1. Pathogens
Agents of Disease

2. I. Overview
Disease
Any change, other than an injury that interferes with the normal functioning of the body
Pathogen
Disease causing microorganisms
Relationship is that of parasite and host with organism it infects
4 types: virus, bacterium, fungus and protozoan

3. II. Agents of Disease Viruses
Infects by attaching to cell surface and injecting genetic information
Common diseases: chicken pox, cold, influenza, mononucleosis, measles, mumps, polio etc.
Bacteria
Produce disease by directly infecting body tissues and/or producing toxins
Common diseases: gonorrhea, diptheria, lyme disease, meningitis, tuberculosis, pneumonia etc.

4. II. Agents of Disease Fungi Most infections occur on skin
Common diseases: athletes foot, ringworm, San Juaquin Valley fever etc.
Protozoans
Commonly found in the tropics where conditions are ideal for growth
Common diseases: malaria, amebic dysentery, African sleeping sickness etc.

5. III. Biology of Viruses Bacteriophage Structure
Head (capsid + nucleic acid) and tail

6. III. Biology of Viruses Lifecycle of a Lytic Virus
Infection, growth, replication, lysis

7. III. Biology of Viruses
Lifecycle of a Lysogenic Virus

8. IV. Biology of Bacteria Structure of a Typical Bacteria
Cell wall, cell membrane, genetic material, cytoplasm, flagella
Classified as rod (bacilli), sphere (cocci) or spiral (spirilla)

9. IV. Biology of Bacteria Bacterial Reproduction
Binary fission (asexual)
Conjugation (sexual)

10. V. Identifying Agents of Disease
Bacterial Diseases

11. V. Identifying Agents of Disease
Viral Diseases