1 / 17

Disease Transmission

Disease Transmission. Terms Associated with Disease Causation & Transmission. Host Agent Environment Fomites Vector Carrier – active Incubatory Convalescent Healthy Intermittent. You will cover these in today’s discussion. Modes of Transmission. Direct Indirect.

merle
Download Presentation

Disease Transmission

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. Disease Transmission

  2. Terms Associated with Disease Causation & Transmission • Host • Agent • Environment • Fomites • Vector • Carrier – active • Incubatory • Convalescent • Healthy • Intermittent You will cover these in today’s discussion.

  3. Modes of Transmission • Direct • Indirect

  4. Chain of Infection • Etiological agent • Source/Reservoir • Portal of exit • Mode of transmission • Portal of entry • Susceptible host

  5. Forms of Disease • Clinical • acute • sub-acute • Non-clinical (Inapparent) • pre-clinical • sub-clinical • chronic (persistent) • latent Your Assignment: familiarize yourself with the definitions of these terms

  6. Disease Investigation • Establish diagnosis • Identify specific agent • Describe according to person, place and time • Identify source of agent • Identify mode of transmission • Identify susceptible populations

  7. Steps in the Investigation of an Epidemic • Define the epidemic • Examination the distribution of cases • Look for combinations of variables • Develop hypothesis (es) • Test hypothesis • Recommend control measures

  8. Determinants of Disease Outbreak • Based on balance of disease in a population • herd immunity • disease restricted to single host • transmission must be relatively direct

  9. Effect of Herd Immunity

  10. Incubation Period • The period of time after an infection is established but before the first signs or symptoms appear • Different diseases generally have different incubation times and symptoms • Therefore, can derive epidemic curves

  11. Epidemic Curve for Single Exposure Common-Vehicle Outbreak

  12. Incubation Period ???????Dependent upon: D = (N)(V) / I Your Assignment: define the variables in this formula

More Related