Babesiosis

Figure 1. Schematic of a blood smear from a cow infected with Babesia bovis. Image courtesy of the Tick Fever Centre
Figure 1. Schematic of a blood smear from a cow infected with Babesia bovis. Image courtesy of the Tick Fever Centre

Babesiosis (also known as red water) is caused by either of the organisms Babesia bovis or Babesia bigemina, both of which are transmitted by the cattle tick. Babesia bovis is only transmitted by cattle tick larvae on pasture; Babesia bigemina is transmitted by the nymph or adult stages of cattle tick.

Babesia bovis (Figure 1) is the most important cause of tick fever disease in Australia; it is responsible for more than 80% of tick fever outbreaks. The course of the disease is quite rapid, and death can occur within a day or two of first observing clinical signs.

Signs

  • Fever, lethargy, depression and weakness.
  • Pale and/or yellow mucous membranes (anaemia and/or jaundice).
  • Loss of appetite.
  • Staggered gait.
  • Muscle tremors.
  • Red urine (especially with B. bigemina; in latter stages with B. bovis).
  • Nervous signs such as charging or head pressing may be a feature of the later stages of Babesia bovis infection.
  • Abortion may occur in cows.
  • Temporary infertility in bulls.

Diagnosis

Many of these clinical signs are non-specific and can be associated with other conditions, so it is important to confirm the diagnosis by examination of blood smears under a microscope.

Treatment and control

See these pages for the treatment and control of tick fever.