Epidemiology- Definition, Tasks, Methods, Natural history of the disease

Question 1

define epidemiology

Answer 1

a science studying the distribution & determinants of disease in human populations and the applications of this study to the control of health problems

Question 2

Tasks of epidemiology

DIDISCE

Answer 2

• Discover: agents, hosts and environmental factors that affect health
• Identify: sections of the population at greatest risk from specific causes of ill health
• Determine: the relative importance of causes of illness, disability & death
• Investigate: outbreaks to identify the source and control
• Study: natural history of disease and injury
• Conduct: surveillance of disease and injury
• Evaluate: effectiveness of preventative and therapeutic health programs and services

Question 3

Methods employed in epidemiology aka Epidemiological studies

Answer 3

can be either observational studies or experimental studies

Question 4

Observational studies

Answer 4

• observational studies do not involve any intervention & lets things take their natural course.
• changes of one characteristic are studied in relation to others
• can be divided into Descriptive or Analytic

Descriptive studies: no control or no comparison group

Analytical studies: DO have controls or comparison groups. used to test hypothesis for etiological factors

Question 5

experimental studies

Answer 5

Experimental studies always have an experimental group and a control group.

The investigator controls exposure often in a randomized way

Question 6

Natural History of Disease

Answer 6

the course of a disease from it’s onset to it’s resolution

1. NO disease
2. Disease Onset: body cannot remain homeostasis
3. Presymptomatic period: the period of time from the cause clinical manifestation of the disease
4. 1. for non infections:
      
      1. induction period: the period of time from the cause to the onset of disease
      2. latent period: the time from the onset of disease onset to detection
   2. for Infectious:
      
      1. induction period: the period from infection to to symptomatic disease
      2. latency period: the time from infection to the development of infectiousness
5. Clinical diagnosis: organs are affect and patient seeks medical assistance.
6. Disease development
7. Post morbid period / resolution
8. Full recovery 2. Death 3. Chronic condition

Question 7

what are the types of natural history of disease

Answer 7

• Acute: short
• Chronic: long
• No disease ⇒primary prevention
• Disease onset
  
  • assymptomatic & early clinical dgnosis⇒ secondary prevention
  • disease development, late clinical diagnosis & disease resolution⇒ tertiary prevention
    *

Question 8

What is the causality sidebar of Koch

Answer 8

Kock postulated the causality of disease in 1884

1. MO’s are present in all those w/ disease
2. MO’s never occur in healthy ppl
3. MO can be isolated, cultured & can pass the disease to others