Babesia

Epidemiology

• Infects a wide range of host species in different areas of the world

Babesiosis has severe effects on cattle production in parts of the world. First of all, it prevents European breeds from being successful in tropical regions where ticks are endemic as well as occurring sporadically in the UK and Ireland causing losses of around £8 million per year.

Life Cycle

Both trans-stadial and trans-ovarian transmission occurs with each female tick producing 3000 eggs and the tick being the definitive host.

Babesia multiplies in the red blood cells by budding and it forms 2-4 daughter cells (species dependent). Giemsa blood smears can differentiate between species using 'Difquik' stain.

• Babesia species are either small or large depending on the size of the daughter cells

• Small Babesia
  • E.g. B. divergens
  • E.g. B. gibsoni
  • Peripheral nucleus
  • Obtuse angle

• Large Babesia
  • E.g. B. major
  • E.g. B. canis-complex
  • Central nucleus
  • Acute angle

• Daughter cells disrupt the red blood cell and are released
  • Spread and infect other red blood cells

• Antigen is released which adsorbs onto other red blood cells
  • Causes haemolysis and haemoglobin pigmentation
  • Causes haemolytic anaemia, haemoglobinuria and fever

Enzootic Instability

• Low rate of transmission

• Few infected ticks

• Infrequent exposure

• Immunity wanes or is completely absent in many individuals

• Low levels of herd immunity

• Higher incidence of disease

Enzootic Stability

• High rate of transmission

• Many infected ticks

• Frequent exposure boosts immunity

• High level of herd immunity

• Lower incidence of disease

Cattle Babesiosis

Babesia canis

Horse Babesiosis

Sheep and Goat Babesiosis

• Babesia bovis myositis
  • In cattle
  • Infrequent muscle necrosis

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