1 / 37

EPIDEMIOLOGY

EPIDEMIOLOGY. Koch’s Postulates (1876). Koch’s Postulates. To prove that a given microorganism is the pathogen for a certain disease one must Isolate From Afflicted Individual Culture Reinfect Previously Unafflicted Individual

vicki
Download Presentation

EPIDEMIOLOGY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EPIDEMIOLOGY

  2. Koch’s Postulates (1876)

  3. Koch’s Postulates • To prove that a given microorganism is the pathogen for a certain disease one must • Isolate From Afflicted Individual • Culture • Reinfect Previously Unafflicted Individual • The previously unafflicted individual must develop the same symptoms/disease state as the original host

  4. Host • Def: Individual afflicted with disease • Factors Affecting Host • Genetic Predisposition • Active Immunity • Other diseases

  5. Example: Individuals with Thalassemia Are Not Good Hosts For Malaria

  6. Reservoir • Def: Naturally occurring population that carries the pathogen. Continual source of pathogen. • Example: Cows and Anthrax

  7. Antigenic Shift • Def: Mutation in the pathogen population that changes their antigens (i.e. proteins that identify them to our immune systems) • Antigenic shifts allow diseases to jump from one species to another

  8. Pathogen • Def: What causes the disease in the host

  9. One pathogen: One disease • The causative agent of Anthrax is Bacillus anthracis. • The causative agent of Lyme Disease is Borelliaburgdorferi • You cannot get Lyme Disease from Bacillus anthracis

  10. Vector • Def: The agent that transfers the pathogen from host to host

  11. Mosquitoes • Most dangerous animal in world (for humans) • Vectors for malaria, dengue, encephalitis, yellow fever, heartworm

  12. EPI Curves

  13. What causes some diseases to become pandemic while others are epidemic or endemic?

  14. R0 = Basic Reproductive Number • Measurement of how many cases will generally derive from a single case of a given disease • R0 < 1 = disease will not spread • R0 > 1 = disease will spread

  15. Comparative R0 Values

  16. Virulence • Def: How much does the pathogen affect the host • Example: Ebola is so virulent, killing the host so rapidly, that it is difficult for the disease to spread to other hosts

  17. Endemic • A disease that is commonly present in a population, generally at low frequencies • Ex: Malaria, Streptococcus A

  18. Epidemic • Large number of afflicted hosts in a small area in a short period of time • Epidemics are generally short-lived due to rapid virulence/effects and limited number of hosts • EX: Ebola

  19. PANDEMIC • Disease that spreads worldwide, creating thousands of cases • Generally, pandemic diseases require common vectors and long incubations or lysogenic modes • Ex: Tuberculosis

  20. Sudden Acute Respiratory Syndrome

  21. How Does The Balance of The Viral Life Cycles Determine If A Disease Is An Epidemic, Endemic or Pandemic?

  22. LAB: Interactive Epidemiology • Purpose: To examine the effects of several parameters of communicable diseases on their epidemiological profile • Method: mathematical modeling

  23. Part 1: NIH Disease Transmission Simulator

  24. Part Two: Pop. Density & Mobility

More Related