Chain of Infection: Steps 2-6

Question 1

List in order the 6 stage of the Chain of Infection.

Answer 1

Infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host

Question 2

List 3 major reservoirs of diseases that infect humans.

Answer 2

Humans, animals, soil and water

Question 3

Diseases that are transmitted from animals to humans are called ______.

Answer 3

Zoonoses

Question 4

What is a portal of exit?

Answer 4

How an infectious microorganism leaves the reservoir/human body

Question 5

List 3 human portals of exit. (body systems)

Answer 5

Respiratory System, Digestive System, Reproductive System, Urinary System, Skin and Blood

Question 6

List infectious diseases associated with each reservoir (animals, soil, water)

Answer 6

Animals - SARS, ringworm
Soil - Clostridium (causes tetanus) Legionella
Water - Giardiasis, Hep A, Polio

Question 7

Define a portal or entry

Answer 7

The path which infectious microorganisms gain entry to a new host.

Question 8

List the main human portals of entry

Answer 8

Inhalation, ingestion, absorption, break in skin, introduction by medical procedure

Question 9

State key standard precaution measures aimed at breaking the chain of infection at both the ‘exit’ and ‘entry’ link

Answer 9

Exit - PPE, hand hygiene, cough etiquette

Entry - PPE, patient placement, isolation, hand hygiene

Question 10

What are the 3 main modes of transmission?

Answer 10

Contact (Direct, indirect and droplet transmission), common vehicle (via air, water, food) and vector (mechanical and biological)

Question 11

List 5 strategies to prevent disease transmission.

Answer 11

Sanitation, hygiene practices, immunisation, isolation, treatment

Question 12

What does sanitation mean?

Answer 12

Provision of clean and/or treated water, refuse collection and disposal including sewage treatment.

Question 13

What do young people, the elderly, chronically ill people, people receiving treatment, pregnant people, people with open wounds/burns and the homeless have in common?

Answer 13

They are susceptible hosts.

Question 14

What are a few ways to help protect susceptible hosts?

Answer 14

Standard precautions, treat underlying health issues, vaccination, education, isolation.

Question 15

What are some limitations to anitbiotics?

Answer 15

• Not effective against viruses
• Side effects
• Antibiotic resistance

Question 16

Why do antibiotics not harm human cells?

Answer 16

Antibiotics target prokaryote cells and humans have eukaryote cells

Question 17

State the main causes of antibiotic resistance

Answer 17

Used widely, rapid growth and mutation rates of bacteria, susceptible bacteria dying off, leaving resistant bacteria to multiply.