Communicable Disease Basics

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Communicable Disease Basics
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Objectives

• Describe three ways infectious agents can be
  transmitted
• Describe at least three ways to decrease risk of
  infections in public settings
• List three examples of common infectious diseases
  and how to reduce risk of infection

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Chain of Infection
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Chain of Infection

• Model used to understand the infection process
• Each link represents step in transmission of
  infection
• Each link has to be present and in order for an
  infection to occur

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

• Bacterial
• Viral
• Fungal
• Parasitic

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2 - The Reservoir
-Where a microorganism normally lives and
reproduces
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Examples of reservoirs

• Humans
• Animals
• Water
• Food

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

• Flu or cold - mucous secretions
• West Nile Virus - when the mosquito bites and
  feeds on the birds blood
• Hepatitis A - stool
• SARS - droplet, contact

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4 - The Route of Transmission (Spread)
-the way the pathogen gets from the reservoir to
the new host
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TransmissionRespiratory 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 lt 3 feet)
• Many diseases spread by respiratory droplets
  e.g. flu, cold, pertussis, SARS
• Can spread germs directly or indirectly

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Droplet Transmission
Agent is coughed or sneezed out into the air and
floats on droplets
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Direct Spread by Droplets

• Close contact with infected person (lt3 ft)
• Infected person coughs, sneezes, talks, sings
• Droplets land directly on mucous membranes (eyes,
  nose, mouth) of susceptible person

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Indirect Spread by Droplets
Droplets with the infectious agent land on a
table, doorknob etc.
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Indirect Spread by Droplets
Someone touches contaminated object
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Indirect Spread by Droplets
Touch nose, mouth, eyes with contaminated hand
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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

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Airborne - This Needs to be Breathed in to be
Infectious
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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

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Other Methods of Transmission

• Food/water/hands contaminated with stool from
  infected person e.g., norovirus
• Blood exposures, sexual contact
• a.k.a. blood-borne e.g. HIV, hepatitis B and C
• Vector-borne
• E.g. Mosquitoes and West Nile virus, malaria
• Unlikely methods of spread in courtroom

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What Do You Need to Do?

• Make sure that you have available for staff and
  patient use an adequate supply of
• surgical masks
• tissues
• alcohol hand rub
• trash cans with foot pedals to lift lid for
  disposing of tissues/masks

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

• Inhale germs

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Other Portals of Entry
Sexual contact
Ingestion
Breaks in Protective Skin Barrier
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6 - The Susceptible Host
-A person who can get sick when they are exposed
to a disease causing pathogen
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How to Break the Chain of Infection
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What Is the Purpose of Respiratory Hygiene?

• To reduce the transmission of airborne diseases

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Hand Hygiene

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

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Use gloves where contact with body secretions and
excretions is taking place
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Cover Your Cough!
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Cough Etiquette

• Limit close contact (lt3 feet) with coughing
  clients
• Cover cough/sneeze with tissue
• Offer mask to coughing clients

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Keep a clean environment

• Clean contaminated surfaces with commercial
  germicidal cleanser or wipes

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Maintain vaccinations for employees

• Flu shot- every year for age gt50 and high-risk
  groups
• Tetanus shot every 10 years
• Hepatitis B for persons who may contact objects
  contaminated with blood
• Pneumovax (pneumonia vaccine) for age 65
• Hepatitis A

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What Are Some of the Airborne Diseases of Concern?

• Pertussis
• Tuberculosis
• Influenza
• Common colds

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Pertussis (Whooping Cough)

• Droplet and contact transmission
• Runny nose and prolonged severe cough
• A bacterial infection
• Most dangerous for babies
• Vaccine preventable for children aged 7 and under

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Tuberculosis

• Agent
• Caused by bacterium, Mycobacterium tuberculosis
• Reservoir
• Humans

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TB in King County
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Latent TB Infectionvs.Active TB Disease
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Latent TB Infection

• Person infected with TB bacteria
• Bacteria kept dormant by persons immune system
• Not sick or contagious
• 10 develop TB disease over life time
• Infection detected by TB skin test

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TB Skin Test (PPD)
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Active TBDisease

• Usually involves lung infection
• Cough gt3 weeks, fevers, weight loss, night sweats
• Can cause serious illness but is treatable with
  antibiotics
• Contagious until appropriately treated

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Preventing Spread of TB

• Patients with TB disease should delay court
  appearance until appropriate duration of therapy
• Patients with active TB are no longer contagious
  after 2-3 weeks of appropriate therapy
• should be cleared by doctor

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Influenza(Flu)

• Agent
• Virus
• Reservoir
• Humans
• Animals (e.g. birds, pigs)
• Generally different strains

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Flu TransmissionRespiratory Droplets

• Direct Close contact (lt3 feet)
• Droplets from cough/sneeze enter mouth, nose,
  eyes of susceptible person
• Indirect Contaminated surfaces
• Cases peak each winter in U.S.

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How Do I Protect Myself From the Flu?

• Flu Vaccine
• Recommended for
• Persons gt50 years old
• Anyone with a chronic illness, such as asthma or
  diabetes
• Children age 6-23 months
• Women who will be pregnant during flu season

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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

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What Can You Do to Reduce Your Chances of Getting
Sick?

• Encourage coughing clients 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
• Offer mask to coughing clients

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Recommendations

• Staff and clients should have access to
• Hand washing facilities
• Tissues
• Trash cans for disposing of tissues
• Consider having alcohol
• hand rub available

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QUESTIONS???