Infections of the Musculoskeletal System III (32) Flashcards
Dr. Erol
What are the other names for bovine footrot?
infectious bovine pododermatitis
interdigital phlegmon
interdigital necrobacillosis
foul in the foot
What is the causative agent of infectious bovine pododermatitis?
fusobacterium necrophorum biotypes A and AB
What is the epidemiology of infectious bovine pododermatitis?
all ages susceptible
infected feet are source of infection
transmission highest in wet, humid conditions
What are clinical findings of infectious bovine pododermatitis?
sudden onset of lameness and fever
typical fissuring, necrotic lesion in the skin at the top of the interdigital cleat
drop in milk production
What is diagnostic confirmation of bovine footrot?
clinical findings
culture may be done
What is treatment and control of bovine footrot?
treatment: antimicrobials
controls: avoidance of abrasive underfoot conditions, footpaths, antimicrobials, vaccination
What is the entry of infection of bovine footrot?
injury to the interdigital skin
laceration of the skin by water, feces, and urine may predispose to injuries
What are the characteristics of f. necrophorum?
a gram-negative, non spore-forming, non flagellated, non-motile, pleomorphic anaerobic bacteria
has a lipopolysaccharide endotoxin capable of necrotizing activity
What are other organisms possibly involved in bovine footrot?
What is the morphology of dichelobacter nodosus?
thick, straight, or slightly curved
bulge at one or both ends
What is the morphology of fusobacterium necrophorum?
irregular staining, long, non-branching filamentous forms
How do you differentiate gram-negative anaerobic bacteria?
usually have a fetid or putrid odor due to volatile fatty acids
Differentiate colonial appearances between dichelobacter nodosus and fusobacterium necrophorum
dichelobacter nodosus: clones of virulent of virulent strains from lesions of ovine foot rot usually have dark central zone, a pale granular middle zone and a spreading irregular periphery with a ground glass appearance
fusobacterium necrophorum: grey round and shiny
Label which one is fusobacterium necrophorum and dichelobacter nodosus to left or right
left: fusobacterium necrophorum
right: dichelobacter nodosus
What are the virulence factors of fusobacterium necrophorum?
leukotoxins
haemagglutinin
haemolysin
dermonecrotic toxin
What are virulence factors of dichelobacter nodosus
type IV fimbriae
serine proteases
List the synergistic causative agents fusobacterium necrophorum has with other bacterial species in the development of foot lesions in ruminants
turperella arcanobacterium pyogenes
dichelobcter nodosus
List the synergy between f. necrophorum and other species
heat-labile factor t. pyogenes - stimulates F. necrophorum replication
leukotoxin f. necrophorum - aids survival of t. pyogenes
facilitates tissue invasion f. necrophorum - by d. nodosus
growth factor d. nodosus - stimulates f. necrophorum
What are the first signs of footrot?
swelling and erythema off the soft tissues of the interdigital space and the adjacent coronary band
[Hind/Fore]-limbs are more commonly affected. [More than one / Only one] is involved at the same time
Hind
Only one
In footrot, typically the claws are ______, and the inflammatory edema is ________ between the two digits
markedly separated
uniformly distributedd
In footrot, the skin of the interdigital space first appears ______; later it _______
discolored
fragments with exudate production
What are the clinical findings of footrot if the disease proceeds unchecked?
weight loss is severe
milk yield is significantly reduced
What is treatment and control of footrot?
penicillin G, footpath with antiseptic
local treatment - essential for longstanding cases
How do you prevent footrot?
footpath with an antiseptic
vaccines - 60% effective
high levels of zinc fed as a supplement
A sheep was diagnosed with infectious footrot and is unable to stand as a result. Identify the source of infection and causative agent
source: discharge from active or chronically infected sheep
dichelobacter nodosus
What is the source of d. nodosus in sheep flocks?
discharge from the active or chronically infected sheep
introduction of a carrier sheep
A young Merino sheep is struggling to bear weight on its left pes. Gram-stained smear reveals this image. Note the classic swollen ends of the organism. What is the virulence factor for this disease?
fimbrae type IV
(dichelobacter nodosus in Infectious footrot in sheep)
How do you diagnose infectious footrot in sheep?
