Communicable Disease Basics

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.

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

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

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

Infectious agents are: Bacterial Viral Fungal Parasitic

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

Examples of reservoirs: Humans Animals Water Food

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

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)

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

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

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

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 http://www.youtube.com/watch?v=RoEqPnx7-Gs&feature=related – Will my eyes pop out?

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

Indirect Spread by Droplets Someone touches contaminated object

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

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

Airborne - This Needs to be Breathed in to be Infectious

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

Respiratory System Inhale germs

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

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

How to Break the Chain of Infection

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

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

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

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

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

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.

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.

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. https://www.youtube.com/watch?v=gXIDTzusIEI 1. 2. 6. 5. 3. 4.