FILARIASISTISSUE NEMATODESIsna IndrawatiDepartment of Parasitology

Lymphatic

Non - lymphatic (subcutaneous)Wuchereria bancrofti

Brugia malayi

Brugia timoriLoa-loa

Onchocerca volvulus

Mansonella (less pathogenic)Classification of medical importance:

Filariasis lymphaticBelongs to superfamily FilaroideaWHO : over 120 million people are currently infected in 73 countries :66% of those infected live in the WHO South-East Asia Region,33% in the African Region,1% in other tropical areas.W. bancrofti, which is responsible for 90% of the cases

Filariasis lymphatic (contd)about 40 million disfigured and incapacitated by the disease.altered lymphatic system and the abnormal enlargement of body parts, causing severe disability. commonly known as elephantiasis.

Countries Endemic for Lymphatic Filariasis in SEAR

Source : WHO (Last update: 27 April 2006)

Host & Geographic distribution

W.bancroftiB. malayiB.timori

Host

Human2 variant : antropophilic (human ) zoophilic : human & animal (feline and monkey)

humangeographicdistributionTropical & subtropical area all over the worldAsia Indonesia (NTT)

Morphology

W.bancroftiB.malayiB.timori

Adultthread-like worms , creamy white with smooth surface

F: 65-100x 0.25 mm, M: 40 x0.1 mmF: 55 x 0.16 mm, M: 22x 0.09 mmF: 21-39x 0.1 mm, M: 13-23x 0.08mmFemale : viviparousAdult : live for 6-8 years (can survive 15 yrs)HabitatAdult: lymphatic systemMicrofilaria : circulate in the blood

Microfilariae

W.bancroftiB.malayiB.timoriSize250-300x 7 200-260x 8 280-310x7HeadLength = widthL = 2 x WL = 3 x WtailNo nuclei in the tail2 nuclei in the end of the tail2 nuclei in the end of the tailBody nucleiFewer & regularDense and irregularBody curvedflexibleCoiled and kinkedSheath present, unstainedpresent, stained pink/darkly present, unstained

MicrofilariaeLive in the blood, sheatedShow periodicityreleased periodically into the peripheral blood from capillary of the lung during certain hoursThe mechanism not fully understood an adaptation of mf to the feeding habit of vectorsInfluenced by circadian rhythm, species , oxygen tension between venous and arterial blood

Periodicity

SpeciesPeriodicityWuchereria bancroftiIndonesia: nocturnal

Brugia malayiNocturnal ; sub periodic nocturnal;

Brugia timorinocturnal

Vectors

W.bancroftiB.malayiB.timoriSpecies Urban : Cx.quinquefasci-atusRural : Anopheles & AedesAntropophilic: An. barbirostriszoophilic: MansoniaAn. barbi-rostrisLife cycle in mosquitoes2 weeks, stadium I, II, III10 days, stadium I, II, III

Clinical symptomscause a broad range of clinical manifestations,most infected people have no symptoms and will never develop clinical symptomsMicrofilaria : occult filariasis / tropical eosinophilia ( respiration)Adult:Acute adenolymphangitis (ADL): Episodes of high fever, painful lymph node, lymphatic inflammationretrograde nature of the lymphangitis

Clinical symptoms (contd)A small percentage of persons will develop lymphedema ( usually after 6 12 months )>> affects the legs, but can also occur in the arms , exclusively with W.bancrofti : breasts and genitalia. This causes hardening and thickening of the skin, which is called elephantiasis

Clinical symptoms (contd)

Wuchereria bancroftiB.malayi & B. timoriAcute: ADL Genital lymphatic system: funiculitis, epidydimitis, orchitisAcute: ADL

Chronic:Elephantiasis of the arms, legs,vulva ,hydrocele, chyluriaElephantiasis of arms & legs Breast & Genitalia involvement is not found in Brugia infection

DiagnosisClinical symptomsDefinitive D/ : detecting mf in blood ( depend on the periodicity of mf) W. Bancrofti : Occasionally mf can be found in hydrocele fluid or chyluria adult worm in biopsy Radio D/ : USG+ Doppler technique may identify motile adult worms in the scrotum (filarial dance)

Diagnosis (contd)Immunological test :W. bancrofti : Assays for circulating antigens: the ELISA and the immunochromatographic card testBrugian filarial : antibody-based assay (dipstick test) has been developed

B timori microfilariaB. malayi microfilariaMicrofilaria W bancrofti

Adult Filaria in the tissue

TherapyDrugs :DEC(Diethyl carbamazine)IvermectinCombination DEC with albendazole or IvermectinSurgical approaches : moderately successful for chronic disabilities management

EpidemiologyAffects men > women (10 to 50 %t of men and up to 10 % of women)W. Bancrofti : rural type > urban B.malayi & B.timori : only in rural areaIndonesia : wide range of prevalence. In Papua up to 70 %

Strategy WHOIn 2000: WHO launched its Global Programme to Eliminate Lymphatic Filariasis (GPELF) The goal of the GPELF is to eliminate lymphatic filariasis as a public-health problem by 2020.

Strategy (contd)The strategy is based on two key components: interrupting transmission through mass drug administration (MDA): implemented to cover the entire at-risk population; alleviating the suffering caused by lymphatic filariasis : through morbidity management disability prevention.

MDAWeekly Epidemiological Report : 53 countries are currently implementing mass drug administration WHOr data : 538 million people received treatment LF around the world in 2011.