ANTC67 – W2
- Study of diseases in population
- We will talk about one of the hallmarks and milestones of epidemiology
John Snow – one of the first Epidemiologists in English world.
- In 1865 there was a huge epidemic – cholera.
- This is pre-bacterial revolution time – there was no understanding of disease
causation as we know it today.
- Say there is a doctor named John Sutherland. Say in a population there are
dots of where cholera was occurring. There are diseases in geographic
spaces. You as his assistant, will say the name of the patient, we ask his age,
did he have diarrhea and if so when was the date of the attack.
- The slide – map of where the cholera and the death occurred. The bottom of
the screen is water. As you move up, you are going into steep incline. Each of
these vertical lines in the bottom are sewers that come from above. The dots
in the map are cholera death. The town is divided in small squares for
o In 26 and 27 there are many dots.
o In 8 there is no cholera deaths.
- This was an early attempt of Sutherland to map the diseases.
o For example, he studied what floor the person was living on, was
there sufficient ventilation, was there garbage or swage, where were
they getting water supply from, was the water quality good, how long
had room been cleaned, etc. in 1865, before Snow.
o Something wrong with what Sutherland did:
He didn’t think of people that did not get cholera.
You have to look at the total population that could have gotten
the disease, then you can do proper epidemiological study. ***
Graunt, J. 1603
- He was one of the first to do Bills of Mortality.
o Bill of Mortality: collecting a systematic record of death.
- Constructed what was called the Life Table.
o Life expectancy of birth/giving the probability of dying at each age
o Women live longer because they are biologically and genetically
o Say you are 90 years old – what is the probability of dying? Very high.
As you move through time in terms of age, the life graph will look like
U. If you are very young and very old, you are more likely to die early.
o Life expectancy is depends on Natural and Political – poor people
- Came up with Systematic classification of diseases - A lot of people were dying of Phthisis (tuberculosis). How is Phthisis
different from Consumption? It is the same thing – they are both repertory.
- Difficult dentition – Prof’s dentist friend said that when the kids were going
through teething, they were rubbing mercury on their teeth so they could
have died from that. The prof thought this could be simpler so he did some
analysis of Seasonal Element and many died in summer after 3 months to 9
months. Baby around that age gets teeth, so you will wean the child – so they
eat other artificial food substitutes instead of biting breasts. The child might
be exposed to pathogens to diarrhea. Mothers are pure, hygienic, and safe.
Weaning diarrhea corresponds with that age that goes through Difficult
- What is Disease Nosology?
o Disease classification.
o Bossier was trying to taxonomize disease on how they are
o Some diseases are air-bourn disease, water-bourn, food-bourn, and
sexually-transmitted. These are simple classification.
Air-bourn disease – transmitted through air (SARS)
Water/food-bourn – sharing water and food (i.e. diarrhea)
Sexually-transmitted disease (AIDS)
o Classification of disease gives etiology (cause)
- In 1798 there was smallpox (still exists in research labs for research
purposes, it has been eradicated but not totally.)
- Jenner discovered that smallpox was invasive within the general public.
- Once a person survives smallpox, they are immune to it forever.
- Coxpox vaccine against smallpox: Cows also have cowpox – milkmaids would
get less chance of getting small pox. So they learned that there is cross
immunity. You can take a sample of this cowpox and inject into a person and
it will give that person immunity. This was a big di