Essential Questions:
How can healthcare workers identify the source of the illness so that it can be prevented and treated?
Haiti was devastated by an earthquake in 2010 and lost most of its infrastructure.
6 months later, people began suffering from diarrhea and dehydration.
Pathology - the scientific study of the nature of disease and its causes
A PATHOGEN is any disease causing agent.
Quick Exercise: How many diseases can you think of?
Other diseases are not contagious:
cancer, lupus, arthritis, allergies
This unit will focus on the first type: the disease, its agents, treatment and history and will cover three main areas of pathology and how the immune system responds to these threats
1. Viruses (virology)�2. Bacteria (bacteriology)�
Some diseases are communicable, such as: AIDS, influenza, chicken pox.
Symptom - evidence of damage to the host (headache)�
Virulence - a measure of pathogenicity, which is the ability to cause disease
Infectious disease - disease that can be transmitted by the host to another host or vector
Disease - an upset in the homeostasis of the host, resulting in generation of observable changes and/or damage to host
Epidemic - when a disease affects a community
Pandemic - when a disease affects the world�Endemic - when a disease is regularly found in a group or region.
Play Pandemic 3
or Plague Inc
Can you think of any themes in pop culture that relate to diseases?
- movies
- games
- tv shows
Disease Categories �
Food and Waterborne - pathogen is in a food or water source (Cholera, E. coli)
Blood Borne - carried in blood or other bodily fluids (HIV, Hepatitis)�Airborne - carried by the air, often affect respiratory tract (Influenza, Common cold)
�Sexually Transmitted - transmitted by sexual contact (Syphilis, Gonorrhea, Herpes)
Zoonotic - carried by animals (Rabies)
�
Organizations Dealing with Health -
Koch's Postulates
If a microorganism is the causative agent of an infectious disease, it must be:
Back to Haiti…...
How would you use Koch’s postulates to identify the cause of the disease in Haiti?
Doctors in Haiti were able to isolate a bacteria from each of the patients.
What is the next step to establish that this particular bacterium is the one causing the illness?
Are there ethical questions to consider here?
This bacterium is Vibrio cholerae, a pathogen that is well known for causing diarrheal disease.
Influenza Pandemic of 1918
[Image: An emergency hospital ward in Kansas during the 1918 flu]
The Germ Theory (around 1860)
*Why is this a theory and not a fact?
Louis Pasteur - developed the germ theory and disproved spontaneous generation, in 1885 he developed the rabies vaccine
Where have you seen the word “pasteurization” ?
Now that you are fairly sure it is cholera causing the disease. The next step would be to establish how the disease is being transmitted. Though we do know now how this disease is transmitted, historically, scientists would not have known.
How would you determine which was the mode of transmission?
1. Water
2. Food
3. Air / Close Contact
4. Blood / Body Fluids
John Snow - The “Father of Epidemiology”
A cholera outbreak in London (1854) prompted John Snow to attempt to discover how the diseases was being spread.
His main tool for investigation was….
A MAP!
How would a map help you find the source of an infection?
Essential Questions:
How can healthcare workers identify the source of the illness so that it can be prevented and treated?
Haiti was devastated by an earthquake in 2010 and lost most of its infrastructure.
6 months later, people began suffering from diarrhea and dehydration.
Some other interesting historical figures:
Edward Jenner
Jonas Salk
Ignaz Semmelweis
Alexander Fleming
Joseph Lister
Emerging Infectious Diseases
infections that have recently appeared within a population or those whose incidence is rapidly increasing. Often, these infections have never been seen before.
“Flatten the Curve”
During the 2020 Pandemic of Covid-19, health officials called for social distancing to “flatten the curve.”
What does that mean?
The story of how Edward Jenner developed the first vaccine.
Semmelweis and Lister - antiseptics and childbed fever and the power of washing your hands
Jonas Salk -polio vaccine