1. Filariasis
Filarial Dermatitis, Cutaneous stephanofilariasis, onchocercosis, dirofilariasis

2. Definition:
chronic parasitic arthropod born disease of domestic animal caused by filarial nematode and characterized by intramuscular, cutaneous and subcutaneous lesion

3. Etiology
Filarial dermatitis caused by parafilaria bovicola and P. multipapillosa
Cutaneous stephanofilariosis caused by stephnofilaria
Onchocercosis
Dirofilariosis
Dipetalonema or filaria evansi

4. 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

5. Epidemiology
Distribution: wide spread in tropical and subtropical countries including Egypt
Animal susceptibility: domestic, wild animal and human
Transmission: biting arthropod

6. 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

7. 2. Cutaneous stephanofilariosis Cause: stephanofilaria Characterized by skin lesion (3-5 cm), exudative, haemorrahgic dermatitis

8. 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

9. 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)

10. 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

11. 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

12. Diagnosis 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

13. 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

14. Treatment Surgical treatment
Two dose of Invermectin with one week interval

15. Control Isolation of infected animal Treatment of infected animal
Control of insect through using of insecticides