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1、Lymphatic Filariasis,B.Ganesh Regional Filaria Training & Research Centre National Institute of Communicable Diseases Kozhikode.,Lymphatic Filariasis,Infection with 3 closely related Nematodes Wuchereria bancrofti Brugia malayi Brugia timori *Transmitted by the bite of infected mosquito responsible

2、for considerable sufferings/deformity and disability *All the parasites have similar life cycle in man *Adults seen in Lymphatic vessels *Offsprings seen in peripheral blood during night,Disease Manifestation,Disease manifestation range from None Acute-Filarial fever Chronic-Lymphangitis, Lymphadeni

3、tis, Elephantiasis of genitals/legs/arms Tropical Pulmonary Eosinophilia (TPE) Filarial arthritis Epididimoorchitis Chyluria, etc.,Distribution,Prevalent world wide in the Tropics and Sub-tropical regions of Africa Asia Western Pacific Parts of Central & South America,Lymphatic Filariasis Endemic Co

4、untries & Territories,Endemic Countries,Global Distribution Map,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,National Scenario,Total Population:110 C Population at risk:45.4 C

5、(in 16 States & 5 UTs) 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,Agent Factors,Host Factors,Man Natural Host Age All age (6 months) Max: 20-30 years Sex Higher in men Migration leading to extension of infection to non-endemic areas

6、Immunity may develop after long year of exposure (Basis of immunity-not known),Social & Environmental Factors,Associated with Urbanization, Poverty, Industrialization, Illiteracy and Poor sanitation. Climate: is an important factor which influences: The breeding of mosquito Longevity (Optimum temper

7、ature 20-300C & Humidity 70%) The development of parasite in the vector Sanitation, Town planning, Sewage & Drainage.,Mode of Transmission & Incubation Period,Lymphatic Filariasis is transmitted by the bite of Infected mosquito which harbours L3 larva. L1: 1-3 hours L2: 3-4 days L3: 5-6 days Pre-pat

8、ent period: (L3 to Mf) Not known Clinical Incubation period: 8-16 months,Lymphatic Filariasis Diagnostic Methods,Diagnosis of Lymphatic Filariasis,Lymphatic Filariasis can be diagnosed clinically and through laboratory techniques. Clinically, diagnosis can be made on circumstantial evidence with sup

9、port from antibody or other laboratory assays as most of the LF patients are amicrofilaraemic and in the absence of serological tests which is not specific other than CFA (ICT). In TPE, serum antibodies like IgG & IgE will be extremely high and the presence of IgG4 antibodies indicate active infecti

10、on.,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 3m pore size membrane filter c. DEC provocative

11、 test (2mg/Kg): After consuming DEC, mf enters into the peripheral blood in day time within 30 - 45 minutes.,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

12、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.,3. Quantitative Blood Count (QBC): QBC will identify the mic

13、rofilariae 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

14、 with microfilaraemia. The constant thrashing movements described as “Filaria dance sign” can be visualized.,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 sp

15、ace 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 wil

16、l show interstial thickening, diffused nodular mottling. 7. Haematology : Increase in eosinophil count,Lymphatic Filariasis Clinical Manifestations,Clinical Manifestations,Manifestations are 2 types Lymphatic Filariasis (Presence of Adult worms) Occult Filariasis (Immuno hyper responsiveness) Clinic

17、al Spectrum,None,Asymptomatic microfilaremia,Filarial fever,Chronic pathology,TPE,Stages in Lymphatic Filariasis,There are 4 stages : Asymptomatic amicrofilariaemic stage Asymptomatic microfilariaemic stage Stage of Acute manifestation Stage of Obstructive (Chronic) lesions,Stage of Asymptomatic ami

18、crofilaraemic,In endemic areas, a proportion of population does not show mf or clinical manifestation even though they have some degree of exposure to infective larva similar to those who become infected. Laboratory diagnostic techniques are not able to determine whether they are infected or free.,S

19、tage of Asymptomatic Microfilariaemic,Considerable proportions are asymptomatic for months and years, though they have circulating microfilariae. They are an important source of infection. They can be detected by Night Blood Survey and other suitable procedures.,Stage of Acute Manifestation,During i

20、nitial months and years, there are recurrent episodes of Acute inflammation in the lymph vessel/node of the limb & scrotum that are related to bacterial & fungal super infections of the tissue that are already compromised lymphatic function. Clinical manifestations are consisting of: Filarial fever

21、(ADL-DLA) Lymphangitis Lymphadinitis Epididimo orchitis,Chronic Manifestation,Chronic (Obstructive) lesions takes 10-15 years. This is due to the permanent damage to the lymph vessels caused by the adult worms, the pathological changes causing dilation of the lymph vessels due to recurrent inflammat

22、ory episodes leading to endothelial proliferation and inflammatory granulomnatous reaction around the parasite. Initially, it starts with pitting oedema which gives rise to browny oedema leading to hardening he tissues. Still late, hyper pigmentation, caratosis, wart like lesions are developed. Eg.

23、Hydrocele (40-60%), Elephantiasis of Scrotum, Penis, Leg, Arm, Vulva, Breast, Chyluria.,2. Occult Filariasis (TPE),Occult or Cryptic filariasis, in classical clinical manifestation mf will be absent. Occult filariasis is believed to be the result of hyper responsiveness to filarial antigens derived

24、from mf. Seen more in males. Patients present with paroxysmal cough and wheezing, low grade fever, scandy sputum with occasional haemoptysis, adenopathy and increased eosinophilia. X-ray shows diffused nodular mottling and interstial thickening.,Hydrocele,Scrotum,Penis,Leg,Arm,Breast,Chyluria & Haem

25、aturia,Classification of Lymphoedema,Lymphoedema is classified into 7 stages on the basis of the presence & absence of the following: Oedema Folds Knobs Mossy foot Disability,Stages of Lymphoedema of the Leg (Stage I),Swelling reverses at night Skin folds-Absent Appearance of Skin-Smooth, Normal,Sta

26、ges of Lymphoedema of the Leg (Stage II),Swelling not reversible at night Skin folds-Absent Appearance of skin-Smooth, Normal,Stages of Lymphoedema of the Leg (Stage III),Swelling not reversible at night Skin folds-Shallow Appearance of skin-Smooth, Normal,Stages of Lymphoedema of the Leg (Stage IV)

27、,Swelling not reversible at night Skin folds-Shallow Appearance of skin - Irregular, * Knobs, Nodules,Stages of Lymphoedema of the Leg (Stage V),Swelling not reversible at night Skin folds-Deep Appearance of skin Smooth or Irregular,Stages of Lymphoedema of the Leg (Stage VI),Swelling not reversible

28、 at night Skin folds-Absent, Shallow, Deep Appearance of skin *Wart-like lesions on foot or top of the toes,Stages of Lymphoedema of the Leg (Stage VII),Swelling not reversible at night Skin folds-Deep Appearance of skin-Irregular Needs help for daily activities - Walking, bathing, using bathrooms,

29、dependent on family or health care systems,Pathology of Lymphatic Filariasis,The pathology associated with lymphatic filariasis results from a complex interplay of the pathogenic potential of the parasite, the tissue response of the host and external bacterial and fungal infections. Most of the path

30、ology associated with LF is limited to the lymphatics.,The damage to the lymphatic vessels is mediated both by an immune response to the adult worms as well as by a direct action of the parasite or the product released by them. In the absence of inflammation, marked lymphatic dilation with lymphoede

31、ma is seen in experimental animals with immune deficiency and when immuno competent cells are induced, it results inflammatory granuloma reactions around the parasite and subsequent obstructions of the lymphatic vessel occurs leading to lymphoedema.,Lymphatic Filariasis Management,Twin Pillars of Ly

32、mphatic Filariasis Elimination,Interrupt transmission Control Morbidity (relief of suffering) # Community-level care of those with disease Lymphoedema Acute inflammatory attacks Hydrocele repair,Management of Lymphatic Filariasis,Treating the infection Treatment and prevention of Acute ADL attacks T

33、reatment and prevention of Lymphoedema,Treating the infection Remarkable advances in the treatment of LF have recently been achieved focusing not on individual but on community with infection, with the goal of reducing mf in the community, to levels below which successful transmission will not occur

34、.,Chemotherapy of Filariasis,Drugs effective against filarial parasites Diethyl Carbomazine citrate (DEC) Ivermectin Albendazole Couramin compound Treatment of microfilaraemic patients may prevent chronic obstructive disease and may be repeated every 6 months till mf and/or symptoms disappears.,Diet

35、hyl Carbomazine Citrate (Hetrazan, Banocide, Notezine),Mode of action: DEC do not have direct action of parasite but mediate through host immune system. Very effective against mf (Microfilariacidal) Lowers mf level even in single dose Effective against adult worms in 50% of patients in sensitive cas

36、es. Dose: 6mg/Kg/12 days Recent dosage: 6mg/Kg single dose Adverse reactions are mostly due to the rapid destruction of mf which is characterised by fever, nausea, myalgia, sore throat, cough, headache. No effect on the treatment of ADL Drug of choice in the treatment of TPE.,Ivermectin,Mode of acti

37、on: Directly acts on mf and no action on adults. Very effective against mf (Microfilariacidal) Lowers mf level even in single dose of 200g 400g/Kg body weight No action on TPE Drug of choice in Co-endemic areas of Onchocerciasis with LF. Adverse reactions are lesser but similar to that of DEC Microf

38、ilariae reappears faster than DEC,Albendazole,This antihelmenthic kills adult worms No action on microfilariae Dose: 400mg/twice day /2 weeks With combination of DEC & Ivermectin, it enhances the action of the drugs. It induces severe adverse reactions in hydrocele cases due to the death of adult wo

39、rms.,Treatment and Prevention of ADL The most distressing aspect of LF is the acute attacks of ADL, which results in considerable economic loss and deterioration of quality of life. Prompt treatment and prevention of ADL are of paramount importance. ADL may be seen both in early & late stages of the

40、 disease. It is due to the infection & inflammation of the skin and affected area due to entry of bacteria or fungus through the entry lesions. The skin becomes warm, tender, painful, swollen, red. Patient develops fever, headache, chills and sometimes nausea and vomiting. Occasionally becomes septi

41、cemic.,First sign will be enlarged, tender and painful L.nodes. SS of inflammation appears later lasting for 4-5days. Peeling & darkening of skin is common. Repeated attacks increase the size of the legs. Management includes symptomatic treatment like relieving pain, care of entry lesions etc. In pa

42、tients with late stages of oedema, long term antibiotic therapy using oral Penicillin or long acting parentral Benzathil Penicillin are used to prevent ADL.,ADL,Cooling the Leg,ADL,ADL,Entry Lesions,Entry Lesions,Ulcers,Surgical Treatment,Hydrocele: Excision Scrotal Elip: Surgical removal of Skin &

43、Tissue, preserving penis and testicles. Lymphoedema (Elephantiasis): Excision of redundant tissue, Excision of subcutaneous and fatty tissues, postral drainage and physiotherapy,Treatment and Prevention of Lymphoedema and Elephantiasis Early treatment with drugs may destroy the adult worms and logic

44、ally prevent the later development of lymphoedema. Once lymphoedema is established there is no cure and the “foot care programme” may offer relief and prevent acute attacks thus preventing further progression of the swelling.,Lymphoedema management helps to eliminate the bad odour to prevent & heal

45、entry lesion to help patients self-confident to reduce the size of the lyphoedema to prevent disability to prevent economic loss,Lymphoedema Management Basic Components and Benefits,Basic Components 1. Hygiene 2. Prevention & cure of entry lesions 3. Exercise 4. Elevation of foot 5. Use of proper fo

46、otwares,Hygiene,Drying the Leg,Prevention & Cure of Entry lesions,Exercise,Elevation of Foot,Elevation of Foot,Use of appropriate Foot ware,Lymphatic FilariasisControl,Lymphatic Filariasis Control Programme,The current strategy of filariasis control (Elimination) is based on: 1. Interruption of tran

47、smission 2. Control of Morbidity Interruption of the transmission can be achieved through: Chemotherapy Vector control An integrated programme is in place for the control of lymphatic filariasis. Earlier, vector control was the main method of control. There are three main reasons why filariasis neve

48、r causes explosive epidemics The microfilariae does not multiply in the vector Infective larvae do not multiply in man Life cycle of the parasite is relatively long (15 ),Case detection and treatment in low endemic areas are suitable for preventing transmission and controlling the disease. In high e

49、ndemic areas, Mass chemotherapy is the approach. DEC medicated salt is also a form of Mass treatment using low dose of drug over a long period of time (1-2 gm /Kg of Salt).,Vector Control,Vector control involves anti larval measures, anti adult measures, personal prophylaxis. An integrated method us

50、ing all the vector control measures alone will bring about sustained vector control. I. Anti larval measures: 1. Chemical control Mosquito larvicidal oil Pyrosene oil Organo phosphorous compounds such as Temephos, Fenthion, 2. Removal of pistia plants 3. Minor environmental measures,Vector Control,I

51、I. Anti adult measures: Anti adult measures as indoor residual spay using DDT, HCH and Dieldrin. Pyrethrum as a space spray is also followed. III. Personal Prophylaxis: Reduction of man mosquito contact by using mosquito nets, screening of houses, etc.,Morbidity Management,Control Morbidity (relief of suffering) # Community-level care of those with disease Lymphoedema Acute inflammatory attacks Hydrocele repair,Thank you,