Difference between revisions of "Dermatophilosis"

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*Caused by [[Dermatophilus congolensis]]
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{{OpenPagesTop}}
**Disease most prevalent in young animals
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Also known as: '''''Cutaneous streptothrichosis'''
**Damage to the skin predisposes to infection; blood-sucking insects also thought to be involved in transmission
 
**Lesions after heavy rainfall predominantly affect dorsum of farm animals
 
**Papules, serous, exudative matting of hair, raised crusty scabs
 
**Scab formation more prominent in sheep and cattle than in horses
 
**Lesions may resolve within weeks if dry weather, or may progress
 
*'''Treatment''':
 
**Parenteral antibiotics e.g oxytetracycline, pr penicillin-streptomycin combinations
 
  
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==Introduction==
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This is a group of diseases affecting the epidermis caused by  [[Dermatophilus congolensis|''Dermatophilus congolensis'']]. It causes a range of conditions in large animals including rain scald in horses and strawberry foot rot in sheep. The disease is associated with skin trauma, prolonged wetting or [[:Category:Integumentary System - Parasitic Infections| parasites]]. Lesions typically involve exudative dermatitis with scab formation. It is a zoonosis affecting humans in close contact with infected animals.
  
[[Image: Dermatophilosis in cow.jpg|100px|thumb|right|<small><center>Dermatophilosis in a cow (Courtesy of Bristol BioMed Image Archive)</center></small>]]
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==Signalment==
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Can be seen in animals of all ages but most commonly occurs in young animals who are chronically exposed to moisture.
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Affects horses, sheep, cattle, goats, pigs and rarely dogs and cats.
  
*Caused by [[Dermatophilus congolensis|''Dermatophilus congolensis'']]
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==History and Clinical signs==
*Affects cattle, horses, sheep mainly
+
Lesions commonly occur following heavy rainfall and commonly affects the dorsum of animals. Any previous trauma or damage to the skin can predispose to infection. Blood-sucking insects are also thought to be involved in transmission.
*More common in wet and warm weather
 
*Transmotted from animal to animal
 
*Lesions tend to form on dorsal back and extremities
 
*Associated with skin trauma, prolonged wetting or [[Parasitic skin infections - Pathology#Parasitic| parasites]]
 
** -> penetration of zoospores
 
*Bacteria proliferate in outer sheath of hair follicles and superficial epidermis
 
*Gram-positive, filamentous branching organisms, subdivided longitudinally and transversly
 
*Causing:
 
**Acute inflammatory response -> neutrophil migration through dermis and epidermis -> formation of microabscesses
 
**Further penetration of bacteria is thus prevented
 
**Regenerated epidermis is invaded again by remaining organisms
 
**Repeated reinfection -> multilaminated pustular crusts
 
*Grossly:
 
**[[Skin Glossary - Pathology|Papules, pustules, crusts]] may coalesce and mat the coat
 
*Microscopically:
 
**Hyperplastic superficial perivascular dermatitis
 
**Multilaminated crusts, alternating keratin and inflammatory cell layers
 
  
[[Category:Cattle]][[Category:Sheep]][[Category:Horse]][[Category:To_Do_-_Clinical]]
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<big>'''[[Dermatophilosis - Horse|Equine dermatophilosis]]
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'''[[Dermatophilosis - Sheep|Ovine dermatophilosis]]
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'''[[Dermatophilosis - Cattle|Bovine dermatophilosis]]
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</big>
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==Diagnosis==
 +
Diagnosis can often be made on history and physical exam. '''Impression smears''' can also be useful when stained with either gram stain or Giemsa and examined microscopically.
 +
 
 +
Additionally it is possible to '''culture material from the crusts''' however this can be difficult due to the slow growing nature of the pathogen.
 +
 
 +
==Pathology==
 +
Grossly:
 +
Papules, pustules, crusts may coalesce and mat the coat.
 +
 
 +
Microscopically:
 +
*Hyperplastic superficial perivascular dermatitis
 +
*Multilaminated crusts, alternating keratin and inflammatory cell layers
 +
 
 +
==Prognosis==
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Good if animals are kept dry. Often re-occurs in wet weather.
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 +
{{Learning
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|literature search = [http://www.cabdirect.org/search.html?rowId=2&options2=OR&q2=dermatophilosis&occuring2=title&rowId=3&options3=AND&q3=&occuring3=freetext&publishedstart=2000&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all&x=39&y=14 Dermatophilosis publications since 2000]
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}}
 +
 
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==References==
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Merck & Co (2008) '''The Merck Veterinary Manual''' (Eighth Edition) ''Merial''
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4th year Veterinary Dermatology notes. Royal Veterinary college. October-November 2008. p60-64.
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 +
 
 +
{{review}}
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 +
{{OpenPages}}
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[[Category:Dermatological Diseases - Pig]][[Category:Dermatological Diseases - Goat]][[Category:Zoonoses]][[Category:Dermatological Diseases - Dog]][[Category:Dermatological Diseases - Cat]]
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[[Category:Expert Review]]
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[[Category:Integumentary System - Bacterial Infections]]

Latest revision as of 18:43, 5 July 2012


Also known as: Cutaneous streptothrichosis

Introduction

This is a group of diseases affecting the epidermis caused by Dermatophilus congolensis. It causes a range of conditions in large animals including rain scald in horses and strawberry foot rot in sheep. The disease is associated with skin trauma, prolonged wetting or parasites. Lesions typically involve exudative dermatitis with scab formation. It is a zoonosis affecting humans in close contact with infected animals.

Signalment

Can be seen in animals of all ages but most commonly occurs in young animals who are chronically exposed to moisture. Affects horses, sheep, cattle, goats, pigs and rarely dogs and cats.

History and Clinical signs

Lesions commonly occur following heavy rainfall and commonly affects the dorsum of animals. Any previous trauma or damage to the skin can predispose to infection. Blood-sucking insects are also thought to be involved in transmission.

Equine dermatophilosis

Ovine dermatophilosis

Bovine dermatophilosis

Diagnosis

Diagnosis can often be made on history and physical exam. Impression smears can also be useful when stained with either gram stain or Giemsa and examined microscopically.

Additionally it is possible to culture material from the crusts however this can be difficult due to the slow growing nature of the pathogen.

Pathology

Grossly: Papules, pustules, crusts may coalesce and mat the coat.

Microscopically:

  • Hyperplastic superficial perivascular dermatitis
  • Multilaminated crusts, alternating keratin and inflammatory cell layers

Prognosis

Good if animals are kept dry. Often re-occurs in wet weather.


Dermatophilosis Learning Resources
CABICABI logo.jpg
Literature Search
Search for recent publications via CAB Abstract
(CABI log in required)
Dermatophilosis publications since 2000


References

Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial

4th year Veterinary Dermatology notes. Royal Veterinary college. October-November 2008. p60-64.




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