lecture notes

1. E p i d e m i o l o g y
Prepared by: JIFAMY F. FAELDIN, RN
Epidemiology
Definition:a.studyof occurrence and distributionof diseases
b. dealswithdistributionanddeterminantsof healthstatesoreventsinaspecifiedpopulation
2 main areas
1. distribution
2. determinants(cause)
Elements
1. disease determinants
2. population
3. disease distribution
Uses of epidemiology
1. studythe historyof healthpopulation
2. diagnose the healthcommunity
3. studythe workof healthservices
4. estimate riskof disease,accidents,defects,andchancesof avoidingthem.
5. Identifysyndromesbydescribingthe distribution,andassociationof clinical phenomena.
6. complete the clinical picture of chronicdisease.
7. search for the causesof healthanddisease.
Epidemiologic triangle
 Each must be analyzedforcomprehensionandpredictionof patterns of disease.
Host
Agent Environment

2. Host-
Agent-
Environment-
Three component of the environment:
1. Physical environment-iscomposedof the inanimatesurroundingssuchasthe geophysical conditions
of the climate.
2. Biological environment- makesupthe livingthingsaroundussuchas plantsandanimal life.
3. Socio-economicenvironment- inthe formof level of economicdevelopmentof community,presence
of social disruptionsandthe like.
1. Agent of disease Etiologic factors, examples
A. Nutritive elements
Excess
Deficiencies
B. Chemical agents
C. Physical agents
D. Infectiousagents
Metazoa
Protozoa
Bacteria
Fungi
Rickettsia
Viruses

3. 2. Host factors (Intrinsic factors)
A. Genetics
B. Age
C. sex
D. ethnicgroup
E. physiologic
F. immunologicexperience
G. inter-currentorpre-existingdisease
H. humanbehavior
Environmental factors (extrinsic
factors)
A. Physical environment
B. BiologicEnvironment
C. Socio- economicenvironment

4. Epidemiologic variables
1. Time- periodtow/c casesbeingstudiedwere exposedtothe source of infectionandperiodduring
whichthe illnessoccurs.
 Epidemicperiod-reportedcasesexceedthe usual number
 Year- variesperseason/affectedbyvariationinthe riskof exposure of susceptible tothe source
of infection
 Periodof consecutive years-recordof casesovera periodof years.
2. persons- referstothe characteristicsof the individualwhowere exposedandwhocontactedthe
infectionorthe disease inquestion.
 Age
 sex
3. place- features, factororconditionswhichexistedinordescribedthe environmentinwhichthe
disease occurred.
Patterns of Occurrence andDistribution
1. Sporadic
2. Endemic
3. Epidemic
4. Pandemic
Epidemiology and surveillance unit
- responsible fortimelyandaccurate informationondiseasesinthe locality.
Responsibilities:
1. Surveillance of infectiousdiseaseswithoutbreakpotential
2. assistinglocal governmentunitininvestigationof outbreakandtheircontrol.
3. Developinginformationpackage onpublichealth.
4. Providingtechnical assistance relatedtoepidemiology.

5. Public HealthSurveillance
- on goingsystematiccollection,analysis,interpretation,anddisseminationof healthdata.
- (consideredINFORMATION LOOPSorCYCLES)
Objectives:
1. Measure the magnitude of the problem.
2. Measure the effectof control program.
The National Epidemic Sentinel SurveillanceSystem(NESSS)
- Hospital basedinformationsystemthatmonitorsthe occurrence of infectiousdiseaseswith
outbreakpotential.
- Servesas supplemental informationsystemof the DOH.
Objectives:
1. Provide earlywarning on occurrence of outbreaks.
2. Provide programmanagers,policymakersandpublicadministrators,rapid,accurate andtimely
information.
NESSS data shows:
D
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T
I
C
Diseases underSurveillance
a. Laboratory Diagnosed
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6. b. ClinicallyDiagnosed
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c. Under surveillance system
Vital Statistics
Statistics- Referstoasystematicapproachof obtaining,organizingandanalyzingnumerical factssothat
conclusionmaybe drawnfrom them.
Vital Statistics- systematicstudyof vital eventssuchasbirths,illnesses,marriages,divorce,separation
and deaths.
Uses of vital statistics
1. indicesof the healthandillnessstatusof acommunity.
2. servesas basesforplanning,implementing,monitoringandevaluatingcommunityhealthnursing
programsand services
Sources of Data
Populationcensus
Registrationof vital data
Healthsurvey
Studiesandresearches
Define:
Rate-
Ratio-
Crude or General rates-
SpecificRates

7. CBR CDR
IMR MMR
CDR
FDR NDR
SDR
IMR
Age specific death rate
Sex specific death rate IR
PR AR

8. Presentation of Data
Line or curvedgraphs
Bar graphs
Pie chart
Functions of the Nurse in Vital statistics
C
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FieldHealthServicesandInformationSystem
Components:
F
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