These information sheets are provided for your interest. They should not replace veterinary advice from your veterinary surgeon.

Whilst every effort is taken to ensure the accuracy and completeness of the information provided at the time of writing, your specific circumstances must be discussed before advice can be given.

Babesiosis (Red Water)

Babesiosis is a tick-borne infection that is fatal in a high proportion of cases. It is caused by a protozoan called Babesia and is found wherever ticks are prevalent. Ticks become infected when they feed on infected cattle and can pass Babesia onto the larvae they produce. Babesiosis is commonly called ‘Red Water’ as it causes the urine to develop a red colour.

Clinical Signs

  • Young animals appear to be fairly resistant to infection with Babesia, and are often asymptomatic
  • Affected animals separate from the herd and stand hunched with an arched back
  • Fever
  • Roughened hair coat
  • Dyspnoea (difficulty breathing)
  • Tachycardia (increased heart rate)
  • Mucous membranes are initially red but as the disease progresses they become pale, due to the disease causing breakdown of red blood cells leading to anaemia
  • Breakdown of red blood cells is often associated with haemoglobin (the red pigment in blood cells) being passed in the urine, giving urine a red colour
  • Elevated heart rate and respiratory rate due to anaemia resulting in lowered capacity to carry oxygen around the body
  • Anorexia
  • Depression
  • Abortion
  • Death

Laboratory diagnosis requires examination of blood smear prepared from a sample collected into an EDTA tube.


One dose of a specific drug active against protozoa (Imizol) is used, and this should clear the infection. A disadvantage of this drug is the long withdrawal periods – meat must be withheld for 213 days and milk must be withheld for 21 days. When a treated animal goes for slaughter, or when milk is sold from a treated animal, the owner must inform the Divisional Veterinary Officer at Animal Health.