Culture Health & Illness Theme two

Human Health & Illness in Evolutionary Perspective

(The Great Epidemiology Transition)

  • How Disease Change over time?
  • Human Evolution took its course +/- 5 million years ago
  • 98.9% of your genes are shared with Chimpanzees
  • Just that small part that makes us human

Story of your Planet

Big Bang Theory

The Earth is +/- 4.7 Billion years old,  +/- 3.5 Billion years ago life started to develop called Bacteria (Algae), all life began in the Sea  +/- 250 Million years ago, Age of the Evolution of Dinosaurs & Reptiles, Life started to change; it was evolving & becoming more complex with no Reason the Dinosaurs Disappeared, makes us think, ''Can This Happen To Us''. +/- 65 Million years ago see the evolving of more small creatures called Mammals (warm blooded),  By +/- 25 Million years ago see special distinct types of Mammals evolving.  One of them being Primates, from Primates we see separate species of Primates evolving,  From this point we see the story of Human evolution & change. At this point we need to understand that there were no continents or countries it was all one, divided into two parts

  • North was called LAURASIA LAND

  • South was called GONDWANALAND

Later on through volcanic sifts we see the land braking into various parts, See some species being isolated from one another. +/- 12 Million years ago see distinct groups of apes & monkeys starting to evolve. +/- 5 Million years ago, this where we see the evolution of HUMANS, this where apes & humans took their separate path on the evolution scale, We as humans developed into a distinct species very different from apes & chimpanzee.

BUT we still share the same genetic structure: we are related prior to the 5 Million years, From 5 to 2 Millions years what was called early pre-human. After 2 Million years called Homo-Erectus- walking up right, Modern day humans today are called Homo-Sapiens Sapiens. Life was basically Hunting & Gathering. We adapted to the diseases of the evolution period- do not affect us today, 10,000 years ago we settled down & started to domesticate animals & plants. This was the changing point for us as a species,Our genes are still programmed to a hunter gather way of life, We are Biologically Hunters & this instinct allows us to adapt to the various environments- Survival of the fittest.

Human Survival over time:

  • We evolved as a creature & changed as a species
  • Our environment changed, we adapted to new viruses
  • Cultural systems evolved over time, the disease Ecology changed CALLED THE EPIDEMILOGICAL TRANSITIONS
  • Major shift through time in relation to humans & Disease


Agricultural Revolution & the spread of Disease

  • Occurred 10,000 years ago (called Agricultural Revolution) *5millions *10,000 *Today Moved Around Arg. Rev
  • With the agricultural revolution about 10,000 years ago, increasing sedentary life and larger population groupings
  • Resulted in the first epidemiological transition in which infectious and nutritional diseases increased.
  • Previously we used to move around in small groups called Bands
  • Nomadic lifestyle based on Kinship
  • Moved around for food to survive
  • There was a natural balance of group size & food resources
  • For nearly Five million years, humans lived in widely dispersed, nomadic, small populations that minimized the effect of infectious diseases.
  • Diseases exposed to: Protozoa & Zoonotic


  • Protozoa can affect humans indirectly through their effect on the environment
  • They are tiny Infectious pathogens (e.g., bacteria, viruses, parasites) BASICLY: Parasitic organisms that produce toxins
  • Contracted through water, Soil & Contaminated Meat
  • Since we lived a nomadic life constantly moving around, spread of the disease was minimal
  • Protozoa TOXINS causes: Nausea, Vomiting, Diarrhea
  • It attacks the Abdomen area of the body
  • As it mutates it cause Nausea, Vomiting, Diarrhea
  • Leading to Dehydration
  • Could have resulted in death (young children mainly)


  • The second class of diseases is Zoonotic, which have animals as their primary host and only incidentally infect humans.
  • Humans can be infected by zoonoses through insect bites, by preparation and consumption of contaminated meat and from wounds inflicted by animals.
  • Certain type of lice also was a problem, they attach themselves to body hair, can cause fever in the Human Host
  • Mosquito's where also a carry of diseases e.g Malaria but only in isolated incidents
  • Illness contracted from animals & insects where:
  • Sleeping sickness, tetanus, scrub typhus, relapsing fever, avian or ichthyic tuberculosis are among the zoonotic diseases that could have afflicted earlier gatherer-hunters

Infectious diseases started to come about after we settled down as a species Agricultural Revolution (10,000 yrs ago)

  • Agriculture was first documented in the Middle East (10,000 yrs ago)
  • Start of producing & experimenting with Cultivation (Wheat, rice, corn & lentils
  • Also started Domesticating cats to chase the rodents from eating the stock; dogs for hunting & herding
  • We see a change of life starting to develop
  • Brought new changes in Social Organisation & new set of Challenges
  • See the rise of Property ownership & inheritance (subject to crops)
  • Linage Started to Develop
  • The rise in Defense
  • Division of Labour
  • Inequalities as a result of population increase
  • Population explosion
  • Protozoa increase; Sedentary life, an important feature of agricultural adaptation, increased parasitic disease
  • Contaminated Water
  • Close contact with Human & Animal waste
  • Nausea, Vomiting, Diarrhea were on the increase
  • Parasites started mutating & adapting to the environment
  • See the rise of bacterial infections
  • Zoonotic Diseases also increased
  • The Zoonotic infections increased because of domesticated animals, such as goats, sheep, cattle, pigs, and Birds, as well as the unwanted domestic animals such as rodents, which developed permanent habitats in and around human dwellings
  • Products of domesticated animals such as milk, hair, and skin, as well as the dust raised by the animals, could transmit anthrax virus
  • Contracted Influenza virus from chickens/birds- present at time of slaughter
  • Start of with upper respiratory infection, Battle to Breath, Headaches & Nausea
  • Population increased Disease started to spread
  • Diet changed, now cultivating limited food as compared to previously
  • This brought about nutrition deficiencies
  • Resistance to Disease, now more prone to Diseases
  • Viral infections were on the increase
  • Due living conditions spread of Small Pox, STDs, Measles
  • During exploration of the Americas, measles wiped out entire groups of Traditional societies in North America
  • 1300's see the spread of the great plague, caused by rodents
  • Carrier of the virus that caused detrimental effects on humans
  • During the First Transition, Technology Started to Develop
  • Try find cures
  • Antibiotics developed
  • Surgery
  • Developed more medicines
  • Immunization to build defense
  • Small doses of measles, small pox given to child to build a defense
  • This was possible through the invention of the Microscope
  • Could see germs, virus, bacteria that the human eyes can see
  • Find ways to fight them off
  • This came about in advances of Medicine in Europe
  • Lifestyle started change
  • could now buy other food products
  • Better sanitation & clean water


  • Occurred at the started of the INDUSTRIAL REVOLUTION
  • 1800's +/-200 years ago
  • This brought new Diseases (not adapted to it as yet)
  • People lived longer (before 38 now 78)
  • Due to lifestyle change
  • Rise of Chronic Degenerative Disease
  • Arthritis (living longer)
  • Advancements in Human Technology to make our lives easier
  • Created Detrimental effects to our health
  • Increase of Pollution (affecting air, water & soil)
  • Introduction of Chemicals in the environment
  • The development of new viruses & Bacteria
  • Causing Allergies to rise
  • Parasites muted one of them called Dust mites
  • Live of Dead Skin, largely found in human households
  • Increased number of people allergic to them
  • Causes irritation to the sinuses
  • Asthma also increased especially in children due to Pollution in the Environment
  • Affecting Respiratory System (lungs)
  • Airways Constricts & gets Inflamed, making it difficult to breath
  • Allergies are a result of the Industrial Revolution
  • We see more & more people allergic to something or the other in the environment
  • Because we are not exposed to our natural environment
  • The air & water are polluted (mutation of bacteria & virus)
  • Our body (immune system) as not adapted to this environment as yet
  • Obesity was on the increase
  • Result of increased Sedentary Lifestyle in Second Transition
  • High intake of Calories that was unhealthy
  • High intake of Carbohydrates (refined white flour to make bread, rice grown with hormones)
  • People opted to eat unhealthy fatty foods because it taste good
  • People became more & more settled and hardly moved
  • Hence the rise of Obesity
  • With Obesity came a whole host of other chronic disease
  • Due to change of lifestyle
  • Most of the Chronic Diseases are controllable by a change in lifestyle
  • BUT Not Easy because of our unhealthy stressful lifestyle & hardly moving around
Discordance Hypothesis
  • We must realize our Biological makeup is as a result of millions of years of evolution
  • Change in ecology over time as a species
  • Our body still not adapted to the Second Transition
  • Evolution takes millions of years, genes still programmed before we were fully Human
  • Before we where Homo sapiens, already laid out even before we fully formed as Humans
  • We only were Homo sapiens 40,000 yrs ago
  • Large Majority of our Biology adapted long before we settled down as a species
  • Genetically we as still the same as our ancestors 40,000 yrs ago
  • Humans have progressed in such a short space of time
  • Evolution of our brain & thought processes
  • Therefore we see the rise in diseases & chronic illness in humans, LIFESTYLE CHANGE
  • Our genes as not evolved yet for us to adapt to the new way of life (still think we in hunter/gather mode)
  • From a genetics point as we moved to the second transition new diseases seem strange to our bodies

Biology & our Lifestyle Change

  • General pattern of original Lifestyle/ biologically programmed:
  • Hunter/gather
  • high fiber food/roughage
  • Fresh food

With the second Transition

  • Meat very different now from before
  • Refined Salt & Sugar
  • Rice & wheat
  • Water
  • Tobacco

Today (Modern lifestyle)

  • Store bought food
  • Highly refined
  • Unhealthy Meat

Second Epidemiological Transition & Modern Chronic Diseases

  • Food compared to our ancestors = over refined & processed Nutrition lost
  • Don't eat enough roughage/fiber
  • Meat= consume everyday as compared to previously
  • Consuming lots of sugar & salt
  • Not adapted to alcohol & tobacco
  • With sedentary lifestyle= lack of excise
  • Exercise more, keep fit
  • Cut down fatty unhealthy foods, refined sugar & salts, cleaning up out environment

High Blood Pressure (H. B. P)

  • Also referred to as Hypertension
  • High salt build up in the blood vessels & fat build up
  • Leads to other Diseases: Heart disease, Stroke, Kidney Disease, birth complication
  • High intake of refined salt that causes H.B.P
  • Came about with new lifestyle
  • Sedentary lifestyle (Disease of Modernization)
  • Rise of Obesity & blood pressure
  • For every 10% of body weight leads to 7% of H.B.P
  • When salt and water levels increase around cells, the excess is drawn into the blood, which is filtered by the kidneys.
  • The Kidneys remove excess salt and water from the blood, both of which are excreted as urine
  • When the kidneys do not work well, fluid builds up around cells and in the blood
  • Causing Kidney failure
  • The heart is the pump that pushes the blood around
  • If there is more fluid in the blood, the heart has to work harder and the blood pressure can go up because there is more pressure on the walls of the blood vessels
  • The heart can get weaker or worn out from the extra work
  • Causing Heart failure
  • Strokes causes by the slow movement of blood to the brain or a burst blood vessel that is caused by pressure placed on the heart

Diabetes Type2

South Africa = highest incidents in the world as society progress and lifestyle change, increase in (Diabetes) High intake of refined sugar resulting in low levels of Hormone insulin. Prevents the removal of extra sugar from the blood stream prevents the sugar from going were it is needed, Simply; it is a transport problem as the body tries to get rid of it can cause kidney disease, nerve Degeneration, Stroke caused by high intake of refined sugar that damages the insulin

Third Epidemiological Transition

  • Happening now
  • See the Mutation of Diseases to another level
  • Disease are becoming immune to medication

TB in South Africa

  • TB was brought to South Africa during the gold rush on the 1800's by European migrants
  • Bad working conditions in the mines
  • Workers were exposed to silica dust, overcrowded hostel living, poor nutritional status and stress, all of which were major contributors to the development of TB.
  • TB spread easily in the mines
  • Ecology plays a major role in the spread of TB Today
  • See the Mutation of TB
  • Starting become more drug resistant (WHY?)
  • 6 Month treat for TB= with a cocktail of drugs know as first line treatment
  • People stop taking medication once they think they are cured
  • When they contract TB again the medication does on work
  • It as Mutated
  • Developing a new Strain of mutated TB
  • Mutated MDR is hence spread
  • Resistance to 2 most powerful line of drugs
  • MDR is treatable by second line drugs (more expensive)= CHEMOTHERAPY
  • People on MDR treatment, if stop taking the second line drugs & get TB again it as mutated further b become immune to the second line drug
  • For this the is no treatment as yet and can lead to dead in a few days

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