年臨床八年制鉤蟲、旋毛蟲

1、Hookworm Hookworm infection is widely distributed in tropical & subtropical, where there are favorable environmental factor for hookworm spreading, including warm, high rainfall, soil pollution by human defection or fertilization with human feces and person walking with bare feet.Hookworm infection

2、is second only to ascariasis as the most common helminthic infection. Hookworm infection has almost eradicated from Europe and United States.Ancylostoma duodenale(十二指腸鉤蟲)- the small intestineNecator americanus (美洲板口線蟲)-the small intestineAncylostoma cerlanicum (錫蘭鉤口線蟲) -rarely infects human beingsAn

3、cylostoma caninum(犬鉤口線蟲)-rarely infects human beingsAncylostoma braziliense巴西鉤口線蟲-creeping erupting, 幼蟲可感染人，引起幼蟲移行癥 鉤蟲是一類口囊發(fā)達(dá)的線蟲，并在口囊內(nèi)有銳利的切器，可損傷腸粘膜，吸食血液和組織液，使患者長(zhǎng)期慢性失血，造成嚴(yán)重危害。鉤蟲寄生小腸引起鉤蟲Hookworm infection is contracted mainly by penetration of the skin or oral mucosa by the filariform larvae ( infecti

4、ve stage) of hookworm. Thus, barefoot farmers and children walking on contaminated soil or eating contaminated vegetables may e infected.Adults of A. duodenale Adults of N. americanusDifferences between two hookwormsMorphologyThe male worm is about 7 to 11 mm in length & about 0.4 mm thickThe female

5、 is larger, 9 to 13 mm long and o.6 mm thickFemales hookworm:9-13 mm long with egg-filled uterus Male hookworms:7-11 mm longPosterior end forms a copulatory bursaAdult: the adult are cylindricalwith the head bent sharply backwards, giving them a hooked appearance. The mouth of hookworm were well dev

6、eloped, with a pair of teeth or a pair of cutting plate.Egg (蟲卵)Egg of two species are nearly indistinguishable. They are ovoid with a thin transparent shell and, measure 60 m X 40 m, a clear space that separates the shell from the yolk cells. The number of yolk cells in egg found in the stool varie

7、s from two to eight.Larvaa rhabditiform larva (桿狀蚴): 275 X 16 m , the newly hatched larva feed actively upon bacteria and organic debris, grow rapidly to a size of 500 to 700 m in 5 days a filariform larva (絲狀蚴 ): slender, nonfeeding the active filarform larva frequent the upper half-inch of soil an

8、d project from the surface-infective stage 頭端 扁平，中間微凹 圓形，無(wú)凹陷 咽管矛 不明顯 明顯 鞘膜橫紋 不明顯 明顯 尾端 逐漸變細(xì) 驟然變尖Ad 絲狀蚴 Na 絲狀蚴They survive best in shaded localities, such as light sandy or alluvial soil or loam covered by vegetation, they are protected from dry or excessive wetness at 0 C larva survive less than 2 w

9、ksat 11 C less than 24 hrsat 45 C less than 1 hrLife cycleHumans almost exclusively are hosts for both hookworm, while dogs also are common host for N. americanus. When eggs are expelled with feces, under optimal conditions ( temperature of 23-33C, shade, and sandy soil rich in organic material), a

10、rhabditiform-larva matures in 1-2 days & hatches from the thin shelled egg, feeds on bacteria & organic material in the soil. After two molts, it es a non-feeding, infective, filariform larva. Final host: man Infective Stage: Larva 3 or filariform larva Infective Route: by skin Food: blood and tissu

11、e fluid Site of inhabitation: small intestine Life span: Ad 15years, Na 3-7years Blood-lung migration: skin, cavum vena , right heart, lungs 成蟲 卵 桿狀蚴 絲狀蚴（感染期） 經(jīng)皮膚 粘膜移行途徑皮膚 小血管 右心 肺 肺部微血管 肺泡 食道 咽 小氣管Ad 保蟲宿主：豬、獅、虎、狗、猴Na 轉(zhuǎn)續(xù) 宿主：猩猩、猴、犀牛等 成蟲寄生部位和攝食 Adult worm in small intestine產(chǎn)卵量 Ova product A.duodenale

12、produces 10000 to 30000 eggs per day N.americanus produces 5000 to 10000 eggs per day絲狀蚴具有向上性、向濕性、向溫性 character of filariform larva : strong thigmotaxis, moisture, thermotaxis (1-2 cm)Penetration skin or oral mucosa (A.d), migration, developmentA.d of filariform larva may invade host skeletal muscul

13、ature Pathogenicity 鉤蟲感染 鉤蟲病 The course of human hookworm disease can be divided into three phases: invasion phase migration phase intestinal phase Invasion phase larval invasion of skin 鉤蚴性皮炎 itching, erythematous papular, vesicular eruption ( with or without edema or enlargement of lymph nodes) se

14、condary bacterial infection creeping eruptionMigration phase 肺部損害 the major features are pulmonary manifestation severe cases: Lofflers syndrome or coughing, dyspnea, pulmonary infiltrate, Eosinophilia, nausea, vomiting -Wakana disease 成蟲所致病變 消化系統(tǒng)的癥狀 nausea, vomiting, abdominal pain, diarrhea, const

15、ipation -intestinal complaints 慢性失血引起貧血 anemia-by buccal capsule & teeth to burrow through the mucosa, feeding upon blood Intestinal phase貧血的原因：成蟲吸血： 吸血量咬附部位粘膜滲血：咬附點(diǎn)滲血量蟲體吸血可以經(jīng)常更換咬附部位，造成新的損傷， 原傷口還繼續(xù)滲血 移位傷口滲血量造血物質(zhì)吸收障礙；小細(xì)胞低色素性貧血Salivary secretions of the worms contain anticoagulants that facilitate blo

16、od feeding A.d 0.15 0.26 ml/worm/24 hrs (3 or 6-8 yrs) egg output 10000 to 30000/d N.a 0.03 0.05 ml/worm/24 hrs (3 yrs or 15 yrs) egg output 5000 to 10000/dKoilonychia (spoon-shaped nails) due to severe chronic iron deficiency.chlorosischildren with severe infection show signs of protein malnutritio

17、n (abdominal distention, facial edema & hair loss) children with chronic hookworm anemia physical growth retardationdeficits in child cognition and intellectual development. reversed by administration of anthelminthic drugsprogressive cardiac insufficiency - congestive heart failure 3 ml to 100 ml/d

18、ay in mild or severe infection 另外與患者原來(lái)的健康狀況Geophagy (allotriophagy) (Pica): a habitual ingestion of nonfoodsubstances , one of diverse cause is iron deficiency anemia(soil, wood, charcoal, paper)異嗜癥 也許是鉤蟲病診斷的一個(gè)線索Infection in infant or children-severe stunted growth die嬰兒鉤蟲病：貧血嚴(yán)重、發(fā)育極差、合并癥多、死亡率高。經(jīng)胎盤 經(jīng)

19、乳汁 經(jīng)皮膚Laboratory Diagnosis -identification of eggs in the stool 糞便檢查 直接涂片法 飽和鹽水浮聚法 Brine floatation method 鉤蚴培養(yǎng)法： Culture of hookworm larva 定量檢查 PCR檢測(cè) 一個(gè)蟲卵即可診斷，并可區(qū)別蟲種 DNA (PCR) can be amplified from a single egg and identity speciesEpidemiology Hookworm is worldwide distributed N. americanus is foun

20、d mainly in moist tropical region such as Southeast Asia 分布較廣泛 A. duodenale is found mainly in dry tropical region such as North Africa, North China 傳染源：患者、帶蟲者傳播因素：a. 適宜蟲卵、幼蟲發(fā)育、存活的條件 A shaded sandy or loam soil, which is a favorable culture medium for hookworm larva. A warm climate, which favors the

21、 development of the eggs and larva and promiscuous defecationMoisture, especially during the worm season of the years when egg and larva development are possibleb.糞便污染土壤 Contamination of the soil by egg-containing fecesc.生產(chǎn)、生活方式 person walking with bare feet.d.個(gè)體抵抗力加強(qiáng)衛(wèi)生宣教，搞好飲食衛(wèi)生糞便無(wú)害化處理加強(qiáng)衛(wèi)生宣教Preventi

22、on & TreatmentTreatment of infected individuals 治療病人和帶蟲者 mebendazole（甲苯達(dá)唑）100mg Bid3days albendazole（阿苯達(dá)唑） 400mg oncefor severe anemia administration of iron 同時(shí)糾正貧血 Sanitary disposal of human excrement 糞管預(yù)防感染Protective measures to prevent contact with infective larva鞭蟲：Morphology and life cycleProla

23、psed rectum with adult T. trichiura.土源性線蟲的生活史特點(diǎn)？感染期？ 感染途徑？致病特點(diǎn)流行情況防治要點(diǎn)Trichinella spiralis旋毛蟲(Trichinella spiralis)成蟲寄生在小腸下部的腸壁，幼蟲寄生在人體橫紋肌中，引起旋毛蟲病(Trichinellosis)，為人獸共患病。也是食源性寄生蟲病，特點(diǎn)：地區(qū)性、群體性、食源性、季節(jié)性 (20140922)Trichinellosis is the disease among human and animal, a zoonosis.The infection is endemic i

24、n many areas of the world where raw or undercooked meat, mainly pork is consumed.雌蟲產(chǎn)出幼蟲經(jīng)血流到肌細(xì)胞內(nèi)成囊而具感染力Morphology Adult small & slender male: 1.5 mm X 0.04 mm female: 3.5 mm X 0.06 mm deposited larvaLarva enveloped, 0.25-0.5 mm X 0.21-0.42 mm Adult T. spiralis in small intestine - the worm is embedde

25、d within the cytoplasm of the columnar cells.Larval T. spiralis in muscle - the worm is embedded within the cytoplasm of the nurse cell.Nurse cell, a nurse cell is an infected cell in the disease trichinosis discovered by Dickson Despommier. A trichinella larva enters a cell and develops there, prob

26、ably as a way of concealing itself from the immune system. The parasite has evolved a way of stimulating blood vessel development around the cell, in order to receive the nutrients it needs. In trichinosis, nurse cells are invariably skeletal muscle cells; these are the only type of cell that can su

27、pport the parasite.Life cycle成蟲和幼蟲均寄生在同一宿主體內(nèi)完成生活史需更換宿主Human infection results from consumption of meat, most communly poorly cooked pork, containing encapsulated larva.Life Cycle of Trichinella spiralisAdult T. spiralis in small intestine - the worm is embedded within the cytoplasm of the columnar c

28、ells.Larval T. spiralis in muscle - the worm is embedded within the cytoplasm of the nurse cell.Nurse cell, a nurse cell is an infected cell in the disease trichinosis discovered by Dickson Despommier. A trichinella larva enters a cell and develops there, probably as a way of concealing itself from

29、the immune system. The parasite has evolved a way of stimulating blood vessel development around the cell, in order to receive the nutrients it needs. In trichinosis, nurse cells are invariably skeletal muscle cells; these are the only type of cell that can support the parasite.Adult 4-6 days lympha

30、tic vessels heart lung spread Larva Larva another 2-3 days LarvaLarvae can survive only in the skeletal muscle & e encysted in 2 to 3 weeksPathogenicityTrichinellosis, mainly result from larval invasion of muscle & othertissues and the hyperimmune reaction of the host to the metabolic by-products and secretions of the larvae Invasion stage: due to penetration of adult female & larva into the mucosa & submucosa, begins 24 hrs after infection and lasts for 1 to 7 days asymptomatic or transient gastrointestipational complaints (1 week)Migration stage: begin