Common Skin Diseases Of Cattle (Ca23)

Front 1

Dermatophytosis (ringworm)

1) Describe aetiology

2) Describe epidemiology

3) Describe clinical signs

4) Describe pathogenesis

5) Diagnosis

6) Treatment

7) Control/prevention

Back 1

1) Zoonotic. Affects value of animals. Trichophyton verrucosum (T. mentagrophytes).

2) Common, worldwide. All ages, most common 2-7m, autumn & winter, intensive management.

-Spores survive for months/years

-Transmitted by clinical cases, carrier animals, fomites

-Incubation period 1w (up to 4w)

-Self limiting, often 1-4m (up to 9m)

3) Non-pruritic, alopecic lesions, +/- stubble of broken hairs; raised lesions w/grey/white powdery surface +/- exudation; often roughlly circular or oval, 3-5cm; common sites calves (periorbital, ears, back) vs adults (thorax, limbs, udder).

4) Infection of keratin of hair & skin. Enzymes attack keratin of actively growing hair-breaks off . Inflammatory rxn (~mild).

5) Clinical signs. Can do microscopy, dermatophyte test medium culture (color change). Definitive dx: culture & ID.

6) Topical: Enilconazole (Imaverol) or hypochlorite spray (Bactoban 55).

Systemic: Grisofulving in feed (not UK), sodium iodide 1g/14kg IV, repeat in 7d (toxicity). Ringvac vax.

7) Vaccination (Ringvac) vs. T. verrocosum-->use for prophylaxis or tx of infected animals (double dose). Disinfection-->clean w/high pressure water jets. Scrub w/hot detergents/disinfectants. Protective clothing, etc.

Front 2

Pediculosis (lice)

1) Describe aetiology

2) Outline life cycle (4)

3) Describe epidemiology

4) Describe clinical signs (where vs what)

5) Diagnosis (& Ddx)

6) Treatment (2)

7) Control

Back 2

1) 2 types of lice. Biting lice-big head. Sucking lice-smaller head.
2) 3-6w, entirely on host, female lay eggs attach to hairs. Nymphs-->several moults-->adult.
3) Survival off host short, usually <1w
-highest populations in cold months when coat long
-low population when skin/coat temp high
-survive summer in protected areas-ears, axillae, jowl, tail
4) Biting lice-neck, withers, tailhead
-Sucking lice-more generalized: head, neck, withers, brisket, tail, axillae, groin.
-Pruritis-->reduced feeding & poor weight gain, reduced milk yield.
-Poor coat, alopecia, excoriation, dandruff.
-Sucking lice-->anemia, reduced immunity.
5) Presence of lice & eggs (Ddx mange)
6) Treat all in-contact animals. Single treatment usually sufficient- re-treatment may be needed w/permethrin (sometimes deltamethrin & alphacypermethrin)
-Pyrethroid pour-ons: deltamethrin (10 mL/animal; 8-10w protection); alphacypermethrin (10mL/animal); Permethrin (1mL/10kg; may need repeat in 4w).
-Endectocides (also treat endoparasites): pour-on vs injection (not v. effective vs biting lice)
7) Treat all animals at housing. Also attention to general health, condition, nutrition of stock, etc.

Front 3

Chorioptic mange
1) Describe aetiology
2) Epidemiology
3) Clinical signs (where vs what)
4) Diagnosis
5) Treatment/control (3)

Back 3

1) Choriopte bovis, surface mite. Life cycle 2-3w. Lives off epidermal debris.
2) Most common mange mite in UK (65%). V. limited survival off host. Transmission through direct contact.
3) i-limbs, tail, perineum, udder, scrotum, neck, & flanks.
ii-papules & pruritis, self-trauma: excoriation, exudation, alopecia, crusts.
4) Hx, CE, skin scrapes
5) -Endectocide pour-on: Ivermectin-repeat in 2w; long acting-single tx.
-Endectocide injection (does not eliminates chorioptes)-may be used when skin pathology severe to allow healing, then follow up w/pour-on product.
-Permethrin pour-on: repeat in 4w.

Front 4

Sarcoptic mange (scabies)

1) Describe aetiology (5)

2) Epidemiology (2)

3) Clinical signs (where vs what)

4) Diagnosis (4)

5) Treatment/control (2)

Back 4

1) Zoonotic. 30% UK mange. Sarcoptes scabei. Burrowing mite. Lifecycle 10-17d.
2) Any age/sex. Direct contact or fomites, survival off animal only few days.
3) i-head/neck lesions-->generalized
ii-Intense pruritis, papular dermatitis, exudate, crusting; self trauma-excoriation, alopecia, thickening +/- 2ndary infections, +/- loss of condition, reduced milk.
4) Hx, CE, skin scrapes, +/- biopsy
5) i-Endectocide injection or pour-on: ivermectin-repeat in 2w. Long acting-single tx. Injection may be preferred when excess crusting/scabs.
ii-Permethrin pour-on: repeat in 4w.

Front 5

Photosensitization

1) Describe aetiology/pathogenesis (3)

2) Clinical signs (where vs what)

3) Diagnosis (2 & ddx)

4) Treatment (3)

5) Control (2)

Back 5

1) -Photodynamic agent in skin. Irradiation of photodynamic agent causes cell death in non-pigmented areas w/out much hair covering. Necrosis & sloughing of skin.
-Via circulation: Primary-defective metabolism (e.g. porphyria) vs. plant origin (e.g. St John's Wort). OR Secondary-Liver disease; failure to metabolize phylloerythrin (chlorophyll breakdown product); builds up in circulation (photodynamic).
-Via contact: Psoralens in sap of ceertain plants.
2) i-Non-pigmented skin exposed to sun-head (muzzle/eyelids), neck, back, flanks, udder, & teats.
ii-Erythema +/- vesicles, edema, necrosis-dry, sloughing & ulceration, pruritis, pain.
3) Clinical signs. 2ndary dz-jaundice, biochemical evidence of liver failure.
*Muzzle/udder lesions-ddx: bluetongue.
4) Cool, shaded, fly-free housing; topical tx of lesions; antibiotics for 2ndary inf, CCS?, tx underlying dz-prognosis often poor.
5) i-control liver disease (fluke, ragwort, bog asphodel)
ii-avoid toxic plants

Front 6

Flies

1) Describe aetiology (2)

2) Clinical signs (5)

3) Treatment (7)

4) Control (biting & nuisance flies-2)

5) Control of summer mastitis (7)

Back 6

1) Non-biting spp (house flies, face flies, head flies) vs biting flies (horn flies, stable flies, horse flies, blackflies, louse fly).
2) *Non-biting: superficial skin damage, transmission of dz like IBK & mastitis.
*Biting: multiple nodules, transmit dz-anthrax, Pasteurella, trypanosomosis.
*Open wounds/lesions on the lower abdomen, udder, & teats can be caused by bites of flies (e.g. Haematobia irritans or Hydrotaea irritans).
*Louse fly: fly worry & irritation, sucks blood from perineal & inguinal regions of cattle.
*Blow fly strike (Lucilia sericata or Phormia terranovae): larval infestation of soiled skin especially in warm damp conditions; wounds (traumatic, castration, dehorning); soiled sheep fleeces.
3) -Manual removal of maggots.
-Clean wounds thoroughly, avoid cytotoxic solutions.
-Apply injectable ivermectin topically.
-Apply fly repellent around wound to prevent re-infestation.
-Continue daily care.
-Systemic antibiotic & anti-inflammatory may be required.
-Wounds are highly vascular & granulate rapidly if kept clean.
*Warble fly larval infestation: notifiable in UK.
4) *Insecticide tx's: synthetic pyrethroid ear tags; pour on pyrethroid products.
*Add'l methods may be used: baits, larvicides where large #s of flies breeding; keep manure dry, compact, covered, & away from animals; reduce food spillage/spoilage, reduce moisture in buildings; biological control; monitoring (e.g. fly traps).
5) *Synthetic pyrethroid ear tags/pour on products.
*Spread in sebum, but little hair & few sebaceous glands on teats-use 2 ear tags, or more frequent or direct application of pour-on products.
*Graze large open fields away from woods & streams.
*Weekly tar/micropore tape application to teats.
*Prevent teat lesions.
*Dry cow tubes.
-Treat cases w/penicillin (or tilmicosin) but permanent udder damage common.