1. Infectious Disease
40-1

2. What is Disease?
Tell me what you think…

3. What is Disease? Disease
Any change in the body, other than injury, that disrupts the normal functions of the body
Disease has many causes
Bacteria
Viruses
Environmental Factors (cigarette smoke, pollution)
Genetics

4. Koch’s Postulate Koch said:
Disease is caused by microorganisms and NOT by curses, evil spirits or night vapors
Yes, for thousands of years, people believed that diseases were caused by those things.

5. Infectious Disease Infectious = can be passed from person to person
Pathogens
Cause disease
EX:
Bacteria
Viruses
Protists
Worms

6. Bacteria Single Celled living organisms
Asexual reproduction
Multiply by themselves
Can easily be seen with a microscope!!
Live & breed in warm, moist environments
Prokaryotes: no nucleus

7. Bacteria and Humans Most bacteria = harmless Good for humans!
many places on our bodies
Intestines…digestion

8. Bacteria as Pathogens Bacteria as Pathogens Break down tissues
Release toxins
EX:
Streptococcus (Strep Throat)
Diptheria
Botulism
Anthrax
E. coli (found in food)

9. Bacteria

10. Treatments for Bacterial Infection
Antibiotics
Kill bacteria, but not body cells
Interfere with the cellular processes of the bacteria
One antibiotic will kill many different kinds of bacteria
Examples: Penicillin, Amoxicillin

11. Virus 1000 times smaller than bacteria!!
Cannot be seen with a microscope
Cannot live or reproduce on their own
Must invade a host cell
Contain RNA or DNA but none of the equipment to reproduce

12. Virus Pathogenic Mutate often Examples: Common cold Influenza Smallpox
Warts
HIV

13. Virus

14. Treatments for Viral Infection
Best treatment:
Rest
Water
No help from Doc!
Antibiotics are NOT effective against viruses because the virus live within your own body’s cells.

15. Why you feel sick when you have an infection
Symptoms caused by your body’s response to the infection
Fever
kill the pathogen
Vomiting, Runny nose, coughing
physically remove the pathogen
You feel tired because your body is working overtime fighting the infection

16. In Review An Infectious Disease is A Pathogen is Bacteria Virus
Disease that can be passed from person to person
A Pathogen is
A disease causing agent
Bacteria
Single-celled living organisms
Killed by Antibiotics
Virus
Tiny particles, need host cell in order to replicate
Antibiotics are INEFFECTIVE