Communicable Diseases

• Bacteria

  • the most common infection-causing microorganisms
• Viruses

  • consist primarily of nucleic acid
  • must enter a living cells in order to reproduce
• Fungi

  • yeasts and molds
• Parasites

  • live on other living microorganism
• CHAIN OF INFECTION

  1. Etiologic Agent (Microorganism)
  2. Reservoir (host)
  3. Portal of Exit from Reservoir
  4. Mode of Transmission
  5. Portal of Entry to the Susceptible Host
  6. Susceptible Host
• Etiologic Agent

  • the extent to which any microorganisms is capable of producing an infectious process depends on the number of microorganism (pathogenicity)
• Etiologic Agent

  • the ability of the microorganism to enter the body, the susceptibility of the host
  • the ability of microorganisms to live in the host's body
• Reservoir

  • source of microorganisms
  • ex. other humans, the client's own microorganism, plants, animals, or the general environment
• People are the most common source of infection for others and for themselves.
• Portal of Exit from Reservoir

  • before an infection can establish itself in a host, the microorganism must leave the reservoir
• Method of Transmission

  • means of reaching another person or host through a receptive portal of entry
• Methods of Transmission:

  1. Direct Transmission
  2. Indirect Transmission

  a.) Vehicle borne transmission

  b.) Vector - borne transmission
• Direct Transmission

  • involves immediate and direct transfer of microorganisms from person to person
  • through touching, biting, kissing, or sexual intercourse
• Droplet Spread is a form of direct transmission but can occur only if the source and the host are within 3 feet of each other.
• Sneezing, coughing, spitting, singing, or talking can project droplet spray into the conjunctiva or onto the mucous membranes of the eyes, nose, or mouth of another person.
• Indirect Transmission

  • may either be vehicle borne or vector borne
• Vehicle Borne Transmission

  • any substance that serves as an intermediate means to transport and introducing infectious agent into susceptible host through a suitable portal of entry
  • ex. Fomites
• Fomites (inanimate objects or materials) such as handkerchiefs, toys, soiled clothes, cooking or eating utensils, and surgical instruments or dressing can act as vehicle.
• Vector - borne Transmission

  • an animal or flying or crawling insects that serves as an intermediate means of transporting the infectious agents
  • ex. injecting salivary gland fluid during biting or by depositing feces or other materials on the skin through the bite wound or a traumatized skin area
• Portal of Entry to the Susceptible Host

  • Before a person can became infected, microorganisms must enter the body.
  • Any break in the skin
  • Often, microorganisms enter the body of the host by the same route they used to leave the source.
  • The skin is a barrier to the infectious agents
• Susceptible Host

  • any person who is at risk for infection
• Compromised Host

  • a person "at increased risk:, an individual who for one or more reasons is more likely than others to acquire an infection
• Impairment of the body's natural defenses and a number of other factors can affect susceptibility to infection.
• Disease Cycle may be broken down by these factors: 

  1. Increasing host resistance
  2. Destruction of the source and the reservoir
  3. Destruction of the agent in the environment
  4. Avoidance of exposure
• Handwashing

  • the most important procedure for preventing the transfer of microorganisms and the therefore nosocomial infection is correct and frequent handwashing
• Proper handwashing should be done on all the following instances:

  • at the beginning of the work shift
  • before and after prolonged contact with the patient
  • before invasive procedure
  • before contact with especially susceptible patients
  • before and after touching wounds
  • after contact with the body substances, even when glove was worn
  • anytime you are in doubt the necessity for doing so
  • at the end of every shift before leaving the health care facility
• Gloves

  • protect the hands when health worker is likely to handle any substances, e.g., blood, urine, feces, sputum, mucous, transmitting their own endogenous microorganisms to individuals receiving care.
• Gloves reduce the chance that the health worker's hands will transmit microorganisms from one client to another client.
• In all situations, gloves are changed between client's contacts.
• Specific Protection Against Disease

  1. Immunization
  2. Chemoprophylaxis
  3. Mechanical Prophylaxis
• Immunization

  • the process of introducing vaccine into the body to produce antibodies that will protect our body against a specific infectious agent
• Most vaccine are given more than once since the first dose gives only half projection the body needs. A second shot or "booster" is needed to give the body full projection against the disease.
• Immunization against communicable disease

  1. For infants
  2. Following exposure
  3. For all persons in endemic areas
  4. For person subject to unusual risk
  5. For known cases
• Vaccines Available for Routine Immunization:

  1. DPT (Diphtheria, pertussis, and tetanus) Vaccine
  2. OPV (Oral Polio Vaccine)
  3. MMR (Measles, Mumps, Rubella) Vaccine
  4. Hib (H. Influenza type B) polysaccharide Vaccine
  5. Hepatitis B Vaccine
  6. BCG (Bacillus of Calmette and Guerin)
  7. CDT (Cholera, Dysentery, Typhoid)
• DPT (Diphtheria, Pertussis, and Tetanus) Vaccine

  • an early start with this reduces the chance of severe pertussis
• Diphtheria

  • caused by Corynebacterium diphtheriae
• Pertussis

  • caused by Bordetella pertussis
• Tetanus

  • caused by Clostridium Tetani
• OPV (Oral Polio Vaccine)

  • the extent of protection against polio is increased the earlier this vaccine is given
  • German Measles - caused by Polio Virus
• MMR (Measles, Mumps, Rubella) Vaccine

  • Measles
  • Mumps
  • German Measles