Week 2: Infection Control

Question 1

Chain of infection

Answer 1

1: Pathogen agent
2 Reservoir (source
3 portal or exist
4 Method of transmission
5 Portal of entry to the susupectible host
6 Susceptibe host

Question 2

First link: aetiology agent

Answer 2

Bacteria- pneumonia, tuberculosis
Viruses; influenza, chicken pox
Fungi; thrush, athletes foot
Protozoa; malaria, giardia
Parasites; lice, scabies

Question 3

Bacteria

Answer 3

Commensals or normalflora
* Pathogenicbacteria contribute to a number of diseases e.g.
– Tuberculosis; pneumonia; bacterial meningitis
* Antibiotics
* Vaccines

Question 4

Viruses

Answer 4

Examples of viral disease: * HIV
* Measles, Mumps, Rubella * Poliomyelitis
* Smallpox
* COVID-19
* Antibiotics don’t work * Antiviral medications * Vaccines

Question 5

Fungi

Answer 5

Superficial fungal infections = usually not dangerous
* Systemic/internal fungal infections = sometimes deadly
* Examples:
– Candidiasis(thrush)
– Athletesfoot
– Pneumocystispneumonia
* Antifungal medications (side effects)
* Treatments that eliminates bacteria give the fungi a change to flourish

Question 6

Protozoa

Answer 6

Examples of disease: – Malaria
– Giardia
* Antiprotozoal medications
* Treat symptoms e.g. dehydration
* Eliminate vectors such as mosquitos

Question 7

Parasite

Answer 7

WIDE RANGE of size, complexity, habits
* Parasites live by taking what they need from their host
* Most parasites don’t benefit by killing their hosts
* Helminths include roundworms, tapeworms and flukes

Question 8

How to break first link

Answer 8

Kill the pathogen:
– Antibiotics
– Antivirals
– Disinfectants – Heat

Remove the pathogen:
– Biohazard waste – Burning
– Burial

Question 9

Herd immunity

Answer 9

occurs when a large portion of a community (the herd) becomes immune to a disease

Question 10

Reservoir: Send Link

Answer 10

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 11

Portal of exit: How the pathogen gets
out of the reservoir

Answer 11

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 12

How to break 3rd link

Answer 12

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 13

Mode of transmission: