FILARIASIS
Filarial Dermatitis, Cutaneous stephanofilariasis,
onchocercosis, dirofilariasis

Definition:
chronic parasitic arthropod born disease of domestic
animal caused by filarial nematode and characterized
by intramuscular, cutaneous and subcutaneous lesion
ETIOLOGY
1.
2.
3.
4.
5.
Filarial dermatitis caused by parafilaria
bovicola and P. multipapillosa
Cutaneous stephanofilariosis caused by
stephnofilaria
Onchocercosis
Dirofilariosis
Dipetalonema or filaria evansi
LIFE CYCLE

Adult worm in skin nodule
Pierce skin and lay egg on surface
Blood sucking fly (intermediate host)
Ingest egg or larvae during blood meal
Larvae developed to infective form (microfilariae)
Infect animal during blood meal
EPIDEMIOLOGY
Distribution: wide spread in tropical and
subtropical countries including Egypt
 Animal susceptibility: domestic, wild animal
and human
 Transmission: biting arthropod

PATHOGENESIS AND CLINICAL SIGNS
Filarial dermatitis:
P. Bovicola and P multipapillosa cause
haemorrhagic dermatitis in cattle, buffaloes and
equine,
Characterised by nodule in head, neck, wither,
shoulder and side
1.
2. Cutaneous stephanofilariosis
Cause: stephanofilaria
Characterized by skin lesion (3-5 cm), exudative,
haemorrahgic dermatitis
3. Onchocercosis:
 Caused by onchocerca spp.
 Microfilaria in skin or subcutaneous lnn
transmit by midges, sand or black fly
 Nodules in subcutaneous tissue of brisket
and lateral surface of thigh, free movable
under skin
 Misdiagnosed with bovine tuberculosis

In horse:
O. cervecalis cause alopecia,
pruritus especially ventral of
abdomen, extend to forelegs, hind
legs, face ,neck and thorax and
inflammation in ligamentum
nauchae through infection with
adult worm
O. Reticulata caused swelling and
inflammation in suspensory
ligament of posterior part of canon
(lameness)
4. Dirofilariosis
Cause: dirofilaria immitis infect dog and cat
 Adult worm present in right vertical,
pulmonary artery and vena cava
 Worm obstruct posterior vena cava and
cause acute hepatic syndrome and sudden
death

5. Dipetalonema or filaria evansi
Infect camel and inhabit in mesenteric,
pulmonary, spermatic and genital blood
vessels or present as cyst in internal organs
 Characterized by emaciation, orchitis,
swollen of scrotum and cardiac insufficiency

DIAGNOSIS
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1.
2.
3.
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1.
Field diagnosis
History
Clinical signs
Epidemiology
Laboratory diagnosis
Sample: skin biopsy, skin scraping, tissue lesion,
blood samples
Detection of microfilaria in blood film after staining
with leishman or geimsa stain
2. Knott or fullborne technique:
1 ml of blood + 9 ml 2% formalin, centrifugation,
sediment stained with MB
3. Histopathological examination
4. Serological test as ELISA
5. Allergic cutaneous test
TREATMENT

Surgical treatment
•
Two dose of Invermectin with one week interval
CONTROL
1.
2.
3.
Isolation of infected animal
Treatment of infected animal
Control of insect through using of insecticides