West Nile virus (WNV) is the leading cause of mosquito-borne disease in the continental United States. It is most commonly spread to people by the bite of an ...SkipdirectlytositecontentSkipdirectlytopageoptionsSkipdirectlytoA-ZlinkWestNilevirusSectionNavigationCDCHomeFacebookTwitterLinkedInSyndicateWestNilevirusMinusRelatedPagesWestNilevirus(WNV)istheleadingcauseofmosquito-bornediseaseinthecontinentalUnitedStates. Itismostcommonlyspreadtopeoplebythebiteofaninfectedmosquito.CasesofWNVoccurduringmosquitoseason,whichstartsinthesummerandcontinuesthroughfall.TherearenovaccinestopreventormedicationstotreatWNVinpeople.Fortunately,mostpeopleinfectedwithWNVdonotfeelsick.About1in5peoplewhoareinfecteddevelopafeverandothersymptoms.About1outof150infectedpeopledevelopaserious,sometimesfatal,illness.YoucanreduceyourriskofWNVbyusinginsectrepellentandwearinglong-sleevedshirtsandlongpantstopreventmosquitobites.PreventionSymptoms,Diagnosis,&TreatmentTransmissionStatistics&MapsWestNileVirus&DeadBirdsMosquitoControlForHealthcareProvidersResourcesAt-A-GlanceMosquitoes&HurricanesCommunicationResourcesCDCDiseaseMapsWestNileVirusandOtherNationallyNotifiableArboviralDiseases—UnitedStates,2018MonitoringandControllingWestNileVirus:AreYourPreventionPracticesinPlace?pdficon[PDF–732KB]MosquitoControlEveryonecanhelp…ActivityandSurveillanceCheckwhereWNVisactive…Feelingfeverish?CoulditbeWNV?Pagelastreviewed:June3,2020Contentsource:CentersforDiseaseControlandPrevention,NationalCenterforEmergingandZoonoticInfectiousDiseases(NCEZID),DivisionofVector-BorneDiseases(DVBD)homeWestNileVirusHomePreventionSymptoms,Diagnosis,&TreatmentTransmissionplusiconBloodTransfusionandOrganDonationMothertoBabyduringPregnancy,Delivery,orBreastFeedingStatistics&MapsplusiconPreliminaryMaps&Datafor2020plusiconDiseaseCasesbyStateActivitybyStateIncidencebyStateFinalMaps&Datafor1999–2019plusiconCumulativeMaps&DataAnnualMaps&DataWestNileVirus&DeadBirdsMosquitoControlForHealthcareProvidersplusiconClinicalEvaluation&DiseaseDiagnos