1、Nematode线虫线虫Introduction to Nematode Class Nematoda（线虫纲线虫纲） about 10 species are medical important General morphological characters of nematodeCylindrical shapenon-segmented (不分节不分节) bilateral symmetry(两侧对称两侧对称）dioecious (雌雄异体雌雄异体) ，females are usually larger the tail of the male usually curled（卷曲）卷
2、曲） or expand to umbrella-like General morphological characters of nematodeCharacters of life cycle Type of life cycleType of life cycle：soil-transmission nematodessoil-transmission nematodes（土源性土源性线虫）线虫）bio-source nematodesbio-source nematodes（生物源性线生物源性线虫）虫） ：需中间宿主：需中间宿主 Infective stageInfective sta
3、ge：Infective eggInfective eggInfective larvaInfective larvacystcystImportant nematodes Intestinal nematode：蛔虫、钩虫、蛲虫、鞭虫等蛔虫、钩虫、蛲虫、鞭虫等 blood namatode丝虫丝虫 Tissue nematode旋毛虫旋毛虫Ascarid/bellyworm/roundworm(蛔虫）。蛔虫）。蛔虫病（蛔虫病（ascariasis)Ascaris lumbricoidesmorphologial of adults cuticlecuticle（表皮）表皮）with circ
4、ular striationswith circular striations （环纹）环纹）SizeSize: : malemale:15:1531cm 31cm femalefemale: 20: 2035cm35cmlips(唇瓣唇瓣) spiculespicule ( (交合刺交合刺) )fertilised egg(受精卵) 50 :malbuminoid coat(蛋白质外膜蛋白质外膜) thick eggshell vitteline layer(vitteline layer(受精膜受精膜) ; ) ;chitinous layer(chitinous layer(壳质层壳质层
5、) )ascarosideascaroside（蛔甙层蛔甙层）unfertilised egg(未受精卵未受精卵) eggdecorticated egg(脱蛋白膜卵)多细多细胞卵胞卵含幼含幼虫卵虫卵Simple life cycle/direct life cyclefinal host：humansinhabited site：small intestine infective stage：infective eggInfective mode ：by ingestionEgg passed in fecesLiver lung migrationSummary of life cycle
6、pathogenecity肺蛔虫病肺蛔虫病（ Loefflers syndrome ）异位寄生异位寄生 lung phase of larval migration larva in section of lung 蛔虫病（蛔虫病（ascariasis ）并发症并发症(complication)intestinal blockage(肠梗阻肠梗阻) Perforation of intestine(肠穿孔肠穿孔) ascariasis of bile duct(胆道蛔虫症胆道蛔虫症) appendicitis(阑尾炎阑尾炎)pathogenecitydiagnosisEtilogical di
7、agnosisEtilogical diagnosisfound characteristic egg in fecesfound characteristic egg in feces；Adult in fecesAdult in fecesjuveniles(juveniles(幼虫幼虫) ) in sputumin sputum Immulogical diagnosisImmulogical diagnosis epidemiologyGeographic distribution: worldwideFactors of high prevalence：Simple life cyc
8、le and produce large numbers of eggStrong resistance to chemical and environmentStool are use for fertilizerPoor sanitation or Low personal hygiene Prevention and control Treatment patients, carriersMebendazole（甲苯达唑）甲苯达唑）Albendazole（阿苯达唑）阿苯达唑） Good hygiene毛首鞭形线虫Trichuris trichiurathe human whipworm
9、live in the caecum(盲肠盲肠)and upper part of the colon(结肠结肠) Morphology of adultMorpholoy of eggbarrel shapepolar plugsyellow brown 生活史生活史(life cycle)Direct life cyclefinal host：humaninfective stage：infective eggroute of infection：by ingestionEgg passed in fecesNo blood-lung migrationpathogenecitydiagn
10、osisFind eggs in fecesFind eggs in feces。Prevention and controlGeograpgic distribution: worldwideGeograpgic distribution: worldwide treatmenttreatment阿苯达唑阿苯达唑albendazolealbendazole甲苯咪唑甲苯咪唑mebendazolemebendazole钩虫钩虫：hookworm Human hookwormHuman hookworm 十二指肠钩口线虫十二指肠钩口线虫（Ancylostoma duodenaleAncylosto
11、ma duodenale）美洲板口线虫美洲板口线虫( (Necator americanus)Necator americanus) hookworm disease/ancylostomiasishookworm disease/ancylostomiasisShape of adult口囊:buccal capsulebuccal capsule 交合伞交合伞copulatory bursa;背辐肋背辐肋dorsal ray 交合刺copulatory spicules Morphology of egg生活史(life cycle)Summary of life cycle Adult
12、live in upper of small intestine Egg passed in feces infective stage：丝状蚴丝状蚴filariform larva 丝状蚴活动特点：向温性、向湿性、聚集性丝状蚴活动特点：向温性、向湿性、聚集性 route of infect：by skin Blood-lung migration丝状蚴丝状蚴Pathogenicity Larval penetration of the skin may lead to ground itch(钩蚴性皮炎钩蚴性皮炎)； larvae migrating through the lungs ma
13、y cause pneumonitis(肺炎肺炎)Pathogenicity Adult feed on the the small intestine mucosa and blood 缺铁性贫血缺铁性贫血Iron deficiency anemia (低色素低色素小细胞型贫血）；小细胞型贫血）； 腹泻和异嗜症；腹泻和异嗜症； 婴儿钩虫病婴儿钩虫病(Infantile hookworm disease) ； 消化道出血消化道出血(Gastrointestinal blooding) 。致病: Pathogenicity贫血原因：贫血原因： 长期慢性失血长期慢性失血(Chronic blood
14、 loss)： 边吸边排边漏；边吸边排边漏； 分泌抗凝素分泌抗凝素anticoagulant； 频繁更换咬附部位；频繁更换咬附部位； 虫体活动造成组织、血管损伤。虫体活动造成组织、血管损伤。diagnosis Etilogical examination（1）direct smear：（2）brine floatation method(饱和盐水浮饱和盐水浮聚法聚法)（3） Larval cultivation(钩蚴培养法钩蚴培养法) （4）larva in sputumdiagnosis Serological test（1）皮内实验（）皮内实验（ID）（2）ELISA:（3）间接荧光抗体试
15、验（间接荧光抗体试验（IFA)epidemiology Factors in prevalence source of infection：patients and carriers。 Way to infectionPrevention and control Treament of source of infection阿苯达唑阿苯达唑albendazole 甲苯咪唑甲苯咪唑mebendazole Good hygiene为什么蛔虫病广泛流行？你能否从虫形态、生态为什么蛔虫病广泛流行？你能否从虫形态、生态 生活史几个方面分析。生活史几个方面分析。为什么小孩蛔虫病多于成人，农村多于城市？为什么小孩蛔虫病多于成人，农村多于城市？一小孩血检嗜酸性粒细胞增加，医生怀疑蛔虫病，一小孩血检嗜酸性粒细胞增加，医生怀疑蛔虫病， 而粪检虫卵阴性，可能是什么原因？你如何处理？而粪检虫卵阴性，可能是什么原因？你如何处理？寄生虫可引起哪几种皮肤病？如何引起？寄生虫可引起哪几种皮肤病？如何引起？思思 考考 题题
