Microbes and Disease –
A study of Epidemiology
The six major methods of transmission:
F.6.1
1. Direct Contact – Norwalk Virus
2. Cuts/Injuries to the skin – Clostridium tetani
3. Water Droplets - Influenza
4. Contaminated Food or Water Clostridium botulinum
5. Insects acting as vectors - Malaria
6. Sexually Transmitted Diseases - Chlamydia
trachomatis
Big Question: What happens once
inside the body?
F.6.2
Two major ways an infection can
manifest
Intracellular Infection
Extracellular Infection
Pathogen rests inside of the cells in the
body
e.g. Chlamydia trachomatis
• Hard to recognize by immune system
• No major symptoms
• No toxins produced - and so they
often to not damage cells immediately
around them, but will cause chronic
problems
Time Lapse
of
chlamydia
infection
Pathogen rests outside of the cells of the
body
e.g. Streptococcus pneumoniae
• Easy to recognize by immune system
• Major, specific symtoms
• Toxins produced, causing immediate
damage to the cells around the
pathogen
Endotoxins vs. Exotoxins
F.6.3
Exotoxins are nasty toxins that cause some of Endotoxins cause (generally) a milder response
the symptoms you are familiar with.
of general fever and achy feelings.
Some examples of diseases caused by
Examples include:
exotoxins are:
Escherichia coli
Botulism
Salmonella
Tetanus
Shigella
Cholera
Pseudomonas
Anthrax
Neisseria
Pertussis
Haemophilus influenzae
Diphtheria
A few of these bacteria emit BOTH types of toxins. Research the
Dysentery
above types and discover which ones!
Evaluating methods of control.
Pasteurization
Which of these would you trust in
your food?
Irradiation
Antiseptics
Disinfectants
F.6.4
Design an Experiment
You should design an experiment through which you can evaluate
the effectiveness of antimicrobial methods:
Disinfectants vs. Antiseptics
You can do this in groups, and you have access to Petri dishes, lab
glassware, rubbing alcohol, hand soap, and any other cleaning
products you would like to use.
The experiment setup should be
Completed by the end of class
On Friday.
The life of a virus - Influenzae
For this reason, we use the term
“Lytic Cycle” to describe what a
virus goes through in the
hijacking of a cell.
Outline where in this process
the different types of
antibiotics would impact the
bacterium. Three
mechanisms: Cell Wall
synthesis, Replication,
Transcription/Translation
F.6.4
The “life cycle” is a somewhat
ambiguous term, considering viruses
are not necessarily “alive.”
F.6.5
Epidemiology Propaganda Posters
You and a group must research one of the five greatest pandemics in human
history:
The Black Plague
The Spanish Flu
The Plague of Justinian
The Antonine Plague
HIV/AIDS (1980)
Your goal is to inform the citizens of that time period of the dangers of the
plague, based on your research. You intend to travel back in time to disperse
these posters, and hopefully mitigate these pandemics as best you can.
You should address the following in at least two well designed, charismatic
posters: The origin
The transmission
The methods of control
Have fun with this – use language and dialect of the time as much as is
appropriate.
F.6.7, 8
Life cycle of the Malaria plasmodium.
F.6.9
The life cycle of the malaria parasite is a two-fold
process, that requires the use of a mosquito for in
order for full maturation to develop.
Once matured – sporozoites are able to infect
hepatocytes and infect humans.
https://www.youtube.com/watch?v=qMNmOsl5_e4
Malaria rates across the world
http://www.who.int/malaria/media/world_
malaria_report_2014/en/
The Prion Hypothesis
F.6.10
1982
Recent Years
1950s
Pygmies - Kuru
1920s
Scrapie – a
spongiform
encephalopathy
found in sheep
1986
All because of this guy…
Creutzfeldt-Jakob Disease
Mad- Cow Disease
Bovine Spongiform
Encephalopathy