Epidemiology

• Handwashing


  backbone of preventing infection
• Epidemiology 


  study of occurence and distribution of diseases
• Epidemiology 


  backbone of prevention of diseases
• John Snow


  Father of Field Epidemiology
• Classifications in Epidemiology

  Sporadic - Cases occur intermittent, occasionally, few cases; more immune, less susceptible
• Classifications in Epidemiology

  Sporadic - Achieved herd immunity - large portion of a community becomes immune to a disease 
• Classifications in Epidemiology

  Endemic - Cases always present; immune = susceptible
• Classifications in Epidemiology

  Endemic

  • Locally Endemic e.g. malaria in Palawan, schistosomiasis in Samar, Filariasis in Mindanao
• Classifications in Epidemiology

  Epidemic/Outbreak - Sudden increase of cases in a short period of time; more susceptible, less immune
• Classifications in Epidemiology

  Pandemic - Worldwide epidemic, several countries affected; Declared ONLY by WHO
• Classifications in Epidemiology


  Point/Common source - Simultaneous exposure e.g. food poisoning
• Classifications in Epidemiology


  Secular Variation - Changes in disease frequence over a period of many years e.g. tuberculosis rampant even in 50’s
• Classifications in Epidemiology

  Cyclical/Seasonal Variation - Recurrent fluctuations of disease like seasonal diseases e.g. dengue in rainy season
• Classifications in Epidemiology



  Propagated - Person to person transmission
• Epidemiologic Triangle

  1. Host
  2. Agent
  3. Environment
• Epidemiologic Triangle

  Host

  • any organism that harbors and provides nourishment for another organism
• Epidemiologic Triangle

  Environment

  • sum total of all external conditions and influences that affects the development of organism
• Epidemiologic Triangle

  Agent

  • intrinsic property of microorganism to survive and multiply in the environment
• Epidemiologic Triangle

  Tree component of the Environment:

  Physical - composed of the inanimate surroundings
• Epidemiologic Triangle

  Tree component of the Environment:

  Biological - makes up the living things around us
• Epidemiologic Triangle

  Tree component of the Environment:

  Socio-economic - may be in form of level of economic development of the community , presence of social disruptions and the like.
• Natural History of Diseases

  Exposure - Latent Period - Incubation Period - Infectious Period - Non-infectious Period