Epidemiology of Filariasis Epidemiology of Filariasis Magnitude of

Epidemiology of Filariasis

Epidemiology of Filariasis ØMagnitude of the problem ØLife cycle: Agent & Vector ØClinical features ØDiagnosis ØTreatment

introduction Ø Caused by the nematode worm either Wuchereria bancrofti or Brugia malayi Ø Transmission: Culex quinquefasciatus & Mansonia annulifera/uniformis Ø Lymphatic system is affected Ø The disease manifests often in bizarre swelling of legs and hydrocele Ø A great deal of social stigma

introduction • A major public health problem in India • Recorded in “Susruta Samhita” • Clarke called elephantoid legs in Cochin as Malabar legs

filariasis Ø Lymphatic filariasis ü Wuchereria bancrofti, ü Brugia malayi ü Brugia timori Ø Lymphatic filariasis ü O. Volvulus ü M. Ozzardi etc

Magnitude of the problem: global Ø A major cause of clinical suffering, disability and handicap Ø Approximately 18% of the world's population — live in areas at risk of infection with lymphatic filarial parasites Ø Approximately one third of those at risk live in India, one third in Africa

Magnitude of the problem: global

Magnitude of the problem in India

Total DALYs lost

Socio - economic burden Ø Second leading cause of disability in the world. Ø Causes stigma, isolation, psychological stress and family discord among the affected individuals Ø Impairs educational and employment opportunities Ø Impedes domestic and occupational activities

Socio-economic burden Ø A male chronic patient on average losses as many as 69 working days/annum Ø The treatment costs incurred by patients range from RS 1 to 1000 per episode an Ø India loses also 1. 2 billion man days due to LF

Epidemiology of Filariasis ØMagnitude of the problem ØLife cycle: Agent & Vector ØClinical features ØDiagnosis ØTreatment

Life cycle of Culex Mosquito

About the vectors • W. bancrofti : Culex mosquitoes in most urban and semi-urban areas • Anopheles in the more rural areas of Africa and • Aedes species in many of the endemic Pacific islands.

The vector Ø Brugian parasites : Mansonia species serve as the major vector Ø Brugian parasites are confined to areas of east and south Asia, especially China, India, Indonesia, Malaysia and the Philippines.

Epidemiology of Filariasis ØMagnitude of the problem ØLife cycle: Agent & Vector ØClinical features ØDiagnosis ØTreatment

Clinical features Ø Asymptomatic microfilarimia Ø Acute manifestations Ø Chronic obstructive lesions Ø Occult filariasis: Tropical Pulmonary eosinophilia

lymphoedema grading • Grade I : Mostly pitting oedema; spontaneously reversible on elevation. • Grade II: Mostly non-pitting oedema; not spontaneously reversible on elevation. • Grade III (elephantiasis): Gross increase in volume in a Grade II lymphoedema, with dermatosclerosis and papillomatous lesions.

elephantiasis

hydrocele

Bancroftian filariasis Ø Lymphatic vessels of the male genitalia are most commonly affected Ø Episodic funiculitis (inflammation of the spermatic cord) epididymitis and orchitis Ø Hydrocele is the most common sign of chronic bancroftian filariasis, followed by lymphoedema & elephantiasis

Brugian filariasis Ø Lymphadenitis: one inguinal lymph node at a time Ø Lymphangitis Ø The infected lymph node may become an abscess, ulcerate, and heal with fibrotic scarring Ø Characteristically, elephantiasis involves the leg below the knee but occasionally it affects the arm below the elbow

Epidemiology of Filariasis ØMagnitude of the problem ØLife cycle: Agent & Vector ØClinical features ØDiagnosis ØTreatment

Laboratory Diagnosis Ø Examining night blood collected by finger pricking Ø Og 4 C 3 ELISA Assay Ø ICT Card Test Ø Polycarbonate membrane filtration Test Ø Other tests Ø Serological techniques Indirect immuno fluorescent assay with mf and adult worm. Ø DNA based diagnostic tests

Wucheraria bancrofti

Epidemiology of Filariasis ØMagnitude of the problem ØLife cycle: Agent & Vector ØClinical features ØDiagnosis ØTreatment

Case treatment Ø Diethylcarbamazine (DEC): 6 mg/kg üFor 12 days over 2 weeks üToxic reactions Ø Ivermectin : 400 micro gm/kg single dose

lymphoedema management Ø Washing Ø Prevention and cure of entry lesions Ø Elevation of the foot Ø Exercise Ø Wearing proper footwear Ø Hydrocelectomy

Washing

Prevention and cure of entry lesions

Exercises

Mass Drug Regimen Ø 6 mg/kg diethylcarbamazine citrate (DEC) + 400 mg albendazole Ø 150 µg/kg ivermectin + 400 mg albendazole (in the case of co-endemicity with onchocerciasis) Ø A third option is to follow a treatment regimen using DEC-fortified cooking salt daily for a period of 12 months

questions Ø Clinical Spectrum of Filariasis Ø Treatment of Lymphatic Filariasis and Mass treatment regimen.

Next class ØFilaria survey ØPrevention & control strategies

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