Trematodes:FLUKES

Completely based on medical text books on parasitology.

1. TREMATODES: FLUKES BY: CHANDANA CHANDRAN

2. CHARACTERISTICS Flat or fleshly, leaf-like unsegmented body. Incomplete alimentary canal. Possess suckers with no hooks. Sexes are separate in Schistosomes , while the others are hermaphroditic. Oviparous

3. GENERAL CHARACTERISTICS Presence of two suckers. Has no body cavity, circulatory and respiratory organs. Alimentary system- mouth surrounded by an oral sucker, muscular pharynx, oesophagus which bifurcates into 2 blind caeca (inverted Y shaped) Rudimentary nervous system – paired ganglion cells.

4. CLASSIFICATION BLOOD FLUKES LIVER FLUKES INTESTINAL FLUKES LUNG FLUKES BASED ON HABITAT:

5. BLOOD FLUKES Family : Schistosomatidae Genus : Schistosoma Species: 1. S. haematobium 2. S. mansoni 3. S. japonicum 4. S. mekongi 5. S. intercalatum

6. SCHISTOSOMES Schistosomiasis ( bilharziasis ) Water-borne disease (Africa, Asia & Latin America). Male worm is broader & lateral border is rolled ventrally into a cylindrical shape, producing a long groove – GYNECOPHORIC CANAL, in which females are held. Live in venous plexus in body of definitive host

7. Characteristics Dioecious Males are shorter and stouter than females Lateral margins of males are folded ventrally to form a gynecophoral canal in which females are received Suckers are armed with delicate spines There is no muscular pharynx Eggs are non- operculated Eggs are fully embryonated when laid Embryonated eggs have a ciliated embryo called miracidium Cercariae have bifid tails There is no encysted metacerciarial stage Infective Stage: cercaria penetrating the unbroken skin

8. BLOOD FLUKES: SCHISTOSOMAS Schistosoma japonicum : Oriental blood fluke Schistosoma haematobium : Vesical blood fluke Schistosoma mansoni : Manson’s blood fluke

9. Features distinguishing Schistosomes from other trematodes Unisexual. Lack muscular pharynx Intestinal caeca reunite after bifurcation to form a single canal. Produce non- operculated eggs. Cercariae have forked tails and infects by penetrating unbroken skin of definitive host.

10. SCHISTOSOMA HAEMATOBIUM

11. HISTORY & DISTRIBUTION Bilharzia haematobium . Bilharz described about the adult worm. Endemic in most parts of Africa, West Asia some parts of India.

12. MORPHOLOGY

13. ADULT WORM FEMALE 20mm long, 0.25mm thick with cuticular tubercles confined to ends. GYNECOPHORIC CANAL MALE 10-15mm long, 1mm thick & covered by finely tuberculated cuticle SUCKERS

14. EGG Ovoid non- operculated Gravid worm has 20-30 eggs in uterus at a time & realises 300 Eggs/day With a brownish yellow transparent shell carrying terminal spine at one pole

15. Life Cycle Definitive host : Humans Intermediate host : freshwater snails Infective form : Cercaria larva

16. CLINICAL FEATURES Classified depending on stages in evolution of infection: During incubation period During oviposition During tissue proliferation & repair

17. 1. Skin penetration & Incubation period Local cercarial dermatitis/ Swimmer’s itch – transient itching and petechial lesions at site of entry of cercariae . Often in visitors to endemic areas than locals Anaphylactic or toxic symptoms – fever, malaise and urticaria . Accompanied by leucocytosis , eosinophilia , enlarged tender liver

18. 2. Oviposition Painless terminal hematuria – initially microscopic later becomes gross. Develops frequency of micturition and burning. Cystoscopy – hyperplasia and inflammation of bladder mucosa.

19. 3. Tissue proliferation and repair Generalised hyperplasia & fibrosis of vesical mucosa with granular appearance – sandy patch. Pseudo abscesses – d/t dense infiltration with inflammatory cells at site of deposition of eggs. Chronic cystitis – secondary bacterial infection. Calculi formation d/t deposition of oxalate & uric acid crystals around eggs. Obstructive hyperplasia of ureters & urethra. Associated Squamous cell carcinoma.

20. LAB DIAGNOSIS Detection of egg: Urine microscopy Bladder mucosal biopsy Detection of antigen: Circulating anodic antigen & Circulating cathodic antigen by ELISA Detection of antibody: Complement Fixation Test (CFT) Immunofluorescence Indirect Hemagglutination Bentonite flocculation test Enzyme linked immunoelectrotransfer blot FAST/ELISA

21. Intradermal skin test(Fairley’s test): Group specific test gives positive to all Schistosomiasis Imaging: X-Ray- bladder and ureteral calcification. USG- hydroureter & hydronephrosis Indirect diagnosis: IVP & Cystoscopy

22. TREATMENT & PROPHYLAXIS DOC – Praziquantel (40mg/kg for 1 day) Alternative DOC – Metriphonate Prophylaxis: Eradication of intermediate molluscan hosts. Prevention of environmental pollution with urine and faeces . Effective treated of infected. Avoid swimming, bathing and washing in infected water.

23. SCHISTOSOMA MANSONI

24. HISTORY & DISTRIBUTION Manson discovered eggs with lateral spines in the feces of a west indian patient that led to the recognition of this second species of human schistosomes . It is widely distributed in Africa, South America and the Carribean islands.

25. HABIT MORPHOLOGY Adult worm lives in the inferior mesenteric vein. S. mansoni resembles S. haematobium in morphology and life cycle, except: Adult worms are smaller and their integuments studded with prominet carse tubercles. The prepatent period is 4-5 weeks.

26. LIFE CYCLE DEFINITIVE HOST: Humans are the only natural definitive hosts. INTERMEDIATE HOST: Planorbid freshwater snails of the genus Biomphalaria . INFECTIVE FORM: Fork-tailed cercaria .

27. PATHOGENICITY AND CLINICAL FEATURES CERCARIAL DERMATITIS: Following skin penetration by cercariae KATAYAMA FEVER: Formation of immune complexes. Signs and symptoms include high fever, rash, arthralgia , etc.. INTESTINAL BILHARZIASIS: Microabscesses . Portal hypertension.

28. LABORATORY DIAGNOSIS Stool microscopy. Rectal biopsy. Serological diagnosis. Imaging. Blood examination.

29. TREATMENT & PROPHYLAXIS DOC – Praziquantel (40mg/kg for 1 day) Oxamniquine (single oral dose 15mg/kg) is also effective. Prophylaxis: Eradication of intermediate molluscan hosts. Prevention of environmental pollution with urine and faeces . Effective treated of infected. Avoid swimming, bathing and washing in infected water.

30. SCHISTOSOMA JAPONICUM

31. COMMON NAME: Oriental blood fluke DISTRIBUTION: Far east, Japan, China.. HABITAT: superior mesenteric vein, also seen in the intrahepatic portal venules and hemorrhoidal plexus of veins MORPHOLOGY: Adult male is comparatively slender(0.5mm thick). Female lays upto 3500 eggs at one time. The prepatent period is 4-5 weeks. Eggs are smaller as compared to S. haematobium and S. mansoni .

32. LIFE CYCLE Similar to S. haematobium , except; DEFINITIVE HOST: man INTERMEDIATE HOST: Amphibian snails of the genus Oncomelania . INFECTIVE FORM FOR HUMAN: Fork tailed cercaria .

33. PATHOGENICITY AND CLINICAL FEATURES KATAYAMA FEVER. CHRONIC ILLNESS. CENTRAL NERVOUS SYSTEMAND LUNGS INVOLVED.

34. TREATMENT & PROPHYLAXIS DOC – Praziquantel (40mg/kg for 1 day) Prophylaxis: Eradication of intermediate molluscan hosts. Prevention of environmental pollution with urine and faeces . Effective treated of infected. Avoid swimming, bathing and washing in infected water.

35. SCHISTOSOMA INTERCALATUM First noted in 1934 in West-Central Africa. Eggs are fully embryonated without any operculum. Eggs are acid-fast. Produces few symptoms involveing the mesentric portal system. Diagnosis is established by detecting the egg in feces and rectal biopsy. Praziquantel is the drug of choice.

36. SCHISTOSOMA MEKONGI First recognized in 1978 is found in Thailand and Cambodia along the Mekong river. Closely related to S. japonicum but is slightly smaller and round. Man and dog are the definitive host. Man acquires infection in the same way as in S. japonicum . Hepatosplenomegaly and ascites are the common clinical finding.

37. HERMAPHRODITIC FLUKES: LIVER FLUKES

38. FASCIOLA HEPATICA COMMON NAME: Sheep liver fluke. HISTORY & DISTRIBUTION: First trematode that was found more than 600 years ago in 1379 by Jehan de brie. Named by Linnaeus in 1758. Largest and most common liver fluke. Cause economically important disease “liver rot” in sheep. F.gigantia is more prevalent in india than F.hepatica . HABITAT: parasite resides in the liver and biliary passages of the definitive host.

39. MORPHOLOGY: Large in size, flat leaf-shaped fluke measuring 30mm long and 15mm broad, gray or brown in color. Adult worm lives 5 years in sheep and 10 years in humans. Has a conical projection anteriorly containing an oral sucker and is rounded posteriorly . EGG: Are large, ovoid, operculated,bile -stained and about 140µm by 80µm in size. Contain an immature larva, the miracidium . Do not float in saturated solution of common salt. Eggs of F.hepatica and Fasciolopsis Buski cannot be differentiated. Eggs are unembryonated when freshly passed.

40. LIFE CYCLE

41. PATHOGENICITY Acute Or Invasive Phase Period during which the fluke migrates from the intestine to the liver and its burrowing through the liver parenchyma. No significant change from the intestine to the liver Parasite may wander or be carried by blood after penetrating a blood vessel to ectopic sites such as lungs, subcutaneous Tissues, brain and the orbit. Abscesses or fibrotic lesions Migration to the liver parenchyma. Traumatic and necrotic lesions.

42. Chronic Or Latent Phase period when the parasite has already reached the bile ducts obstruction in the vessel inflammatory and adenomatous changes of the biliary epithelium fibrosis of the ducts pressure atrophy of the liver parenchyma intensive periductal fibrosis Heavy infections erosion of the epithelium young worms wander back into the liver to produce abscess pockets and to seed the vital liver tissue with their eggs

43. DIAGNOSIS Clinical- based on: Biliary symptoms. Moderate to high eosinophilia . Eating watercress as a green salad( metacercaria in vegetation) Laboratory Recovery of the eggs in the patient’s stool or from duodenal or biliary tract drainage. Serodiagnosis -helpful but not adapted for routine diagnosis.

44. TREATMENT AND PROPHYLAXIS Oral triclabendazole (10mg/kg once) is the treatment of choice. Alternative drug is bithionol (30-50mg for 10-15days). Prednisolone at a dose of 10-20mg/kg is used to control toxemia. PHROPHYLAXIS Health education. Control of snails. Proper disposal of human, sheep and cattle feces. Proper disinfection of watercresses and other water vegetations before consumption.

45. DICROCOELIUM DENTRITICUM Morphology slender, lancet shaped, flat transparent, aspinous body 5 to 15 mm by 1.5 to2.5 mm Acetabulum lies at the beginning of the second fifth of the body two large, slightly lobed testes situated obliquely to each other anterior to the small subglobose ovary just behind the ventral sucker  voluminous uterine coils in the posterior thirds of the worm Subglobose  ovary lies to the right of the midline and somewhat anterior to the equator of the worm discrete vitelline follicles occupy lateral fields in the middle of the body. Eggs are deep golden-brown thick shelled, distinctly operculated , measuring38 to 45u by 22 to 30u containing a fully developed miracidium .

46. LIFE CYCLE

47. TREATMENT AND PROPHYLAXIS Praziquantel -25 mg per kg TID for 2 consecutive days PROPHYLAXIS: no effective measures of control Fresh herbs collected from grazing areas for use as food for humans should be washed to remove the ants.

48. CLONORCHIS SINENSIS COMMON NAME: Chinese liver fluke HABITAT: Biliary tract and sometimes pancreatic duct. MORPHOLOGY: ADULT WORM: 10-25mm long and 3-5mm broad. Can survive for 15 years in biliary tract. EGGS: Flask shaped, 35µm by 20µm with a yellowish brown shell.

49. LIFE CYCLE

50. PATHOLOGY Distal bile ducts are irritated mechanically and by its toxic secretions Slight leukocytosis and eosinophilia in early infection Enlarged tender liver Bile ducts thicken and become dilated and tortuous Adenomatous proliferation of the  biliary epithelium Fibrosis and destruction of hepatic parenchyma Liver function is impaired although SGPT and SGOT are normal

51. DIAGNOSIS CLINICAL DIAGNOSIS Suggestive in patients from endemic areas with: History of eating uncooked fish. Symptoms of biliarytract disease intermittent jaundice bouts of fever right upper quadrant pain LABORATORY DIAGNOSIS Finding the characteristic eggs in the feces or biliary drainage or duodenal aspiration. Eggs to be differentiated from opistorchid and heterophyid flukes.

52. TREATMENT AND PROPHYLAXIS Praziquantel -25 mg per kg TID for 2 consecutive days PROPHYLAXIS: Proper cooking of fish. Proper disposal of feces. Control of snails.

53. OPISTHORCHIS SPECIES

54. INTESTINAL FLUKES

55. FASCIOLOPSIS BUSKI COMMON NAME: Giant intestinal fluke. First described by busk in 1843. HABITAT: Duodenum or jejunum of pigs and man. MORPHOLOGY: Largest fluke. Thick, fleshy, ovate.Flesh-coloured . 2-7.5 x 1-2 cm. Oral sucker and ventral suckers present.Typical trematode alimentary canal with unbranched intestinal caeca . Two dendritic testes. Single branched ovary. Vitellaria on lateral sides and a convoluted uterus and genital pore that is anterior to theventral sucker. EGG: Yellowish and oval. 130-140 x 80-85 μ. Thin walled with small operculum. Undeveloped ovum.

56. PATHOLOGY Attached to intestine by suckers. Mucosa inflamed, ulcerated and abscesses form. Epigastric pain , nausea , diarrhoea . Heavy infection leads to oedema , ascites and anarsaca . Toxic products of worm. Anaemia , leukocytosis , lymphocytosis , and esinophilia . Good prognosis if worm treated early. 1000-2000 worms affect intestinal secretions and food passage and intoxication and sensitization.

57. LIFE CYCLE

58. DIAGNOSIS, TREATMENT AND PROPHYLAXIS DIAGNOSIS: Eggs in feces. Differentiate from F. hepatica, Gastro discoides and Echinostoma sp. Adult worms vomited or passed in stool. TREATMENT: Praziquantel (15 mg/kg) body weight, single dose is the drug of choice . PROPHYLAXIS: Sanitary disposal of human feces. Discourage use of night soil. Restrict pigs. Snail control. Health education. Cooking or steeping of water plants.

59. HETEROPHYES HETEROPHYES MORPHOLOGY: Pyriform , greyish , 1.3 x 0.5 mm.Oral , Ventral and Genital suckers. EGG: Light brown in colour , thick shell, operculated , 29 x 16μm, Fully developed miracidium . TREATMENT: Praziquantel (15 mg/kg) body weight, single dose is the drug of choice . PROPHYLAXIS: Sanitary disposal of human feces. Discourage use of night soil. Restrict pigs. Snail control. Health education. Cooking or steeping of water plants.

60. METAGONIMUS YOKOGAWAI MORPHOLOGY: Small, 1.4 x 0.6 mm. Pyriform shape with rounded posterior and tapering anterior. Large ventral sucker. EGG: Light yellow-brown, thin-shelled, operculated , 28x17 μ m, mature miracidium . TREATMENT: Praziquantel (15 mg/kg) body weight, single dose is the drug of choice . PROPHYLAXIS: Sanitary disposal of human feces. Discourage use of night soil. Restrict pigs. Snail control. Health education. Cooking or steeping of water plants.

61. LUNG FLUKES

62. PARAGONIMUS WSTERMANI Common name: Oriental lung fluke History and Distribution: P. westermani was discovered in 1878 by Kerbert in the lungs of Bengal tigers that died in the zoological gardens at Hamberg and Amsterdam. The parasite is endemic in the Far East—Japan, Korea, Taiwan, China, and south east asia —Sri Lanka and India. Cases have been reported from Assam, Bengal, TamilNadu , and Kerala. P. mexicanus is an important human pathogen in Central and South America.

63. MORPHOLOGY ADULT WORM: The adult worm is egg-shaped about 10 mm long, 5 mm broad and 4 mm thick and reddish brown in color. The integument is covered with scale like spines. It has 2 unbranched intestinal caeca which end blindly in the caudal area. They have a lifespan of up to 20 years in humans. EGG: The eggs are operculated , golden brown in color and about 100μm by 50μm in size. They are unembryonated when freshly laid.

64. LIFE CYCLE

65. CLINICAL FEATURES , DIAGNOSIS, TREATMENT AND PROPHYLAXIS Clinical features: Peribronchial granuloma and cystic dilation of bronchi. Dyspnea , hemoptysis , pneumonitis , bronchiectasis , abcess , pneumothorax . Extrapulmonary lesions in brain and intestine. Diagnosis: Ova in sputum, X-ray and CT scan of chest , CFT, IHA, and ELISA. Treatment: Praziquantel is the drug of choice. Prophylaxis: Adequate cooking of crabs and crayfish, eradication of molluscan hosts and treatment of infected persons.

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