WEEK 2 - CHAIN OF INFECTION

Question 1

CAUSATIVE AGENT (PATHOGEN) - BACTERIA

Answer 1

• Commensals or normal flora
• Pathogenic bacteria contribute to a number of diseases
  · e.g. Tuberculosis; pneumonia; bacterial meningitis
• To prevent: Antibiotics and Vaccines

Question 2

CAUSATIVE AGENT (PATHOGEN) - VIRUS

Answer 2

• Viral disease:
  · HIV
  · Measles, Mumps, Rubella
  · Poliomyelitis
  · Small pox
  · Covid-19
• Antibiotics don’t work
• To prevent: Antiviral medications and Vaccines

Question 3

CAUSATIVE AGENT (PATHOGEN) - FUNGI

Answer 3

• Superficial fungal infections = usually not dangerous
• Systemic/internal fungal infections = sometimes deadly
• Examples:
  · Candidiasis(thrush)
  · Athletes foot
  · Pneumocystis pneumonia
• To prevent : Anti-fungal medications (side effects) and Treatments that eliminates bacteria

Question 4

CAUSATIVE AGENT (PATHOGEN) - PROTOZOA

Answer 4

• Examples of disease:
  · Malaria
  · Giardia
• To prevent: Antiprotozoal medications, Treat symptoms e.g. dehydration
  and Eliminate vectors such as mosquitos

Question 5

CAUSATIVE AGENT (PATHOGEN) - PARASITE

Answer 5

• Examples:
• Lice
• Scabies
• Roundworms
• Tapeworms
• Parasites live by taking what they need from their host

Question 6

HOW DO WE BREAK THE FIRST LINK - CAUSATIVE AGENT

Answer 6

• Kill the Pathogen:
• Antibiotics
• Antivirals
• Disinfectant
• Remove the Pathogen:
• Biohazard waste
• Burning
• Herd Immunity

Question 7

THE RESERVOIR - SOURCE

Answer 7

• Where pathogens hang out
• Food, water, animals, people, environmental surfaces

Question 8

HOW DO WE BREAK THE SECOND LINK - THE RESERVOIR

Answer 8

• Eliminate the reservoir (sources), e.g. food, animals, people
• Isolate the reservoir from the at-risk population
• Treat the reservoir -vaccine, filtration of water supplies

Question 9

PORTAL OF EXIT

Answer 9

• Specific to the reservoir:
• Coughing, sneezing, bleeding, breathing, defaecating, urinating etc.
• The bite of a vector species
• Humans error e.g., spills
• Mechanical failure e.g., faulty filtration; wet masks

Question 10

HOW DO WE BREAK THE THIRD LINK - PORTAL OF EXIT

Answer 10

• Block the pathogen as it leaves the reservoir e.g. cough etiquette; care with body fluids
• Remove access - prevent humans from accessing contents of reservoir
• Eliminate outlet from reservoir - e.g. spill prevention

Question 11

ROUTE OF TRANSMISSION

Answer 11

• Direct Contact:
  -Skin to skin
• Mucous membranes
• Droplet:
• Sneezing
• Coughing
• Vertical Transmission:
• Mother to baby
• Airborne:
• Particles in the air

-Vehicle-borne:
- Agent transferred by inanimate object e.g. pen

• Vector-borne:
• Vector such as mosquito

Question 12

HOW DO WE BREAK THE FOURTH LINK - ROUT OF TRANSMISSION

Answer 12

• Standard Transmission
• Transmission-based Precautions
• Stay home, if sick

Question 13

PORTAL OF ENTRY

Answer 13

-Cut with open wounds
- IV sites
- urinary catheters
- respiratory tract
- broken skin

Question 14

HOW DO WE BREAK THE FIFTH LINK - PORTAL OF ENTRY

Answer 14

• Care for your skin
• Beware of sharps
• Use appropriate Personal Protective Equipment (PPE)
• DON’T touch your eyes, nose, mouth or other mucus membranes unless you have JUST washed your hands

Question 15

SUSCEPTIBLE HOST

Answer 15

• This is anyone at risk of infection due to:
• Impaired immune system
• Impaired integumentary system
• e.g. old, young and patients with low immunity

Question 16

HOW DO WE BREAK THE SIXTH LINK - SUSCEPTIBLE HOST

Answer 16

• Employing appropriate precautions to protect those with low immunity
• Vaccination – herd immunity
• Use appropriate Personal Protective Equipment (PPE)