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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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Wucherer ia banc ro ft iMorphology
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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Wucherer ia banc ro ft iMorphology
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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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