L4: General Epidemiology of Communicable Diseases (Immunity Levels of Prevention) Flashcards
Def of Immunity
Defense mechanisms that protect from microorganisms & harmful agents
Types of Immune Defenses
- Innate
- Acquired
what is Innate Immunity?
Do not depend on previous exposure to infection.
Examples of Innate Immunity
- Intact skin & mucous membranes.
- Coughing & sneezing blinking reflexes
- GIT: Normal bacteria flora - Gastric acidity
Types of Acquired Immunity
- Naturally acquired
- Artificially acquired
Types of Naturally acquired immunity
- Passive
- Active
Types of Passive naturally acquired Immunity
- Trans-Placental
- Mother’s Milk
Trans placental immunity
- During last weeks of pregnancy
- Immune mothers transfer IgG to fetus.
- Infant will be immune for 6-9 months.
Examples of Trans placental immunity
measles, polio & chicken pox
Mother’s milk immunity
- IgA, lysozymes, macrophages are secreted in colostrum & breast milk.
- Gives protection for 6 months.
types of Active immunity
Types of Artificially Acquired Immunity
- Passive (Seroprophylaxis)
- Active
Characters of Passive Artificially Acquired Immunity
- Using serum contains immunoglobulins (g) or lymphocytes.
- Used in prophylaxis or treatment & before or after exposure.
- Gives Rapid but short-time protection.
Types of Passive Artificially Acquired Immunity (Seroprophylaxis)
- Animal (Heterogenous)
- Human (Homogenous)
Compare between animal & Human Passive Artificially Acquired immunity in terms of:
- Preparation
- Advantages
- Disadvantages
- Types
what are types of human immunoglobulins?
- NHI
- SHI
Compare between NHI & SHI in trems of:
- Preparation
- Uses
Types of active artificially acquired immunity
- Live
- LAV
- Killed or Inactivated
- Toxoid
- Conjugate
- Subunit
Live Vaccines
Small pox vaccine prepared from cow pox virus
Compare between LAV & Killed vaccine Vaccines
in terms of:
- Preparation
- Efficacy
- Doses
- Immunosuppresed?
- Examples
Toxoid Vaccines
- Prepared from detoxicated exotoxin.
- Loss toxicity but retain antigenicity.
- E.g. Diphtheria & Tetanus.
Conjugate Vaccines
- Meningococcal vaccine → capsular polysaccharide.
- Pneumococcal vaccine → Capsular polysaccharide.
Subunit Vaccines
Surface antigen - For viral B hepatitis → Two types:
- HBAg from plasma of chronic carries.
- Genetic engineering in yeast cells.
Hazards of immunization
Contraindications to child vaccination
Def of Herd Immunity
- State of immunity in a group or community.
- It represents resistance of group to spread of infectious agent d.2 immunity of high proportion of persons in this group.
Principle of Herd Immunity
- If large proportion of population is immune → the entire population is likely protected because chance is small that an infected person will encounter a susceptible person.
Requirment of Herd Immunity
Herd immunity is optimal when population is randomly mixed (no clustering of susceptible persons).
levels of prevention
1ry & 2ry & 3ry
1ry Level of Prevention
General Measures
1ry Level of Prevention
Specific Measures
1ry Level of Prevention
Chemoprophylaxis
1ry Level of Prevention
Disadvantages of Chemoprophylaxis
2ry Level of Prevention
3ry level of prevention
Rehabilitation
3ry level of prevention
