Infectious Foot Diseases Flashcards

1
Q

Why is foot and mouth disease prevalence and control important?

A

Highly infectious- causes fever, lameness with tongue, feet, snout and teat lesions

Causes economic devastation

Caused by Aphthovirus

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2
Q

What infectious foot disease is shown in this image?

A

Bovine digital dermatitis

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3
Q

Why is digital dermatitis important?

A

Major cause of lameness- 70% of UK farms- welfare

Causes milk drop

Treatment- efficacy, costs, environment, milk discard

Increased culling rate

Increased labour cost

Economic loss

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4
Q

Where is the lesion usually located in bovine digital dermatitis?

What is its aetiology?

A

Lesion located above the coronet between heel bulbs mainly reported on rear feet

Aetiology:

Precise cause not proven- antibiotics lead to transient improvment

Bacteria are present in lesions
Spirochaetes are most frequently reported organism

Evidence suggests treponemes are the agents

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5
Q

What phylum of bacteria is shown in the following photo?

If you are told it is likely to cause bovine digital dermatitis what genus might you say it belonged to?

What kind of bacteria are this genus?

A

Phylum- spirochaete- spiral shaped

Genus- treponemes

Gram negative anaerobes

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6
Q

How is bovine digital dermatitis treated?

A

Diagnosis- visual- lameness and lesion score

No single effective treatment:

  • Footbaths- chemical (formalin/copper sulphate), antibiotic (lincospectin)
  • Topical treatments- tetracycline (blue spray)
  • Penicillin or macrolides
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7
Q

What is known about bovine digital dermatitis transmission?

A

Outbreaks tend to be seasonal- highest incidence in winter months (housing)

Cattle can carry disease onto new farms

Cleaner farms have fewer outbreaks

Ruminant GI tract, slurry, direct contact and foot trimming equipment all identified as infection reservoirs/transmission routes

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8
Q

How can farmers try to control BDD?

A

Host immunity- not protective

Regular footbathing

Improve farm hygiene and appropriate foot trimming with disinfected equipment

Herd biosecurity

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9
Q

What condition do the following diseases show?

A

Contagious ovine digital dermatitis

Emerging disease

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10
Q

Why is resolition of contagious ovine digital dermatits important?

A

Sheep lameness is a big problem

Frequenlty results in loss of entire foot horn capsule

Severe foot lesions and substantial pain and suffering

Pathology similar to BDD- spirochaetes identified

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11
Q

How is contagious ovine digital dermatitis diagnosed and treated?

A

Diagnosis is normally visual- lameness and lesion score

No single effective treatment:

  • Footbaths- chemical (formalin/zinc sulphate), antiobiotic (less used)
  • Topical- tetracycline (blue spray)
  • Amoxicillin/penicillin or macrolides
  • Systemic macrolides and amoxicillin show efficacy- AMR!
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12
Q

What are the risk factors identified for contagious ovine digital dermatitis?

A
  • Dairy cattle in close proximity- same bacteria
  • Foot rot
  • Sheep can ‘carry’ disease to new farms
  • Ruminant GI tract- direct contact and foot trimming equipment
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13
Q

How can farmers try to control contagious ovine digital dermatitis?

A

Regular foot bathing should help

Improve hygiene and appropriate foot trimming with disinfected equipment

Individual systemic LA amoxicillin treatment

Flock biosecurity

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14
Q

What are the problems casued from ovine footrot?

A

Extremely painful disease- affected animals have rapid weight loss

Large economic impact- £24m

Cost from lost production, preventitive measures and treatment

In some cases death from starvation and thirst

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15
Q

Describe the pathology of ovine foot rot

A
  • Begins as interdigital dermatitis
  • Then interdigital hoof wall lesions form
  • Leads to seperation of hoof from underlying tissue
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16
Q

What is the primary agent of ovine foot rot and how does it cause the disease?

A

Primary agent- Dichelobacter nodosus- gram negative anaerobe

Produced extracellular proteases- key for virulence

Has fimbriae conferring motility and adherence

Fimbral proteins- highly immunogenic

17
Q

How is ovine foot rot transmitted?

How is it diagnosed and treated?

A

Transmitted from reservoir- infected foot, direct transmittion survives for short period in environment

Diagnosis based on clinical signs

Treatment- hoof trimming and topical disinfectants or antibiotics
formalin and zinc sulphate in footbaths

Systemic amoxicillin and streptomycin= alternative

18
Q

How is ovine foot rot controlled?

A

Footbathing, foot trimming

Antibiotic injection- LA amoxicillin

Vaccination based on fimbrial proteins

Biosecurity- isolaiton and selection for resistance

19
Q

What is ovine interdigital dermatitis commonly known as?

A

Scald

20
Q

How does scald present?

When does it occur?

A

Presents as red/pink inflammation of the skin betweeb claws with white/grey pasty ‘scum’ on top

Occurs when wet underfoot

21
Q

What is considered the primary agent of scald?

How is it treated and controlled?

A

D. nodosus- same as footrot

Treatment and control is the same as footrot

22
Q

What is the correct name for foul in the foot?

A

Interdigital necrobacillosis

23
Q
A
24
Q

What are the clinical signs of foul in the foot?

A

Severe lameness

Animal frequently holds leg in air to relieve pressure

Swelling of interdigital space

Fever, anorexia

Reduced milk yield

25
Q

How is foul in the foot treated and controlled?

What acts as a reservoir?

A

Treatment- 3 Day systemic penicillin, oxytet or macrolide

Control- footbathing with disinfectants

Infection reservoir- environment and manure