Medical Microbiology

GeneralEpidemiology 27

Table 1. 8 EpidemiologicalTerminology

Term Definition

Sporadicoccurrence Isolatedoccurrenceofaninfectiousdiseasewithnoappar-

entconnectionsbetweenlocalitiesortimesofoccurrence

Endemicoccurrence Regularandcontinuingoccurrenceofinfectiousdiseasesin

populationswithnotimelimit

Epidemicoccurrence Significantlyincreasedoccurrenceofaninfectiousdisease

withingivenlocalitiesandtimeperiods

Pandemicoccurrence Significantlyincreasedoccurrenceofaninfectiousdisease

withinagiventimeperiodbutwithoutrestrictiontogiven

localities

Morbidity Numberofcasesofadiseasewithinagivenpopulation

(e.g.,per 1 000, 10000 or 100000 inhabitants)

Incidence Numberofnewcasesofadiseasewithinagiventimeperi-

od

Prevalence Numberofcasesofadiseaseatagivenpointintime

(samplingdate)

Mortality Numberofdeathsduetoadiseasewithinagivenpopula-

tion

Lethality Numberofdeathsduetoadiseaseinrelationtototal

numberofcasesofthedisease

Manifestationindex Numberofmanifestcasesofadiseaseinrelationtonum-

berofinfections

Incubationperiod Timefrominfectionuntiloccurrenceofinitialdisease

symptoms

Prepatency Timebetweeninfectionandfirstappearanceofproductsof

sexualreproductionofthepathogen(e.g.,wormeggsin

stool)

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Kayser, Medical Microbiology © 2005 Thieme