1. KEY CONCEPT Germs cause many diseases in humans.

2. Diseases caused by germs, such as the E
Diseases caused by germs, such as the E. Coli bacteria can be fatal (death)
, the bacteria that caused the “Black Death” or the Plague originated from fleas on rats
Has killed approx.
100 MILLION
people
New diseases
HIV
SARS
Avian Flu (bird flu)
Swine Flu

3. Germ theory proposes that microorganisms cause diseases.
led to rapid advances in understanding disease
Can be infectious (polio, flu), caused by germs
or noninfectious (cancer, heart disease) caused by genes or lifestyle

4. Disease-causing agents are called pathogens.
What would happen if pathogens were eliminated?
We wouldn’t get sick

5. There are different types of pathogens.
Bacteria are single-celled organisms.
cause illness by destroying cells
release toxic chemicals
Exs:
E. Coli
Salmonella
“Food Poisoning”

6. Viruses are disease-causing strands of DNA or RNA that are surrounded by a protein coat.
Take over a healthy cell
Force cells to produce more of the virus
Smaller than bacteria
Exs:
HIV
Influenza
Herpes
*Common Cold
AIDS

7. Fungi can be multicellular or single-celled.
take nutrients from host’s cells
occur in warm and damp places
Ex: Athlete’s foot, yeast, mold

8. Protozoa are single-celled organisms
Prey on other cells
use host cells to complete their life cycles
take nutrients from host cell
Ex: Malaria, dysentery

9. Parasites are multicellular organisms.
grow and feed on a host
possibly kill the host
Ex: Heart worm
Round worm
Elephantiasis- mosquitos

10. Direct contact requires touching an infected individual. Includes:
Vectors any person or animal that carries and transmits a pathogen to another living organism.
Direct contact requires touching an infected individual. Includes:
kissing
sexual intercourse
hand shaking
bite
Ex:
Lime Disease- ticks
Malaria- mosquito
West Nile Virus- mosquito
Rabies- rabid animal
HIV- infected person
tick

11. Pathogens can enter the body in different ways.
Direct contact require an infected person or animal to physically touch a healthy person Ex: Rabies, HIV
Indirect contact does not require touching an infected individual.
touching an infected surface
breathing in infected air Ex: SARS Tuberculosis

12. Different pathogens cause common infectious diseases.