医学寄生虫学：旋毛形线虫

1旋毛形线虫

Trichinella

spiralis

2Brief

introductionSpiralwormThesmallestnematodeparasiteofhumans.Cause

of

trichiniasis(旋毛虫病）Zoonosis3Trichinellaspiralis----smallestnematode4MorphologyAdultthread-like，small,♂1.4-1.6mm,♀3-4mm

LongPharynx(咽管)

posteriorpartofpharynx：stichocytes(圆盘状杆细胞）5reproductivesystem：singletract（单管型）♂：alargecopulatorypseudobrsa(交配器）

nocopulatoryspicule（交合刺）.♀

uterus，vulva(阴门)6Larvae

（ovoviviparous卵胎生）NewbornlarvaLarvainmuscle

bloodstream→

striatedmuscles(横纹肌)Cyst(larvaencysted)LarvaeofTrichinella,（freedfromtheircysts,0.8to1mm.

7larvacapsule（幼虫囊包）inskeletalmuscle0.25～0.5×0.21～0.42mm.inpressedmuscletissuesample8Lifecycle

Adults(insmallintestinecopulation）♀♂

died5~7dNewbornlarvaepenetrateintestine—blood—striatedmuscles

cysts(1month)6~7m

calcificationofcysts

(inmeat）Cystsoftrichinellainraworuncookedmeat

Ingested,

gastricacidseveralhourslaterlarvaeinvadesmallintestinemucosa

48h，molt4times9LifecycleLarvaeMolt4times10LifecycleThelarvaeenterbloodvessels

Prefer

highlyactivemuscles11LifecycleIn

musclecellanintracellularparasitemanipulatesthehostcelltoitsneeds12LifecycleHostcell：Losesitsmyofilament(肌丝)SeveraladditionalsubcellularchangesoccurEnclosed

byacollagencapsule1314KeypointsofLifecycleAdults(inintestine)；larvae(instriatedmuscle横纹肌）ChangingthehostsisnecessarytocompletethelifecycleInfectivestage:larvacystTransmission:ingestionofuncookedporkwithcystReservoirhost:mostcarnivorous(肉食）andomnivorous（杂食）animals15Pathogenesis&ManifestationsInvolvedtissues:Gastrointestinaltract,blood,&striatedmuscle

Symptoms:Stronglyassociatedwithingestiondose(>1200larvae→leathal)Acuteinflammatoryresponse,granulomas(肉芽肿),cyst,cystscalcify

Threestages:invade,migratory&encystationofthelarvaeandtissuerepairImmunity:infectionofhumaninducesspecifichumoralandcell-mediatedimmunereaction.16Invadephase侵入期Intestinalstage:肠型期1weekUlceration(溃疡),mucosalhyperaemia(粘膜充血),hemorrhages(出血)intestinalinflammationGastrointestinalsymptoms:

fever,disgusting,vomiting,anorexia(食欲减退),abdominaldiscomfort,diarrhea,

Theadultentersthemucosaofthesmallintestine17Migratoryphase幼虫移行期Seriouscomplications:myocarditis(心肌炎),pneumonia&meningoencephalitis（脑膜脑炎）,mortality3%Periorbital

andfacialedema（眼睑浮肿）Conjunctivitis（结膜炎）Myalgias（肌痛）Splinter

hemorrhagesRashes

(皮疹)Blood

eosinophiliaFeverandchillsHeadacheDizziness

18Typicalclinicsymptoms:Fever

,Myalgia

EdemaEosinophilia

MigratoryphaseSwolleneyes(periorbitaledema)

19Encystation囊包形成期FormationofcystintissuesInflammationdisappeargraduallyMildSevere:Deathisusuallycausedbyheartfailure,

respiratorycomplications,

kidneymalfunction.20Diagnosis

Clinicalsymptoms，eosinophilia,historyLaboratorydiagnosis:

immunodiagnosis(免疫诊断)&musclebiopsyImmunodiagnosisIDT:intradermaltest皮内试验

Bentoniteflocculation(BFT皂土絮状试验)21Laboratorydiagnosis•Biopsyofmuscle

Seldomemployed,

butaccurate

22EpidemiologyWorldwide

distributionInChina,15provinces(Tibet,Yunnan,Henan,andthenortheastpartofChinaTransmission：salting,drying,smoking,ormicrowavingInfectionmayoccuringroupwhosharefoodSourceofinfection:120+mammals（pigs,cats,foxes,rats,etc)Strongresistanceto:23TeatmentandcontrolEatinghabitsControlofmeat,rat,deadanimals,wildlifeNoreallysatisfactorytreatmentfor