Download Chapter 8 - Cynthia Clarke

Robbins Chapter 8
Health and Disease
Overview 1
• This chapter concerns morbidity, the fourth demographic measure (as well as a continued discussion of mortality caused by
disease).
• Morbidity is the one factor that was largely ignored in the chapter on population.
• Morbidity is of major concern, in addition to measuring health status, as it links to economic factors, too.
• After WWII, as a part of the faith in science and technology there was a belief that infectious disease would be eradicated.
There was some reason for this optimism:
• There had been developed vaccines against some of the major killers.
• And the combination of sanitation and DDT had been shown to be powerful against malaria
• And there were curative drugs for TB.
• Smallpox was gone, polio was nearly gone.
• It was suggested measles would be eradicated by 1982.
• Then, there was a major shift away from this optimism;
• This new view is what Marc Lappé called therapeutic nihilism (the attitude that nothing will work).
• Many things contributed to the cognitive shift:
1. Emergent diseases were documented.
• One of the first shocks to this worldview was presented by the introduction of AIDS.
• Other new diseases have also appeared: SARS, avian flu and hemorrhagic fevers such as Ebola
2. Another factor associated with the change is the emergence of anti-biotic resistance diseases.
3. Yet other disease, once thought to be coming under control re-emerged:
• Malaria, cholera and TB have reemerged in deadlier forms.
• Measles cases were 4X as prevalent in 1993 as in 1983.
Overview 2
• Global disparity in causes of death
• While the global death rate from infectious diseases in 32%, in the periphery it reaches 42%.
• This is yet another example of the disparity between the wealthy and poor nations Signature diseases
• Robbins explains that each time has its own signature disease.
• A signature disease is one that epitomizes the health stressors of that time period.
• In the 14-15th centuries it was bubonic plague; in the 16th-17th centuries it was syphilis, in the 19th century it was
tuberculosis (TB; a.k.a., “consumption”).
• Today, it is AIDS.
• The signature disease tells us much about the social and cultural patterns of the time. As a consequence, there are
several major questions we need to ask:
1. What do we do that exposes others to disease?
2. How do we create the conditions for unique interactions between pathogens, their environments and their hosts?
3. What features of human societies make pathogens more or less lethal?
• We need to look at a number of contributing factors. For instance,
1. Population density is one factor that affects the emergence and frequency of a disease.
2. The division of people into rich and poor.
3. Public policies come into play, including programs that cut health, sanitation, and education.
• How medical research dollars are spent makes a difference (one of my professors used to say that ‘white
congressmen’ diseases were more likely to be funded. He meant cancer and heart diseases).
• Only 13% of the global research budget is for tropical diseases.
• Infectious diseases are not the only problem; as we have discussed earlier, environmental pollutants and lack of food
are also concerns.
Primer on How to Die of an Infectious Disease 1
• What determines the relationship with the infectious pathogens we share?
• We are filled with and surrounded by microbes, but for most of the time, we stay healthy.
• Sometimes bacteria, viruses and parasites invade and cause disease; these are called pathogens.
• From a strictly biological stance, whether a microorganism is infectious is determined by using Koch’s Postulates.
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The pathogen must be found in all individuals with the disease.
The pathogen must be isolated and grown in pure culture.
The culture should cause the disease when introduced into another health individual.
The pathogen can be isolated from the second individual and grown in culture. These postulates are not always
met, for instance if a second individual is infected, s/he may not get sick for a number of reasons.
From a public health stance, for a disease to occur at least 4 things must happen:
1. Come in contact with the pathogen or the vector (the organism that carries the pathogen).
2. The pathogen must be virulent, have the capacity to kill (I disagree, to make sick is enough to make it a concern).
3. The pathogen must invade our immune system.
4. It must be able to circumvent whatever measures our society has developed to prevent it from doing harm.
Primer on How to Die of an Infectious Disease 2
• What actions of humans increase their likelihood of coming into contact w/ an infectious pathogen?
• Cultural practices are the primary way humans set themselves at risk.
• Humans change their environments and the size, density and distribution of human settlements.
• Lyme disease is one example of how these changes can be deleterious.
• This disease was first reported in 1975 in Connecticut.
• It was found that a tick was the vector.
• The disease became an issue as forest was decimated beginning in the 17th-18th centuries.
• Further, the natural targets such as bears, wolves and mountain lions were gone. Now the reservoir was
mice and deer.
• This brought the vector, along with the parasite, Borrelia, into closer contact with humans.
• Malaria is another such example, as is Ebola.
• So why is malaria so often found in association with humans? Farming!
• In the Middle Ages it was thought malaria was caused by bad air (thus the name of mal aria)
• Today we recognize malaria is the result of contact with infected mosquitoes of the genus Anopheles
• One suggestion is that malaria became a significant disease among humans only after we became farmers.
• What about Ebola? How did it transmit? Bush meat is a likely explanation.
• Bush meat is also the likely reason AIDS became an epidemic.
Primer on How to Die of an Infectious Disease 3
• What actions of humans increase likelihood of coming into contact w/an infectious pathogen? (cont.)
• Many of our infectious diseases are derived from our ancestral species and also infect the closely related primates.
These include ectoparasites such as lice, ticks and fleas as well as helminths (parasitic worms), protozoa, fungi and
bacteria.
• Carnivores are at risk of picking up the pathogens from their prey.
• Many zoonoses, diseases of contact with other animals, were first contracted among food foraging populations.
• Exposure to animals increased where these animals were domesticated.
• Best option for a parasite is to ‘do-no-harm. So what happens when the pathogen become lethal?
• Most of the microbes or pathogens with which we come in contact do no or little harm, but there are exceptions.
• Why? Here are 4 factors that may help answer this question:
1. The newer the disease the more likely it is harmful as the parasite and host have not had time to adapt to each
other.
2. Vector-spread pathogens are more harmful as the parasite is not dependent on humans for their existence.
3. When spread by an external medium, such as water, as high infection rates increase the chances of continuing
the chain though washing and clothes.
4. The ease of transmission in that is it kills quickly but is not passed on this is a disadvantage. This is called
breaking the ‘chain of transmission’.
Primer on How to Die of an Infectious Disease 4
• Best option for a parasite is to ‘do-no-harm (continued)
• So, let’s examine the idea that EASILY transmitted diseases are MORE likely to be lethal is suggested by Paul Ewald
(His idea being that no selective pressure to spare the host). Example is Ebola
• The corollary is the idea that HARD to transmit diseases are LESS likely to be lethal is of equal importance. Example
is STDs such as AIDs.
• This idea of Ewald’s is not always the case, but the idea does give us an option.
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If you can make the price a pathogen pays (more difficult to transmit) it will become less virulent.
Clean up water supplies, protect oneself from mosquitoes, and alter behaviors around STDs should be making the
diseases less deadly, and also preventing transmission.
Is there anything that can save us?
• We have our immune system, but it can become weakened
• Further, microbes are very adept at overcoming our immune responses; there are more of them and they reproduce
faster.
• What next? What is the cure?
• Humans have always sought ways to overcome disease: 1) Ceremonies, use of plants and other materials are
common; and 2) both the prevention & cure of infectious disease have been overcome with vaccines and
antibiotics, as well as through sanitation campaigns.
• As we know microbes have found ways past these measures.
• Partly because as many ½ of the 150 million prescriptions in the United States each year are for the wrong
thing!
• Also, ½ the antibiotics in the US are used on livestock, in aquaculture and other biological industries.
• One example of the troubles is that drug-resistant TB is moving from poor countries to the rich.
Relationship between Culture and Disease 1
• Overview
• How we lead our lives greatly influences how well we can counter the effects of pathogens.
• So how do lifeways expose people to disease and/or contribute to the spread of these pathogens?
• Gathering and hunting to early agriculture.
• Nomadic, small-scale societies do not provide the best host environments in that the pathogens have no-where to go
after ravaging the small group.
• Therefore, most of the early pathogens must have depended on the health of the host and were less harmful.
• Among the disease that meet these criteria would be yaws, the herpes virus and many of the intestinal illnesses.
• ‘All bets were off’ when humans shifted from the foraging lifestyle to farming.
• Sedentary populations are more likely to engage in long distance trade.
• They create more favorable conditions: permanent shelters bring rodents, garbage and polluted water
• Alteration of the landscape by horticulture, animal husbandry and agriculture exposed humans to new diseases.
• Improvements in cooking technology, especially pottery, did allow for longer cooking times (more healthy), but
also may have encouraged growth of some bacteria, as did storage.
• Regular contact with domesticated animals exposed humans to additional infections.
• An interesting article you might read is The arrow of disease.
• On the next page is a table from another text. I provide it as an FYI.
Diseases Humans Derive from Domesticates
Relationship between Culture and Disease 2
• “Graveyards of mankind”
• The greater the population density the easier it is for infectious diseases to spread.
• By 2,000-4,000 years ago, writings started to discuss lice, bedbugs, and ticks associated with dense living
conditions.
• In Rome, there was only a 1 in 3 chance of living until 30 years in the cities, but in the rural areas it was 70%
(more than double).
• In 430 B.C.E. (before common era), an epidemic killed ½ the population.
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• During more recent times, with the beginnings of the Industrial Revolution, cities became much larger.
Five diseases in particular benefited from the expansion of urban environments: bubonic plague, leprosy, cholera,
tuberculosis and syphilis.
Bubonic plague (Yersinia pestis,; a.k.a., the Black Death)
• This disease spread during the 14th century by traders.
• In addition to banning people from their cities, scapegoats were labeled and tens of thousands of Jews were
slaughtered.
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On a different note, you might be interested in watching the video (found in the library) where there may be a genetic
relationship between surviving the plague and resistance to AIDS: The Mystery of the Black Death.
Leprosy (Mycobacterium leprae and Mycobacterium lepromatosis)
• Represents the adaptation of a parasite to changing environment.
• In 1200 C.E., this disease swept over Europe due to the lack of sanitation.
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This disease numbs the extremities and so disfigurement results.
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By 1980, most the world’s population exhibited antibodies to the disease.
Relationship between Culture and Disease 3
• Cholera (Vibrio cholerae)
• Western records of cholera date back as early as 1503 and seem to have originated in India.
• Only after about 1817 was the first pandemic noted when the disease spread out of India.
• There were pandemics of this disease between 1830 to 1896. As it struck the poor disproportionately it was thought
to be due to lower-class immorality.
• The famous John Snow showed it was being spread by water.
• He is considered the founder of epidemiology (the study of disease processes at the population level).
• In 1849 he showed the water connection when he removed the handle from a contaminated well in London and the
rate of the disease dramatically fell.
• Not until the 1880s was the specific pathogen was identified.
• This disease is caused by a bacterium that is transmitted by fecal matter in water.
• The cause of death is diarrhea through dehydration. By about 1960, rehydration solutions were developed (Here is
one website that talks about this idea: http://rehydrate. org/solutions/homemade. htm#recipes).
• Tuberculosis (Mycobacterium tuberculosis)
• This was the most deadly disease of the 19th century.
• We know that this bacteria has caused disease in human for at least 5,000 years from written records.
• May predate domestication and one clue is that humans can give the disease to cattle and M. bovis can be
contracted from cattle.
• This means the disease can go in both directions. When a disease spreads in this manner we call this breaking the
species barrier.
Relationship between Culture and Disease 4
• Tuberculosis (Mycobacterium tuberculosis; continued)
• Only about 10% how are exposed exhibit signs of the disease.
• It is droplet-borne so higher the population density the easier it is transmitted.
• TB has declined in the US. AT 38/1000 in 1850, down to 0.6/1000 in 1940.
• Hypotheses as to why this decline include: 1) better nutrition; and 2) the elimination of the horrible working conditions
during the Industrial Revolution
• Syphilis
• The type of bacterium that causes the disease is called a spirochete as it is spiral-shaped (Treponema pallidum
subspecies pallidum).
• Treponema pallidum endemicum (called endemic syphilis or bejel, siti, dichuchwa, njovera, or skerljevo), T.
pallidum pertenue (yaws), and T. carateum (pinta), are closely related but not sexually transmitted.
• They appear to be similar morphologically and serologically, but exhibit small genetic differences. But as to
antigenic differences, there appear to be none.
• This link summaries the several types, and their pathologies
• There is a significant debate over rather syphilis originated in the New World and spread to the Old World.
• Until recently, this was the accepted view among paleopathologists (students of old diseases).
• New evidence suggests this disease may have been in the Old World prior to first contact.
• The organism has very few genes and does not appear to be able to swap genes with other bacteria.
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It is so small it goes under the immunological radar of the host.
This means it can not develop antibiotic resistance.
Relationship between Culture and Disease 5
• Syphilis (continued)
• Cities increase risk of STDs. Movement to the cities, especially by unaccompanied men, increased the incidence.
• First seen in Europe in 1495 among French soldiers, so dubbed the French disease.
• Also blamed on the indigenous peoples of the New World.
• This last may not be accurate. Great video, in our library, called The syphilis enigma
• Seeing this physical effects makes the Tuskegee Experiment even more horrendous.
• It was not until July of 1972 that Americans began to learn what had happened:
• Starting in 1932, 400 poor black Alabaman men were studied by the Public Health Service.
• The study consisted of leaving this men untreated and watching them die.
• Even after penicillin, the first known cure, was being used in 1947, they were left untreated.
• Many of the wives and children of these men were also infected.
• President Clinton apologized in 1973, the Office for Human Research Protections (OHRP) was formed, as
were Institutional Review Boards (IRBs)
• This case of medical abuse in not as isolated as we would wish to think, race becomes the basis for the treatments
which individuals receive and it also affects what resources the person brings into treatment.
Relationship between Culture and Disease 6
• Urbanization
• The pace of urbanization increased in the 20th century and the spread of diseases became easier with international
transit.
• Urban slums are spreading as people are pushed/pulled off farms and into cities where wages/jobs are scarce.
• A child of these slums is 40X more likely to die of infectious disease than a child from the rural area of the same
country.
• Cysticercosis (produced by tapeworms) and found in undercooked pork is now being seen in the water. This water
source is now a way to contract the disease.
• Diseases of environmental change
• The rate at which we are constructing our commercial and industrial centers has expanded in the last 50 years, as has
the rate of environmental destruction
• All this construction opened new habitats for pathogens
• Dam building has had a major impact on the presentation of some infectious diseases.
• The functions of dams is most often to generate hydroelectric power and for irrigation.
• An unintended consequence is that malarial prevalence increases do to the introduction of large volumes of
stagnant water (perfect for breeding of mosquitoes).
• In addition to the spread of malaria, dams have increased the presence of two other parasitic diseases:
sschistosomiasis (Bilharzia) and onchocerciasis (River Blindness)
• Onchocerciasis is a parasitic worm transmitted by the black fly (Simulium damnosum).
• Schistosomiasis is a worm that is transmitted by snails during the larval form of the parasite. This disease is
ancient and is documented among the ancient Egyptians and Chinese.
Relationship between Culture and Disease 7
• Diseases of environmental change (continued)
• One example was the building of the Daima Dam, Senegal River, by the Mauritanian, Senegalese, and Malian
governments.
• About 200 million infected each year with schistosomiasis and is extremely devastating to populations infected.
• The dam also halted the flow of water used to make salt.
• In Brazil, the highway spread both diseases and intruders.
• Among the diseases was dengue fever.
• The deforestation of the Amazon helped this mosquito-borne virus return to this part of the world.
• The raw sewage, fertilizers, pesticides and other chemical waste serve as nutrients for algae.
• They bloom more often and in larger numbers, in the 1970s researchers learned that cholera can live inside
algae.
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Diseases of human ecology
• We see a new manifestation of the flu each year.
• Every droplet from the infected person contains between 50,000-500,000 virus particles.
• It is highly contagious and attacks the upper respiratory system.
• First definitively described in C.E. 1173 in Europe and first pandemic in C.E. 1580.
• The 1918 flu pandemic killed between 50-100 million people worldwide.
• The origin of influenza: Avian flu and H1N1.
• Asia, especially southern China has been an incubator for 2 reasons:
• Here fowl and pigs are intermingled in large numbers, along with humans.
• China has a dense population on the migration routes of wild birds.
• The high demand for meat is expanding the ‘incubators’ to many more places.
Relationship between Culture and Disease 8
• Diseases of human ecology (continued)
• We see a new manifestation of the flu each year.
• Every droplet from the infected person contains between 50-500,000 virus particles
• It is highly contagious and attacks the upper respiratory system.
• First definitively described in C.E. 1173 in Europe and first pandemic in C.E. 1580.
• The 1918 flu pandemic infected 500 million of those it killed between 50-100 million people worldwide (10-20%
mortality rate).
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The origin of influenza: Avian flu and H1N1
• Asia, especially southern China has been an incubator for 2 reasons:
• Here fowl and pigs are intermingled in large numbers, along with humans
• China has a dense population on the migration routes of wild birds
• The high demand for meat is expanding the ‘incubators’ to many more places
• The sloppy mechanism of reproduction and the ability to adapt to the immune properties of the host make the flu virus
extremely variable.
• Examples of recent outbreaks include:
• In 1997 the avian flu was identified in Hong Kong.
• It ravaged the Asian chicken population, killing 120 million by 2004
• Only a few cases of human-human transmission, all others from bird-human, which slowed the spread
• Swine flu appears to have first emerged in Wisconsin, with a single case reported.
• Swine flu re-emerged in 2010 and infected about 59 million Americans, killing 12,000.
• Started in La Gloria, Mexico near a Concentrated Animal Feed Operation (CAFO).
• Robbins describes Laurie Garrett’s account of the spread on pp. 237-238.
AIDS and the Culture of Capitalism 1
• AIDS is the signature disease of our time.
• AIDS acts as a marker to separate the core and the periphery.
• In industrialized countries, infectious diseases cause 1.2% of deaths, in the periphery it is 42%
• You might be interested in the statistics published by the WHO on infectious diseases.
• Origins of AIDS
• First noted in San Francisco in 1981.
• In 1983 it appeared in Zaire, and it may have been in Europe as early as 1959 (not yet confirmed).
• It was called GRID (Gay-related immunodeficiency disease). This label had consequences:
• The effect of labeling the disease as GRID was that any researcher who suggested it was transmitted heterosexually
struggled to get published in the early 1980s.
• Reagan administration did not want to fund research on this disease.
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Pat Robertson denounced that the disease could be transmitted heterosexually or that condoms could prevent
infection
• By 2003, about 28 million have died of AIDS, and perhaps 34-47 million more are infected.
• Sub-Saharan Africa has the highest rate with 21-27 million infected (7.5-6.5% of its population) with HIV/AIDS.
• The fastest rate of increase is now seen in Eastern Europe, South and Southeast Asia.
• In North America, between 880,00 to 2.2 million have cases of HIV.
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It is likely the disease originated in either Central or West Africa after WWII from a primate species (another
consequence of expanded deforestation) -- think bush meat.
AIDS and the Culture of Capitalism 2
• How did the disease spread?
• Think global space: This idea that we are interconnected by transport.
• While blood transfusions spread some, mostly a consequence of the global space.
• One example in the sex trade into Thailand, another is for business and labor migration, and a third is war.
• Who gets infected with AIDS?
• In the US, the response was influenced by the concept that HIV/AIDS is a disease of homosexuals and so took on a
moral tone.
• In the US, and globally, it is the poor who have been disproportionately infected. Haiti is one example:
• In the 16th and 17th centuries the Taino, the first people, were exterminated.
• Haiti has been passed from Spain to France and then to independence as the result of a slave revolt in 1804.
• America dominates Haiti today (neo-colonialism, where an independent country remains obligated/tied to a colonial
country).
• The attempt at tourism collapsed when Haiti was labeled as the originator of HIV/AIDS.
• HIV/AIDS is not only a marker of poverty, but also of gender and age. Globally, women are the majority of the cases.
• They are infected at younger ages.
• In many countries 60% of new cases are women between 15-24 years.
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In another study of several African and Asian countries, women were twice as likely as men to be infected.
• Wives contract the disease from husbands, or from prostitution.
• Sex education is discouraged in many countries and gender roles can prohibit women refusing sex with their spouses or
requiring the use of condoms.
• Women pass the disease onto their children.
AIDS and the Culture of Capitalism 3
• Who gets treated?
• While there is now a drug that restores the immune system, it is not readily available in the poorer countries.
• The cost is high. When S. Africa made generics, the American drug companies sued them, but lost.
• In spite of best efforts, access to drugs in poor countries is extremely limited.
• Who gets blamed?
• Common theme: Problems caused by the core’s exploitation of the periphery are blamed on the periphery.
• The Haitians were blamed, as part of the ‘4-H club’ (homosexuals, hemophiliacs, heroin users, and Haitians).
• It was not until 1985 that is label was changed at the CDC (Centers for Disease Control).
• The CDC refused to admit its error.
• The Haitians were blamed because of racism.
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