Infectious Foot Diseases Flashcards
(25 cards)
Why is foot and mouth disease prevalence and control important?
Highly infectious- causes fever, lameness with tongue, feet, snout and teat lesions
Causes economic devastation
Caused by Aphthovirus
What infectious foot disease is shown in this image?
Bovine digital dermatitis
Why is digital dermatitis important?
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
Where is the lesion usually located in bovine digital dermatitis?
What is its aetiology?
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
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?
Phylum- spirochaete- spiral shaped
Genus- treponemes
Gram negative anaerobes
How is bovine digital dermatitis treated?
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
What is known about bovine digital dermatitis transmission?
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
How can farmers try to control BDD?
Host immunity- not protective
Regular footbathing
Improve farm hygiene and appropriate foot trimming with disinfected equipment
Herd biosecurity
What condition do the following diseases show?
Contagious ovine digital dermatitis
Emerging disease
Why is resolition of contagious ovine digital dermatits important?
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
How is contagious ovine digital dermatitis diagnosed and treated?
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!
What are the risk factors identified for contagious ovine digital dermatitis?
- 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
How can farmers try to control contagious ovine digital dermatitis?
Regular foot bathing should help
Improve hygiene and appropriate foot trimming with disinfected equipment
Individual systemic LA amoxicillin treatment
Flock biosecurity
What are the problems casued from ovine footrot?
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
Describe the pathology of ovine foot rot
- Begins as interdigital dermatitis
- Then interdigital hoof wall lesions form
- Leads to seperation of hoof from underlying tissue
What is the primary agent of ovine foot rot and how does it cause the disease?
Primary agent- Dichelobacter nodosus- gram negative anaerobe
Produced extracellular proteases- key for virulence
Has fimbriae conferring motility and adherence
Fimbral proteins- highly immunogenic
How is ovine foot rot transmitted?
How is it diagnosed and treated?
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
How is ovine foot rot controlled?
Footbathing, foot trimming
Antibiotic injection- LA amoxicillin
Vaccination based on fimbrial proteins
Biosecurity- isolaiton and selection for resistance
What is ovine interdigital dermatitis commonly known as?
Scald
How does scald present?
When does it occur?
Presents as red/pink inflammation of the skin betweeb claws with white/grey pasty ‘scum’ on top
Occurs when wet underfoot
What is considered the primary agent of scald?
How is it treated and controlled?
D. nodosus- same as footrot
Treatment and control is the same as footrot
What is the correct name for foul in the foot?
Interdigital necrobacillosis
What are the clinical signs of foul in the foot?
Severe lameness
Animal frequently holds leg in air to relieve pressure
Swelling of interdigital space
Fever, anorexia
Reduced milk yield
