Clinical Helminthology: Filarial Nematode

Latin word "filum' which means "thread"

Filarial Nematodes etymology

Filarial Nematodes

Are arthropod-transmitted parasites

Filarial Nematodes

It infects the circulatory and lymphatic systems, muscles, connective tissue or serous cavities

nocturnal (10 PM- 2AM)
diurnal (10 AM-2 PM)
sub-periodic (timing of occurrences not clear)

Filarial Nematodes periodicity

larviparous

Filarial worms are

Morphology
Location in the host
Type of periodicity

Filarial worms key characteristics for species identification:

Microfilariae

Filiform (Adult)

Filarial worms morphology

Microfilariae

A motile, slender larva produced by an adult filaria

150 um to 350 pm

Microfilariae is usually detected in the blood length:

Sheathed = enveloped
Unsheathed = naked

Microfilariae outer covering

Filiform (Adult)

Creamy white and assume a threadlike appearance

Adult males - 20 to 500 mm

Adult females - twice the size of the males

Filiform (Adult) size

Mouth
-no definite lips; inconspicuous buccal cavity

Esophagus
- cylindrical, no cardiac bulbs has anterior muscular and posterior glandular portion

Filiform (Adult) Organs and its characteristics

Lymphatic filariasis
Subcutaneous filariasis
Serous cavity filariasis

Classification of Filariasis

Wuchereria bancrofti
Brugia malayi
Brugia timori

Lymphatic filariasis

Loa loa
Onchocerca volvulus
Mansonella streptocerca

Subcutaneous filariasis

Mansonalle ozzardi

Serous cavity filariasis

Specimen:blood (nocturnal)

Cephalic Space: short

Tail: sheathed

Nuclei: do not extend to the tip of tail

Wuchereria bancrofti specimen, cephalic space, tail and nuclei

Specimen:blood (nocturnal)

Cephalic Space: long

Tail: sheathed

Nuclei:
extend to the tip
non-continuous flow
two nuclei at the tip

Brugia malayi specimen, cephalic space, tail and nuclei

Specimen:blood (diurnal)

Cephalic Space: short

Tail: sheathed

Nuclei:
extend to the tip
continuous flow

Loa loa specimen, cephalic space, tail and nuclei

Specimen: skin snips

Cephalic Space: long

Tail: unsheathed

Nuclei: do not extend to the tip

Onchocerca volvulus specimen, cephalic space, tail and nuclei

Specimen: blood

Cephalic Space: short

Tail: unsheathed

Nuclei: extend to the tip

Mansonella perstans specimen, cephalic space, tail and nuclei

Specimen: skin snips

Cephalic Space: long

Tail: unsheathed

Nuclei:
extend to the tip
shepherd's crook/ walking stick

Mansonella streptocerca specimen, cephalic space, tail and nuclei

Specimen: blood

Cephalic Space: short

Tail: unsheathed

Nuclei: do not extend to the tip

Mansonella ozzardi specimen, cephalic space, tail and nuclei

Wuchereria bancrofti (nocturnal)
Brugia malayi (nocturnal)
Loa loa (diurnal)
Mansonella perstans
Mansonella ozzardi

Parasites Specimen: blood

Onchocerca volvulus
Mansonella streptocerca

Parasites Specimen: skin snips

Wuchereria bancrofti
Loa loa
Mansonella perstans
Mansonella ozzardi

Parasites Cephalic space: short

Brugia malayi
Onchocerca volvulus
Mansonella streptocerca

Parasites Cephalic space: long

Wuchereria bancrofti
Brugia malayi
Loa loa

Parasites tail: sheated

Onchocerca volvulus
Mansonella perstans
Mansonella streptocerca
Mansonella ozzardi

Parasites tail: unsheated

Wuchereria bancrofti
Onchocerca volvulus
Mansonella ozzardi

Parasites Nuclei: do not extend to the tip

Brugia malayi
Loa loa
Mansonella perstans
Mansonella streptocerca

Parasites Nuclei: extend to the tip

Brugia malayi

Parasites Nuclei: non-continuous flow

Loa loa

Parasites Nuclei: continuous flow

Culex quinquefasciatus
Aedes polynesiensis
Anopheles
Mansonia

Wuchereria bancrofti vectors

Elephantiasis in lower extremities and genitalia

WITH chyluria

Wuchereria bancrofti disease

diethylcarbamazine
ivermectin-albendazole

Wuchereria bancrofti treatment

Mansonia
Anopheles
Aedes
Armigeres

Brugia malayi vectors

elephantiasis in upper extremities

WITHOUT chyluria

decreased CD4 count

Brugia malayi disease

diethvlcarbamazine
anti-inflammatory drugs

Brugia malayi treatment

Mango/ Deer/ Tabanid fly
~ Chrysops silacea
~ Chrysops dimidiate

Loa loa vectors

Fugitive or Calabar swellings
Strong eosinophilia

Loa loa disease

surgical removal of adult worms
diethyIcarbamazine

Loa loa treatment

Black fly/ Buffalo gnat
~Simulium damnosum

Onchocerca volvulus vectors

river blindness
onchocercomata
lizard skin- dry and scaling changes leopard skin- blotchy depigmentation

Onchocerca volvulus disease

ivermectin
diethvlcarbamazine should not be used

Onchocerca volvulus treatment

Biting midges (Culicoides)

Mansonella perstans vectors

Calabar-like swellings
Kampala

Mansonella perstans disease

diethylcarbamazine
metronidazole

Mansonella perstans treatment

Biting midges (Culicoides)

Mansonella streptocerca vectors

pruritic dermatitis

Mansonella streptocerca disease

diethylcarbamazine

Mansonella streptocerca treatment

Biting midges (Culicoides)

Mansonella ozzardi vectors

urticaria and lymphadenitis
skin itching and arthralgias

Mansonella ozzardi disease

ivermectin

Mansonella ozzardi treatment