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1.22.2.10 - Circulation, Blood Brain Barrier and Infection - Coggle Diagram

- - - - Bacteraemia
      - Viraemia
    - - Intra-axonal modes of spread
      - This is a risk to CNS, as there is a blood vessel for every neuron, meaning the pathogen can get into the nervous system once it is in the bloodstream.
- - - - Have host cell binding proteins that bind receptors on endothelial cells. These are essential for infection to progress
    - - Have adhesion molecules
      - These are common surface proteins - e.g Pili or outer membrane proteins that increase adhesion of bacteria to cells
      - The binding may trigger specific invasion mechanisms
      - Once inside the cell the bacteria require virulence factors to survive and acquire nutrients in the intracellular environment
- - - - Depression
      - Pyrexia
      - Cervical pain
      - Hyperaesthesia
      - Photophobia
      - Generalized rigidity
      - Seizures
      - Paralysis local and general
      - Ataxia
      - Papilloedema
      - Possible ophthalmic inflammation.
      - Systemic signs: Septic shock and brachycardia.
    - - Glucose - will decrease
      - Specific gravity - will increase
      - Immunology via serology or cytology
      - Microbiology
      - Enzyme analysis for cell breakdown
- - - - It is relatively labile: sensitive to heat, desiccation, lipid solvents and non-ionic detergents and disinfectants. Therefore isolation of affected animals and disinfection can help control outbreaks
      - Vaccines : H protein can be used to induce neutralising antibodies
  - - - Ocular and nasal secretions
      - Confirmation by PCR recommended
      - Pen site test
    - - 1-3 working days
      - Quantitative measure of viral load- allows the test to discriminate vaccine interference from infection with a wild-type strain of distemper virus
      - The amount of virus during infection is typically exponentially more than would be detected because of recent vaccination
- - - - Incubation period of neural listeriosis ranges from 14 to 40 days
      - Dullness, cirlcing and tilting of head facial paralysis
      - Unilateral facial paralysis can result in drooling and droppinig of eyelids and ears
    - - Do not feed poor silage
      - Ensure feed method used reduces ocular contact
      - Vaccines do not work as the pathogen is intracellular
- - - - Tetanus (Clostridium tetani).
      - Botulism (Clostridium botulinum).
      - Oedema disease (E. coli) (see CAR Bacteria –Host interaction lecture).
    - - Rye grass staggers (Neotyphodium lolii fungal endophyte - New Zealand).
      - This occurs sporadically in UK with imported rye grass.
    - - Algae
    - - Lead
      - Arsenic
      - Organophosphates
  - - - Toxin presence confirmed by PCR assay of bacterial DNA from wound tissue.
      - Clinical evaluation.
    - - A vaccine is available for horses (most will be vaccinated) and cattle.
      - Early intervention, including wound cleaning, boosting immunity, parenteral antitoxin administration, and muscle relaxants.
      - Any horse with a wound that is not vaccinated will be treated with antitoxin prophylactically.
      - Supportive therapy  Monitor for return of normal clinical parameters.
      - Antitoxins that neutralize circulating toxin are only effective before the toxin has entered the nerve terminals.
      - Recovery is by axonal sprouting and re-innervation  Slow (up to 3 months)
  - - - Supportive therapy  Monitor for return of normal clinical parameters.
      - Antibiotics are not advocated as they will have little effect on bound toxins.
      - Euthanasia
      - In ruminants, clinical signs will not resolve until the neurotoxin has decayed; this will take a number of weeks/months.  usually impractical to attempt nursing for this period of time and consideration must be given to the welfare implications for the affected animal.