Section 5 Communicable Diseases

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Section 5 Communicable Diseases

• N205 2009

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History of Communicable diseases

• 1720, 1st quarantine in Canada for bubonic plague
• 16th Century, Europeans bring infectious disease
  to Canada and to Aboriginal peoples (STIs, TB,
  influenza, measles, mumps, smallpox)
• 18th and 19th centuries, Industrial revolution
  with overcrowding, poor sanitation, contaminated
  water - led to communicable disease
• 1900 communicable diseases were the leading
  causes of mortality in Canada
• Presently improved nutrition and sanitation,
  vaccines, and antibiotics have had a huge impact
  in relation to communicable diseases

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Current perspective

• Infectious diseases have not vanished
• Organisms once susceptible to antibiotics are
  becoming increasingly drug resistant
• New killers are emerging, and old familiar
  diseases are taking on different, more virulent
  characteristics

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Infection and disease

• Infection Refers to the entry, development and
  multiplication of the agent in the host.
• Disease One of the possible outcomes of
  infection.
• Ex A person can test positive with HIV and not
  have the disease of AIDS or be infected and have
  the disease
• Communicable means that the disease is capable of
  being transmitted to another.
• All communicable diseases are infectious diseases
  not all infectious diseases are communicable
  diseases.
• What is an example of a vaccine preventable
  disease that is not communicable?

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Etiology

• The science and study of the causes of disease
  and their mode of operation.

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New infectious diseases

• Some examples?

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Communicable diseases

• 1. Vertical transmission
• Passing an infection from parent to offspring
  through sperm, placenta, milk, or contact in the
  vaginal canal at birth
• 2. Horizontal transmission
• Person-to-person spread of infection
• Can happen by
• Direct / indirect contact
• Common vehicle
• Vector-borne

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Communicable diseases

• Incubation The time interval between invasion by
  an infectious agent and the first appearance of
  signs and symptoms of the disease. The time is
  variable from a few hours with a food borne
  disease to years with a disease such as AIDS.
• Communicable The time interval during which an
  infectious agent may be transferred directly or
  indirectly from an infected person to another
  person.
• For some diseases, a person can be communicable
  before the appearance of signs and symptoms.
• From a CHN perspective why would the above
  information be important to know?

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Examples of incubation periods and communicable
periods
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Major infectious diseases by means of transmission
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Portal of entry

• Respiratory
• Oral
• Reproductive
• Intravenous
• Urinary
• Skin
• Gastrointestinal
• conjunctival

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Food borne diseases

• Often categorized as food infection or food
  intoxication
• Food infections can be bacterial, viral, or
  parasitic
• What is an example of a food infection disease?

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Food intoxication

• Results from toxins produced by bacterial growth
  or Chemical contaminants (e.g., heavy metals)
• A variety of disease-producing substances
  naturally found in certain foods.
• What are some examples?

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Water borne Diseases

• What are some examples of water borne diseases?

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Zoonoses

• Animals can be a source of infectious diseases in
  humans. More than 185 diseases have been shown to
  be transmitted to humans from animals.

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Influenza Virus

• Acute, highly infectious, respiratory illness
  caused by the influenza virus.
• There are 3 types of influenza virusesA,B,and C.
• The viruses are transmitted among humans by
  respiratory secretions through sneezing,coughing,a
  nd contact with contaminated articles.

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Influenza virus
Virus contains 2 surface proteins Haemagglutinin
(H) Neuraminidase (N)
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Influenza virus strains

• Type Amoderate to severe illness
• all age groups
• humans other animals
• cause pandemics
• Type Bmilder epidemics
• humans only
• primarily affects children
• Type Crestricted to humans
• no epidemics

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Communicability

• Adults are typically infectious the day before
  symptoms start through 5 days after onset
• Children can be infectious for gt 10 days, while
  young children can shed virus for lt 6 days before
  illness onset

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Pandemic Influenza
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Pandemic Influenza

• A new influenza virus arising from a major
  genetic change antigenic shift or adaptive
  mutation
• The population will be very susceptible with
  little or no immunity

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Pandemic

• 1918-1919
• Spanish Flu,H1N1
• 20-40 million deaths worldwide
• 99 of deaths among
• those lt65 yrs

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Pandemic 1957-58

• Asian flu,H2N2
• Worldwide excess mortalitygt2 million
• 1957,incidence was greatest in school age,young
  adults,pregnant.
• 1958,2nd wave impacted those gt65yrs
• Most mortality was among those compromised

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Pandemic 1968-69

• Hong Kong flu,H3N2
• Mildest of the 3 Pandemics
• Global excess deaths 1 million
• People gt65 yrs most affected

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Impact of pandemic (2006)

• 75 of people will be infected
• 15-38 will be clinically ill
• 6.8-17 will require outpatient care
• 0.1-0.3 will require hospitalization
• 0.03-0.1 will die
• Based on CDC Flu-aid formula

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Impact Nova Scotia (2006)

• 681,005 will be infected
• 136,201-345,042 will be clinically ill.
• 61,744-154,361 will require outpatient care
• 908-2724 will require hospitalization
• 272-908 will die
• Stats Canada 2001

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Impact on GASHA CBDHA (2006)

• 132,000 will be infected
• 26,400 to 66,880 will be clinically ill
• 11,968 to 29,920 will require outpatient care
• 176-528 will require hospitalization
• 53-176 will die
• Approximate population of 176,000

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Preventable strategies

• Get the flu vaccine
• The influenza vaccine will help the body build
  antibodies to fight influenza infections and can
  prevent the mixing of influenza viruses.
• Cover the mouth and nose when sneezing or
  coughingUse a tissue or cough into your elbow to
  avoid getting droplets on your hands.
• Wash hands frequently
• Use soap and water for at least 15 seconds, or
  use an alcohol-based hand cleaner.
• Do not go to work when ill If you have a cough
  and a fever, it is best to rest at home. This
  will speed recovery and help prevent the spread
  of infection.
• Practice good health habits to encourage a strong
  immune systemGet plenty of sleep, keep
  physically active, manage stress, drink plenty of
  fluids and eat nutritious foods.

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Solution
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Pandemic planning

• Components of plans
• Surveillance
• Vaccines
• Antivirals
• Public Health Measures
• Health Services
• Emergency Planning
• Communications
• Canadian pandemic planning
• http//www.hc-sc.gc.ca/pphb-dgspsp/cpip-pclcpi/ind
  ex.html

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Vaccine preventable Infectious diseases

• Need to know the diseases that are vaccine
  preventable, both lay terms and medical term.
• This is an evolving area where new vaccines are
  being developed.

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In Class Group assignment Vaccine preventable
diseases Table 15-4 Textbook

• Before you look up anything on the disease, have
  a discussion on what you think you know about the
  disease, have each person in the group identify
  one assumption about the disease. Ex I think
  that rabies has something to do with dogs.
• What are the main symptoms of the disease?
• What is the agent that causes the disease?
• What is the occurrence (epidemiology) of the
  disease in Canada?
• How is it transmitted?
• Go back to your assumptions truth/false.

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Why we immunize

• Vaccines save lives A public health success
  story
• Vaccines are safe (benefits outweigh risks) and
  effective, while vaccine-preventable diseases
  can cause permanent disability or even death ie
  german measles cause birth defects in children
• Its a small world Travel can spread
  comparatively rare diseases very quickly
• Some diseases, like tetanus, are spread via the
  environmentimmunization is the most effective
  method of prevention
• For many vaccine-preventable diseases, there are
  no effective treatments

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Immunization

• Immunization programs are considered to be the
  most cost-beneficial health intervention and one
  of the few that systematically demonstrate far
  more benefits than costs ( Health Canada, 2007).

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Immunology 101

• Immunology 101
• Bacteria and viruses have unique proteins and
  polysaccharides (complex sugars) on their
  surfaces called antigens which can replicate
  themselves in a matter of hours
• The immune system targets antigens
• Lymphocytes that produce antibodies against the
  antigen, the reaction is contained in Memory
  cells that enable the immune system to recognize
  germs it has seen before creating immune memory
• Long-lasting immunity depends on memory cells
• Immune memory is specific to a particular germ
• Immunity The ability the immune system acquires
  to identify the presence of a germ and destroy
  it
• Two ways to achieve immunity 1 Natural infection
  or 2 immunization
• Natural infection causes illness and can lead to
  complications, permanent damage. Severe cases
  can result in death

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How do Immunizations work?

• Vaccine contains the agent (virus or bacteria)
  but it has been modified so that it doesnt
  replicate well or doesnt replicate at all. After
  the first vaccine is given to a person, the body
  produces antibodies in small concentrations (The
  primary response).
• When subsequent injections of the same antigen
  are given, the body recognizes the antigen and
  antibodies are produced much faster and in higher
  concentration (the secondary response)
• Once the initial series is completed, boosters
  are often required to maintain an adequate
  concentration of antibodies.
• Vaccines protect without causing severe illness
  called active immunization
• Passive immunization
• Herd immunity

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Immunology of vaccines

• Types of Vaccines

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Vaccine success in Canada

• Summary of diseases and vaccines, Canada

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Risks and benefits of vaccines

• Summary of diseases and vaccines, Canada

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Vaccine success stories

• Smallpox has been eradicated. No cases anywhere
  in the world since 1979
• Children are no longer vaccinated against
  smallpox
• Paralytic polio
• - Eliminated from the Western hemisphere,
  Western Europe, Australia, New Zealand,
  Japan, China, Indonesia, Southeast Asia
• Global eradication campaign underway Cases have
  dropped from 350,000 in 1988 to 20,000 in 1999
• Polio will only be completely eradicated if all
  children are vaccinated
• Source Canadian pediatric society 2006

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Why we (still) immunize

• When vaccination rates decline, rates of disease
  increase
• Example In the late 1980s, states in the former
  Soviet Union saw vaccine supplies disrupted,
  collapse of public health system and
  socioeconomic instability
• Result Decrease in childhood immunization rates
• Diphtheria epidemic followed more than 150,000
  cases and more than 4,000 deaths in the newly
  independent and Baltic states
• Mass vaccination program eventually controlled
  the epidemic
• Lesson Complacency can be fatal

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Contraindications to Immunizations

• Minor acute illness is not a contraindication.
• Immunization should be deferred with moderate or
  acute febrile illnesses because the reactions may
  mask the symptoms of the illness.
• The side effects of the immunization may be
  accentuated by the illness.

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Vaccine preventable diseases

• What are some of the issues involving vaccine
  preventable diseases today?

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Vaccine preventable diseases
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Vaccine preventable diseases
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Vaccine preventable diseases
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Vaccine preventable diseases
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The Canadian Immunization Awareness Program

• Developed due to
• ? conflicting media reports (safety)
• ? myths (immune system, alternate
• therapies)
• uninformed health professionals,
• had never seen the diseases (complacency)

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Nurses and Immunizations

• The decision to immunize falls within the scope
  of practice of medicine and registered nurses
  need to have a drs order or medical directive.
  Nurses can administer vaccines but are required
  to be
• Accountable to their clients to make sure the
  information that they give re vaccines is
  accurate and up to date
• Requires to be competent to provide emergency
  care in the event of an adverse reaction
• Aware and knowledgeable re policies and
  directives around immunizations
• Need to be certified

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Public Health Nurses Role in Immunization

• Provide immunization programs that meet the needs
  of the population (assess, plan, publicize,
  implement, evaluate)
• Ensure that an accurate record keeping system of
  communicable disease occurrence and immunizations
  is in place.
• Assist in reducing or eliminating client and
  provider barriers to acquiring immunization.

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Non-vaccine infectious diseases

• Listeriosis
• Avian influenza
• Creutzfeldt-Jakob disease
• Lyme disease
• Norwalk or noroviruses
• SARS
• Tuberculosis (TB)
• West Nile virus
• Clostridium difficile virus (c difficile)

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NS Health protection Act Required reading

• Legislation passed fall 2005 that enables public
  health officials to protect the public.
• It deals with notifiable diseases or conditions,
  communicable diseases, health hazards, public
  health emergencies and food safety.
• The act is meant to define the responsibilities
  and duties of PH officials.

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NS Health Act

• What are notifiable diseases or conditions?
• Who is required to report?
• What is a Public Health Emergency?
• What is an example of a dangerous disease?
• What is an example of a health hazard?
• The chief MOH can declare a state of emergency.
• What might be involved in a state of emergency?

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Public Health Nurse Roles and responsibilities

• Has immunity for performance of duty under the
  act.
• Assists the MOH in enforcing the act
• A PHN who is investigating a suspected case of
  communicable disease or exposure to a health
  hazard can ask the police for assistance to
  follow through on ie entering a premise to
  inspect etc.

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List of Reportable Diseases

• All provinces and territories in Canada are
  required to report communicable diseases to the
  Department of health
• The Public Health Agency of Canada maintains a
  list of Nationally Notifiable Infectious Diseases
  which must be reported

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E-coli 0157H7 A reportable communicable disease

• Outbreak Oct 2008 traced to a Harveys in North
  Bay Ontario
• Caused by a particular strain of bacterium thus
  the E-coli 0157H7
• Found in animals such as beef, shed through their
  feces
• There is currently a vaccine for cattle against E
  coli 0157H7
• Largest water borne outbreak in Canada 2000
• Linked to the municipal water that was
  contaminated with animal feces

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Communicable Disease Investigation

• Identify the agent
• Determine the mode of transmission
• How susceptible the population is
• Estimate impact on the population

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NS Communicable disease surveillance system

• Physician or lab reports to Medical Officer of
  Health (MOH) or delegate re disease
• MOH assigns the case to PHN
• PHN completes investigation and management
  reports
• PHN completes surveillance forms and forwarded on
  to the provincial dept. of health
• Dissemination of information

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Department of Health

• Legislation re notifiable diseases
• Providing and administering vaccines
• Surveillance for adverse reactions to
  immunizations
• Monitors, investigates and responds to outbreaks
  of disease
• Reports immunization coverage rates

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Prevention and Control of Communicable Diseases

• Prevention and control programs seek to reduce
  the prevalence of a disease to a level at which
  it no longer poses a major community health
  problem
• Elimination The removal of the disease from a
  large geographical area, such as a country or
  region of the world
• What is an example of a vaccine preventable
  communicable disease that has been eliminated
  from Canada?
• Eradication The irreversible termination of all
  transmission of infection by extermination of the
  infectious agents worldwide
• What is an example of a communicable disease that
  has been eradicated worldwide?

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Surveillance of Communicable Diseases

• Surveillance Systematically collecting,
  organizing, and analyzing current, accurate, and
  complete data for a defined disease condition

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Person, place time
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Policy decision re health surveillance

• Policy example prevention of neural tube defects.

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Part 2 Public Health Act Deals with Food safety

• Not under Dept of health but the Department of
  Agriculture and Fisheries.
• Public health inspectors work under the
  environment work closely with MOH if a food
  hazard exists
• All food establishments are inspected require
  permits and licensure that need to be followed.
  Also guidelines re people who work in the food
  industry and if they have a communicable disease
  .
• What has been a recent issue re inspections of
  restaurants?

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Ethics

• Ethics The branch of philosophy that deals with
  the distinction between right and wrong, with the
  moral consequences of human actions.
• Ethics involves making judgments based on ethical
  principles

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Ethical Principles Community Practice

• Beneficence
• autonomy
• Nonmaleficence Harm principle
• Justice Reciprocity i.e. If a person is
  quarantined they need to be compensated
• Transparency
• Least restrictive

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Ethical Dilemma

• An ethical dilemma involves a conflict between
  choices.
• Ethical dilemmas are faced by CHN on a very
  regular basis. Examples confidentiality.

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Ethics Values

• The Code of Ethics for Registered nurses(2008) is
  based on 7 values that we as nurses need to
  believe in and operate from. (Safe, competent
  compassionate ethical care, health and
  well-being, choice, dignity, confidentiality,
  justice accountability).
• Values are the criteria by which decisions are
  made.

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Decision making frameworks

• 1.Clarify the ethical dilemma
• 2. Who are the interested parties? What are their
  relationships?
• 3. What values are involved?
• 4. Weigh the benefits and burdens.
• 5. Look for similar cases.
• 6. Discuss with relevant others.
• 7. Does the decision accord with legal and
  organizational rules?
• 8. Am I comfortable with the decision?