, but they also just feel malaise, a general sensation of not being well.

This seeming laziness and other behaviors when people are sick and malnourished was alluded to also in the previous century by Pettenkofer, who advocated nutrition and fresh air, adequate warmth as well as clean water, and finally was able to sell his program on the argument that healthy workers are more productive and economically efficient. (Rockefeller came to a similar conclusion years later, which led to his funding a program for hookworm eradication.

The hero for the story of the recognition and treatment of hookworm in America is Charles Wardell Stiles, a parasitologist (a kind of zoologist) who studied in various places in Europe as so many late 19th century scholars did—America being relatively intellectually impoverished, especially scientifically, in that era. He learned about hookworm, and became aware that it was common in the South. Probably it was a major cause of death at the infamous Andersonville confederate  prison for captured union troops, who died in the thousands from disease. Most doctors didn’t recognize the prevalence of this disease, attributing the symptoms to sheer laziness and lack of character. They were shocked to find how widespread and common it was!

 There’s a whole sub-story here about how Stiles and a few other people finally maneuvered and sold the public health approach, and John D. Rockefeller Junior (shown at left, picture taken around 1910), who at that point had inherited his father’s wealth (near left they are walking together) seeded a health institute and invested in a program to educate folks. This was partly altruistic and partly economic good sense—healthier workers make for more prosperity.

Another pioneer in the field of hookworm research was Dr. Charles C. Bass, (shown to the right), of the Tulane University School of Medicine in New Orleans. Later in life he became a pioneer of plaque control in dental hygiene (about which we'll talk later in this lecture, and this also has its own webpage). Bass co-wrote one of the first books on the nature of hookworm disease---life cycle, diagnosis, treatment, prevention.

The Anti-Hookworm Campaign in the South (1910-1915)

 The key was a mixture of things: First, there was treatment, which was uncomfortable, involving a chemical that killed the worms, or at least stunned them and made them loosen their grip, and then a strong purgative, generally Epsom salts, to wash it out. But that wasn’t enough. How to prevent re-infection?  A variety of chemicals were used over the next twenty years, with fewer side effects. Some of the improvements were dramatic, people becoming far more active, feeling better.  (There's a humorous story of one uneducated fellow complaining in a letter that, in feeling better, he also became more physically aggressive and got into trouble for that!)

  The plan was to generate a new social norm. (This could be an interesting social studies project for high school students! How would they plan such a promotional- educational program?) In the south, the planning drew a bit on the ritual of the religious revivals, making it a social affair, with food, speeches, honoring guests.

     Another technique was the use of handbills, announcements:  as at right.

  The problem is that sanitation takes work, and if you have no energy, and feel bad, there’s little motivation to keep a clean home.

Also, building a proper privy took time, required supplies, was a hassle. Also, they attracted flies, unless screening was easily available, and stunk—the bushes were cleaner.

But people couldn’t afford shoes; and shoes in those years often didn’t fit well and hurt!

Even less could you afford shoes for kids who then grew out of them too quickly!

 Still, the Rockefeller-funded campaign was promoted—there were a number of heroes here, as it was multi-state, regional, and in the face of a wide range of resistances. Set it up at the fair, make it the in-thing to do.
The same problem is going on today, by the way, in rural China, india, and elsewhere: It's quite a challenge to sell people on effective fecal waste control!

Part of the problem is that it is easy to do it wrong, to not have the proper equipment. For example, on the right, if one builds the cesspool under the privy so that it is really just a gap in the rocks, it's likely to leak the contents downward into the creek, which pollutes all those who live downstream.


 The WPA in the Depression advanced this significantly—playing off George Murray’s presentation on the Depression and what was done. I want to say that even today there’s a question as to how to spend the money, and the investment in infrastructure versus just loans so someone can borrow to open a little boutique— community versus private enterprise– is a lively balance. And let’s not forget sewage and water treatment—as a book on toilets and waste control points out, we need to address this problem even today in the USA!
Children’s health-promotion books are still being written and used today.

Below right is a promotional signs for proper privy building, setting.


So there have been continued efforts in this direction. The international work continues to be challenging, and the Bill and Melinda Gates Foundation recently gave a multi-million dollar grant to the Sabin Foundation to do research on a vaccine against hookworm.

The real moral of this story is that public health has to not just sell to the bureaucrats and politicians, but also to the people, when a change of personal health habits are needed. (Of course this has relevance today in considering the major challenges of smoking, alcohol abuse, drug abuse, lack of exercise, obesity, unsafe sex, premature or unwanted pregancy, reckless driving or driving without seatbelts, and other public health challenges. We are all being asked to subsidize these follies through higher taxes and medical insurance premiums, and we no longer can afford to do so.)

Dental Hygiene & Plaque Control

The last third of this lecture is devoted to another problem in hygiene---dental hygiene. It's not just about brushing your teeth and avoiding sweets---that we learned about in school. Since that time, though, the microbiology and biochemistry of dental plaque---that build-up of bacteria and secretions at the gum line---has been implicated as the major cause of tooth decay, and I discuss that with pictures more fully on an associated webpage.  (It may also affect other health problems, too!)


This webpage presents the lecture I gave on March 2, 2009, for Senior University Georgetown. I described some stories regarding the discovery of the cause of cholera, especially in the 19th and 20t century; stories about the disease of  hookworm, especially in the early 20th century; and in that talk and a related webpage, the rationale for the use of dental floss in preventive dentistry. All three endeavors are ongoing. Cholera is still present with epidemic outbreaks wherever water treatment is not optimal. Hookworm is still prevalent where people walk barefoot and defecate onto the ground---which still happens in many parts of the world. And middle-aged people are still losing teeth unnecessarily because of gum disease and cavities that could be prevented by flossing regularly; and many people in our own culture still hardly appreciate exactly why they should develop this hygiene habit. As I said, I found that the history of medicine demonstrates how we can be wrong and also right, or vice versa, as we collectively grope towards more useful understandings of our world and seek to promote healing. In studying for and making these presentations, I confess that I realized more fully how in a larger sense this is also for me a spiritual path. I invite you to read these stories and the other lectures on the website, and tell friends about them. We can learn from stories—not just Bible stories, but all sorts of stories. History can be a great source of various kinds of lessons. I hope you have enjoyed.


Altman, L. K. (1987). Who goes first? The story of self-experimentation in medicine. New York: Random House. [pp. 23-25 on Pettenkofer; pp 166-169 on Arthur Loos.]

Bray, R. S. (2000). Armies of pestilence: the impact of disease on history. New York: Barnes & Noble. (Chapters 19-22 on Cholera.)

Franklin, J. & Sutherland, J. (1984). Max von Pettenkofer: The last of the miasmatists (ppg 139-182), in: Guinea-pig doctors: self-experimentation in medicine. New York: William Morrow & Co.

Magner, Lois N.  1992. A history of medicine. New York: Marcel Dekker.

Magner, Lois N.  1994. A history of the life sciences (2nd ed.). New York: Marcel Dekker.

Williams, Greer. (1969). The plague killers. New York: Charles Scribner's Sons.