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Flashcards

Infectious Foot Disease

Rhiannon Llwyd Infectious Diseases Inglês 40 flashcards

Flashcards do conjunto (40)

  1. 1Why are infectious foot diseases in cattle important?pain = lameness = reduction in production
    around 70% UK cattle have this
  2. 2What species does foot and mouth disease affect?cloven hoofed animals
    cattle, swine, sheep, goats
    >70 species of wild animals
  3. 3Why is foot and mouth disease so important and what effect does it have on ruminants and other species?highly infectious, characterized by fever, lameness + tongue, feet, snout, teat lesions
    high morbidity, low mortality allows for economic devastation
  4. 4What is the cause of foot + mouth disease?foot + mouth disease virus = aphthovirus
  5. 5What is Bovine Digital Dermatitis (BDD)?infectious lameness in cattle
    first identified in 1974
    now endemic in many countries (dairy esp) (2017 UK - most dairy herds, 30-60% morbidity)
    leads to considerable economic loss
    very painful for animals concerned
    reduction in milk yields + reproduction
  6. 6Where are bovine digital dermatitis lesions normally located?lesion located above coronet between heel bulbs
  7. 7What is the prevalence of BDD on on dairy farms in the UK?currently 70% UK dairy herds have BDD with prevalence on each farm of about 40%
  8. 8What is the importance of digital dermatitis within the farming industry and what effects does it have on the indusry?major cause of lameness = welfare issue
    milk drop
    treatment = efficacy, costs, environment, milk discard
    increased culling rate
    increased labour costs = £100+ per case, England + Wales = £40-100 million per annum
  9. 9What effect does bovine digital dermatitis have on cattle?disease of dairy cattle which causes severe lameness
    lesions mainly in housing periods and on rear feet
    now reported in beef cattle
  10. 10What is the aetiology of bovine digital dermatitis?precise cause not proven
    antibiotics lead to transient improvement
    bacteria present in lesions = many isolated (fusobacteria, dichelobacter, campylobacter, mycoplasma, spirochaetes)
    spirochaetes = most frequently reported organism in DD tissues
  11. 11What is spirochaete staining in BDD?BDD skin biopsies stained with silver nitrate identify characteristic spiral organisms
    spirochaetes always seen in BDD lesions; not seen in normal skin
  12. 12What do you often see co-infection with?several phylotypes
    treponema medium-like = human periodontal spirochete
    treponema phagedenis-like = human commensal of genital urinary tract
    treponema denticola-like = human periodontal spirochete
  13. 13What are the aetiological agents of BDD that have been identified?evidence suggests treponemes
    polymicrobial symbiotic pathogenesis suggested (frequently 5 different treponeme species co-infect)
    many treponemes involved similar to human oral + genital treponemes
    important species = T. medium-like, T. phagedenis-like + T. denticola-like (now T. pedis)
    no virulence factors identified, these bacteria are fastidious anaerobes which require complex media supplemented with serum for growth
  14. 14How do you diagnose BDD and what treatment is available?diagnosis normally visual (lameness + lesion score), no single effective treatment
    common treatment = footbaths (chemical: formalin/copper sulphate), antibiotic e.g. lincospectin, topical (tetracycline spray), penicillin (systemic) or macrolides (systemic/oral) likely better BUT milk withdrawal + antibiotic stewardship issues so NOT USED, recurrence of DD is common
  15. 15What do we know so far about the transmission of BDD?outbreaks of BDD within herds tend to be season dependent with highest incidence in winter (housing), cattle can carry disease onto new farms, cleaner farms have fewer outbreaks, ruminant GI tract, slurry, direct contact + foot trimming equipment all identified as infection reservoirs/transmission routes
  16. 16What is done to try and control BDD and are there any new methods in place/available?only vacc (novartis) withdrawn from market (lacked efficacy), host immunity - not protective, regular footbathing helps control + prevent new cases, improve farm hygiene + appropriate foot trimming with disinfected equipment, herd biosecurity, new antibiotics, additional transmission prevention and/or effective vaccines needed
  17. 17What is contagious Ovine Digital Dermatitis and what are the key things to know?emerging disease, considered 35-53% of UK sheep flocks have CODD, prevalence 2.2% but up to 50%, more severe than + similar prevalence to footrot, which costs the sheep indusry £24M/year, costs attributed to lost production, preventive measures + treatment, sheep lameness problem, frequently results in loss of entire foot horn capsule, severe foot lesions + substantial pain + suffering, pathology similar to BDD - spirochaetes identified, same three treponeme phylogroups implicated
  18. 18How can you diagnose CODD?diagnosis normally visual (lameness + lesion score)
  19. 19What treatment methods are available for CODD?no single effective treatment
    common treatments: footbaths = chemical (formalin/zinc sulphate), antibiotic (lincospectin), topical treatment = tetracycline spray, penicillin (systemic) or macrolides (systemic/oral) likely better - show efficacy but antibiotic stewardship issues!
  20. 20What do we know about the transmission of CODD?dairy cattle in close proximity = risk factor + same bacteria, foot rot also a risk factor, sheep can carry disease onto new farms, ruminant GI tract, direct contact + foot trimming equipment all identified as infection reservoirs/transmission routes
  21. 21What can we do to control CODD?no vaccine + host immunity - not protective, regular foot bathing should help, improve farm hygiene + appropriate foot trimming with disinfected equipment (some guidelines suggest do not trim infectious sheep lesions), flock biosecurity - purchasing sheep from known sources/health status, isolate lame sheep, new antibiotics, additional transmission prevention and/or effective vaccines are needed
  22. 22What is ovine footrot and what are the key things to remember?90% UK sheep have footrot, prevalence 3.7%, extremely painful disease, affected animals = rapid weight loss, footrot costs sheep industry £24M/year, costs attributed to lost production, preventive measures + treatment, causes lameness + loss of body condition (reduced feed intake), in some cases death from starvation + thirst
  23. 23How does the disease start and progress?begins as interdigital dermatitis then interdigital hoof wall lesions leading to separation of hoof from underlying tissue
  24. 24What is the causative agent of Ovine Footrot?primary agent = dichelobacter nodosus = straight/curved rod, not flagellated, fastidious gram negative anaerobe
  25. 25What is the pathogenesis of Ovine Footrot?produce extracellular proteases = key for virulence, has fimbriae conferring motility + adherence, fimbrial proteins = highly immunogenic = basis of serotyping of D. nodosus, ten major serogroups (A-I and M)
  26. 26What is the infection reservoir for ovine footrot?infected foot, transmitted direct/indirect contact, survives short time in environment
  27. 27Do you see ovine footrot all over the world?occurs on all continents, most serious in regions with a mild climate + periods of abundant rainfall (UK!), improves during dry periods in endemic areas e.g. Australia, another gram-negative anaerobe, fusobacterium necrophorum also implicated = polymicrobial
  28. 28How can you diagnose Ovine Footrot?natural infection produces no immunity, diagnosis based on clinical signs, culture-based diagnosis not routine as fastidious
  29. 29What treatments are available for ovine footrot?treatment = hoof trimming + topical disinfectants or antibiotics: 5-10% formalin, 5% zinc sulfate or oxytetracycline spray, formalin + zinc sulfate in footbaths, systemic penicillin + streptomycin = alternative (vacc)
  30. 30How can we control ovine footrot?footbathing, foot trimming?, antibiotic injections, vaccination: based on fimbrial proteins e.g. 8-10 serogroups, biosecurity, isolation + selection for resistance (culling), typical control strategies utilises whole-flock control strategies including foot-bathing + vaccination
  31. 31What is ovine interdigital dermatitis = scald?96% of UK sheep flocks have scald, prevalence 6.9%, painful, most common cause of lameness in sheep, occurs when wet underfoot, no under-running of hoof wall or sole + no foul smell, now generally considered an early presentation of footrot
  32. 32What are the clinical signs of ovine interdigital dermatitis (scald)?red/pink inflammation of skin between claws with white/grey pasty 'scum' on top
  33. 33What is the causative agent of ovine interdigital dermatitis (scald)?D. nodosus, previosuly considered F. necrophorum primary, ongoing research into role of F. necrophorum
  34. 34What is the treatment + control methods for ovine interdigital dermatitis?same considerations as footrot
  35. 35What are the causative agents of bovine footrot?fusobacterium necrophorum + baceriodes melaninogenicus, F. necrophorum associated with sheep footrot is a distinct variant from bovine footrot F. necrophorum
  36. 36What is foul in the foot?interdigital necrobacillosis = bovine foot rot (but considered different to sheep disease), fusobacterium necrophorum + bacteriodes melaninogenicus, considered requires injury to interdigital skin, sudden onset, acute disease
  37. 37What are the clinical signs associated with 'foul in the foot'?severe lameness, animal frequently holds leg in air to relieve pressure, swelling of interdigital space, fever, anorexia, reduced milk yield
  38. 38What is the infection reservoir for 'foul in the foot'?environment and manure
  39. 39What treatment is available for 'foul in the foot'?3 day systemic penicillin, oxytet or macrolide (topical not effective)
  40. 40What can we do to control 'foul in the foot'?footbathing with disinfectants

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Infectious Diseases FlashCards sobre Infectious Foot Disease, criado por Rhiannon Llwyd em 19-03-2020.
Criado por
Rhiannon Llwyd
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