CPHM MIDTERM WEEK 10

• 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


  Readily transferred from one infected person to a susceptible and uninfected person and may be caused by microorganisms
• Types of Microorganism causing infections

  • Bacteria
  • Viruses
  • Fungi
  • Parasites
• 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
• 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), 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


  1. Direct transmission

  2. Indirect transmission (vehicle borne or vector borne)
• 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
• Specific protection against Disease


  • Immunization
  • Chemoprophylaxis
  • Mechanical Prophylaxis
• Immunization


  The process of introducing vaccines into the body to produce antibodies that will protect our body against a specific infectious agent.
• Immunization against communicable disease


  • For infants
  • Following exposure
  • For all persons in endemic areas
  • For person subject to unusual risk
  • For known cases
• Vaccine available for routine immunization


  • DPT (Diptheria, pertussis and tetanus) vaccine
  • OPV (Oral Polio Vaccine)
  • MMR (Measles, Mumps, Rubella) vaccine
  • Hib (H.influenza type B) polysaccharide vaccine
  • Hepatitis B vaccine
  • BCG (Bacillus of Calmette and Guerin)
  • CDT (Cholera, Dysentery, Typhoid)
• OPV (Oral Polio Vaccine)


  • the extent of protection against polio is increased the earlier the OPV is given

  • Poliomyelitis- caused by Polio virus
• MMR (Measles, Mumps, Rubella) vaccine


  • Measles- caused by Measles virus

  • Mumps- caused by Mumps virus

  • German measles- caused by Rubella virus
• DPT (Diptheria, pertussis and tetanus) vaccine


  • An early start with DPT reduces the chance of severe pertussis

  • Diptheria- Caused by Corynebacterium diptheriae

  • Pertussis- Caused by Bordetella pertussis

  • Tetanus- Caused by Clostridium tetani
• Hib (H.influenza type B) polysaccharide vaccine

  • Meningitis- Caused by Haemophilus influenza
• Hepatitis B vaccine


  • an early start of hep. B reduces the chance of acquiring hepatic CA
• BCG (Bacillus of Calmette and Guerin)


  • Given at the earliest possible protects against the possibility of infectionfro other family members.

  • Tuberculosis- caused by Mycobacterium tuberculosis
• CDT (Cholera, Dysentery, Typhoid)


  • Cholera- Caused by Vibrio cholera

  • Dysentery- Caused by Shigella dysenteriae

  • Typhoid- Caused by Salmonella typhii
• Pathogen:Prions


  Living: No

  Cellular: No

  Nucleic Acid (DNA): No

  Prokaryotic/Eukaryotic: N/A

  Uni/Multicellular: N/A

  Features: Protein that has been altered from its normal structure. Converts normal proteins to prions.

  Disease: Mad Cow Disease
• Pathogen:
Viruses


  Living: Debatable

  Cellular: No

  Nucleic Acid (DNA): Yes

  Prokaryotic/Eukaryotic: Neither

  Uni/Multicellular: Debatable

  Features: Consist of DNA or RNA enclosed in protein, living inside cells. They invade and hijack host cells, causing their cytoplasm to produce more viruses

  Disease: AIDS, herpes, Influenza
• Pathogen:
Bacteria


  Living: Yes

  Cellular: Yes

  Nucleic Acid (DNA): Yes

  Prokaryotic/Eukaryotic: Prokaryotic

  Uni/Multicellular: Uni

  Features: Simple cells with no internal membranes. Single strand of DNA that reproduces asexually inside a host rapidly, and their wastes are often harmful

  Disease: Cholera
• Pathogen:
Protozoans


  Living: Yes

  Cellular: Yes

  Nucleic Acid (DNA): Yes

  Prokaryotic/Eukaryotic: Eukaryotic

  Uni/Multicellular: Uni

  Features: Microscopic, single-celled organisms with internal membranes. Reproduce asexually.

  Disease: Malaria
• Pathogen:
Fungi


  Living: Yes

  Cellular: Yes

  Nucleic Acid (DNA): Yes

  Prokaryotic/Eukaryotic: Eukaryotic

  Uni/Multicellular: Multi

  Features: Heterotrophic organisms. Contains a membrane bound nucleus, a cell wall and no chloroplast.

  Disease: Ringworm
• Pathogen:
Macroparasites


  Living: Yes

  Cellular: Yes

  Nucleic Acid (DNA): Yes

  Prokaryotic/Eukaryotic: Eukaryotic

  Uni/Multicellular: Multi

  Features: Organisms that are visible to the naked eye, often vectors diseases. Either endoparasitic (live in host) or ectoparasitic (live on host)

  Disease: Intestinal worms
• Cellular (Living)


  Parasites (e.g. helminthes)

  • Tapeworm

  Protozoa (e.g. plasmodia)

  • Malaria

  Fungi (e.g. tinea)

  • Athlete's foot

  Prokaryote (i.e. bacteria)

  • Leprosy
• Acellular (Non-Living)


  Virus (e.g. HIV)

  • AIDS

  Prion

  • CJD