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Clostridia (Understand the clinical significance of clostridial disease in…
Clostridia
Understand the clinical significance of clostridial disease in domestic and wild species
Pathogenesis
Neurotropic:
C.tetani and C.botulinum
All species
Histotoxic (damage to tissue)
C.perfringens, C.sordelli, C.colinum,
C.chauvoei and C. novyi
Cattle, sheep, pigs, horses and poultry
Enterotoxaemias
C.perfringens
Most species
Antibiotic induced diarrhoea
C.difficile and C.spiroforme
Rabbits, guinea pigs, hamster, foals, pigs, dogs and laboratory animals
Cattle
Table
C.chauvoei
Gangrenous processes in the muscle -
causes damage to the carcass
Economic problem - subclinical
Other species to
Sudden death
Black gut/neck/leg/liver
Malignant oedma
Redwater
Sheep
Acute
C.septicum
Inflammation of abomasal wall
Generalised oedema
C.septicum - Braxy, malignant
oedema and necrotic dermatitis
Wildlife
May see in birds in the summer
Botulism
Enterotoxaemias
Sudden death
Enterotoxaemias
Sheep, lambs, calves, piglets
Occasionally foals
Acute and highly fatal
Alpha toxin
Lechithinase
Attacks cell membranes causing
cell death and destruction
Beta toxin
Lethal and necrotising
Epsilon toxin
Protoxin activated in the
intestine by proteases
Increase gut permeability
Damages vascular endothelium
Iotat toxin
Protoxin
Pathogenesis not well understood
Horses
Tetanus =
C.tetani
Enteritis
C.perfringens/difficle
Wound infections =
C. perfringens
C.septicum
C.chauvoei
C.sporogenes
Enteritis and wound infection
Anerobic and flesh eating
Airate
Pigs
Sudden death
C.novyi
Considered if sow death
rises above 4%
Enteritis
C.perfringens
Piglets
Sows
Weaners
Growers
Sows
Sudden death
Gangrene characterised by painful
and discoloured swellings
Fluid and gas are often present in the tissues
Piglets
Diarrhoea 0-5 days of age
Rotten smelling watery diarrhoea
often blood stained with mucus
Diarrhoea 6-21 days of age
High mortality
Necrosis of the small intestine
May be scouring
Gas in small intestine at PM
Weaners and growers
Sudden death in growing pigs
Haemorrhage - faeces
Diarrhoea
Painful and discoloured swellings over muscle masses
Gangrene
Poultry
Necrotic enteritis
Chickens
Turkeys
Ducks
Wild birds
C.perfringens type A and C
Intestinal necrosis and
Cholangiohepatitis
Kidneys often have pale,
prominent lobular outlines
Most common
17-20 days
May occur in 7 day chicks
Predisposing factors
Feed:
Rye, barley, wheat, fish meal
Coccidiosis
Aid clostridia in gaining access to nutrinss
Survive well on degraded parts of cells
Viral infection
Husbandry practices
Breed?
Pathogenesis poorly understood
Clinical signs
Acute forms = Death
Mild
Ruffled feathers
Huddle
Depressed and can stop eating
Untreated - duration = 2 weeks
Severe
Small intestine severe
necrosis and haemorrhaging
Bacteria can enter the peritoneum
Same as coccidia
Control measures
Biosecurity
Effective cleaning and disinfection - spores
fumigating with formaldehyde
Careful selection of antibiotic treatment
Effective pasture management
Remove predisposing factors
Companion animals
Antibiotic induced diarrhoea is common
in rabbits, hamsters, guinea pigs
All coprophagic
Re- digestion kills bacteria in the caecum
Give with probiotic
Rabbits
Tyzzr disease
C.piliforme
Profuse watery diarrhoea, anorexia, lethargy, staining of the hindquarters and death within 1-3 days in weaning rabbits 6-12 weeks old
Acute outbreaks
Greater than 90% mortality
Rabbits:
Mucoid enteropathy
Diarrhoea
Unknown cause
Minimal inflammation, hypersecretion, accumulation f mucus in the small and large intestine (blocks intestine)
Exotics = Underdiagnosed
Vaccination
Cattle blackleg
Pigs
Shhep and goats:
8 different species including tetanus
Horses - tetanus
Diagnosis
Farm history
Clinicl signs and history
PCR
Culture
Gross and histopathological findings
Epidemiology
Worldwide distribution
Incidence varies - depends in vaccination etc...
Understand how to identify and culture clostridia species
Gram positive
Capsulated
Anaerobic
Endospore producing
May distend the cell
Oval or spherical
Dry can survive for many thousands of years
Middle of cell
Rods
Motile
Flagella
Not clostridium perfringens
Haemolytic
Enterotoxins
Clostridium perfringens:
5 types A-E
C.tetani:
Tetanolysin = Lysis or RBCs
Tetanospasmin = Neurotoxin
C.difficle:
Most common
Toxin A
Enterotoxin
Toxin B:
Cyttoxic activity
C.botulinum:
7 types of neurotoxin
Man susceptible to:
A,B,E,F,G
Animals susceptible to:
A,B,C,D
C.sordelli
Lecithinase
Fibrinolysin
Oxygen liable haemolysin
Beta toxin:
Lethal
C.novyi
3 types
A and B
C non-pathogenic
Found in envoronment and intestines of health and animals
Commensal
Family:
Clostridiaceae
203 species
5 sub species
Culture
Blood agar 40-48 hrs
Anaerobically
35-37 degrees C
Egg Yold agar 16-24 hrs
Robertson's cooked meat broth 16-24 hrs
Many selective medias available
Identification:
Alpha and beta haemolysis
Most are beta haemolytic