SkipdirectlytositecontentSkipdirectlytopageoptionsSkipdirectlytoA-ZlinkSkipdirectlytoA-ZlinkSkipdirectlytoA-ZlinkYellowFeverSectionNavigationCDCHomeFacebookTwitterLinkedInSyndicateTransmissionofYellowFeverVirusMinusRelatedPagesYellowfevervirusisanRNAvirusthatbelongstothegenusFlavivirus.ItisrelatedtoWestNile,St.Louisencephalitis,andJapaneseencephalitisviruses.Yellowfevervirus istransmittedtopeopleprimarilythroughthebiteofinfectedAedesorHaemagogusspeciesmosquitoes.Mosquitoesacquirethevirusbyfeedingoninfectedprimates(humanornon-human)andthencantransmitthevirustootherprimates(humanornon-human).Peopleinfectedwith yellowfevervirus areinfectioustomosquitoes(referredtoasbeing“viremic”)shortlybeforetheonsetoffeverandupto5daysafteronset.Yellowfevervirus hasthreetransmissioncycles:jungle(sylvatic),inter­mediate(savannah),andurban.Thejungle(sylvatic)cycleinvolvestransmissionofthevirusbetweennon-humanprimates(e.g.,monkeys)andmosquitospeciesfoundintheforestcanopy.Thevirusistransmittedbymosquitoesfrommonkeystohumanswhenhumansarevisitingorworkinginthejungle.InAfrica,anintermediate(savannah)cycleexiststhatinvolvestransmissionof virusfrommosquitoestohumanslivingorworkinginjungleborderareas.Inthiscycle,theviruscanbetransmittedfrommonkeytohumanorfromhumantohumanviamosquitoes.Theurbancycleinvolvestrans­missionofthevirusbetweenhumansandurbanmosquitoes,primarilyAedesaegypti.Thevirusisusuallybroughttotheurbansettingbyaviremichumanwhowasinfectedinthejungleorsavannah.Pagelastreviewed:January15,2019Contentsource:CentersforDiseaseControlandPrevention,NationalCenterforEmergingandZoonoticInfectiousDiseases(NCEZID),DivisionofVector-BorneDiseases(DVBD)homeYellowFeverHomePreventionVaccineexpandVaccineRecommendationsReactionstoYellowFeverVaccineYellowFeverVaccine,Pregnancy,&ConceptionTransmissionSymptoms,Diagnosis,&TreatmentMapsexpandAfricaSouthAmericaLinks&ReferencesFrequentlyAskedQuestionsForHealthcareProvidersexpandClinical&LaboratoryEvaluationDiagnosticTestingVaccineInformationTestingforVaccineA