Microbial skin disease 2 Flashcards
Viral and protozoal
Outline the importance of lumpy skin disease
- Morbidity variable, mortality usually ow
- Economic importance due to huge production loss
Describe the clinical signs of lumpy skin disease
- Pyrexia, inappetance, abortion, reduced lactation
- Skin lesions: 0.5-5cm cutaneous nodules, 1-2 days after onset of pyrexia esp. on head, neck, perineum, genitalia, and udder
- Similar lesions in GIT and lungs
Give examples of parapoxviruses and their importance in humans
- Contagious pustular dermatitis (orf), pseduocowpox, bovine papular stomatitis
- All zoonotic, similar presentation in humans
Describe the clinical signs of orf
- Proliferative ulcerative lesions following trauma to lips/muzzle, coronary band
- Lesions also on ewe’s teats (pain, mastitis)
- Clinical disease espically in lambs <2mo as these fail to suckle due to discomfort in mouth
Outline the importance of orf
- Significant economic losses
- Serious welfare issue
- Lesions may lead to secondary bacterial infections
Describe common secondary infections that can occur as a result of orf
- Staph aureus, leading to severe facial dermatitis
- Dermatophilus congolensis, leads to granulomatous masses at coronary band (strawberry footrot in sheep)
Describe the treatment for orf
- No effective treatment
- treat secondary infection, analgesia
- Vaccine available but only for flocks with existing problem
- Can be used in response to an outbreak
- Disinfect building as virus remains infective in environment for many months, and in dried scabs
What is the most common infectious cause of teat disease in cattle?
Pseudocowpox (udder also affected)
Describe the appearance of bovine papular stomatitis and outline its importance
- Erythematous raised papules/ulcers on muzzle, lips, oral cavity
- Usually animals <2yo
- Mild disease, short immunity
- Differential for FMDV
What are the clinical signs of Scrapie?
- Pruritus
- trembling
- Nibbling, teeth grinding
- Nervous, aggressive
- Loss of condition
- Ataxia, collapse, death
How is Scrapie diagnosed?
- Clinical diagnosis can be reliable
- Also post-mortem histology, demonstration of PrP
Outline the control of Scrapie
- Cull affected sheep and descendants
- Select for genetically resistant sheep
- National Scrapie Plan 2001, Compulsory Flocks Scheme
List the key small animal viral skin diseases
- Canine papillomas
- Feline papillomas
- FeLV/FIV
- Feline calicivirus
- Feline herpesvirus
- Canine distemper virus
- Cowpox
- Myxomatosis
How is canine papilloma virus transmitted?
Direct and indirect contact, common in groups of dogs
Describe the appearance of canine papilloma virus lesiosn
- Warts
- Mouth, lips, eyes: smooth shiny plaques or papillated lesions
- Footpads: firm, hyperkeratotic, often horn-like lesions
- Young and adult dogs affected, usually multiple lesions
Outline the treatment of canine papillomas
- Usually allow to resolve spontaneously, although new ones may develop
- Surgery if causing problems
- Topical keratolytic/softening preparations (water and petroleum jelly) can decrease discomfort but will not alter course of infection
- Imiquimod cream, interferon, azithromycin have anecdotal evidence, but poorly vaidated
With what other disease may canine papillomas be confused? Why is this important?
- Pigmented viral plaques seen commonly in French Bulldogs and Pugs
- These pigmented plaques may not resolve and need treatment
- Immunosuppressives should be avoided as can allow viral proliferation
Describe the clinical signs and clinical significance of canine distemper virus
- Hardpad
- Naso-digital hyperkeratosis
- respiratory, GI and neurological symptoms, very sick dogs
- Rarely seen now due to vaccination
Describe the prevalence and cause of feline papillomas
- Rare
- Associated with immunocompromise e.g. FeLV, FIV and other causes of impaired immune function
What cutaneous presentations may be seen with FeLV/FIV?
- FeLV may cause cutaneous sarcomas
- Chronic or recurrent pyodermas, cutaneous horns
What are the clinical signs of feline calicivirus/herpes virus?
- Oral ulceration, can occasionally affect the skin
- Mild sneezing and conjunctivitis
- +/- lameness, polyarthritis
- +/- small ulcers/crusts (can look like cat bites)
- +/- severe favial dermatitis
- rare virulent form leads to marked crusting, oedema, systemic disease and death
Outline the management for feline calicivirus
Vaccination
What presenting sign is Calicivirus a key differential for?
Head and neck pruritus (plus the other clinical signs of course)
Outline the occurrence of cowpox in cats
- Uncommon
- Cattle rarely the cause, smal wild animals are a natural reservoir
- Cats infected by wild animals while hunting e.g. voles, woodmouse
Explain the transmission of cowpox to cats
- From voles, woodmice etc when hunting
- Bite, becomes infected, often head, neck, forelimbs, leads to small nodule and viraemia, within 10-14 days secondary lesions over body
Describe the clinical signs of cowpox in cats
- +/- mild pyrexia, inappetance, depression (mild viraemia)
- Papules, nodules, plaques, crusts (secondary lesions all over body)
- Rarely pruritic, occasionally systemic infection
When is cow pox most commonly seen in cats?
July to November
What are the differential diagnoses for signs that may indicate cowpox in cats?
- Eosinophilic grnauloma
- Cat bite abscess
- Dermatophytosis
- Superficial pyoderma
- Mycobacterial infection (feline leprosy)
Outline the treatment of cowpox in cats
- NOT STEROIDS: will lead to death
- Often resolves self
- Broad spec. antibiotics if necessary
What is the main protozoal agent that causes cutaneous disease
Leishmania
Describe the global distribution of Leishmania
- Global
- Med and Portugal particularly affected, now reports in Northwest Europe
- Not yet in UK, only if travel abroad
How is Leishmaniasis spread?
Bloodsucking phlebotomine snadflies
Identify reservoirs for Leishmaniasis
- Domestic and wild dogs
- Rodents
- Other wild animals
What is the importance of the incubation period for Leishmaniasis?
- Incubation can be weeks to years, mainly in dogs <5yo
- Dogs imported from endemic areas e.g. med, may develop disease months or years later
What are the 2 possibly lymphocytic responses and outcomes following infection with Leishmania?
- Th1 response: cell mediated immunity and resistance
- Th2 response: humoral response and persistent infection and clinical signs
Describe the pathogenesis of Leishmaniasis
- Circulating immune complexes lead to renal, joint and ocular lesions
- Non-suppurative granulomas, hepatic, enteric and osseus disease
- Slowly progressive, multi-systemic
In what proportion of cases do cutaneous signs develop, and identify these
- 80%
- Exfoliative dermatitis (akak asbestos scales)
- Nasodigital hyperkeratosis
- Ulcers (esp. on pressure points, extremities, M-C junctions)
- Paronychia
- Alopecia (esp. head, periocular)
- Sterile pustular dermatitis
- Diffuse erythema, erythematous plaques
- Nodules, papules
- Secondary pyoderma, demodicosis
Describe the systemic signs of Leishmaniasis
- Generalised lymphadenopathy
- Anaemia
- PUPD/glomerulonephritis, renal failure
- Hepato/splenomegaly
- Exercise intolerance, weight loss, pyrexia
- Ocular lesions, coagulopathies, lameness, meningitis, V, D, URT signs
Describe the diagnosis of Leishmaniasis
- Demonstration of organism in macrophages in LN or bone marrow aspirates (indicates active infection)
- Serology or PCR
- Skin biopsies suportive
- Antibodies difficult to identify if active or previous infection
Outline the treatment and management for Leishmaniasis
- Meglumine antimonate, sodium stibogluconate, pentamidine, metronidazole, ketoconazole
- Incurable, relapses after treatment
- Euthanasia valid option
- Vaccination available but not 100% effective
- Prevention key
Explain the use of Meglumine antimonate an sodium stibogluconate in the treatment of Leishmaniasis
Works by inhibiting DNA replication and transcription
What type of drug is pentamidine?
Anti-protozoal and anti-fungal
Which drugs are licensed in the treatment of Leishmaniasis?
None
Explain the importance of all vesicular diseases
- Some notifiable
- Economic losses (slaughter policies, movement restrictions, mortality, production loss, loss of sales/shows, increased labour for nursing)
- Some are zoonoses
List the zoonotic viral and protozoal cutaneous diseases
- Vesicular stomatitis
- Bovine herpes mammillitis
- Cowpox
- Parapoxviruses
- Leishmaniasis
Outline the environmental management regarding dermatophytosis infection
- Thorough disinfection
- Use Chlorhexidine
- Wash bedding twice consecutively at high temperature long washes, or dispose
- Temporary bedding until end of treatment
- Do not share brushes etc.
- Environmental decontamination with 1:10 dilution of bleach
- Enilconazole soln 0.2% also effective
- Vacuuming and safe disposal of vacuumed hair
- Virkon where bleach cannot be used
Describe the treatment of animals in contact with an animal diagnosed with dermatophytosis
- Topical minimum, ideally systemic treatment
- Topical: MIconazole for cats, enilconazole for dogs
- Systemic: itraconazole licensed for cats, itrafungol also licensed for cats, for dogs use ketoconazole (licensed) or itraconazole (not licensed for dogs, but safer)
Describe the treatment of an animal for dermatophytosis using enilconazole
- Not effective alone
- Need to remove crusts with hard brush soaked in solution
- Spray whole body at first application
- Wash 4 times at 3 day intervals
- Can dip thoroughly in bath containing emulsion
What are the side effects of enilconazole?
- Hypersalivation
- Idiopathic muscle weakness
- Slightly increased serum ALT concentration
Evaluate the use of malaseb shampoo in the control of dermatophytosis
- Contains miconazole and chlorhexidine
- Licensed for dogs and cats
- Not very practical if have multiple animals to wash
- Can be helpful in control
- Wash twice weekly, minimum contact time 10 mins
What information should be given to an owner when treating an animal for dermatophytosis
- Is zoonotic, need to go to doctor
- Environment needs thorough disinfection
- IN contact animals are at risk
- Once treated, short lived immunity
- Animal is not cured when they look better
- Clip area if possible rather than shaving to facilitate treatment penetration
