HLTB21H3 Lecture Notes - Estuary, Etiology, Health Geography
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Until 19 th
Believed disease was caused by bad vapors one would have to inhale and that
would cause disease
referred to a bad odour from those vapors.
Pettenkofer refused germ theory which was
Germ Theory: there was an X factor in the air and Y factor in the soil.
The uniting of X and Y caused the disease
- infection caused by contact with person to person
-*focus on the people that supported the contagion theory (names on the
- People didn’t want to believe this theory because it seemed conservatism. It
involved quarantining people, which people didn’t necessarily improve of.
7 pandemics are still ongoing today
1) 1816-1821: cholera spread through out to the world in early 19th century
2) a 1829- 1851: lot happened in social transformation in second pandemic. A lot
was done in terms of public health and sanitation measures in general
7) 1961. ongoing up to present day but believes to be the end of the pandemic
Map of Cholera 2002-2003
solid blue colors are cases of cholera that came from the region
and blue dots are imported cases
ie: NA limited to imported cases
Graph: Countries/areas reporting Cholera and cases reported by year 1993-
1) about over 80 countries reported cholera and this went down by half in 2003
2) right side of axis is the total reported cases
There is cyclic pattern of cholera (line graph).
Reported Cases 2004-2007 MAP
resurfaced in NA
1) died down in European northern hemispheres
2) differences in southern and central Africa
Spatial patterns play a big role in finding the role of cholera in 10th century able to see
affects of pandemics through spatial patterns.
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Map Cholera, areas, reporting outbreaks 2007-2009
areas of outbreaks in 2007 –2009
black: imports outbreaks
Much less outbreqks than in 2004-2007
Example of spatial patterns.
Slide 7 graph-Number of cases reported in Canada 1995-2004
Not many cases
Trends goes down, but for the most part its cyclic
Its mostly imported cases of cholera
huge outbreak of cholera in Egypt
vibrio cholera was the agent of disease
in order for vibro to cause damage it has to be infected with two viruses
1) that gene causes people to excrete fluids out of the body, through diarrhea
in order for strain to be effective it needs that gene that causes the diarrhea
two viruses needs to be used
1) ABILITY TO enter bacteria
2) the toxin coding virus itself IS important
Infection with Cholera
These excretions are sent to the environment and anyone in contact with those
microbes are at risk.
NOT restricted to consumptions. People can bathe in the water, but consumption is the
most common route.
Microbe tends to live on surfaces
letal not lethat
Picture – Slide 10
Cholera is classic example of the epi triad
Agent, host ,environment
Cholera has an environmental resevoir
Microbe sits in biological surfaces, in those bacteria on the slide
An imbalance in the enviroment make it available for infection
Once environmental conditions change it can either cause
1) more cases
2) or die down the cases
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