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Sudden death in lambs - Coggle Diagram

- - - - Mannheim haemolytica ('septicaemiac pasturella')
        
        Clinical signs
        
        depression
        
        endotoxaemia
        
        pleurisy
        
        haemorrhage
        
        12 serotypes
        
        signalment
        
        adult sheep
        
        lambs <12w
      - Bibersteinia trehalosi
        
        Causes
        
        movement
        
        Diet change
        
        august-september
        
        death 7-10d post infection
        
        systemic haemorrhage
        
        necrotic infarcts
      - Mycoplasma ovipneumoniae ('atypical pneumonia')
        
        Clinical signs
        
        generally mild symptoms
        
        non progressive
        
        chronic
        
        hepatisation
        
        abscesses
        
        soft cough
        
        periods of housing
        
        Histology
        
        lymphocytic cuffing
        
        hyperplasia bronchial epithelium
    - - Stress induced
      - commensals
      - housing
      - border disease
      - change of nutrition
      - climatic
    - - vaccination
        
        1st dose 3-6w
        
        2nd dose 4-6w later
        
        Heptavac P
        
        Lamb dysentry (<1w)
        
        Clostridium perfringens type B
        
        unvaccinated dams or lambs up to 3w.
        
        High milk intakes can predispose
        
        outbreaks can occur in unhygienic conditions
        
        Older lambs may show signs of abdominal pain +/- haemorrhagic diarrhoea before death
        
        pulpy kidney (lambs 3+ w)
        
        Clostridium perfringens type B
        
        fast growing lambs after waning of maternal immunity
        
        outbreaks occur after a change to a better diet
        
        sporadic cases in adult sheep esp. tups
        
        struck (fast growing lambs, older)
        
        tentanus (all sheep)
        
        clostridia metritis
        
        blacks disease (all sheep)
        
        black leg (all sheep)
        
        Mannheimia haemolytica - bacterial pneumonia (lambs)
        
        Pasteurella trehalosi - septicaemia pasteurella (lambs)
        
        Ovivac P
        
        Blacks disease
        
        Tetanus
        
        Pulpy kidney
        
        Braxy
        
        Mannheimia haemolytica - bacterial pneumonia (lambs)
        
        Pasteurella trehalosi - septicaemia pasteurella (lambs)
      - Desirable due to economic cost of treatment, losses and reduction of weight gains in survivors
    - - differentiation from other causes of respiratory disease is based on high mortality and rapid progression to death
      - necroscopy examination
        
        gross and histopathologic findings
        
        lesions
        
        subcutaneous haemorrhage
        
        epithelial necrosis
        
        tongue
        
        pharynx
        
        oesophagus
        
        occasionally abomasum and intestine
        
        Enlargement of tonsils and retropharyngeal lymph nodes
        
        peracute, multifocal, embolic necrotising lesions in lung and liver
        
        PCR analysis of lung tissue better than microbial culture to identify presence of M haemolytica, B trehalosi and P. multicoda
    - - early identification and effective antibiotic therapy
      - often unrewarding due to rapid lung damage and endotoxin release
      - parenteral fluids and anti-inflammatory agents important adjuncts.
- - - - predominantly via aerosol route by inhalation of infected respiratory secretions
      - also colostrum and milk
    - - weight loss
      - crackles
      - dyspnoea
      - copious amounts of serous nasal discharge
    - - 'wheelbarrow test'
        
        causes considerable distress, stop as soon as clear fluid from nostrils - euthanasia if positive result
        
        Not all cases of OPA produce fluid in detectable amounts
        
        fluid may be seen when lowers head to feed
      - USS
        
        superficial lung lesions
        
        changes in superficial lung parenchyma
- - - - very high egg counts
    - - hibernates within ewe
    - - anaemia
      - scour (rare)
      - Bottle jaw (caused when low blood protein levels)
        
        oedema in the intermandibular space
  - - - ewe not involved in infection to lamb
    - - most disease is before eggs produced