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.
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.