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FILARIASIS

DEPARTEMENT OF PARASITOLOGY

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CLINICAL CASE2

A 28-year old male came to Community Health Centrewith complaints swelling of right leg from thigh totoes. The swelling occurred once every 5-6 months. Itstarted 4 years ago along with hardness and swelling

of inguinal lymph nodes. He also developed chills andfever. About 4-5 days later the fever stopped, but theswelling of the leg increased. At this stage he hadchills with severe pain in the right leg. This lasted for

10-12 days, after which the pain subsided. During thistime he had ulcers on the swollen leg with bleedingand a yellow discharge. This remained for 2 days.Later the swelling decreased and the ulcers startedhealing.

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3

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Learning issues4

1. Agents of the disease

2. Pathogenesis

3. Diagnosis

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References5

King, C.L. 2001. Transmission intensity and human immune responses to

lymphatic filariasis. Parasite Immunology 23 (7): 363371

Melrose, W.D. 2002. Lymphatic filariasis: new insights into an old disease.

International Journal for Parasitology32(8), 947-960

Muller, R. and Wakelin, D. 2002. Worm and Human Disease. 2th edition.

London. CABI Publishing

Palumbo, E. 2008. Filariasis: diagnosis, treatment and prevention. Acta

biomedical. 79. 106-109

Rahmah, N., Lim, B. H., Khairul Anuar, A., et al. 2001. A recombinant

antigen-based igg4 ELISA for the specific and sensitive detection of brugia

malayiinfection. Transactions of the royal society of tropical medicine andhygiene 95(3): 280-284

World Health Organization. 1999. Collaborative global programme to

eliminate lymphatic filariasis: Programmes backround and overview towards

initiating a National programme to eliminate lymphatic filariasis .

WHO/CEE/FIL World Health Organization, Geneva, 1-25

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Lymphatic Filariasis

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Causative agents7

1. Brugia malayi

2. Wuchereria bancrofti

3. Brugia timori

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8

Wucherer ia banc ro ft i

The larva was found by Demarquay (1863)

and Wucherer (1866)

The adult was first found by Bancroft in 1876

Nocturnal periodicity

Vector: CulexandAedes

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Wucherer ia banc ro ft iMorphology

9

Adults look like thin and long threads

Female is 80-100 mm, male is 25-45 mm with

spiral-shaped tail

Fertilized eggs is 30-40 x 20-25 m, the egg

cell develops rapidly to form a larva while in

the uterus

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10

Microfilaria is sheated and smooth-shaped,

0.24-0.35 mm long

Regular nucleus, no terminal nucleus

Cephalic space: the length is equal with the

width

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11


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12

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L3 enter human body

13 The L3 enter the skin of the

human host through thepuncture site of the mosquito

when it takes its second blood

meal.

Details of larvae molting and

development in humans arelargely unknown, but it is

thought the larvae almost a

year to:

Migrate to the lymphatics

Mature undergoing two molts

and to become an adult

Mate

Produces microfilariae

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Brug ia malayi14

The larva was first observed from a native

Sumatera by Brug (1927)

Nocturnal periodicity

Vector: Mansonia uniformis (rural) and

Anopheles spp. (urban)

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Brugia malayiMorphology

15

Adult resembles that ofW bancrofti

Female is 43-55 mm, male is 13-23 mm with

spiral-shaped tail

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Brug ia malayiMorphology

16

The larva is sheated and slightly winding (kinky),

0.18-0.23 mm long

Irregular nucleus, 2 terminal nucleus

Cephalic space: the length is twice as the width

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17

Brugia malayiMorphology

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18

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Pathogenesis19

Inflammation occurs when worms die, either drug-induced or spontaneously.

Granulomas arise around those worms,characterized by macrophages which develop intogiant cells: as plasma cells, eosinophils andneutrophils.

Clinical symptom is filarial fever starting when theworm died and leads to retrograde lymphangitis(painful with swelling), and lymphadenitis, whichlasts for 1 week.

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Pathogenesis20

Lymph vessels dilation, not obliteration, is probably theearly event following antigenic stimulation, which springlarvae are being released. These larvae are degenerateand will be taken up by phagocytic cells.

These accompanied by triggering of the innate immunesystem, release proinflammatory cytokines andmolecules that promote lymphangiogenesis.

The enlarge lymph vessels become less efficient attransporting lymph from the periphery, which in the legsis always oriented against gravity, more vulnerable toexogenous microorganisms.

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Pathogenesis21

Insufficient fluid transport will lead to fluidextravasations, particularly in the lower limbs, andeventually to lymphoedema.

L3 preferentially stimulate IL-4 and IL-13 release frombasophils as well as histamine release. In addition,basophils comprise approximately 1% of cells in PBMCand their contribution to the observed cytokineproduction can be substantial. Therefore mast cells andbasophils may play an important role in regulating thehost response to filarial infection by affecting T-celldifferentiation, local blood flow, lymphocyte proliferationor by release of histamine or other prostanoids.

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7

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ManagementDiagnosis

24

Clinical manifestations

Laboratory diagnosis

Microscopic

Immunodiagnosis

Molecular technique

Ultrasonography

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Clinical Manifestations25

Acute filariasis

Chronic filariasis

Atypical presentation

Asymptomatic carrier

L h ti l dil t ti l

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Lymphatic vessel dilatation, valve

incompetency, lymphatic back flow, pooling &

oedema26

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Adult worms in the lymphatic

system

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Microscopy for Filaria

Nucleopore membran(Knotts concentration)

Staining thick blood filmwith Giemsa

Specific but not sensitive,depends on:

Timing of sampling(periodicity)

Volume of blood (volumeincrease sensitivityincrease)

Nucleopore membrane(knotts concentration)

Staining of the blood film Mor holo ical

28

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Periodicity

Definition:Relative density of microfilaria in peripheralcirculation

> 24 hours per cycle

Nocturnal periodic: peak microfilaria at aroundmid-night but very low or absence during theday

Diurnal periodic: peak microfilaria during the day

but low or absence at night Nocturnal subperiodic: peak microfilaria density

at night with lower density during the day

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Periodicity

Microfilariae stay in the lung during thedaytime and come rarely out to theperipheral vessels, but soon after sunsetthey begin to appear in the peripheral blood,increasing in number from 10 p.m. until 6a.m. (nocturnal periodicity)

There are a number of theories Photodynamic substance theory by Masuya Fluorescent substances in the microfilarias

body are injured by the sunlight (W bancroftiand B malayi)

Microfilaria ofLoa loa has no fluorescentsubstance at all

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Ultrasonography31

Detect the motile adult worms within thelymphatics, scrotum and breast (term filarial

dance signs). Detecting W bancroftionly.

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Immunodiagnosis32

Brugia rapid

Antibody detection

assay

Detects IgG4

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Immunodiagnosis33

Antigen detection

assay

For bancroftian

filariasis

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THANK YOU

filaria 2012 rev

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