Asian tiger mosquito - Aedes albopictus (Skuse)

Aedes albopictus is a competent vector of many viruses including dengue fever (CDC 2001) and Eastern equine encephalitis virus (Mitchell et al. 1992). Its life ... commonname:Asiantigermosquito scientificname:Aedesalbopictus(Skuse)(Insecta:Diptera:Culicidae) Introduction-Distribution-Description-LifeCycle-MedicalSignificance-Surveillance andManagementofAedesalbopictus-SelectedReferences Introduction(BacktoTop) TheAsiantigermosquito,Aedesalbopictus(Skuse),wasfirstdocumentedintheUnitedStatesinTexasin1985(SprengerandWuithiranyagool1986).Ayearlater,theAsiantigermosquitowasfoundinFloridaatatiredumpsitenearJacksonville(O'Meara1997).Sincethattime,this specieshasspreadrapidlythroughouttheeasternstates,includingallofFlorida's67counties(O'Meara1997). Figure1.AdultAsiantigermosquito,Aedesalbopictus(Skuse).PhotographbyJ.L.Castner,UniversityofFlorida. ThearrivalofAedesalbopictushasbeencorrelatedwiththedeclineintheabundanceanddistributionoftheyellowfevermosquito,Aedesaegypti(Linnaeus).ThereareanumberofpossibleexplanationsforthecompetitiveexclusionofAe.aegyptibyAe.albopictus.Thedeclineislikelyduetoacombinationof(a)sterilityofoffspringfrominterspecificmatings;(b)reducedfitnessofAe.aegyptifromparasitesbroughtinwithAe.albopictusand;(c)superiorityofAe.albopictusinlarvalresourcecompetition(Lounibos2002).ThedistributionofAe.aegypticurrentlyislimitedtothesoutheasternquadrantoftheU.S.,andsmallareasinNewYorkandArizona(DarsieandWard2005). Aedesalbopictusisacompetentvectorofmanyvirusesincludingdenguefever(CDC2001)andEasternequineencephalitisvirus(Mitchelletal.1992).Itslifecycleiscloselyassociatedwithhumanhabitat,anditbreedsincontainerswithstandingwater,oftentiresorothercontainers.Itisadaytimefeederandcanbefoundinshadyareaswhereitrestsinshrubsneartheground(KoehlerandCastner1997).Aedesalbopictusfeedingpeaksintheearlymorningandlateafternoon;itisanopportunisticandaggressivebiterwithawidehostrangeincludingman,domesticandwildanimals(Hawley1988). Distribution(BacktoTop) ThedistributionofAedesalbopictusissubtropical,withatemperatedistributioninNorthAmerica,andintheUnitedStateshasexpandedrapidlyoverthepastfewyears.ThisspecieswasfirstdocumentedinTexasin1985andiscurrentlyestablishedin866countiesin26states(CDC2001). Figure2.CenterforDiseaseControlrecordeddistributionofAedesalbopictus(Skuse),theAsiantigermosquito,intheUnitedStates,bycounty,2000.Reviewed10November2003).Forpossibleupdatessee:http://www.cdc.gov/ncidod/dvbid/arbor/albopic_97_sm.htm. TheworldwidedistributionincludesmostofAsiaandcoverstropicalandsubtropicalregionsworldwidewithintroductionsintotheCaribbean(MorbidityandMortalityWeeklyReport1989).EndemictoAsiaandthePacificislands,therangehasgreatlyexpandedtoincludeNorthandSouthAmerica,AfricaandEurope(O'Meara1997). Description(BacktoTop) AdultAedesalbopictusareeasilyrecognizedbytheboldblackshinyscalesanddistinctsilverwhitescalesonthepalpusandtarsi(Hawley1988).Thescutum(back)isblackwithadistinguishingwhitestripedownthecenterbeginningatthedorsalsurfaceoftheheadandcontinuingalongthethorax.Itisamedium-sizedmosquito(approximately2.0to10.0mm,malesareonaverage20%smallerthanfemales).Differencesinmorphologybetweenmaleandfemaleincludetheantennaeofthemaleareplumousandmouthpartsaremodifiedfornectarfeeding.Theabdominaltergitesarecoveredindarkscales.Legsareblackwithwhitebasalscalesoneachtarsalsegment.TheabdomennarrowsintoapointcharacteristicofthegenusAedes.Fieldidentificationisveryeasybecauseofthesedistinctfeatures. Figure3.AdultAsiantigermosquito,Aedesalbopictus(Skuse).PhotographbyMicheleM.Cutwa,UniversityofFlorida. Figure4.AdultAsiantigermosquito,Aedesalbopictus(Skuse),dorsalviewshowingwhitedorsalstripe.PhotographbyJamesGathany,CentersforDiseaseControlPublicHealthImageLibrary. Forapictorialkey(thatincludesthelarval,pupalandadultstageformanycommonFloridamosquitoes)toidentifyAe.albopictusandothermosquitoesofFlorida,see:http://fmel.ifas.ufl.edu/key/. LifeCycle(BacktoTop) Aedesalbopictusoverwinterintheeggstageintemperateclimates(LyonandBerry2000)butareactivethroughouttheyearintropicalandsubtropicalhabitats.Eggsarelaidsinglyonthesidesofwater-holdingcontainerssuchastires,animalwateringdishes,birdbaths,flowerpotsand naturalholesinvegetation(Hawley1988).Theyareblackandovalwithalengthof0.5mm.Eggscanwithstanddesiccationuptooneyear.Larvalemergenceoccursafterrainfallraisesthewaterlevelinthecontainers.Theeggsmayrequireseveralsubmersionsbeforehatching(Hawley1988).Additionally,oxygen(O2)tensiongreatlyaffectsegghatch(Hawley1988).AnumberofstudieshaveshownlowO2tensionstimulatesthehatchingofAedesalbopictuseggsandisamoreimportantfactorthanfloodingortemperatureoninducingegghatch(Hawley1988).Developmentistemperaturedependent,butthelarvaeusuallypupateafterfivetotendaysandthepupalstagelaststwodays(Hawley1988).Larvae,alsocalledwigglers,areactivefeeders.Theyfeedonfineparticulateorganicmatterinthewater.Thelarvaeuseabreathingsiphontoacquireoxygenandmustperiodicallycometothesurfacetodoso.Thelarvaedevelopthroughfourinstarspriortopupation.Unlikemanyotherinsects,thepupaeofmosquitoesareactiveandshort-lived.Theydonotfeedbutcanmoveabout. Figure5.LarvaoftheAsiantigermosquito,Aedesalbopictus(Skuse).PhotographbyMicheleM.Cutwa,UniversityofFlorida. Figure6.PupaoftheAsiantigermosquito,Aedesalbopictus(Skuse).PhotographbyMicheleM.Cutwa,UniversityofFlorida. MedicalSignificance(BacktoTop) Aedesalbopictusisknowntobeacompetentlaboratoryvectorofmorethan30viruses.Ofthese30onlyafewareknowntoaffecthumans;theyareeasternequineencephalitis(EEE),CacheValleyvirus,dengue,St.LouisandLaCrosseencephalitisviruses(CDC2001,Hawley1988).Despitebeingfeaturedastheferocioustigermosquito(ABCnews2001)ithasnotbeenfoundtobeasignificanthealthconcernandisinfactalessefficientvectorthanotherAedesmosquitoes.Aedesalbopictushasbeenimplicatedinthetransmissionofdengue,butthisisnotamajorvector. Aedesaegyptiisthemostcompetentvectorofdenguevirus(Gulber1998).TheAsiantigermosquitoisconsideredamaintenancevectorandoccasionallyisinvolvedwithdenguetransmissioninAsia(CDC2001).DengueviruswasisolatedfromcollectionsofAe.albopictusinMexicoafteranepidemic(Lounibos2002).Despiteoccasionalviralisolations,thereisnoevidencethatthismosquitoisapublichealththreatintheUnitedStates.ThereisoneisolatedincidenceinPolkCounty,FloridawhereAe.albopictuswasimplicatedinthetransmissionofeasternequineencephalitisin1991(MooreandMitchell1997).MorerecentlytherewasanisolationofLaCrossevirusfoundinfieldcollectedAe.albopictusinNorthCarolina(Gerhardtetal.2001).Theimplicationsofthesefindingsarethatthismosquitoshouldbemonitoredfordiseaseactivity,butatthistimeshouldnotbeconsideredapublichealththreat. SurveillanceandManagementofAedesalbopictus(BacktoTop) AfterenteringtheUnitedStatesalmosttwentyyearsago,Aedesalbopictushasspreadthroughoutmuchoftheeasternstates.Themosquitowasmostlikelytransportedalonghighwaysandothermajorroadwaysinshipmentsofusedtiresimportedfromothercountriesforretreading.OnJanuary1988,theU.S.PublicHealthServicerequiredallusedtiresenteringtheU.S.fromknownendemiccountriesbedry,cleanandtreatedwithfumigants(MooreandMitchell1997).SurveillanceforAe.albopictuswasinitiatedin1986andthisspeciescontinuestobemonitoredbypublichealthagencies(MorbidityandMortalityWeeklyReport1989). Managementofadultpopulationsismorecomplicatedthanforotherspeciesduetoinsecticidetolerancetomalathion,temephosandbediocarb(MorbidityandMortalityWeeklyReport1987).Inmanysuburbanareas,complaintstohealthdepartmentsaremorefrequentlyduetoAe.albopictusthaninformeryearswhenAe.aegyptiwasthemostcommonlyreportednuisancemosquito(MorbidityandMortalityWeeklyReport1989).Sourcereductionisaneffectivewayforpeopleinthecommunitytomanagethepopulationsofmanymosquitoes,especiallycontainerbreedingspeciessuchastheAsiantiger.Theremovalofmosquitobreedinghabitatcanbeaneffectivemethodformosquitocontrol(DameandFasulo2003). Eliminateanystandingwaterontheproperty,changepetwateringdishes,overflowdishesforpottedplants,andbirdbathwaterfrequently.Donotallowwatertoaccumulateintires,flowerpots,buckets,rainbarrels,guttersetc.Usepersonalprotectiontoavoidmosquitobites.LongsleevesandinsectrepellentsuchasDEETwillreduceexposuretobites.TheAsiantigermosquitoisadaybiterwithfeedingpeaksearlymorningandlateafternoon,sobylimitingoutdooractivitiesduringcrepuscularperiods(dawnanddusk)whenmosquitoesaregenerallymostactive,bitescanbeavoided. SelectedReferences(BacktoTop) ABCnews.2001.FerocioustigermosquitoinvadestheUnitedStates.July30. CentersforDiseaseControl.(2001).InformationonAedesalbopictus.ArboviralEncephalitides.http://www.cdc.gov/ncidod/dvbid/arbor/albopic_new.htm(January2018). CentersforDiseaseControl.1986.EpidemiologicnotesandreportsAedesalbopictusIntroduction--Texas.MorbidityandMortalityWeeklyReport35:141-2. CentersforDiseaseControl.1987.Currenttrendsupdate:AedesalbopictusInfestation—UnitedStates.MorbidityandMortalityWeeklyReport36:769-773. CentersforDiseaseControl.1989.Update:Aedesalbopictusinfestation—UnitedStates,Mexico.MorbidityandMortalityWeeklyReport38:440,445-446. DarsieRF,WardRA.2005.IdentificationandGeographicalDistributionoftheMosquitoesofNorthAmerica,NorthofMexico.UniversityofFloridaPress,Gainesville,FL.300pp. GerhardtRR,GottfriedKL,AppersonCS,DavisBC,ErwinPC,SmithAB,PanellaNA,PowellEE,NasciRS.2001.FirstisolationofLaCrosseVirusfromnaturallyinfectedAedesalbopictus.EmergingInfectiousDiseases7:807-811. GublerDJ.1998.Dengueanddenguehemorrhagicfever.ClinicalMicrobiologyReviews480-496. HawleyWA.1988.ThebiologyofAedesalbopictus.JournaloftheAmericanMosquitoControlAssociation.Supplement#1.p.1-40. KoehlerPG,CastnerJL.(1997).Bloodsuckinginsects.EDIS.http://edis.ifas.ufl.edu/IN019(January2018). LounibosPL.2002.Invasionsbyinsectvectorsofhumandisease.AnnualReviewofEntomology47:233-266. LyonWF,BerryRL.1991.Asiantigermosquito.OhioStateUniversityExtensionFactSheetHYG-2148-98. MitchellCJ,NiebylskiML,SmithGC,KarabatsosN,MartinD,MutebiJP,CraigGBJr,MahlerMJ.1992.IsolationofeasternequineencephalitisvirusfromAedesalbopictusinFlorida.Science257:526-527. MooreCG,Francy,DB,EliasonDA,MonathTP.1988.AedesalbopictusintheUnitedStates:rapidspreadofapotentialdiseasevector.JournaloftheAmericanMosquitoControlAssociation4:35-61. MooreCG,MitchellCJ.1997.AedesalbopictusintheUnitedStates:ten-yearpresenceandpublichealthimplications.EmergingInfectiousDiseases3:329-334. O'MearaGF.(1997).TheAsiantigermosquitoinFlorida.EDIS.http://edis.ifas.ufl.edu/MG339(January2018). SprengerD,WuithiranyagoolT.1986.ThediscoveryanddistributionofAedesalbopictusinHarrisCounty,Texas.JournaloftheAmericanMosquitoControlAssociation2:217-219.