Communicable Diseases

• Communicable diseases 

  • are often the leading causes of all illness in the country today. 
  • Most often they afflict the most vulnerable, the young and the elderly. 
  • They have numerous economic, psychological, disabling and distinguishing effects to the emergence of newly discovered diseases and the re-emergence of old ones. 
  • Communicable diseases are readily transferred from one infected person to a susceptible and uninfected person and maybe caused by microorganisms.
• Bacteria - the most common infection-causing microorganisms
• Viruses - consist primarily of nucleic acid and therefore must enter a living cells in order to reproduce
• Fungi - includes yeast and Molds
• Parasites - Live on other living microorganism
• Etiologic agent

  • The extent to which any microorganisms is capable of producing an infectious process depends on the number of microorganism (pathogenicity)., the ability of the microorganisms to enter the body, the susceptibility of the host, and the ability of microorganisms to live in the host’s body.
• Reservoir

  • There are many reservoirs, or sources of microorganisms. Common sources are the 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 the Reservoir

  • Before an infection can establish itself in a host, the microorganism must leave the reservoir.
• Method of transmission

  • After the microorganism leaves its source reservoir, it requires a means of transmission to reach another person or host through a receptive portal of entry.
• • Direct transmission - involves immediate and direct transfer of microorganisms from person to person through touching, biting, kissing, or sexual intercourse.
• • Indirect transmission - may either be vehicle borne or vector borne
• • Vehicle borne transmission - a vehicle is any substance that serves as an intermediate means to transport and introduce infectious agents into susceptible hosts through a suitable portal of entry.
• • 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 - a vector is an animal or flying or crawling insects that serves as an intermediate means of transporting the infectious agents. Transmission may occur by 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 become infected, microorganisms must enter the body. 
  • The skin is a barrier to infectious agents; however, any break in the skin can readily serve as a portal of entry. 
  • Often, microorganisms enter the body of the host by the same route they used to leave the source.
• Susceptible host

  • A susceptible host is any person who is at risk for infection. 
  • A compromised host is 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.
• I. Immunization

  • Is the process of introducing vaccines into the body to produce antibodies that will protect our body against a specific infectious agent.
  • Most vaccines 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 a person subject to unusual risk.
  5. For known cases.
• II. Chemoprophylaxis

  • Administration of drugs to prevent occurrence of infection.
  • e.g. Penicillin for gonorrhea, Chloroquine for malaria, INH for tuberculosis
• III. Mechanical Prophylaxis

  • Placing mechanical barriers between the sources of agent and host such as use of mosquito nets, masks or gloves
  • Health education of mothers, relative and attendants in the practice of strict aseptic methods of umbilical care in the newborn.
• Protection against Diseases

  • Handwashing - The most important procedure for preventing the transfer of microorganisms and therefore nosocomial infection is correct and frequent handwashing.
  • PPEs