Filaria
FILARIA
Parasitology Department
Medical Faculty of USU
• Superfamily Filarioidea
• Family Acanthocheilonematidae
• Widespread in the tropic, subtropic, and
temperate zones
FilariaGeneral
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temperate zones
• Many species known as parasite in humans:
Wuchereria bancrofti, Brugia malayi, B.
timori, Loa loa, and Onchocerca volvulus
• Vector: blood-sucking insects
• Vivipar
• The larva is called microfilaria
• The internal structure f the microfilaria is very
important for the diagnosis of filariasis
FilariaGeneral
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• Filaria is devided 3; based on their habitat
such as:
1. Lymphatic Filaria
2. Cutaneous Filaria
3. Body Cavity Filaria
Lymphatic Filaria
• Consist of:
– Wuchereria bancrofti
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– Wuchereria bancrofti
– Brugia malayi
– Brugia timori
Wuchereria bancrofti
• This worm is responsible for 90% of lymphatic
filariasis in the worldwide.
• Vivipar;
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• Vivipar;
• Infective stage: Larvae st.3
• The larva was found by Demarquay (1863) and
Wucherer (1866)
• The adult was first found by Bancroft in 1876
• Nocturnal periodicity
Morphology
• Microfilaria:– Sheath (+)– Cephalic space:
Cephalic space
Body nuclei
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Length = wide (1:1)– Body Nuclei :
Discrete (Regular)– Body curve: Smooth– Tail: No nuclei at the
tip of the tail
Tip of the tail
Morphology
• Adult worm:– Long-slender w/ smooth cuticle and bluntly
rounded ends– The head is slightly swollen and bears two
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– The head is slightly swollen and bears two circles of well defined papillae
– The mouth is small and lack of buccal capsule– Males: ± 40mm long and 100µm wide– Females: ± 6cm-10cm long and 300µm wide
Life cycle:
Vector: transmission larvae std.3 through
wound puncture
Resting stageMosquito ingest the mf
8/28/2009 Dewi M. Darlan 8Thoracic duct
Lymphatic system
Microfilariae
At the blood circulation
Epidemiology
• Host can be infected; there is no host reservoir
• Periodicity: Nocturnal
• Rural strain :– An. letifer ; – An. Maculatus ; – An. whartoni
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• Periodicity: Nocturnal – An. whartoni – An. balabacensis- S– An. flavirosrtis - S– An. leucosphyrus
Vector:Urban strain :•Culex quinquefasciatus•Culex fatigans
Brugia malayi
• The larva was first observed from a native Sumatera by Brug (1927)
• Nocturnal periodicity
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• Nocturnal periodicity
• Vector: Mansonia uniformis (rural) and Anopheles spp. (urban)
Brugia malayi
• Morphology:– Adult worm:�Males:
• 13.5-20.5 mm long and 70-80 µm wide
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• Tail is curved ventrally and Spicules are unequal and dissimilar
�Females: • 80-100 mm long and 240-300 µm wide• Fingerlike tail cover with minute cuticular bosses
• Microfilaria:
– Sheath (+) stained; pinkish-red
– Cephalic space:
length : wide = 2:1
– Body nuclei: overlapping;
Ceph.
space
Body nuclei
Morphology
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– Body nuclei: overlapping; irregular
– Body curve: wrinkled
– Presence of sub-terminal and terminal nucleus
Sub-terminal
nukleus
Terminal
nukleus
Brugia timori
••Overlapping body Overlapping body nucleinuclei��Sheath does not Sheath does not
stain pinkish but stain pinkish but
(bluish)(bluish)
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(bluish)(bluish)
��Cephalic space Cephalic space
elongated, ratio elongated, ratio
1:31:3
��Presence of subPresence of sub--
terminal and terminal and
�� terminal nucleusterminal nucleus
Assignment
�List morphologic differentiations among microfilariae of W.
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microfilariae of W. bancrofti, B. malayi, and B. timori
Cutaneous filaria
• Consist of:– Onchocerca volvulus
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– Onchocerca volvulus– Loa-loa
Onchocerca volvulusGeneral
• Final host is humans, causes onchocercosis
(river blindness, the blinding filarial d’ses,
Robles d’ses)
• Vector: females of Simulium spp. (black fly)
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• Vector: females of Simulium spp. (black fly)
• Distributed in Africa and Central and South
America
• Adults are tangled together in a tumor
(onchocercoma) formed in the subcutaneous
tissue
Onchocerca volvulusGeneral
• Microfilariae are occasionally found
in peripheral vessels, but normally
stay i/t lymph sinuses near the body
surface o/t host
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surface o/t host
• Female is 30-50 cm, male is only 2-
4.5cm long
• Microfilaria is 0.22-0.36mm,
unsheated, bulbous head, no
terminal nucleus
Onchocerca volvuluslife cycle
• Adults live in onchocercoma
• Insect bites and sucks hydrocele and
microfilaria from the tumor, and get infected
by the larvae
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by the larvae
• Microfilariae enter insect’s chest muscles →molt twice → become infective → get out o/t
chest to proboscis
• Microfilariae will be injected to a human
through the bite o/t insect
Onchocerca volvulusMorphology
• Microfilaria:– Unsheath– Body nuclei separated
Cephalic
space
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(moderately compact)– Cephalic space: 1:2– End: tapered & flexed– No terminal nucleus
• Vector: Simulium fly
end
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Loa-loaGeneral
• Also called the African eye worm
• Causes Loaiasis (Calabar swelling)
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swelling)
• Adults in subcutaneous tissue, esp. conjunctivae
• Spead in tropical Africa
• Final host: humans and apes
• Vector: Chrysops spp.
Loa-loaMorphology
• Microfilaria:– Sheath (+) un-stain– Body nuclei as
compact column of
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compact column of nuclei that extends to the tail
– Short cephalic space, ration 1:1
– No terminal nucleus
Loa-loaMorphology
• Female is 5-7cm, and male is 3-3.5cm long
• Microfilaria is 0.25-0.3mm, sheated
• Diurnal periodicity (neither fluorescent
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• Diurnal periodicity (neither fluorescent substance nor granules are found in its body)
• Vector: Chrysops fly
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Dracunculus medinensisGeneral
• Also called dragon worm
• Final host: mainly humans
• Distributed in Middle East and
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• Distributed in Middle East and Southeast Asia
• I’mediate host: Cyclops• Habitat is subcutaneous tissues
Dracunculus medinensisGeneral
• Adult female is very thin and long, 70-120cm long, male is very short, being only 4cm long
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long
D. medinensisLife Cycle
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