Filarial worms dr. rs 28 08-2017

MBBS UG MICROBIOLOGY THEORY CLASS LECTURE POWERPOINT PPT KARPAGAM FACULTY OF MEDICAL SCIENCES AND RESEARCH, COIMBATORE

1. FILARIAL WORMS Dr. R.Someshwaran , MBBS, MD., Assistant Professor , Department of Microbiology, Karpagam Faculty of Medical Sciences and Research, Othakalmandapam , Coimbatore-641032

2. Objectives of today’s class To enlist the human filarial worms (Nematodes) To understand and explain the morphology, life cycle, clinical presentation and pathogenesis of various filarial worms infecting humans To understand and explain the lab diagnosis, treatment and prevention of various filarial worms infecting humans

3. HELMINTHOLOGY Helminths are multicellular, bilaterally symmetrical animals Helminths – 2 Phylum 8/28/2017 3

4. Differences between Cestodes , Trematodes & Nematodes CESTODES TREMATODES NEMATODES Shape Tape like segmented Leaf like unsegmented Elongated, cylindrical, unsegmented Sexes Sexes not separate Monoecious Hermaphrodite Sexes not separate Monoecious except Schistosoma Sexes are separate Diecious Head end Suckers, often with hooks Suckers, no hooks No suckers, no hooks, well developed Alimentary canal Absent Present, incomplete, no anus Present, complete, anus present Body cavity Absent Absent Present 8/28/2017 4

5. NEMATODES CLASSIFICATION (LOCATION OF ADULT IN BODY) INTESTINAL NEMATODES: Small intestine: Ascaris, Ancylostoma, Necator, Strongyloides , Trichinella . Large intestine: Enterobius, Trichuris TISSUE NEMATODES (Somatic nematodes): Lymphatic: Wuchereria , Brugia Sub-cutaneous: Loa loa , Onchocerca , Dracunculus Mesentry : Mansonella spp., Conjucntiva : Loa loa Zoonotic filariasis : Dirofilaria spp.,

6. NEMATODES CLASSIFICATION (MODE OF INFECTION) By ingestion: Eggs: Ascaris, Enterobius, Trichuris Larvae within intermediate host: Dracunculus Encysted larvae in the muscle: Trichinella By Penetration of Skin: Ancylostoma, Necator, Strongyloides By blood sucking insects: Filariae By inhalation of dust containing eggs: Ascaris, Enterobius

7. NEMATODES CLASSIFICATION (BASED ON THEY LAY EGGS/LARVAE) Oviparous: Egg laying nematodes Unsegmented eggs: Ascaris, trichuris Segmented eggs: Ancylostoma, Necator Eggs containing larvae: Enterobius Viviparous: Producing larvae Ex: Trichinella , Wuchereria , Brugia , Dracunculus Ovoviviparous: Laying eggs containing fully formed larvae which hatch out immediately: Strongyloides .

8. HUMAN FILARIAL WORMS Filarial worms belong to Superfamily: Filarioideae . Thread like worms transmitted by blood sucking insects (Arthropods) Vector borne disease / Zoonotic disease Infection by any filarial worm is called as ‘ Filariasis ’. Morphological forms: Adult worm & Microfilariae (embryo)

9. HUMAN FILARIAL WORMS Microfilaria (mf): Sheathed & Unsheathed/naked Sheathed mf: Retain their egg membrane Unsheathed mf: Ruptures out from the egg membranes 8 species of filarial worms infect humans Humans are the Definite hosts

10. Classification of Human filarial worms Lymphatic filariasis : Wuchereria bancrofti ( Bancroftian filariasis ) Brugia malayi (Malayan filariasis ) Brugia timori Subcutaneous filariasis : Loa loa ( Calabar swelling/Fugitive swelling) Onchocerca volvulus (River blindness, dermatitis) & Mansonella streptocerca (Skin diseases) Serous cavity filariasis : Mansonella ozzardi (Non-pathogenic) & Mansonella perstans (Non-pathogenic)

11. Classification of Human filarial worms Zoonotic filariasis : Dirofilaria immitis Dirofilaria repens Brugia pahangi Brugia beaveri Brugia leporis

12. Filarial nematode Habitat of Adults Habitat of Microfilaria Vector Microfilaria periodicity LYMPHATIC FILARIASIS Wuchereria bancrofti Lymphatic tissue Blood Culex quinquefasciatus (W) Anopheles in rural Africa Aedes spp., Nocturnal (M) Sub-periodic (R) Brugia malayi Lymphatic tissue Blood Mansonia spp., Anopheles Mansonia spp., Coquillettidia Nocturnal (M) Sub-periodic (R) Brugia timori Lymphatic tissue Blood Anopheles barbirostris Nocturnal SUBCUTANEOUS FILARIASIS Loa loa Subcutaneous tissue, Conjunctiva Blood Chrysops (Deer fly) Diurnal Onchocerca volvulus Subcutaneous tissue Skin and eye Simulium (Black fly) None Mansonella streptocerca Subcutaneous tissue Skin Culicoides (Midges) None SEROUS CAVITY FILARIASIS Mansonella perstans Body cavities, Mesentry Blood Culicoides (Midges) None Mansonella ozzardi Body cavities Blood Culicoides (Midges) Simulium (Black fly) None

13. Filarial nematode Characteristic feature of Microfilaria Epidemiology LYMPHATIC FILARIASIS Wuchereria bancrofti Sheathed, Pointed tail tip free of nuclei South America, Africa, Asia Brugia malayi Sheathed, blunted tail tip with two terminal nuclei Pacific Islands Brugia timori Sheathed longer than Mf. malayi SE Asia, India, Indonesia SUBCUTANEOUS FILARIASIS Loa loa Sheathed, nuclei extending up to pointed tail tip West and Central Africa Onchocerca volvulus Unsheathed, blunt tail tip free of nuclei S. And C. America and Africa Mansonella streptocerca Unsheathed, blunt tail tip with nuclei W. And C. Africa SEROUS CAVITY FILARIASIS Mansonella perstans Unsheathed, pointed tail tip free of nuclei S. And C. America Mansonella ozzardi Unsheathed, pointed tail tip with nuclei S. And C. America Carribean Islands

14. Head and Tail ends of Microfilariae

15. LYMPHATIC FILARIASIS Wuchereria bancrofti Brugia malayi Brugia timoria

16. Global Scenario Population at risk : 1.2 Billion No. of countries : > 80 Mf carriers : 76 Million Diseased : 44 Million Hydrocele : 27 Million Lymphoedema : 16 Million TPE : 1 Million

17. National Scenario Total Population : 110 C Population at risk : 45.4 C (in 16 States & 5 UT’s) Total infected : 51.7 M ( Wb - 99.4 % and Bm - 0.6 %) No. of diseased : 22.5 M Mf carriers : 29.2 M Hydrocele : 12.9 M

18. EPIDEMIOLOGY

19. Mode of Transmission & Incubation Period Lymphatic Filariasis is transmitted by the bite of Infected mosquito which harbours L 3 larva. L 1 : 1-3 hours L 2 : 3-4 days L 3 : 5-6 days Pre-patent period: (L 3 to Mf) Not known Clinical Incubation period: 8-16 months

20. Clinical Manifestations Manifestations are 2 types Lymphatic Filariasis (Presence of Adult worms) Occult Filariasis (Immuno hyper responsiveness) Clinical Spectrum None Asymptomatic microfilaremia Filarial fever Chronic pathology TPE

21. Stages in Lymphatic Filariasis There are 4 stages : Asymptomatic amicrofilariaemic stage Asymptomatic microfilariaemic stage Stage of Acute manifestation Stage of Obstructive (Chronic) lesions

22. Wuchereria bancrofti Bancroftian Filariasis

23. Wuchereria bancrofti

24. Wuchereria bancrofti - Adult

25. LIFECYCLE OF W. bancrofti

26. Filarial fever

27. Complications

28. Lab diagnosis

29. Laboratory Diagnosis 1. Demonstration of microfilarae in the peripheral blood a. Thick blood smear: 2-3 drops of free flowing blood by finger prick method, stained with JSB-II b. Membrane filtration method: 1-2 ml intravenous blood filtered through 3 µ m pore size membrane filter c. DEC provocative test (2mg/Kg): After consuming DEC, mf enters into the peripheral blood in day time within 30 - 45 minutes.

30. 2. Immuno Chromatographic Test (ICT): Antigen detection assay can be done by Card test and through ELISA. Circulating Filarial Antigen detection is regarded as “Gold Standard” for diagnosing Wuchereria bancrofti infection. Specificity is near complete, sensitivity is greater than all other parasite detection assays, will detect antigen in amicrofilaraemic as well as with clinical manifestations like lymphoedema , elephantiasis.

31. 3. Quantitative Blood Count (QBC): QBC will identify the microfilariae and will help in studying the morphology. Though quick it is not sensitive than blood smear examination. 4. Ultrasonography: Ultrasonography using a 7.5 MHz or 10 MHz probe can locate and visualize the movements of living adult worms of W.b . in the scrotal lymphatics of asymptomatic males with microfilaraemia . The constant thrashing movements described as “ Filaria dance sign” can be visualized.

32. 5. Lymphoscintigraphy : The structure and function of the lymphatics of the involved limbs can be assessed by lymphoscintigraphy after injecting radio- labelled albumin or dextran in the web space of the toes. The structural changes can be imaged using a Gamma camera. Lymphatic dilation & obstruction can be directly demonstrated even in early clinically asymptomatic stage of the disease. 6. X-ray Diagnosis: X-ray are helpful in the diagnosis of Tropical pulmonary eosinophilia. Picture will show interstial thickening, diffused nodular mottling. 7. Haematology : Increase in eosinophil count

33. Peripheral smear showing Microfilaria

34. CLASSICAL FILARIASIS vs OCCULT FILARIASIS CLASSICAL FILARIASIS OCCULT FILARIASIS CAUSE Inflammatory changes to Devoloping worms and adult Hypersensitivity reaction to Microfilaria antigen PATHOLOGY Acute inflammation and epitheloid granuloma Eosinophilic granuloma ORGANS AFFECTED Lymph nodes & Lymphatic system Lung, liver and spleen MICROFILARIA Present in blood Present in affected tissues & absent in blood THERAPEUTIC RESPONSE No response Responds to microfilaricidal agent SEROLOGICAL TESTS Antobody not diagnostic IgE Ab Highly sensitive

35. DEC PROVOCATION TEST Diethyl carbamazine 2mg/kg Body weight 20-50 mins later – peripheral smear for microfilariae.

36. Post DEC Provocation test

37. Tropical Pulmonary Eosinophilia

38. Brugia malayi Malayan Filariasis

39. LIFE CYCLE

40. Brugia malayi

41. Brugia malayi

42. Microfilaria of Wuchereria bancrofti & Brugia malayi Features Wuchereria bancrofti Brugia malayi Appearance Graceful sweeping curves Kinky with 2 ⁰ curves Size 250-300 micrometres long 175 to 230 micrometres Cephalic space Length to width ratio 1:1 Length to width ratio 2:1 Stylet at anterior end Single Double Excretory pore Not prominent Prominent Nuclei column Large coarse discrete nuclei Overlapping blurred nuclei Tail Pointed & free of nuclei Pointed with 2 distinct nuclei Sheath Faintly stained Well stained

43. Wuchereria bancrofti vs Brugia malayi

44. Wuchereria bancrofti

45. Brugia timori Lymphatic filariasis

46. Brugia timori

47. Loa loa African eye worm Calabar swelling Fugitive swelling Adult: 3-7cm long Treatment: Dec. Surgical removal

48. CALABAR SWELLING

49. Loa loa Subcutaneous nodules

50. LIFE CYCLE

51. Loa loa

52. Onchocerca volvulus River blindness Convoluted or Blinding filaria 50cm long adult worm

53. Onchocerca volvulus

54. Onchocerca volvulus

55. Mazzotti reaction DEC treatment causes intense reaction with rash, pruritus, facial edema , fever, hypotension, lymphadenopathy and occ. Eye damage. Drug of choice is Ivermectin

56. Life cycle

57. Mansonella streptocerca Subcutaneous filariasis

58. Life cycle

59. Mansonella ozzardi

60. Mansonella perstans Usually nonpathogenic

61. Mansonella perstans

62. Zoonotic filariasis Dirofilaria immitis – Dog heart worm Dirofilaria repens (dogs) – subcutaneous and conjunctival nodules in humans Dirofilaria conjunctivae (humans) Brugia pahangi - cats and dogs

63. Dirofilaria immitis

64. Dirofilaria immitis

65. Dirofilaria repens

66. Brugia pahangi

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