Medicalarthropods

醫(yī)學(xué)節(jié)肢動物

TeachingpointsMorphologyofarthropodsClassificationofmedicalarthopodsHarmfuleffects

onhumanCriteriatojudgemedicalarthropodMosquitoesandfliesthelargestphylum,accountfor75%ofallanimals

MedicalarthropodsArthropodswithmedicalimportance:parasiticarthropods,orvectorsofpathogens

Medicalarthropodology(entomology)asubjecttostudy:

morphology,classification,lifecycle,ecology,geographicaldistribution,pathogenesis,regularityofdiseasetransmissionandcontrolstrategiesI

Introduction

Bilaterialsymmetry,Segmentationofbodyandappendages

(antennae,palpsandlegs)

Exoskeleton(外骨骼)

:

consistsof

chitinandquinonetannedprotein

Opencirculatorysystem:

thebodycavityishemocoel,fullofhaemolymph

MoltingorecdysisandMetamorphosis(變態(tài))ⅡMorphologyofarthropods1ClassInsecta

(昆蟲綱)3parts(head,thoraxandabdomen),3pairsoflegs,1pairofantennae

(觸角)

Example:mosquito,fly,flea,louse,etc2ClassArachnida

(蛛形綱)2parts(cephalo-thoraxandabdomen)orasacombinedbody，4pairsoflegs,noantennae

Example:tick,mite,spider,etcⅢArthropodsofmedicalimportance3ClassCrustacea(甲殼綱)

cephalothoraxandabdomen,2pairsofantennae,5pairsofwalkinglegs,mostliveinwater

Example:shrimp,crab,cyclops，etc4ClassChilopoda

(唇足綱)

slender,flatandsegmentedbody,1pairofantennae

Example:

Centipede

5

Class

Diplopoda(倍足綱)

longpipe-shapedandmulti-segmentedbody,1pairofantennae

Example:diplopod

ⅢArthropodsofmedicalimportance1.Directinjury2.Indirectinjury:diseasestransmission

Arbo-disease:diseasestransmittedbymedicalarthropodsMechanicaltransmission:

notmultiplyordevelopinthearthropodnotanintegralpartofthelifecycleofthepathogenBiologicaltransmission:

eithermultiples,develops,orbothinthevector.onepartofthelifecycleofthepathogenⅣHarmfuleffects

onhumanAnnoyanceandsuckingblood

Damagebytoxicsubstances

biting/contact/activeprojection/ingestion

Example：

Paederusfuscipus:dermatitis

Allergicreaction(anaphylaxis)

allergen:saliva,secretoryandexcretory

substancesExample:dustmites(allergicrhinitisandasthma)Invadingtissues

Example:

Myiasis,scabies，Tungiasis，

Directinjury

InsectsPathogensDiseases

housefly,cockroachSalmonellasppSalmonellosishouseflycommabacillus

cholera

(霍亂弧菌）housefly,cockroachE.histolyticaamebicdysentery

ExamplesofmechanicaltransmissionFordevelopment：pathogenstransmittedhaveaperiodofdevelopmentinthearthropodvectors

Example:MicrofilariaeinmosquitoesForproliferation：pathogenstransmittedmultiplyinthevectors

Example:Yersinapestis

(鼠疫桿菌)infleas;DenguevirusinmosquitoesCyclopropagative(developmentandproliferation)：

Example:

PlasmodiuminmosquitoesTransovarialpassage(經(jīng)卵傳遞)：Thepathogennotonlycandevelopand/ormultiplyinfemalearthropod,butalsoinvadeitsovary.Filialgenerationisinfectious,too.

Example:

ForestencephalitistransmittedbyhardtickFourstylesofbiologicaltransmissionBiologicalevidences

：Closerelationshipwithhumanbeing;Predominantspecies;Lifespanislongenough.

Epidemiologicalevidences

：Thegeographicaldistributionandseasonalexistenceareconsistentwiththearbo-disease.Laboratoryevidences：Thesuspectedvectorsshouldbesuccessfullyinfectedinthelab.Naturalinfectionevidences(mostimportant)：Inepidemicseason,thepathogencanbeexaminedfromthearthropodinepidemicarea.ⅤCriteriatojudgemedicalarthropodEnvironmentalmanagement：reduceorcontrolbreedingsitesbyimprovementofenvironmentandsanitationPhysicalmeasures：bed-netetcChemicalmeasures：insecticidesBiologicalmeasures：BacillusthuringiensisGeneticmeasures：produceinfertilitymalesofmosquitoⅥControl:integratedmanagementClassInsecta

昆蟲綱ThelargestandmostwidelydistributedtaxonwithinthePhylumArthropod.Insectscomprisethemostdiversegroupofanimalsontheearth,withover800,000speciesdescribed

MorphologicalcharactersofInsectaCompoundeyesantennaabdomenthoraxheadHeadApairofcompoundeyesApairofantennaeApairofpalpsMouthpartsChewingtype(咀嚼式)

SuckingtypeSpongingtype3parts:prothorax,mesothoraxandmetathorax3pairsoflegs:consistsofcoax(股),trochanter(轉(zhuǎn)),femur(股),tibia(脛),andtarsus(跗)1-2pairsofwings:Somehind-wingshavemodifiedintoknobbedstructures,calledhalters(平衡棒，abalancingorgan).Thorax11segmentsEcto-reproductionorgans(thoselast3segmentsfuse)AbdomenMetamorphosis(變態(tài))Thedevelopmentofarthropodincludes

embryonic(completedinegg)andpost-embryonicdevelopment

Fromeclosion(孵化)oflarvaornymph(若蟲)toadult,therearewidelydifferencesinthemorphology,structures,physiologicalfunction,livinghabits,behaviourandinstinct.Allthechangesarecalledasmetamorphosis.ConsistsofcompleteandincompletemetamorphosisImportantConceptsinlifecycleadultpupalarvaeggscompletemetamorphosisPupastage;Larvadiffersitsadultinmorphologyandlifehabitsignificantly.Example:mosquito,fly,sandfly,fleaetc.incompletemetamorphosiseggnymphadultbedbugNopupa

stage;Thelarva/nymphstageissimilartotheadultinmorphologyandlifehabits,butthesexualorgansstillundevelopedorimmature.Example:louse,bug,cockroach,etc.Instar:

thestagebetweentwomoltingsPupation:

theprocessthatthelarvagrowsintopupa.Emergence:

theprocessthattheadultisexposedoutfromthepupaOtherConceptsinlifecycleMosquitoesbelongtotheFamilyCulicidae.Therearemorethan3,500speciesthroughouttheworldandover350speciesoccurinChina.Anopheles（按蚊）,Culex（庫蚊）and

Aedes（伊蚊）arethemostimportantfromthemedicalpointofview.MosquitoesProboscis(喙）RequirewaterfordevelopmentFemalesfeedonblood30-300eggsoviposited）Adultslive1-3weeksLifecycle4timesofmoltinginlarvae）Freeswimmingbutnonfeedingfor2-3days）

EggLarvaPupaRestpostureHeadoffemaleWingsandlegsBreedingsites

PhysiologyandEcology

PaddyorricefieldsSlowlyflowwaterJungleorforestareaDirtywaterContainerHabitofsuckingblood:

Prefersuckinghumanordomesticanimalblood;Differentfeedingtimeduotodifferentspecies:

Aedessearchforabloodmealearlyinthemorning;

Anophelesintheevening;Culexatduskandafterdark.Gonotrophiccycle

:Thebloodmealisessentialfortheovarydevelopmentandoviposition.Theperiodfromsuckingbloodtoovipositionisabout2-3days.

Physiologicalage:

numbersofexperiencedgonotrophiccycle(criteriumtojudgetheageofmosquito)

Seasonaldistributionandoverwinter

Longevity：1-2wintropicalareas;

3-4worlongerintemperateregionsPhysiologyandEcology

Directharm:

disturbance,suckingblood

Indirectharm(biologicaltransmission)

Harmfuleffects

onhuman

VectorsPathogensDiseasesAnopheles

sinensisA.Anthropophagus

Plasmodium

Malaria

A.minimusA.dirusCulexpipienspallensW.brancrofti

Filariasis

bancroftiC.pipiensfatigansA.

sinesisandA.

B.malayi

FilariasismalayiAnthropophagusAedesaegyptiA.albopictusDenguevirusDengue-feverC.Tritaeniorhynchus

JanpaneseB

EpidemicBencephalitisvirus

encephalitis

Mosquito-bornediseasesThereareover10,000speciesknownoffliesintheworld.Fourfamilieswithmedicalimportance:Muscidae

CalliphoridaeSarcophagidaeOestridaeFliesbacterialbomb

Chrysomyiamegacephala(goldenfly)Deepreddishcompoundeyes,greenbluemetaliccolorLuciliasericata(greenfly)GreenmetaliccolourwithsilverwhitefaceMuscadomestica(housefly)4

black

strips

onthedorsalsideBoettcheriscaperegrina(fleshfly）3

strips

ontheback,tesselatedscalesindorsalabdomen

MorphologicalcharactersandlifecyclelarvapupaLargecompoundeyes,female

separatedandmaleclose.Lappingmouthparts(舐吸式口器)Clawmatandfeet

fullofhairHabitat:

feedingonorganicmaterial,feces,garbageplantorotherdecayingmaterialFeedinghabit:

feedingfrequently,feedingwhilepasspartiallydigestedmeals(easilytransmitpathogensfromitsintestinaltract)

1.Unabletofeedthemselves:Oestridae2.Suckingblood:Stomoxyscalcitrans3.Omnivorous(雜食）:mostflies

Over

winter:

mostinthepupastage

EcologyandlivinghabitHarmfuleffectsonhuman

Mechanicaltransmission:morethan100pathogens

1.Morphologicalbases:

distributedhairdenselyonclawmatandfeet;2.thepowerfulflight

3.feedinghabits

Biologicaltransmission:

Tsetseflies(Glossina):AfricanTrypanosomiasis

TissueInvasionandparasitism:

MyiasisAfemaleTsetsefly

DorsalveinheartarteryOpen