Babesiosis - Cattle

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  • Cattle
    • Sudden onset
    • Often fatal if untreated
    • Causes 'pipestem' faeces
    • Clumping of red blood cells in brain capillaries can occur causing neurological signs

Epidemiology

  • Determined by:
    • Number of infected ticks seeking a blood meal (tick pressure)
    • Calves under 9 months are refractory to disease
      • Can develop immunity if exposed without showing clinical signs
    • 'Premunity' (a good protective immunity) develops quickly in infected cattle causing a 'carrier state'
    • Immunity can wane in the absence of re-infection
    • Uninfected cattle remain susceptible
  • Predisposing factors:
    • Susceptible animals introduced into an infected area
    • Infected ticks introduced into a clean area
    • Infected cattle introduced into an area with clean ticks
    • Temporary reduction in the tick population decreasing the transmission rate (causing enzootic instability)
    • Infected are transported or stressed in other ways, e.g. parturition
  • In the UK
    • Sporadic disease
    • Enzootic instability
    • Occurs mostly during the spring and autumn during periods of greatest tick activity
    • Occurs mostly in stressed cattle under 2 years old on rough grazing
    • B. divergens the most common species
    • Ixodes ricinus is the vector
    • Trans-ovarial transmission to the next generation occurs
    • B. major occurs in South East England but is not pathogenic
  • Overseas
    • B. bovis causes considerable losses in cattle in many tropical and sub-tropical areas
      • In Australia an attenuated vaccine is used
      • Vector is Boophilus
    • B. bigemina causes problems in Africa and South America