课件：蛔虫、鞭虫、钩虫北大.ppt

复习题？,1.试述保虫宿主与转续宿主的区别。,2.寄生虫为什么能在有免疫力的人体中生存而 不被排除？,2019,-,1,寄生虫病的传播途径包括污染或含有寄生虫的感染期的,土壤 水 食物 节肢动物传播媒介,2019,-,2,寄生虫感染阶段是指寄生虫的：,感染人体阶段 感染保虫宿主阶段 感染中间宿主阶段 感染中间宿主阶段 感染昆虫媒介阶段,2019,-,3,人体寄生虫病的传染源包括：,仅有病人和带虫者 医学节肢动物 所有野生动物 病人、带虫者、感染的动物,2019,-,4,关于蛲虫，下列哪项是错误的：,1.生活史简单 2.感染率儿童高于成人，城市高于农村 3.生活史属间接型 4.带虫者和病人是唯一的传染源 5.感染方式主要是人群中的间接接触和肛门 手口直接感染,2019,-,5,Ascaris Lumbricoides,P162,2019,-,6,Ascaris Lumbricoides,Ascaris lumbricoides , common saying “round worm of man”, is the largest of the intestinal nematodes parasitizing humans. It is the most common worm found in human. It is worldwide in distribution and most prevalent through out the tropics, sub-tropics and more prevalent in the countryside than in the city,2019,-,7,似蚓蛔线虫（蛔虫）,Ascaris lumbricoides,一、形态,成虫,活体,2035cm,1531cm,活体,2019,-,8,Adult worm of A. lumbricoides,2019,-,9,蛔虫唇 瓣扫描电镜图,“品”,2019,-,10,脱蛋白质膜受精卵,虫卵,2019,-,11,卵,感染期卵,二 生 活 史,录像,录像,2019,-,12,侵入肠粘膜的小V、小L,蛔虫幼虫的体内移行：,2019,-,13,1. Site of inhabitation: small intestine 2. Infetive stage: embryonated eggs 3. Route of infection: by mouth 4. No intermediate and reservoir hosts 5. Life span of the adult: about 1 year,生活史的特点：,2019,-,14,III. Pathogenesis,There are two phases in ascariasis: 1. The blood-lung migration phase of the larvae: During the migration through the lungs, the larvae may cause a pneumonia. The symptoms of the pneumonia are low fever, cough, blood-tinged sputum, asthma. Large numbers of worms may give rise to allergic symptoms. Eosionophilia is generally present. These clinical manifestation is also called Loefflers syndrome.,2019,-,15,2. The intestinal phase of the adults. The presence of a few adult worms in the lumen of the small intestine usually produces no symptoms, but may give rise to vague abdominal pains or intermittent colic, especially in children. A heavy worm burden can result in malnutrition. More serious manifestations have been observed. Wandering adults may block the appendical lumen or the common bile duct and even perforate the intestinal wall. Thus complications of ascariasis, such as intestinal obstruction, appendicitis, biliary ascariasis, perforation of the intestine, cholecystitis, pancreatitis and peritonitis, etc., may occur, in which biliary ascariasis is the most common complication.,录像,2019,-,16,致病（pathogenesis),录 像,1、幼虫致病,2、成虫致病,蛔虫性哮喘,掠夺营养,引起变态反应 哮喘,荨麻疹,2019,-,17,并发症 (国内报告 8468例),胆道蛔虫症 4556例(53.8%) 蛔虫性肠梗阻 2337例(27.6%) 蛔虫性阑尾炎 143例 蛔虫性胰腺炎 17例 蛔虫性哮喘 1352例 蛔虫性肝脓肿 33例,2019,-,18,直接涂片法,四、诊断（diagnosis),改良加藤法,录 像,2019,-,19,五、流行与防治 (Endemity and Prevention),World wide distribution, very common in China, especially in the countryside. Factors favoring the spread of the transmission: 1. Simple life cycle. 2. Enormous egg production ( 240,000 eggs/ day/ female ). 3. These eggs are highly resistant to ordinary disinfectants (due to the ascroside). The eggs may remain viable for several years. 4. Social customs and living habits. 5. Disposal of feces is unsuitable.,流行,2019,-,20,1.Treatment to ascariasis: Mebendazole, Albendazole and Levamizole are effective. 2.Sanitary disposal of feces. 3.Hygienic habits such as cleaning of hands before meals. 4.Health education.,防治,2019,-,21,Trichuris trichiura (毛首鞭形线虫),1. Introduction: The common name of Trichuris trichiura is whip-worm(鞭虫), adults live in caecum (盲肠) of human and result in trichuriasis(鞭虫病),2019,-,22,2. Morphology:,1) Adults resemble a whip, anterior with a hair-like lash and posterior with the handle. Mouth cavity is provided with a minute spear 2) Male: about 4 cm long, posterior is spirally coiled. 3) Female: about 5 cm long, posterior extremity straight.,2019,-,23,4) Egg,A typical barrel shape with two polar plugs (2) Size: 50-54 m by 22-23 m (3)The external layer of the shell of the egg is yellow brown (4) An ovum is in the egg when it passed with stool,2019,-,24,3. Life cycle,adults （cecum）,eggs,1T7T/daily,moist、warm 35w,infective eggs,larvae （small intestine）,adults （cecum）,migration down cecum,Larvae do not enter circulation system！,ingestion,2019,-,25,2019,-,26,4. Pathology Feeding on tissue fluid and blood; The slender anterior ends penetrate into the gut mucosa and make lesions;,2019,-,27,Symptoms:,Symptoms are determined largely by the worm burden: light infections are asymptomatic. Heavier infections are characterized by: 1) chronic mucous and bloody diarrhea 2) abdominal pains 3) hemorrhage and anemia (贫血) or rectal prolapse (直肠脱垂) in heavy infection children 4) The infection may result in malnutrition and growth retardation,2019,-,28,5. Diagnosis,Diagnosis is based on symptoms and the presence of eggs in feces,2019,-,29,6. Prevalence and control,Trichuriasis often prevail with ascariasis 17.38% of population infected with this parasite in China The treatment and control can refer to ascariasis,2019,-,30,十二指肠钩口线虫和美洲板口线虫（钩虫）,(Hookworm),一、形态,成虫,十二指肠钩口线虫,美洲板口线虫,前进,Ancylostoma duodenale,Necator americanus,and,2019,-,31,消化系统的特点：,1、口囊发达 2、咽管壁肌肉发达 3、头腺、咽管腺分泌抗凝 素、乙酰胆碱酯酶。,2019,-,32,大小,体形,口囊,交合伞,背辐肋,十二指肠钩虫,美洲钩虫,“C”,“S”,两对钩齿,一对板齿,交合刺,尾刺,有,无,圆形,扁圆形,远端分两支， 每支再分3小支,基部先分两支， 每支再分2小支,: 1013 x 0.6mm,: 8 11 x 0.40.5mm,: 911 x 0.4mm,: 7 9 x 0.3mm,前进,2019,-,33,十二指肠钩虫口囊,美洲钩虫口囊,实物扫描电镜图,2019,-,34,十二指肠钩虫口囊,美洲钩虫口囊,实物标本,2019,-,35,十二指肠钩虫交合伞,美洲钩虫交合伞,2019,-,36,十二指肠钩虫背辐肋,2019,-,37,美洲钩虫背辐肋,2019,-,38,十二指肠钩虫背辐肋,美洲钩虫背辐肋,2019,-,39,钩虫卵,中等大小,椭圆形,无色透明,48个卵细胞,极薄,卵壳与卵细胞 间有透明间隙,虫卵,2019,-,40,二 生 活 史,2019,-,41,迁延移行,二 、生活史,录像,2019,-,42,侵入皮肤小V、小L,钩蚴的体内移行,录像,2019,-,43,生活史的特点：,1、寄生部位： 2、感染期： 3、感染途径： 4、感染方式： 5、迁延移行： 6、丝状蚴特性： 7、转续宿主：,小肠,丝状蚴,皮肤、口、胎盘、乳汁等,接触泥土、生食蔬菜和转续宿主肉类、母婴传播等,向温性、向触性,猪、犬、灵猫等,2019,-,44,录 像,1、幼虫致病,2、成虫致病,三、致病（pathogenesis),2019,-,45,1、边吸血边排血；,2、咬附部位渗血；,3、更换咬附位置，原伤口仍渗血；,4、虫体活动造成组织、血管损伤引起失血。,钩虫引起贫血的原因：,2019,-,46,四、诊断（diagnosis),直接涂片法,饱和盐水浮聚法,钩蚴培养法,2019,-,47,五、流行与防治 (Endemity and Prevention),1.种植蔬菜与经济作物地区 2.用新鲜粪便施肥 3.种植时手脚接触泥土的机会多,钩虫病流行的特点与原因,2019,-,48,五、流行与防治 (Endemity and Prevention),录像,1、被钩蚴污染的尿布；,2、睡沙袋、穿“土裤子”；,婴儿感染钩虫的途径：,3、经胎盘感染；,4、经乳汁感染；,2019,-,49,钩虫病的防治,控制传染源 a).治疗钩蚴性皮炎:用左旋咪唑或15% b).治疗钩虫病:首选肠虫清(阿苯达唑),联合用药,如:甲苯咪唑+噻嘧啶,噻嘧啶+左旋咪唑,粪便无害化处理 个人防护,噻苯咪唑软膏涂擦.,2019,-,50,蛔虫的感染阶段是：,受精卵（含一个卵细胞） 感染性虫卵 未受精卵 脱蛋白质膜受精卵,思考题？,2019,-,51,蛔虫的流行与蛔虫的：,未受精卵有关 受精卵与未受精卵都有关 受精卵无关 受精卵有关,2019,-,52,蛔虫的主要致病阶段是：,受精卵 未受精卵 感染性虫卵 成虫,2019,-,