98. Malignant oedema. Flashcards
Occurrence aetiology epidemiology?
Occurrence: worldwide, rare, sporadic, not uniform
Aetiology:
- C. septicum (toxins: alpha, beta, gamma, delta ʹ same effect as blackleg) Most common
- C. novyi: toxins & EC enzyme lipase/lecitinase
- C. sordelli: toxins (rare alone but can be in combo)
- C. histolyticum toxins & EC enzyme protease Most widespread
- different bacteria can cause practically the same disease
Epidemiology
o Wound infection = place of entry (soil faeces)
o Sporadic, but can be aggregated (sharing, castration etc)
Pathogenesis and clinical signs?
Pathogenesis
o Infection wound Æ muscles: oedema, gas, necrosis
o Effect of toxins Æ death
o Course depends on the agent, toxins and virulence factors
Clinical signs (same for all bacteria)
o Incubation 1-2 days
o General: Fever, depression, anorexia, dyspnoe
o Around wound: oedema, swell, skin necrosis
o Movement problems
o Foals: haemorrhagic diarrhoea
PM lesions?
PM lesions
o Depend on the agent:
- C. septicum: haemorrhagic lesions, gas bubbles
- C. novyi: no gas bubbles
- C. histolyticum: haemorrhagic lesions, histolysis
o Gas bubbles, muscle dystrophy, necrosis
o Foals: haemorrhagic enteritis
Diagnosis?
Diagnosis
- Epidemiology
- clinical signs
- PM lesions
- Detection of the agent:
- Bacterium culture (identification),
- staining (different dye colours for different bacterial sp.),
- IF,
- PCR,
- can appear as Cl septicum in PM!
Differential diagnosis treatment and prevention?
Differential diagnosis:
- blackleg,
- purulent lesions,
- abscesses,
- anthrax,
- pasteurellosis,
- bluetongue
Treatment:
- wound toilette,
- disinfection,
- Diarrhoa: atbs, fluid therapy
Prevention, control:
- prevention of wounds,
- in case of wounds:
- AB treatment,
- vaccination (anatoxin & anaculture)
