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1、Nematode,线虫,Introduction to Nematode,Class Nematoda（线虫纲）about 10 species are medical important,General morphological characters of nematode,Cylindrical shapenon-segmented(不分节)bilateral symmetry(两侧对称）dioecious(雌雄异体)，females are usually larger the tail of the male usually curled（卷曲）or expand to umbrel
2、la-like,General morphological characters of nematode,Characters of life cycle,Type of life cycle：soil-transmission nematodes（土源性线虫）bio-source nematodes（生物源性线虫）：需中间宿主Infective stage：Infective eggInfective larvacyst,Important nematodes,Intestinal nematode：蛔虫、钩虫、蛲虫、鞭虫等blood namatode丝虫Tissue nematode旋毛虫
3、,Ascarid/bellyworm/roundworm(蛔虫）。蛔虫病（ascariasis),似蚓蛔线虫Ascaris lumbricoides,morphologial of adults,cuticle（表皮）with circular striations（环纹）,Size:male:1531cm female:2035cm,lips(唇瓣),spicule(交合刺),fertilised egg(受精卵),albuminoid coat(蛋白质外膜),thick eggshell,vitteline layer(受精膜);chitinous layer(壳质层)ascaroside
4、（蛔甙层）,unfertilised egg(未受精卵),egg,decorticated egg(脱蛋白膜卵),多细胞卵,含幼虫卵,Simple life cycle/direct life cyclefinal host：humansinhabited site：small intestine infective stage：infective eggInfective mode：by ingestionEgg passed in fecesLiver lung migration,Summary of life cycle,pathogenecity,肺蛔虫病（Loefflers syn
5、drome）异位寄生,lung phase of larval migration,larva in section of lung,蛔虫病（ascariasis）并发症(complication)intestinal blockage(肠梗阻)Perforation of intestine(肠穿孔)ascariasis of bile duct(胆道蛔虫症)appendicitis(阑尾炎),pathogenecity,diagnosis,Etilogical diagnosisfound characteristic egg in feces；Adult in fecesjuvenile
6、s(幼虫)in sputum Immulogical diagnosis,epidemiology,Geographic distribution:worldwideFactors of high prevalence：Simple life cycle and produce large numbers of eggStrong resistance to chemical and environmentStool are use for fertilizerPoor sanitation or Low personal hygiene,Prevention and control,Trea
7、tment patients,carriersMebendazole（甲苯达唑）Albendazole（阿苯达唑）Good hygiene,毛首鞭形线虫Trichuris trichiura,the human whipworm live in the caecum(盲肠)and upper part of the colon(结肠),Morphology of adult,Morpholoy of egg,barrel shape,polar plugs,yellow brown,生活史(life cycle),Direct life cyclefinal host：humaninfecti
8、ve stage：infective eggroute of infection：by ingestionEgg passed in fecesNo blood-lung migration,pathogenecity,diagnosis,Find eggs in feces。,Prevention and control,Geograpgic distribution:worldwide treatment阿苯达唑albendazole甲苯咪唑mebendazole,钩虫：hookworm,Human hookworm 十二指肠钩口线虫（Ancylostoma duodenale）美洲板口线
9、虫(Necator americanus)hookworm disease/ancylostomiasis,Shape of adult,口囊:buccal capsule,交合伞copulatory bursa;背辐肋dorsal ray,交合刺copulatory spicules,Morphology of egg,生活史(life cycle),Summary of life cycle,Adult live in upper of small intestine Egg passed in fecesinfective stage：丝状蚴filariform larva丝状蚴活动特点
10、：向温性、向湿性、聚集性route of infect：by skinBlood-lung migration,丝状蚴,Pathogenicity,Larval penetration of the skin may lead to ground itch(钩蚴性皮炎)；larvae migrating through the lungs may cause pneumonitis(肺炎),Pathogenicity,Adult feed on the the small intestine mucosa and blood 缺铁性贫血Iron deficiency anemia(低色素小细胞
11、型贫血）；腹泻和异嗜症；婴儿钩虫病(Infantile hookworm disease)；消化道出血(Gastrointestinal blooding)。,致病:Pathogenicity,贫血原因：长期慢性失血(Chronic blood loss)：边吸边排边漏；分泌抗凝素anticoagulant；频繁更换咬附部位；虫体活动造成组织、血管损伤。,diagnosis,Etilogical examination（1）direct smear：（2）brine floatation method(饱和盐水浮聚法)（3）Larval cultivation(钩蚴培养法)（4）larva i
12、n sputum,diagnosis,Serological test（1）皮内实验（ID）（2）ELISA:（3）间接荧光抗体试验（IFA),epidemiology,Factors in prevalence source of infection：patients and carriers。Way to infection,Prevention and control,Treament of source of infection阿苯达唑albendazole 甲苯咪唑mebendazoleGood hygiene,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。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，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？,思 考 题,
