Denguevirusisasingle-strandedRNAvirusofabout50nmindiameterbelongingtothegenusFlavivirus.Dengueanddenguehemorrhagicfeverarecausedbyoneoffourcloselyrelated,butantigenicallydistinct,virusSEROtypes(DEN-1,DEN-2,DEN-3,andDEN-4).Infectionwithoneoftheseserotypesdoesnot
providecross-protectiveimmunity,sopersonslivinginadengue-endemicareacanhavefourdengueinfectionsduringtheirlifetimes.ThevirusesaretransmittedbyAedesaegypti,adomestic,day-bitingmosquitothatpreferstofeedonhumans.Infectionwithdenguevirusesproducesaspectrumofclinical
illnessrangingfromanonspecificviralsyndrometosevereandfatalhemorrhagicdisease.Itisprimarilyadiseaseofthetropics;itsglobaldistributioniscomparabletothatofmalaria,andanestimated2.5billionpeopleliveinareasatriskforepidemictransmission.Globally,thereareanestimated50to100
millioncasesofdenguefeverandseveralhundredthousandcasesofdenguehemorrhagicfever.Thecase-fatalityrateofDHFinmostcountriesisabout5%;mostfatalcasesareamongchildrenandyoungadults.
ImportantriskfactorsforDHFincludethestrainandserotypeoftheinfectingvirus,aswellastheage,immunestatus,andgeneticpredispositionofthepatient.Riskgroupsareresidentsoforvisitorstotropicalurbanareas.
Thepresenceofvirusresp.infectionmaybeidentifiedbyserology(detectionofantibodiesbyELISA).
Infectionproduceslifelongimmunity,buttheantigenicallydistinctserotypesdonotprovidecross-protectiveimmunity,soapersoncantheoreticallyexperiencefourdengueinfections;adenguevaccineisnotavailable.