FilariasisFilariasis

Libson TangLibson Tang

Epidemiology- InternationalEpidemiology- International

120 million in 80 countries120 million in 80 countries 1 billion at risk1 billion at risk 90% - Wucheraria Bancrofti90% - Wucheraria Bancrofti Remainder – Brugia MalayiRemainder – Brugia Malayi

Epidemiology - SabahEpidemiology - Sabah

2000 – 103 cases, predomimantly Brugia 2000 – 103 cases, predomimantly Brugia MalayiMalayi

Vectors – Wucheraria BancroftiVectors – Wucheraria Bancrofti

Major – Culicine Mosquitoes ( urban and Major – Culicine Mosquitoes ( urban and semi-urban areas )semi-urban areas )

Anophelines – Rural areas ( mainly Africa )Anophelines – Rural areas ( mainly Africa ) Aedes – Endemic Pacific IslandsAedes – Endemic Pacific Islands

Vectors – Brugia MalayiVectors – Brugia Malayi

MansoniaMansonia AnophelineAnopheline Mainly confined to east and south Asia, Mainly confined to east and south Asia,

especially India, Malaysia, Indonesia, the especially India, Malaysia, Indonesia, the Philippines, and China. Philippines, and China.

Pathogenesis and PathologyPathogenesis and Pathology

Complex interplay of the pathogenic Complex interplay of the pathogenic potential of the parasite, the immune potential of the parasite, the immune response of the host, and external response of the host, and external ('complicating') bacterial and fungal ('complicating') bacterial and fungal infections.infections.

Most recognizable – Genital damage Most recognizable – Genital damage ( Hydroceles ) and ( Hydroceles ) and Lymphoedema/elephantiasis Lymphoedema/elephantiasis

Histologically - dilatation and proliferation of Histologically - dilatation and proliferation of lymphatic endothelium & abnormal lymphatic endothelium & abnormal lymphatic function lymphatic function

'non-inflammatory pathway' 'non-inflammatory pathway' ‘‘inflammatory pathway‘ - adenitis and inflammatory pathway‘ - adenitis and

retrograde lymphangitis retrograde lymphangitis bacterial and fungal superinfections bacterial and fungal superinfections

Clinical FeaturesClinical Features Chronic manifestations:Chronic manifestations: Hydrocoele (most Hydrocoele (most

common ), elephantiasis, Chyluria common ), elephantiasis, Chyluria Acute manifestations:Acute manifestations: Acute inflammatory Acute inflammatory

episodes 'DLA'(dermatolymphangioadenitis) , episodes 'DLA'(dermatolymphangioadenitis) , 'filarial fever' , tropical pulmonary eosinophilia, 'filarial fever' , tropical pulmonary eosinophilia, acute inflammatory reaction acute inflammatory reaction

Asymptomatic PresentationsAsymptomatic Presentations Other Syndromes:Other Syndromes: arthritis (typically arthritis (typically

monoarticular), endomyocardial fibrosis, monoarticular), endomyocardial fibrosis, tenosynovitis, thrombophlebitis, tenosynovitis, thrombophlebitis, glomerulonephritis, lateral popliteal nerve palsy, glomerulonephritis, lateral popliteal nerve palsy, and others. and others.

DiagnosisDiagnosis

Until recently, diagnosis depended on the Until recently, diagnosis depended on the direct demonstration of the parasite direct demonstration of the parasite

Antigen detection:Antigen detection: Circulating filarial antigen Circulating filarial antigen (CFA) - 'gold standard' for diagnosing (CFA) - 'gold standard' for diagnosing Wuchereria bancroftiWuchereria bancrofti infections. infections.

Clinical DiagnosisClinical Diagnosis

ManagementManagement Treating the infection:Treating the infection: DEC (6 mg/kg per DEC (6 mg/kg per

day) for 12 days in bancroftian filariasis and day) for 12 days in bancroftian filariasis and for 6 days in brugian filariasis, repeated at 1-for 6 days in brugian filariasis, repeated at 1-6 monthly intervals if necessary 6 monthly intervals if necessary

Ivermectin Ivermectin Albendazole Albendazole Side effects : headaches, fever, myalgia, Side effects : headaches, fever, myalgia,

lymphadenopathy and occasionally rash, lymphadenopathy and occasionally rash, itching itching

Treating the consequences: Treating the consequences: treatment of treatment of infection in communities with either infection in communities with either intermittent (monthly, 6-monthly, yearly) intermittent (monthly, 6-monthly, yearly) drug administration or the steady use of drug administration or the steady use of DEC-fortified table/cooking saltDEC-fortified table/cooking salt

Intensive local hygiene efforts and antibiotic Intensive local hygiene efforts and antibiotic ointments ointments

PreventionPrevention

By decreasing contact between humans and By decreasing contact between humans and vectors or by decreasing the amount of vectors or by decreasing the amount of infection the vector can acquire infection the vector can acquire

Population:Population: through reducing the numbers through reducing the numbers of mosquito vectorsof mosquito vectors

2-drug treatment regimens (selecting among 2-drug treatment regimens (selecting among albendazole and either ivermectin or albendazole and either ivermectin or diethylcarbamazine [DEC])diethylcarbamazine [DEC])

Individuals:Individuals: personal repellents, bednets or personal repellents, bednets or insecticide-impregnated materials. insecticide-impregnated materials.

Prophylactic regimen of DEC (6 mg/kg per Prophylactic regimen of DEC (6 mg/kg per day x 2 days each month) day x 2 days each month)

Thank YouThank You