Lecture 5: Microbial Pathogenicity & Immunity

Question 1

Define pathogenicity

Answer 1

the ability to cause disease by overcoming host defense

Question 2

Define virulence

Answer 2

the degree of pathogenicity. To cause a disease most pathogens must gain access to host, adhere to host tissue, penetrate or evade host defense, and damage host tissue

Question 3

What are the main portals of entry?

Answer 3

1. Mucous membranes
2. Skin
3. Parenteral route (deposited directly into tissues when barriers are penetrated)
   - Most pathogens have a specific portal of entry

Question 4

Talk about the mucous membrane portal of entry.

Answer 4

Most bacteria gain access to body by penetrating mucous membrane lining of:
Respiratory tract (most frequently used)
Gastrointestinal tract
Genitourinary tract
Conjunctiva
Diseases cause by respiratory tract:
Common cold, pneumonia, tuberculosis, influenza and measles
Diseases of mucous membrane of conjunctiva:
Conjunctiva, trachoma and ophthalmia neonatorum