Heartwater

  • Severe disease of ruminants in sub-Saharan Africa caused by Cowdria ruminantium
  • Vectors include Amblyomma ticks
  • Carrier status can occur for up to 8 months in adult cattle and wildebeest
  • Clinical disease in calves and lambs
  • Clinical signs
    • Incubation period 4 weeks
    • Acute fever
    • Neurological signs including chewing, twitching of eyelids, circling, high-stepping gait, convulsions and recumbency; can be fatal
    • Subacute cases suffer from hydropericardium, hydrothorax and pulmonary oedema and congestion; splenomegaly and haemorrhages may occur
  • Diagnosis
    • Clinical and post mortem findings in endemic areas suggestive
    • Orgnisms present in nuclei of endothelial cells in Giemsa-stained brain tissue
    • PCR, indirect immunofluorescence, ELISA and western blot
  • Treatment and control
    • Tetracyclines during early disease
    • Immunisation using infected blood