蛔蟲、鞭蟲、鉤蟲(北大)課件

1、Ascaris LumbricoidesP162 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 a

2、nd more prevalent in the countryside than in the city 2035cm1531cm Adult worm of A. lumbricoides蛋白質(zhì)膜蛋白質(zhì)膜卵殼卵殼卵細(xì)胞卵細(xì)胞新月形間隙新月形間隙卵黃顆粒卵黃顆粒n 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 th

3、e adult: about 1 year 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 wor

4、ms may give rise to allergic symptoms. Eosionophilia is generally present. These clinical manifestation is also called Loefflers syndrome. n 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

5、 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

6、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.哮喘哮喘,蕁麻疹蕁麻疹(國內(nèi)報告國內(nèi)報告 8468例例)膽道蛔蟲癥膽道蛔蟲癥 4556例例(53.8%)蛔蟲性腸梗阻蛔蟲性腸梗阻 2337例

7、例(27.6%)蛔蟲性闌尾炎蛔蟲性闌尾炎 143例例蛔蟲性胰腺炎蛔蟲性胰腺炎 17例例蛔蟲性哮喘蛔蟲性哮喘 1352例例蛔蟲性肝膿腫蛔蟲性肝膿腫 33例例 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

8、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.n1.Treatment to ascariasis: Mebendazole, Albendazole and Levamizole are effective.n2.Sanitary disposal of feces.n3.H

9、ygienic habits such as cleaning of hands before meals.n4.Health education.Trichuris trichiura (毛首鞭形線蟲毛首鞭形線蟲)1. Introduction: The common name of Trichuris trichiura is whip-worm(鞭蟲鞭蟲), adults live in caecum (盲腸盲腸) of human and result in trichuriasis(鞭蟲病鞭蟲病) 2. Morphology:1) Adults resemble a whip, an

10、terior with a hair-like lash and posterior with the handle. Mouth cavity is provided with a minute spear2) Male: about 4 cm long, posterior is spirally coiled.3) Female: about 5 cm long, posterior extremity straight. 4) Egg nA typical barrel shape with two polar plugs (2) Size: 50-54 m by 22-23 m (3

11、)The external layer of the shell of the egg is yellow brown (4) An ovum is in the egg when it passed with stool 3. Life cycle adults（cecum） eggs1T7T/daily moist、warm 35w infective eggs larvae （small intestine） adults （cecum） migration down cecum Larvae do not enter circulation system！ingestion 4. Pa

12、thologynFeeding on tissue fluid and blood;nThe slender anterior ends penetrate into the gut mucosa and make lesions;Symptoms:Symptoms are determined largely by the wormburden: nlight infections are asymptomatic. nHeavier infections are characterized by: 1) chronic mucous and bloody diarrhea 2) abdom

13、inal pains 3) hemorrhage and anemia (貧血) or rectal prolapse (直腸脫垂) in heavy infection children 4) The infection may result in malnutrition and growth retardation 5. DiagnosisnDiagnosis is based on symptoms and the presence of eggs in feces 6. Prevalence and controlnTrichuriasis often prevail with as

14、cariasisn17.38% of population infected with this parasite in China nThe treatment and control can refer to ascariasis十二指腸鉤口線蟲美洲板口線蟲“C”“S”有有無無: 1013 x 0.6mm: 8 11 x 0.40.5mm: 911 x 0.4mm: 7 9 x 0.3mm美洲美洲美洲1 1、邊吸血邊排血；、邊吸血邊排血；2 2、咬附部位滲血；、咬附部位滲血；3 3、更換咬附位置，原傷口仍滲血；、更換咬附位置，原傷口仍滲血；4 4、蟲體活動造成組織、血管損傷引起失血。、蟲體活動造成組織、血管損傷引起失血。 1.1.種植蔬菜與經(jīng)濟作物地區(qū)種植蔬菜與經(jīng)濟作物地區(qū) 2.2.用新鮮糞便施肥用新鮮糞便施肥 3.3.種植時手腳接觸泥土的機會多種植時手腳接觸泥土的機會多1 1、被鉤蚴污染的尿布；、被鉤蚴污染的尿布；2 2、睡沙袋、穿、睡沙袋、穿“土褲子土