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The Cestodes (tape worm).

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Presentation on theme: "The Cestodes (tape worm)."— Presentation transcript:

1 The Cestodes (tape worm)

2 Nematode trematode

3

4 common features of Class Cestoda
1. Adult worm is flattened ribbon-like 2. Body wall: Tegument and subtegument; and no body cavity.

5 body wall construction:
substantia corticalis: microvilli、cytomere 、basal membrane ①scratch intestinal mucosa ②conduce(to)attachment ③expand surface area of absorption ④possess sensory function ⑤to resist digestion subcutaneous stratum: annuliform muscle、vertical muscle、oblique muscle help the proglottid Slipping and falling off

6 3. The body is composed of a head, neck and segmented strobilus (链体)
3.The body is composed of a head, neck and segmented strobilus (链体). The head has suckers, rostellum (顶突) and hooklets or sucking grooves. The neck is the budding zone from which segments are formed. The strobilus consists of immature, mature and pregnant proglottides.

7 Strobila (链体): (1)Scolex (头节) - equipped with organs of attachment: suckers, hooks, grooves. (2)Neck (颈部) - germinal portion (3) Proglottids (节片) - immature, mature, gravid(孕节).

8 4. They are hermaphroditic
4.  They are hermaphroditic. There is a set of female and male reproductive organs in every mature proglottid.

9 5. Digestive tract is absent
5. Digestive tract is absent. Nutrition is absorbed by villi of body surface. Nematode trematode

10 6.  They are biohelminths. Intermediate hosts are indispensable.
7.  All adult worms parasitize digestive tracts of mammals.

11 8. The developing stages in intermediate hosts are called metacestode (中绦期), such as cysticercus (囊尾蚴), hydatid cyst (棘球蚴), cysticercoid (似囊尾蚴), procercoid (原尾蚴), plerocercoid(裂头蚴).

12 PHYSIOLOGY AND PATHOGENESIS:
1. Surface absorption capabilities. 2. Highly developed reproductive functions. 3. Anaerobic metabolism (无氧代谢).

13 PHYSIOLOGY AND PATHOGENESIS: (2)
4. No external environment development. 5. All species are parasitic. 6. Pathogenic stage may be adult or the larvae.

14 Tapeworms are classified into two orders:
(1).Cyclophyllidea (圆叶目): The head is spherical with suckers, hooklets. The uterus has no opening. One intermediate host is required. The eggs contain an oncosphere (六钩蚴). They are medically important, such as Taenia solium (链状带绦虫), Taenia saginata (肥胖带绦虫) and Echinococcus granulosus (细粒棘球绦虫).

15 Cyclophyllidea (圆叶目)

16 (2). Pseudophyllidea (假叶目): The head is spear-like with sucking grooves. The uterus has an opening. Two or more intermediate hosts are required. The eggs contain a coracidium(钩球蚴) and have to get into water to develop. Human being occasionally get infection. This worms include Spirometra mansoni(曼氏迭宫绦虫) and Diphyllobothrium latum(阔节裂头绦虫).

17 Pseudophyllidea (假叶目):

18 Pseudophyllidea (假叶目):
Cyclophyllidea (圆叶目)

19 Taenia solium(pork tapeworm)
Adult worms live in human small intestine causing taeniasis (绦虫病). The larval stage (Cysticercus cellulose 猪囊尾蚴) lives in pig or human tissues causing human cysticercosis(囊尾蚴病或囊虫病).

20 GENERAL INTRODUCTION:
1. Worldwide distribution. 2. Large tapeworm. 3. Taenia solium:  Laval infection cause serious clinical disease --- CYSTICERCOSIS.

21 Adult: Taenia solium (pork tapeworm)

22 Adult of the Pork Tapeworm
averages 2 – 4 meters long.

23 I. Morphology 1.   Adult is flattened ribbon-like, creamy white in color, measures about 2-4 m and has proglottides. scolex : global, 1mm. With 4suckers, 1rostellum(顶突) and 25-50 hooklets arranged in a double crown It consists of neck: it’s the narrowest part of the body and budding zone containing germinative tissue immature proglottides:width>length strobila mature proglottides: width=length gravid proglottides: width<length

24 Immature proglottides are transverse rectangle, located in the anterior part of the body and inner organs are developing. Mature proglottides are square in shape and located in the mid part of the body and have testes, a centrally straight uterus and 3 lobes of ovary . Pregnant(gravid) proglottides are longitudinal rectangle, located in the posterior part of the body and contain a branched uterus filled with eggs. The number of main branches on each side of the uterus stem is 7-13.

25

26 scolex

27 Mature proglottid

28 India Ink Technique Note : less than 13 lateral uterine branches (one side). In this species the uterus of the gravid proglottid has between 7 and 13 lateral branches on each side.

29 2. Egg, The eggs of Taenia saginata and T
2.  Egg, The eggs of Taenia saginata and T. solium are indistinguishable morphologically. The eggs are spherical, diameter 31 to 43 µm, with a thick radially striated brown embryophore (胚膜). Inside each is an oncosphere (六钩蚴) with 6 hooklets. t

30 3. Cysticercus cellulose
3.Cysticercus cellulose. It is a semitransparent and elliptic bladder, like a white pomegranate seed (石榴籽)about 0.6-1cm. There is fluid and a white scolex with 4 suckers and hooklets in the bladder.

31 The scolex invaginates in the bladder The scolex evaginates
Under stimulation of bile The scolex invaginates in the bladder The scolex evaginates

32

33 Cysticerci in myocardium

34 II. Life cycle 1. final host: man,
2.  Intermediate host: swine (or man), 3.  Infective stage: cysticercus and egg, 4.  Infective mode: eating raw bean-pork or egg 5. Site of inhabitation: adult in small intestine; cysticercus in tissues, 6. Infective mode of cysticercosis: endogenous, exogenous auto-infection and foreign source; 7.  Life span: more than 25 years; cysticercus can survives 5-6 years in human body.

35

36 Life Cycle of Taenia solium
Attach to intestinal mucosa scolex evaginates adults grivad proglottides develop into fall off duodenum In human small intestine and are 2-3 months discharged in feces man eats cysticercus in raw pork ───────────────────────────── swine ingests eggs In intermediate hosts man gets infection 60-70days develop into cysticercus onchosphere hatch in all parts of the body larval migration in duodenum penetrate intestinal wall into blood stream

37 III. Pathogenesis and Clinical Manifestations
1.   Taeniasis: It is caused by the adult residing in small intestine of the man. The adult irritates the small intestine causing discomforts, such as abdominal pain, anorexia, chronic indigestion, diarrhea, emaciation and etc. The patient is usually no obvious symptom, only complaining passing proglottides.

38 2.   Cysticercosis: It is caused by the cysticerci living in human tissues. The manifestations vary with the number of cysticerci and the tissues and organs involved. Cysticercosis is divided into four types.

39 (1) Subcutaneous type: The subcutaneous nodules are usually found in head, limbs, neck, abdomen and back. They are movable and painless.

40 (2) muscles type:

41 Note this cysticercus in the tongue

42 (3) Ocular type: The cysticercus is usually found in the vitreous body or subretina. Visual disturbance often occurs. The died body of worm may provokes local inflammation causing blindness.

43 (4) Brain type: The symptoms are related to the site of infection. The patients may manifest headache, nausea, vomiting, epilepsy (癫痫), paralysis (瘫痪), weakness in limbs, diplopia(复视), dizziness, mental disorder. Epilepsy is the most frequent symptoms of brain cysticercosis.

44 Brain type

45 IV. Diagnosis 1.Taeniasis: Confirmative diagnosis of taeniasis is made by finding gravid proglottides or egg in stool. (1) direct fecal smear (2) brine floatation technique **(3) cellophane-tape technique

46 the examination of a transparent plastic adhesive tape
previously applied to the perianal region

47 Showing some eggs of Taenia spp. and an egg of E.vermicularis.
Scotch-tape smear Showing some eggs of Taenia spp. and an egg of  E.vermicularis.

48 2. For cysticercosis (1) Specific diagnosis is difficult to establish, the history and adult worm infection attribute to strong suspicion. (2) Biopsy to subcutaneous lesions. (3) computerized axial tomography

49 (CT) or (MRI). are used for the diagnosis of brain type and ophthalmoscope examination is used for ocular form. 3.   Immunological tests are for reference only. IHA, ELISA, Dot-ELISA McAb-CAg.

50 V. Treatment and prevention
1. Treatment of Taeniasis: (1) Chinese herb medicine: pumpkin seed and areca nut (槟榔) . The recognition of a scolex in the patient’s stool after the application of taenifuge is important. When the entire worm has been expelled, the therapy is successful, otherwise the strobila regrow. (2) Praziquantel may be used.

51 2. Treatment of cysticercosis: Surgical removal is required for ocular and superficial cysticercoses. Praziquantel may be used to treat brain cysticercosis , but the patients should take praziquantel in hospital.

52 3. Prevention: (1) Health education (2) Avoid eating raw bean-pork
3.   Prevention: (1) Health education (2) Avoid eating raw bean-pork. (3)avoid pigs eating human stool. (4) sanitary inspection of slaughter and sanitary disposal of night soil.

53 VI. Epidemiology This disease is prevalent all over the world except Muslim and Jew areas. The infection of T. solium is closely associated with the method of pig-raising and the sanitary condition.

54 Taenia saginata (肥胖带绦虫,牛带绦虫,牛肉绦虫或无钩绦虫)
Adult worms live in human small intestine causing taeniasis. Larval stage (Cysticercus bovis) lives in cattle tissues. This disease is prevalent all over the world.

55 Differences between T. solium and T. saginata
1. Body length T. saginata T. solium

56 2. scolex T. solium T. saganita

57 Mature proglottids of Taenia sp.

58 3. Mature proglottid T. solium T. saginata

59 4. Gravid proglottid T. solium T. saginata
In this species the uterus of the gravid proglottid has between 7 and 13 lateral branches on each side. T. saginata the uterus of the gravid proglottid has between 15 and 30 lateral branches on each side .

60 5. cysticercus Cysticercus cellulose Cysticercus bovis

61 COMPARASON OF THE TWO TAPEWORMS:
T. solium T. saginata 1. Size m m 2. Scolex Rostellum & hooks No 3. Mature Proglottid: Ovary lobes lobes 4. Gravid proglottid : Lateral Uterine Branches< >15

62 COMPARASON OF THE TWO TAPEWORMS: (2)
T. solium T. saginata 5. Intermediate Host: Swine & Humans, Cattle 6. Disease caused : Taeniasis & cysticercosis, Taeniasis only 7. Infective stage: Egg & Cysticercus, Cysticercus Only 8. Mode of infection : Cross or autoinfection, Cross only

63 COMPARASON OF THE TWO TAPEWORMS: (3)
T. solium T. saginata 9. Diagnosis : Gravid proglottid, Gravid proglottid Egg may be found in stool, Egg may be found in stool, Perianal egg exam Perianal egg exam

64 COMPARASON OF THE TWO TAPEWORMS: (3)
T. solium T. saginata 10. Clinical significance: Much more important, Less important 11. Chemotherapy: Should be instant , Not so urgent

65 II. Life cycle The intermediate host is cattle and cysticercus bovis can not live in human. The others same as those of T. solium. III. Pathogenesis: Usually only single worm is present and the patient is no symptom. Some patients may complain of migrating proglottids from anus with pruritus at the perianal region. Abdominal discomfort, nausea, vomiting, constipation or diarrhea may occur.

66 IV. Diagnosis Finding of gravid proglottids or eggs at the perianal region by cellophane tape method. V. Epidemiology: T. saginata has a world-wide distribution. Human infection is acquired from consumption of raw beef containing the cysticercus bovis. Cattle become infected from grazing on the ground polluted by human feces containing the eggs of the parasite. It is important to have latrines and manure pits far away from the pastures. VI. Treatment: Same as tha of T. solium

67 ** Echinococcus granulosus(dog tapeworm)
There are three developmental stage in lyfe cycle including egg, larva and adults. Adult worms live in the small intestine of dogs, wolves and other canines. The larval stage lives in the tissues of herbivores or men, so man is a intermediate host of Echinococcus granulosus. It causes echinococcosis (hydatid disease or hydatidosis). Hyditid cyst chiefly lives in the liver of human body.

68 Adult morphology The globular scolex bears a rostellum with hooklets and 4 sukers. Slender neck. Immature proglottid Mature proglottid Gravid proglottid consists of uterus with irregular lateral branches filled with eggs. All kinds of proglottids only one.

69 The egg,34 to 41um in diameter, has a brown,thick,radially striated embryophore surrouding an oncosphere,six-hooked embryo, and is similar in appearance to those of Taenia worms Egg

70 Hydatid Cyst: Laminated layer Cyst wall Germinal layer Protoscolex
Hydatid fluid Hydatid cyst Protoscolex Brood capsules Daughter cysts Granddaughter cysts Laminated layer Germinal layer contents Cyst wall hydatid sand

71 Hydatid cyst Largest larval stage of all tapeworms

72 Notice the scolex armed with suckers and hooklets.
Protoscolex Notice the scolex armed with suckers and hooklets.

73 Life cycle The definitive hosts are dogs, wolves, and other canines. The adult inhabits their small intestine. The eggs discharged from the ruptured proglottid, pass to outside with feces. The intermediate hosts are sheep, cattle, goats, camels, horses and human beings.

74 Life cycle

75 When the intermediate hosts ingests eggs, they hatch in the duodenum and penetrate the intestinal mucosa and are carried by the blood to the liver, brain, heart, bones, kidneys and other tissues. When they are earten by a definitive host such as dogs, each of the individual protoscolex may develop into an adult worm in about 7 to 8 weeks. Then the adult worm may discharge eggs.

76 Conclusion of life cycle
1.Definitive host: dogs, wolves, and other canines. 2.Intermediate host: herbivores and humans. 3.Infective stage: protoscloex (to definitive host) egg (to intermediate host) 4.Route of transmission: protoscolex are eaten by definitive host, eggs are ingested by intermediate host.

77 Pathogenesis and syptomatology
The common pathogeneses are: Local compression and excitation: the cyst acts as a sapce-occupying lesion,produces damage on adjacent tissues, example for liver,lung,brain,kidney and so on

78 Hydatid cyst in liver Cyst in liver, there may be hepatomegaly, right upper quadrant pain, jaundice, hepatic mass, etc.

79 Hydatid cyst in lungs Cyst in lungs may give rise to cough,shortness of breath, hemoptysis(咯血), or chest pain.

80 Hydatid cyst in brain Cysts within the central nervous system will produce serious damage. The common symptoms are headache, nausea, vomiting,epilepsy, dizziness,mental confusion,and weakness in limbs.

81 Hydatid cyst in kidney Cysts live in the kidney may induce circulating antigen-antibody complexes deposit in the kidney,initiating inflammation

82 Pathogenesis and syptomatology
b) Secondary hydatid cyst inflammation: Rupture of hydatid cyst may release the fluid, lead to dissemination of infection and produce secondary hydatid cysts, or provoke inflamation.

83

84 Pathogenesis and syptomatology
C) Allergic reaction: the cyst fluid contains parasite antigens, which can sensitize the host, so pruritus and urticaria occur usually. If the cyst ruptures spontaneously or during trauma or surgical removal,life-threatening anaphylaxis can occur.

85 Pathogenesis and syptomatology
d) Poisoning and gastrointestinal dysfunction The patient may present with anorexia, loss of body weight, maldevelopment due to the toxin of parasite.

86 Laboratory diagnosis observe the protoscolex with microscope in sputum,尿液、腹水或胸水 IHA、ELISA Dot-ELISA Chest X-ray, CT, MRI and ultrasonography(超声)

87 The end See you next time

88 cysticercus囊尾蚴 procercoid原尾蚴 plerocercoid裂头蚴 hydatid cyst 棘球蚴
(spirometra mansoni) cysticercus囊尾蚴 hydatid cyst 棘球蚴 procercoid原尾蚴 (Diphyllobothrium latum) cysticercoid 似囊尾蚴 (hymenolepis nana)

89 head has suckers, rostellum and hooklets
neck budding zone from which segments are formed strobilus immature proglottides mature proglottides pregnant proglottides

90 Laminated layer Germinal layer Protoscolex Brood capsules Daughter cysts Granddaughter cysts


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