other skin conditions Flashcards
dermatophytosis in cattle
- which kinds?
- how common? transmission?
- risk factors?
§ Trichophyton verrucosum
§ Trichophyton mentagrophytes
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§ Common in cattle
§ Animal to animal and fomite transmission
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Risk factors
§ Young animals
§ Over-crowding
§ Poor nutrition
§ Indoor housing
§ Warm and humid environment
dermatophytosis pathogenesis? distribution and appearance of lesions?
Pathogenesis
§Invades fully keratinized, non-living tissue
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Distribution
§Head and trunk
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Appearance
§ Multifocal, Alopecia, Excessive crusting
§ +/- ring pattern
§ Erythema absent or obscured
dermatophytosis diagnosis
Direct microscopic examination
§ Skin scraping
§ Hair shaft examination
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Fungal culture
§ Broken hairs
§ Avoid large crusts
§ Use specialized media
dermatophytosis treatment
§ Lime sulfur dip
§ Enilconazole rinse
§ Shampoos > Miconazole or ketoconazole, 3-4% chlorhexidine shampoo
§ Vaccination > T. verrucosum, T. mentagrophytes
can bovine dermatophytosis affect humans?
yes, eg. calf infected with trichophyton verrucosum can pass it to farmer
dermatophilosis
- pathogen
- nature of the disease?
- transmission?
- pathophysiology
Dermatophilus congolensis
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§ Chronically affected animals
§ Direct contact or mechanical vectors
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Pathophysiology
§ Moisture +/- epidermal damage
§ > zoospores germinate > proliferate
§ > invade deeper epidermal layers
dermatophilosis distribution, appearance of lesions
Distribution
§ Distal extremities
§ Dorsum
§ Muzzle and pinnae
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Appearance
§ Encrusted, proliferative dermatitis
§ Papules, ulcerations
§ Suppurative crusts
§ Alopecia
dermatophilosis diagnosis
§ Impression smear
> Railroad-track cocci
§ Bacterial culture
§ Histopathology
§ Polymerase chain reaction
dermatophilosis treatment
§ Remove from moist environment
§ Remove crusts
§ Topical iodophors or lime sulphur
§ Systemic therapy > ONLY IF SEVERE
> Penicillin
> Trimethoprim sulfamethoxizole
> Oxytetracycline, Long-acting
common foot disorders
- digital dermatitis (actually affects palmar aspect right above hoofs)
- sole ulceration
- wall disorder
- interdigital hyperplasia
interdigital dermatitis
- pathogens
- lesion distribution, appearance
- risk factors
- significance
§ Dichelobacter nodosus
§ Treponema spp
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Distribution
§ Epidermis of interdigital skin
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Appearance
§ Small, circular ulcers
§ White-grey exudate
§ Hypertrophy
§ Increased axial hoof wall growth
§ Hyperkeratosis and heel cracks
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Risk factors
§ Chronic moist environment
§ Poor hygiene in dairies
§ High stocking rates
§ Contaminated pastures
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Impact
§ Moderate- severe lameness
§ Loss of body condition
§ 50% morbidity in affected dairy herds
interdigital dermatitis treatment
§ Topical oxytetracycline spray
> SID for 3 days
> 95% recovery rate in 3-4 days
> More effective than foot baths
§ D. nodosus serogroup-specific vaccine > Effective for sheep flocks
interdigital dermatitis pevention and control
§ Decrease exposure to moist
environments
§ Decrease stocking density
§ Improve hygiene in housing areas
§ Rest pastures with affected animals
digital dermatitis
- pathogens
- significance, when we see it?
- morbidity
§ Treponema spp.
§ Anaerobic organisms
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§ Major cause of economic losses
§ Freestall dairy cattle herds
> Lameness in 1st and 2nd lactation cows
> Lesions in older lactation cows
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§ High morbidity
§ Majority of adults affected within one year
§ Eradication is unlikely in endemic populations
digital dermatitis risk factors
§ Muddy or wet conditions
§ Rough flooring
§ Uncomfortable, unsanitary bedding
§ Inadequate drainage
§ Over-crowding
§ Poor sanitation of hoof-trimming equipment
§ Replacements from off premise
digital dermatitis pathogenesis
§ Multifactorial disease
§ Treponema spp
> Invades epidermis and dermis
§ Secondary bacterial invasion
digital dermatitis lesion distribution and appearance
Distribution
§ 80% Plantar aspect of hind limbs, Distal to dewclaws, Extend into interdigital space
§ 75% one limb
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1st stage
§ Small, focal, reddened, circumscribed lesions
§ Extremely painful, hairs on periphery of lesion
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2nd stage
§ Larger ulcerated lesions
§ Peripheral hairs 2-3x longer than other hairs
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3rd stage
§ Lesions have rough, encrusted surface
§ Gray in color
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4th stage
§ Chronic proliferative lesions
§ Varying degrees of hyperkeratosis
§ Black papilliform projections
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5th stage
§ Healing of the lesion
digital dermatitis - relationship of lameness to lesions
Lameness is not consistently related to lesion size or chronicity
digital dermatitis treatment, efficacy, other considerations
§ Topical antibiotics daily (5-14 days)
§ Powder or spray
> Oxytetracycline
> Lincomycin
§ Reoccurrence is high
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§ Parenteral antibiotics
> Penicillin, Ceftiofur
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§ Ensure all withdrawal times are communicated
§ Know regional restrictions for antimicrobial use
digital dermatitis control, when it is useful
Medicated foot baths
§ Low prevalence herds > Most effective with <10% incidence rate
medicated footbaths for digital dermatitis - how to maintain, options for medication?
§ Maintenance
> Water or mild detergent foot bath first
> Change foot bath every 150-300 passages
> Minimum diameters
> Cover to prevent rain dilution
> Place in exit alley
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§ 5% formalin
§ Oxytetracycline
§ Lincomycin
§ Copper sulfate
§ Zinc sulfate (20%)
§ Sodium hydroxide
papillomas in cattle
- when do we see them? signs?
- cattle vs goats vs sheep
Cattle
§ Very common
§ Appear at < 2 years of age
§ May spontaneously regress
§ Generally asymptomatic
> Exceptions: Teat, penile, interdigital, and alimentary
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Goats
§ Relatively rare
§ Head/ neck or mammary
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Sheep
§ Rare
bovine paillomas - pathogen, characteristics?
Bovine papillomavirus
§ Carcinogenic
§ Double-stranded DNA virus
§ Generally species-specific (One exception)
§ Site specific
§ 20+ types classified, 5 sub-groups
morphologic classification of papillomas
§ Type 1- Typical
§ Cauliflower appearance
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§ Type 2- Pedunculated
§ Narrow base
§ Peduncle shape
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§ Type 3- Atypical
§ Flat
§ Entirely connected to skin
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§ Type 4- Filamentous
§ Highly keratinized surface
§ Thin base
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§ Type 5- Rice-form
§ Small papillomas
papillomas transmission
§ Direct
§ Via fomites > Dehorning, tagging, etc
papillomas dx
§ Clinical appearance
§ Biopsy
§ Serology
§ PCR
papillomas tx
§ Benign neglect
§ Crushing or surgical removal
§ Cryosurgery
§ Autogenous vaccine
papillomas prevention and control
§ Isolate affected animals
§ Disinfect all shared equipment
§ Autogenous vaccine
§ Commercial vaccine
pseudocowpox
- pathogen
- geographic distribution
- lesion location and appearance
§ Parapoxvirus
§ Common worldwide
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Distribution
§ Teat
§ Uncommonly: udder, scrotum
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Appearance
§ 2-3mm papules > crusting > circular spread
§ 10 days later > ring/ horseshoe shaped scabs
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- affects humans!!
bovine herpes mammillitis
- pathogen
- geographic spread, epidemiology
- lesions distribution and appearance
§ Bovine herpesvirus 2
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Epidemiology
§ Widely disseminated
§ Epidemic or endemic
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Distribution
§ Oral, udder, or generalized
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Appearance
§ Edema, sensitivity to palpation
§ Vesicles > ulcers > scabs
bovine herpes mammillitis Dx, Tx, mgmt
Diagnosis
§ Virus isolation
§ BHV-2 serum neutralization test
§ Histologic demonstration of virus
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Treatment
§ Ulcers heal in 3-10 weeks
§ Topical or parenteral antimicrobials
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Management
§ Segregate
§ Milk affected cows last
§ Disinfect milking equipment
§ Proper hand hygiene
bovine cutaneous lymphosarcoma
- two forms, characteristics
- lesion distribution, appearance
- clinical signs
- Dx
- Tx
Two forms
§ Systemic lymphoma
> Bovine leukemia virus +
> Primary or secondary site
§ Cutaneous form of lymphosarcoma
> Very rare
> < 3 years of age
> Not associated with Bovine leukemia virus
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Distribution
§ Neck, shoulders, back, croup
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Appearance
§ Intradermal, plaques with white-gray scabs
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Clinical signs
§ Dependent on systemic involvement
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Dx: Biopsy
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Tx
§ Spontaneous regression may occur
> Returns with systemic involvement
§ Supportive care
photosensitization
- types
- requirements
§ Type I- ingestion of photodynamic agent
§ Type II- congenital abnormality
§ Type III- liver disease > Accumulation of phylloerythrin
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Requirements
§ Presence of photodynamic agent
§ White or lightly pigmented skin
§ Ultraviolet A light
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some plants that contain photodynamic agents (type 1 photosensitization)
- St. John’s wort
- buckwheat
- perennial ryegrass
- whiteheads
some plants that lead to photosensitization via liver effects (type 3)
- puncture vine
- agave
- signal grass
photosensitization
- lesion distribution and appearance
- clinical signs
Distribution
§ Hairless, white, or low pigmented skin
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Appearance
§ Erythema, edema, pain on palpation
§ > blistering, serum exudation
§ > thickening and fissuring
§ > necrosis and sloughing
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Clinical signs
§ Associated with affected areas and severity
§ Associated with liver disease if present
photosensitizatoin diagnosis
§ Clinical appearance
§ Presence of or access to toxic plants
§ Elevation in hepatic/hepatobiliary enzymes
§ Liver biopsy
§ Post-mortem examination
photosensitization treatment
§ Remove from source of toxin
§ House away from UV light
§ Wound management
§ Feed cereal or low quality grass hay
