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− | *Caused by [[Stephanofilaria spp.|''Stephanofilaria stilesi'']] | + | *Caused by [[Stephanofilaria stilesi|''Stephanofilaria stilesi'']] |
| *Occurs in cattle, buffalo, goats | | *Occurs in cattle, buffalo, goats |
| *Transmitted by [[Insecta|flies]] | | *Transmitted by [[Insecta|flies]] |
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| **Eosinophils, adult and microfilarial parasites | | **Eosinophils, adult and microfilarial parasites |
| **[[Skin Glossary - Pathology|Epidermal hyperkeratosis, parakeratosis, acanthosis]], eosinophilic microabscesses and crusts | | **[[Skin Glossary - Pathology|Epidermal hyperkeratosis, parakeratosis, acanthosis]], eosinophilic microabscesses and crusts |
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| + | ===Gross pathology=== |
| + | *Lesions begin as small circular patches on the ventral midline with serous exudate. |
| + | *These enlarge and coalesce producing lesions 25cm or more in diameter. |
| + | *Hemorrhage develops along the periphery while the older, central areas develop scabs or dry crusts. |
| + | *Healing lesions are alopecic, lichenified plaques. |
| + | *Lesions may also occur on the flank, udder, teats, face and neck. |
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| + | ===Histopathology=== |
| + | *Adult parasites occur within cystic diverticula of hair follicles or free within the adjacent dermis. |
| + | **Parasites may have lateral cords and lateral cuticular projections. |
| + | **The thick intestine is distinctive. |
| + | **Microfilariae within uteri is the key feature. |
| + | ***Microfilariae also occur free within the dermis, in dermal lymphatics, or in the surface exudate. |
| + | *There is little dermal reaction to adults in cystic hair follicles, but their presence within the dermis elicits eosinophilic and mononuclear inflammation. |
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| + | ===Differential diagnosis=== |
| + | # Pelodera strongyloides: |
| + | #*Rhabditid parasite, adults 1-1.5mm long, found in follicles |
| + | #*uteri contain eggs, not microfilaria. |
| + | # Dermatophytosis (Trichophyton verrucosum is most common) |
| + | # Mange (Chorioptes bovis) |
| + | # Fly bite dermatitis |
| + | # Contact dermatitis |
| + | # Zn-responsive dermatitis |
| + | # Other subcutaneous filarid parasites: |
| + | #*Parafilaria bovicola (adult worms 30-70mm long, found coiled in nodules in subcutaneous and intramuscular connective tissues; not seen in US) |
| + | #*Onchocerca gutterosa (adult worms 60mm long, found in nuchal ligament and subcutaneous connective tissues). |
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| + | {{unfinished}} |
| + | [[Category:Integumentary System - Helminth Infections]] |
| + | [[Category:To_Do_-_Dermatology]][[Category:To Do - Minor]] |