《旋毛虫、丝虫》PPT课件.ppt

1、Review of intestinal helminths,Ascaris lumbricoides (roundworm) 似蚓蛔线虫（蛔虫） Trichuris trichiura (whipworm) 毛首鞭形线虫 （鞭虫） Enterobius vermicularis (pinworm) 蠕形住肠线虫（蛲虫） Ancylostoma duodenale Necator americanus,(hookworms) 钩虫,Trichinella spiralis 旋毛形线虫,Tissue-blood dwelling nematodes,-Filaria 丝虫,Wuchereria

2、bancrofti 班氏吴策线虫 Onchocerca volvulus 旋盘尾丝虫,The history of Trichinella spiralis,In year 1835，Young Jim Paget, a first year medical student at London Hospital Medical School, rushed into the autopsy room. The 51 yr-old Italian bricklayer who had died of tuberculosis, and that they were now dissecting,

3、 also had sandy diaphragm, a condition that dulled even the sharpest of scalpels. Well, anyway, when they had all cleared the room, Jim quietly stole back in and removed a small bit of muscle tissue from the diaphragm. He was more than curious as to the nature of sandy diaphragm. He first examined i

4、t with his trusty hand lens he carried for just such a situation. He thought he saw small worms coiled up inside each nodule. Upon even higher magnification, the presence of coiled worms was revealed. (From ),Trichinella spiralis,Jim Paget Worms in the “sandy diaphragm”,Trichinell

5、a spiralis,Trichina worms were observed in pork in 1846 by Joseph Leidy. He saved hundreds of lives by recommending cooking pork at a high enough temperature to kill the organism.,Life cycle work out in1850s By Rudolph Virchow.,Trichinella control,Rudolf Virchow (Germany) suggested mandatory diagnos

6、is of all meat at the slaughterhouses in 1877 This has greatly reduced trichinellosis as human health Problem.,Worldwide Distribution Parasitic zoonosis Food borne parasitosis,Trichinella spiralis - cause 旋毛虫病 trichinosis, trichiniasis, or trichinelliasis,Distribution of Trichinella spiralis,Trichin

7、osis is most common in temperate and arctic climates - high prevalence in pork-eating areas of the world.,arctic,temperate,Adults of Trichinella spiralis,Adults : small, 1.54 mm Larva: females give birth to larva ( Eggs: hatch in uterus 子宫),stichosome,Hatched Larva,杆状体,成虫形态在诊断上无意义！,特点：直接产幼虫,Encysted

8、 larva 幼虫囊包- infective stage,0.250.5mm 0.210.42mm Lemon shape 12 larva in the cyst,Life cycle,Adult female in mucosa of small intestine Trichina cysts in skeletal muscle骨骼肌,Pathogenisis,3 stages ： 1. Invasion 1 week,first symptoms appear 12 hours to 2 days following ingestion of trichina cysts,Nause

9、a, vomiting, diarrhea, abdominal pain, headache with slight fever,2. migration of larvae 2 week to 2 months,penetration and encystment in skeletal muscles 骨骼肌,migration of larvae 2 week to 2 months,Eosinophilia 嗜酸性细胞增多 Deaths are rare and due to myocarditis 心肌炎, encephalitis 脑炎 and pneumonia肺炎,Weakn

10、ess， Headache and dizziness 头昏， Fever,chills and sweating, Myalgia 肌痛,perorbital edema,splinter hemorrhages （under finger nails）,3.calcification (if one survives stage2!) - occurs several months after infection - calcium is deposited around the cysts - Larva eventually die in a year or longer,In hum

11、an infections, 5 larvae/gram body weight are fatal.,Muscle biopsy : trichina cysts can be seen with microscope,Muscle samples were squeezed between two glass plates,2. ELISA to identify Trichinella antibodies,Diagnosis,肌肉压片,Others？:,Epidemiology,1. Cosmopolitan distribution 2. Source of infection is

12、 pork or pork products infection is most frequents among ethnic groups disposed to eat raw or poorly cooked pork products,Treatment of Trichinella spiralis,Drugs: Mebendazole（甲苯哒唑） Albendazole（阿苯哒唑,丙硫咪唑） Others:,Prevention of Trichinella spiralis,Thorough cooking (temperature above 58o C) microwave

13、cooking of pork roasts and chops (with bone) is NOT effective in killing trichina 2. freezing for 20 days will kill temperate climate strain - freezing is NOT effective against the arctic strain - smoking, salting, and drying pork, bear or other meat will NOT kill trichina larvae,Prevention of Trich

14、inella spiralis,3. - Do not feed pork scraps in garbage to pigs - eliminate rats in areas where pigs are kept,Tissue-blood dwelling nemotodes,Filaria -cause filariasis,Four important filarial worms parasitic in humans are: Wuchereria bancrofti 班氏吴策线虫 Onchocerca volvulus 旋盘尾丝虫 Brugia malayi 马来布鲁线虫 Lo

15、a loa 罗阿罗阿线虫,W. bancrofti is strictly a human pathogen and is distributed in tropical areas worldwide More than 80 million were affected,Orient, South Pacific, and Southern Asia to India overlaps with Wuchereria bancrofti - but does not occur in Africa or South America,B. malayi infects a number of

16、wild and domestic animals,Morphology-Adults of Wuchereria bancrofti,Adults occur in the lymphatic vessels,（Adult B. malayi are only half the size of W. bancrofti ）,filariform larva 丝状蚴,Microfilariae of Wuchereria bancrofti,Microfilariae are seen in blood smears and are DIAGNOSTIC worms are 230-320 m

17、 long,Morphological differences of microfilariae of Wuchereria bancrofti and Brugia malayi,Wuchereria bancrofti Brugia malayi Length 244-296 5.3-5.7 177-230 5 -6 (m) Appearance graceful sweeping Irregular kinky 体态 curves curves Cephalic space length equals width length twice width 头隙 Body nuclei wel

18、l defined, discrete, blurred, intermingled 体核 round, uniform sized nuclei crowded together Tail no terminal nuclei two terminal nuclei 尾核,Filariform larve-infective stage,Microfilariae of Wuchereria bancrofti,Nocturnal periodicity of microfilariae 夜现周期性,Pathology of Wuchereria bancrofti,Incubation p

19、eriod no symptoms 3 clinical phases: microfilaremia - no symptoms or mild symptoms,微丝蚴血症,Acute allergic inflammatory phase a. lymphadenitis, lymphangitis 淋巴结炎 淋巴管炎,Acute allergic inflammatory phase b. filarial fever 丝虫热 c. funiculitis, orchitis, epididymitis 精索炎， 睾丸炎，附睾炎,3. chronic Obstructive phase

20、,Elephantiasis 象皮肿,The disfigured legs of lymphatic filariasis patients waiting for medical attention,b. chyluria 乳糜尿,hydrocele testis 鞘膜积液,Brugia malayi 马来丝虫,Adults live in lymphatic vessels and cause elephantiasis in arm and leg. Difference between W.r and B.m? discuss later,Diagnosis,Identifying

21、microfilaria in blood or other fluid direct blood films concentrations of blood specimens and urine specimens Identifying adults Serologic testing,Epidemilogy,World Wide distribution Source of infection: patients and infected patients Transmission: by mosquitto Brugia malayi Wuchereria bancrofti,Tre

22、atment of Wuchereria bancrofti,Drugs : hetrazan 海群生 are somewhat effective kill microfilariae and adults with careful administration,6 mg/kg diethylcarbamazine citrate (DEC) + 400 mg albendazole; 150 g/kg ivermectin + 400 mg albendazole (in the case of co-endemicity with onchocerciasis) A third opti

23、on is to follow a treatment regimen using DEC-fortified cooking salt daily for a period of 12 months.,Global Programme to Eliminate Lymphatic Filariasis,others: Pressure bandages on enlarged limbs forces lymph out. 弹力绷带捆绑 Surgery can be used to remove elephantoid tissue if muscle involvement is mini

24、mal. 外科手术,Onchocerca volvulus 旋盘尾丝虫,Causative agent of onchocerciasis （river blindness）,90 million, 17.6 million, 326 thousand,Adults of Onchocerca volvulus,Skin nodule,Microscopic section showing adults and scar tissue reaction,Microfilariae of Onchocerca volvulus,Unsheathed microfilariae occur in

25、the skin, never the bloodsteam,Simulium 蚋,Pathogenisis of adults,Nodules (about -1 inch in diameter) are most common in Africa Nodules in Central & South America. Nodules are relatively benign,Microfilariae in the skin - itching is so severe some people have committed suicide,Pathogenisis of Microfi

26、lariae,Microfilariae in skin - in parts of Africa, the skin of the scrotum 阴囊 and inguinal area 腹股沟 loses its elasticity,2. Microfilariae invade the eye (occur as microfilariae die in the eye),Microfilariae invade the eye,In many parts of Africa, the sighted young are responsible for leading the older blind adults.,Diagnosis of Onchocerca volvulus,Examination of microfilariae or adult in skin nodule, eye etc.,TREATMENT of Onchocerca volvulus