DOH133 Lecture Notes - Lecture 3: Prostaglandin, Escherichia Coli, Thermostat
Explain the methods of disease transmission
1. Contact Transmission
- Direct – requires close association between infected and susceptible host
- Indirect – fomites – living on items
- Droplets
2. Vehicle transmission of disease
- Food
- Water
- Air
3. Vector transmission of disease
- Arthropods, especially fleas, ticks, and mosquitoes
- Mechanical transmission – Arthropod carries pathogen on feet
- Biological Transmission – pathogen reproduces in vector
Explain how nocosomial infections can be prevented
1. Aseptic techniques
2. Contaminated material disposal
3. Frequent hand washing
4. Prescription of antibiotics only where appropriate
5. Monitoring/sampling of clinic items (instrument sterility)
Mechanisms of Microbial Pathogenicity
What is the difference between ID50 and LD50
ID50: Infectious dose for 50% of the test population
LD50: Lethal dose (of a toxin) for 50% of the test population
-The lower the LD50, the more virulent the population
How do bacterial pathogens damage host cells?
1. Using the host nutrients
2. Causing direct damage
3. Producing toxins
4. Inducing hypersensitivity reactions
Name a common A/B toxin and explain the general function of the A & B
domains of these toxins.
- Clostridium Botulinum
- Clostridium tetani
- Exotoxin
Document Summary
Explain the methods of disease transmission: contact transmission. Direct requires close association between infected and susceptible host. Indirect fomites living on items: vehicle transmission of disease. Mechanical transmission arthropod carries pathogen on feet. Biological transmission pathogen reproduces in vector. Explain how nocosomial infections can be prevented: aseptic techniques, contaminated material disposal, frequent hand washing, prescription of antibiotics only where appropriate, monitoring/sampling of clinic items (instrument sterility) What is the difference between id50 and ld50. Id50: infectious dose for 50% of the test population. Ld50: lethal dose (of a toxin) for 50% of the test population. The lower the ld50, the more virulent the population. How do bacterial pathogens damage host cells: using the host nutrients, causing direct damage, producing toxins, inducing hypersensitivity reactions. Name a common a/b toxin and explain the general function of the a & b domains of these toxins. The ab toxins are two component protein complexes secreted by a number of pathogenic bacteria.
