NOTES for Week 13

Origins of Disease a conference at IUN November 20, 1999. These are notes taken at that conference and are included here for reference.

Dr. Ewald: Until recently, medicine has been seen mechanistically. The body and cells were thought of as machines. Now, new questions are asked: Why are things the way they are? Why are some diseases more severe than others? The thinking is evolutionary in perspective.

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I. Gregory Cochran, PhD Catching onto What's Catching; The Starting Scope of Infectious Diseases He seeks to see disease in an evolutionary perspective. "The big old diseases are infectious." Natural selection optimizes function and reproductive success, so there is still the question: why do we get sick at all?

There are some problems not solved by natural selection presented in increasing importance:

1. BLIND ALLEYS: The principle here is that once committed to a path, nature continues along it. A favorite example is that retinal connections are in front of the retina instead of behind the retina. Blind alleys are a design problem. They are universal flaws.

2. IATROGENOMIC CONFLICTS: Genes that pursue their own interests harm the whole organism. Examples are the mouse T alleles, myotonic dystrophy, and "the parliament of genes" . . . the idea that some genes can suppress other genes; they compete with each other.

3. TRADEOFFS: An animal can't be big and light at the same time. One is at the expense of something else. These are physics, pleiotropy and aging, and universality. (My note: pleiotropy is if one allele can control two or more traits. It occurs frequently.)

4. MUTATIONS: They are estimated at 1/14,000. Duchenne's muscular dystrophy, achondroplasia may illustrate that some sites are more vulnerable to mutation than others.

5: NOVEL ENVIRONMENTS: These are things like computers, stuck in traffic jams, smoking, alcohol.

6. "GERMS" Microorganisms evolve and mutate along with us.

.....

Germs can evolve rapidly, they grow exponentially, and are the most important causes of troubles for humans in history. Some defenses can be 'expensive.' Examples are sickle cell anemia and cystic fibrosis. Cochran showed a "40 Thieves" list of human diseases. Malaria is the nastiest disease in the world. Smallpox was probably second on this list.

"Cryptic pathogens" are the one with a long delayed onset, possibly invisible (internal lesions instead of external ones), and are difficult to cultivate in the laboratory. Ulcers nowadays are believed caused by Helicobacteria pylori-a chronic infection.

When the "chain of causation" is identified in infectious disease, it is possible to prevent infection. Similarly, the biochemistry of the virus may offer clues. Some viruses seem to disable the internal "anti cancer" genes.

.....

II. Randolph Nesse, MD Darwinian Medicine: The Evolutionary Basis of Health and Disease

Why isn't the body better? Or, why didn't natural selection do a better job? Did natural selection fail? So, what are some candidates for criticism?

-The appendix, wisdom teeth.

-Retina cells "inside out"

-Blood for the heart derived directly from the chambers

-Zippers in the belly for birthing

-Stop all cancer growth

-Improve the immune response.

.....

Doctors go on false assumptions. Darwinian medicine offers an alternative. Natural selection is a process. Genes become more common if they produce more successful phenotypes. Neo Darwinians propose these ideas:

-Traits need proximate and evolutionary causes.

-Kin selection is important.

-Group selection is feeble.

-Reproductive success is everything.

-Chance is a powerful factor.

*****Important note: useful traits will go away quickly if they aren't important. Why is the polar bear white? The proximal reason is genes and DNA. The evolutionary reason is survival.

.....

This is a list of suspected reasons why natural selection hasn't cured humans of their ills.

1. MISMATCH: Evolution is too slow to catch up to traffic jams, computer keyboards, boring classes, and fat-laden pizza. Myopia (nearsightedness) doesn't occur in foragers, but does in us because of reading. Myopia a 'quirk' of modern environments.

2. CONSTRAINTS: Birth has always been through the pelvis, so we are stuck with that birthing avenue.

3. TRADEOFFS: If we stand upright, we are faced with all of the limitations of bipedalism.

4. COMPETITION: This is with other organisms. The 'game' has made us that way.

5. FITNESS: Men die seven years before women do. Grandmothers seem important for survival of children and grandchildren. Thus, they are a cultural advantage.

6. BENEFITS: Pain seems like a disadvantage, but people's born without it are usually dead by age 30 years.

7. CHANCE:

8. DEFENSES

• Fever is an evolutionary adaptation to fight infection. It is a useful defense, but it doesn't work well with malaria which seems to do just fine in a fever. Reptiles when infected will seek a warm spot to heat up and ward off infection. Also, fever has a specific mechanism of regulation.
• Studies of children with a fever show that they recover quicker without antipyretics than they do with them.
• Lomotil© is NOT an advantage when diarrhea is a defense. In disease, there is a difference between a MANIPULATION and a DEFENSE. Cholera induces diarrhea as a manipulation-it washes away all of the competitive microorganisms.
• Anemia (reduction of iron in the blood) is a defense when the body reduces the iron level in order to deprive bacteria of it. Egg whites bind iron-an egg's defense in the barnyard amidst filth.
• Nausea during pregnancy is a defense mechanism-prevents ingestion of hazardous foods that can cause birth defects.
• A high uric acid level is a great antioxidant thus extending life, but unfortunately, some folks get gout.
• Some genes convey an advantage in youth (high calcium levels promote bone healing) but are a disadvantage in older age (calcification of arterial plaques).
• Senescence is a lack of repair.

  ....

  In science and especially medicine, we should consider alternatives.

  .....

  III. Alan Hudson Chlamydia Pneumonia: From Atherosclerosis to Alzheimer's, the Pathogen of the Decade

  The genus Chlamydia has four species:

  -C. trachomatis: trachoma, STDs and others

  -C. psittaci: animal pathogens; these wiped out the turkey industry in England 15 years ago.

  -C. pecorum: animal pathogens

  -C. pneumoniae: respiratory & other diseases

  .....

  Chlamydias are mucosa organisms. That is how they spread. They cause a powerful inflammatory response and cause disease at the site of inflammation. Chlamydias are obligate intracellular parasites. It has an intracellular and extracellular phase. They can cause long term infection. Chlamydias were defined as a new species in 1989. Besides many infections, it is implicated in atherosclerosis, heart disease, and reactive arthritis. By definition, reactive arthritis requires evidence of previous infection. Some data even implicate it in multiple sclerosis and late set Alzheimer.

  Chlamydia is a very successful opportunistic pathogen. The organism of ubiquitous; it is everywhere. Reinfection is common. Epidemics appear every 5-7 years.

  The first evidence for C. pneumoniae and atherosclerosis was serological. What happens is that infected cells accumulate cholesterol.

  There is a dental connection. C. trachomatis are probably implicated in TMJ (temporomandibular joint disorder). Forty-five% of TMJ patients test positive. Virtually no control subjects are serologically positive. Note this: seventy percent of patients had exposure to birds. C. psittaci causes a disabling arthritis in race horses.

  ....

  IV. Paul Ewald The Future of Darwinian Medicine: The Transition from Understanding to Evolutionary Management

  IF evolution shapes disease, THEN we may have an opportunity to control the evolution of pathogenic organisms.

  Medicine has three major success stories

  • Hygienic improvements
  • Vaccines
  • Use of drugs such as antibiotics

  .....

  In theory, the possibility of a fourth one is the control of the evolutionary trajectory of disease organisms. Can they be made more mild? Can the evolutionary course of organisms be shaped and directed?

  Antibiotic resistance is a terrible problem. When we use antibiotics, we must accept the resistance problem.

  How do you control virulence? In studies of diarrhea, is shown that when you clean up water supplies, the most virulent of the organisms are the first to be obliterated. Are more toxic microorganisms also the most drug resistant? This has implications for hospital infections. Once microorganisms get established in hospitals the microorganisms do not depend on host movement. Person-to-persons spread becomes important. The mode of transmission seems to cause virulence.

  .....

  READER pp 158-168 "Gender and Generation in Poor Women's Household Health Production Experiences"

  This awkward title is about one of the major topics this week: the health of women. Separate articles deal with this topic in world perspective, more specifically with female circumcision (covered below in these NOTES, and an article on birth control in antiquity which traces the loss of women's reproductive rights).

  Read the introduction in italics closely. Pay attention to the influence of socioeconomic status and gender on health. Learn the term Anglo. Notice how nearly all household health care is delivered by women. Women are the caretakers of humanity. Men come across as novices.

  Notice how in this study, Anglo women depended on their husbands and Mexican American women depended more on their female kin. Also, home health care is segregated heavily by gender. Read the article for its content and reflect on your own life. It is a shame that we don't have more men in this class for purposes of discussion.

  .....

  READER

  "Gender and Women's Health" pp 343-344

  In much of this course, I've paid little attention to the author's 'conceptual tools.' In this week's reading, however, be sure to read them closely. Note that

  • •Gender is cultural, sex is biological
  • •Power relationships in patient-doctor encounters.
  • •Women's reproductive health is an important issue in a medical anthropology-a focus augmented by the many women anthropologists in this field.
  • •Women's health is politicized. If you doubt this, listen to Joseph Shiedler sometime when he is in the news.

  .....

  "Medical Metaphors of Women's Bodies" pp 345-356.

  See what you can do with this one. It isn't easy! It won't be on the final.

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  "Turn-Taking in Doctor-Patient Dialogues" pp 357-365

  As you read this, reflect on your own patient-doctor relationships.

  How do you feel about the doctor interrupting patients as a device to exercise power? What about gender overriding status-like when a man calls a woman physician a 'lady doctor!'

  I will tell you from experience that I get more respect from doctors when I wear a shirt and tie. Our clothing is like armor. Never underdress in any encounter with the opponent!

  .....

  "Accounting for Amniocentesis" pp 366-374.

  This article is engaging reading. Read it.

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  "Culture, Scarcity, and Maternal Thinking . . . " Pp 375-387.

  As you read, contrast your own expectations with what is described in this article.

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  Original Articles

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  Female Circumcision; Female Genital Mutilation

  In this article, female circumcision will be called FGM. This is the intentional alteration of the female external genitalia. It is still done on more than two million girls and women each year; roughly 100 million women living today have undergone the procedure. The practice continues mostly in 28 African nations and some areas of Asia. It is becoming increasingly common in immigrant communities in the United States, Canada, Europe, and Australia. FGM touches at the very core of women's rights, cultural relativism, and family privacy.

  What is FGM? It is a diversity of procedures that vary in practice. They are summarized below, graded by their intensity.

  • Literal circumcision is the least mutilating form of female circumcision. It is called sunna which means duty in Arabic. It is roughly analogous to male circumcision. In the female it is removal of the clitoral prepuce with a razor or knife, often with no anaesthesia.
  • The second form, called excision or clitorectomy means the cutting out of the whole clitoris and possibly parts of the labia minor, often without benefit of anaesthesia.
  • Pharonic circumcision is the oldest of the three operations. It is also known as infibulation because of its association with the old Roman practice of fastening a clasp or fibula through the labia majora to ensure chastity. The pharonic operation involves a complete removal of the clitoris, labia minora and majora with the two sides of the wound stitched together leaving a Q-tip size opening for passage or urine and menstrual blood. In rural setting, no anaesthesia and the two sides are stitched together with thorns. The girl's legs are often bound together for as long as 40 days to ensure the desired tightly bound aperture.

  .....

  What are the consequences of FGM? The pharonic form has the greatest impact on women's health. In that form the woman is 'reopened' with a razor; a particularly insensitive husband will tear the area open on the wedding night. Sexual intercourse is painful, not satisfying.

  There are birthing problems. Child delivery can be impaired with the child's head becoming impacted in the vagina leading to a stillbirth. In some unfortunate childbirths, a fistula would open between the colon and vagina, leading to seepage of feces and/or urine from the vagina. These unfortunate women are in a debilitating condition. They are often ostracized and divorced by their husbands. Monthly periods are often painful; simply voiding can take fifteen minutes. Many women feel like 'damaged goods' and are horribly embarrassed by a routine OB gynecological exam.

  Why is it performed? First, you must understand that while it is often done in Islamic countries, Islamic law and the Koran do NOT require FGM. It is deeply embedded in tradition and culture. It is NOT simply ended by civil law forbidding the procedure. Reasons for FGM are social control, proof of virginity, initiation into womanhood, cleansing by removal of the clitoris seen by some as a male organ in women.

  Who does it? For the most part, women do it to women. Some consider a woman incomplete without having had it done.

  ..... CJ '99

  Resources

  Abusharaf, R. "Unmasking Tradition A Sudanese anthropologist confronts femkale 'circumcision' and its terrible tenacity' The Sciences March/April, 1998.

  Brune, T. "Refugees' beliefs don't travel well" Chicago Tribune October 28, 1996.

  Burstyn, L. "Female Circumcision Comes to America" Atlantic Monthly October, 1995.

  Dettwyler, K. "Female Circumcision" in Angeloni, E. ed. Annual Editions Anthropology 95/96. Guilford: Dushkin Publishing Group/Brown & Benchmark, 1995.

  Dettwyler, K. Dancing Skeletons: Life and Death in West Africa Prospect Heights: Waveland Press, 1994.

  Tomes, S. "Sharing the pain Model describes danger of female circumcision" Chicago Tribune May 5, 1999.

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  13.6 Should Boys Be Circumcised?

  The age-old procedure of circumcision is the increasingly controversial center of a modern-day debate. Is the surgical removal of the foreskin from the penis a benefit, medically unnecessary, or even harmful? Studies abound, but are often contradictory. The Biblical command in God's word to Abraham: "Every man child among you shall be circumcised." Many African tribes also circumcise boys as a rite of passage.

  Although Jewish and Islamic males throughout the world undergo circumcision as a requirement, males of other faiths outside the United States are almost without exception not circumcised. As recently as 1980, circumcision was routine and rarely mentioned. Then, 90% of newborn males were circumcised. Today only 60% undergo the procedure. Now, anti circumcision groups have sprung up, the largest of which is Nocirc, founded by a California nurse. Seattle physician George Denniston is so strongly opposed to circumcision - he calls it "a national tragedy" - that he carries pickets and proselytizes other physicians.

  Edgar Shoen, an Oakland, California pediatrician and a prominent proponent of circumcision, feels so strongly about it that he publishes sentimental poetry supporting the procedure.

  Each side has its evidence. Proponents cite recent studies by researchers around the world that have shown uncircumcised men to be at higher risk for penile cancer and various diseases, including AIDS. Moreover, foreskin-related problems require as many as 10% of uncircumcised males to undergo the procedure post-infancy when it is much more traumatic.

  Scores of recent studies have also shown that urinary-tract infections, which are uncommon in uncircumcised males, occur from 1% to 4% of those who are not. In one of every 100 cases of UTI, the newborn kidney suffers damage that results in failure of the organ as an adult.

  Robert Baily, a UIC professor of epidemiology and anthropology cites several studies over the last ten years that show that male circumcision helps prevent HIV infection. International public health officials have shied away from this idea, fearing a clash with cultural and religious mores in non-circumcising countries. Baily and Halperin report that the risk of HIV infection is two to eight times higher for uncircumcised men.

  .....

  Opponents of circumcision say the pro-circumcision studies are tainted by money - the $10,000 a year, before expenses, that circumcising physicians can typically earn from the $150 fee-and call the procedure needless torture. But practitioners say it doesn't appear to hurt that much. (My note: I can't imagine any man saying such a thing!)

   

  Nearly all insurers pay for circumcision, but that doesn't mean they view the elective procedure as a medical necessity. In a 1994 letter defending Blue Cross Blue Shield of Utah's decision to reimburse for circumcision, its president noted that "circumcision provides no demonstrably medically necessary purpose, (but) it is rooted in our culture."

  Author Ron Goldman says cutting off part of a child's genitals has a very deep psychological impact on him when grown. Other men claim that circumcision has a desensitizing effect on a man's sex life. Circumcision opponents are seizing on the female genital mutilation issue and are trying to force an extension of laws against FGM to under aged males. They argue that there is no medical or legal basis to distinguish between male and female circumcision.

  One physician thoughtfully observes that this is a trivial issue. "If you can't get past this one (as a married couple), you are in trouble."

  ..... CJ '99

  Resource

  "French block vasectomy ads; cite code of 1800" Chicago Tribune November 4, 1999.

  Helliker, K. 'Anxious Parents Question Merit of Circumcision" Wall Street Journal 27 May 1996.

  Kiester, E. and Kiester, S. "The Circumcision Debate" Readers Digest January, 1997.

  Madhani, A. "Circumcision urged as way to confine AIDS spread" Chicago Tribune November 19, 1999.