Difference between revisions of "Dermatophilosis"

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
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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-{{unfinished}}
+{{OpenPagesTop}}
+Also known as: '''''Cutaneous streptothrichosis'''
-{| cellpadding="10" cellspacing="0" border="1"
+==Introduction==
-| Also known as:
+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.
-| '''Cutaneous streptothrichosis'''<br> '''Lumpy wool'''<br>'''Strawberry foot rot'''
-|-
-|}
-==Description==
-A group of diseases affecting the epidermis caused by  [[Dermatophilus congolensis|dermatophilus congolensis]] . Causes a range of conditions in large animals including rain scald in horses and strawberry foot rot in sheep. Lesions typically involve exudative dermatitis with scab formation. 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.
-==Diagnosis==
-Can often make a diagnosis 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.
 ==History and Clinical signs==
-Lesions commonly occur followng 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.
+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===
+<big>'''[[Dermatophilosis - Horse|Equine dermatophilosis]]
-Three clinical syndromes have been documented:
-*rain scald
-*Mud fever
-*Grease heel.
-Typically  hair becomes matted and focal lesions develop into crusts and thick scabs covered by layers of yellow-green pus. When scabs are removed the hair is taken with them and alopecia results. Rain scald commonly affects the dorsum, shoulders and neck. It can however extend to lower portions of the body and abdomen. It typically begins as small rough raised bumps and can go un-noticed in0 long haired regions. Mud fever looks similar to rain scald but affects the pasterns and distal limbs. White legs and white- skinned areas are most commonly affected. Grease heel is a disease complex which presens in the same way as rain scald and mud fever over the heels. It produces a grey exudate which feels greasy to touch. The disease complex can involve dematophilosis as well as a number of other conditions including dermatophytosis, pastern folliculitis, pyoderma, photosensitisation, contact dermatitis and chorioptic mange.
+'''[[Dermatophilosis - Sheep|Ovine dermatophilosis]]
+'''[[Dermatophilosis - Cattle|Bovine dermatophilosis]]
+</big>
-===Ovine dermatophilosis===
+==Diagnosis==
-Three clinical syndromes have been documented:
+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.
-*Lumpy wool
-*Strawberry foot rot
-*Fleece rot
-Fleece infection is known as lumpy wool. Infection passes from ewe to lamb during suckling and hence lesions first appear on the head which leads to infection on the trunk. In wet weather can result in high morbidity outbreaks. Large areas of the fleece can be affected where crusts of varying thickness become evident. On haired skin, crusts can become very thick and can form horn like structures. In rams, severe infections can result in the scotum and surrounding skin becoming affected.
-Strawberry foot rot is a condition affecting the skin from the coronet to the carpus or hock. The disease occurs as a result of [[Orf|Orf]] and Dermatophilus infection. Scabs get rubbed away leaving the granulating surface qhich resembles a strawberry.
+Additionally it is possible to '''culture material from the crusts''' however this can be difficult due to the slow growing nature of the pathogen.
-Fleece rot
+==Pathology==
-A condition thought to be assosiated with dermatophilosis, but also involves pigment producing bacteria which stains the wool a characteristic yellow colour. Predisposes to [[Blowfly Strike| fly strike]].
+Grossly:
+Papules, pustules, crusts may coalesce and mat the coat.
-===Bovine dermatophilosis===
-Is rarely reported but causes lesions are distributed over the head, dorsum, neck and chest. Cattle that stand for long periods in deep water and mud develop lesions over the flexor surfaces of the joints. Dairy cows may develop lesions on the udder.
-[[Image: Dermatophilosis in cow.jpg|100px|thumb|right|<small><center>Dermatophilosis in a cow (Courtesy of Bristol BioMed Image Archive)</center></small>]]
-Lesions may resolve within weeks if dry weather or prolonged wetting of infected areas can lead to secondary bacterial infection which can result in limb oedema and cellulitis.
-==Pathology==
-Grossly: [[Skin Glossary - Pathology|Papules, pustules, crusts]] may coalesce and mat the coat
 Microscopically:
-**Hyperplastic superficial perivascular dermatitis
+*Hyperplastic superficial perivascular dermatitis
-**Multilaminated crusts, alternating keratin and inflammatory cell layers
+*Multilaminated crusts, alternating keratin and inflammatory cell layers
+==Prognosis==
+Good if animals are kept dry. Often re-occurs in wet weather.
-==Treatment==
+{{Learning
-Horses:
+|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]
-Bring affected animals into a dry environment and isolate. Scabs should be soaked and removed. Chlorhexidine and benzoyl peroxide are recommended as topical antibacterials.
+}}
-Tack and any other equipment should be disinfected to avoid further infection. Systemic antibiotics should be administered if secondary infection is present. Owners should be educated about the condition and warned that reoccurence may occur in wet weather.
-Farm animals:
-Bring affected animals into a dry environment. Investigate any underlying problems which may predispose to the infection.
-Antibiotics can be given intramuscularly and typically work following one dose. However is signs do not resolve a 5 day course should be administered. Penicillin and streptomycin are good choices for this disease.
-Additionally Dips containing 0.2% Copper Sulphate or 0.5% Zinc sulphate can be affective.
-==Prognosis==
-Good if animals or kept dry. Often reoccurs in wet weather.
 ==References==
+Merck & Co (2008) '''The Merck Veterinary Manual''' (Eighth Edition) ''Merial''
+th year Veterinary Dermatology notes. Royal Veterinary college. October-November 2008. p60-64.
+{{review}}
+{{OpenPages}}
+[[Category:Dermatological Diseases - Pig]][[Category:Dermatological Diseases - Goat]][[Category:Zoonoses]][[Category:Dermatological Diseases - Dog]][[Category:Dermatological Diseases - Cat]]
+[[Category:Expert Review]]
-*Associated with skin trauma, prolonged wetting or [[Parasitic skin infections - Pathology#Parasitic| parasites]]
+[[Category:Integumentary System - Bacterial Infections]]
-** -> 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
-[[Category:Cattle]][[Category:Sheep]][[Category:Horse]][[Category:To_Do_-_Caz]]
-[[Category:Sheep]][[Category:Pig]][[Category:Cattle]][[Category:Goat]][[Category:Zoonoses]][[Category:Dog]][[Category:Cat]]