1. Communicable Disease Basics

2. What is the difference between a communicable and non-communicable disease?
Make a list of all the non-communicable diseases you can think of? Do the same for communicable diseases.

3. Chain of Infection Infectious Agent Infectious Agent Susceptible Host
Reservoir
Portal of Exit
Portal of Entry
Mode of Transmission

4. Chain of Infection Model used to understand the infection process
Each link represents step in transmission of infection
Each link has to be present in order for an infection to occur

5. 1 - The Infectious Agent
-any disease causing microorganism (pathogen)

6. Infectious agents are:
Bacterial
Viral
Fungal
Parasitic

7. 2 - The Reservoir
-Where a microorganism normally lives and reproduces

8. Examples of reservoirs:
Humans
Animals
Water
Food

9. 3 - The Portal of Exit
-route of escape of the pathogen from the reservoir.

10. Examples of portals of exit:
Flu or cold - mucous secretions
STI - mucous to mucous contact
Hepatitis A - stool
SARS - droplet, contact
Skin to Skin – Herpes (Type 1)

11. 4 - The Route/Mode of Transmission (Spread)
-the way the pathogen gets from the reservoir to the new host

12. Transmission: Respiratory Droplets
From respiratory tract (i.e., nose, mouth) secretions of infected person
E.g. cough, sneeze
Do not circulate in air for long time or travel far (mostly < 3 feet)
Many diseases spread by respiratory droplets; e.g. flu, cold, pertussis, SARS
Can spread germs directly or indirectly

13. Agent is coughed or sneezed out into the air
Droplet Transmission
Agent is coughed or sneezed out into the air
and floats on droplets

14. Direct Spread by Droplets
Close contact with infected person (<3 ft)
Infected person coughs, sneezes, talks, sings
Droplets land directly on mucous membranes (eyes, nose, mouth) of susceptible person
– Will my eyes pop out?

15. Indirect Spread by Droplets
Droplets with the infectious
agent land on a table, desk, light switch, doorknob etc.

16. Indirect Spread by Droplets
Someone touches contaminated object

17. Indirect Spread by Droplets
Touch nose, mouth, eyes with
contaminated hand

18. Airborne Transmission
Germs stay suspended in air on small particles
Uncommon method of transmission
Only occurs for certain germs, such as tuberculosis
Less commonly for flu, SARS

19. Airborne - This Needs to be Breathed in to be Infectious

20. 5 - The Portal of Entry
-route through which the pathogen enters its new host

21. Respiratory System
Inhale germs

22. Breaks in Protective Skin Barrier
Other Portals of Entry
Sexual contact
Ingestion
Breaks in Protective Skin Barrier

23. 6 - The Susceptible Host
-A person who can get sick when they are exposed to a disease causing pathogen

24. How to Break the Chain of Infection

25. Hand Hygiene
Wash hands frequently with soap and warm water for at least 20 seconds
Alcohol hand gels

26. Cough Etiquette Limit close contact
Cover cough/sneeze with tissue or elbow pit ☺

27. Keep a clean environment
Clean contaminated surfaces with commercial germicidal cleanser or wipes

28. What Is the Purpose of Respiratory Hygiene?
To reduce the transmission of airborne diseases

29. Habits for Good Health Avoid close contact with people who are sick
Stay home when sick
Cover mouth/nose with tissue when coughing/sneezing
Avoid touching nose, mouth, eyes
Wash hands often with soap/water or alcohol rub

30. What Can You Do to Reduce Your Chances of Getting Sick?
Encourage coughing friends to wash their hands (or use alcohol hand rub)
Wash your own hands frequently
Wipe down counters, pens, phones, computer keyboards, etc. with disinfectant cleaner as needed
Cough etiquette - cover with tissue
Eat healthy and have your vitamins.

31. Review Questions 1 & 2
#1. Explain how communicable disease are spread- use details and examples from the notes to strengthen your response. (You may draw a picture and use words to explain)
#2. What can you do to reduce your risk of getting sick? List a minimum of 3 tips.

32. Review
Directions: Name each stage in the chain of events (use your notes if you need to). While watching the video, document specific examples from the video of each stage. 1. 2. 6. 5. 3. 4.