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Bovine babesiosis
Bovine babesiosis is a blood disease transmitted by ticks. A microscopic parasite enters red blood cells and causes them to burst. The released hemoglobin passes into the urine and colors it dark red or brown: this is the sign which gave th...
What is it?
Bovine babesiosis is a blood disease transmitted by ticks. A microscopic parasite enters red blood cells and causes them to burst.
The released hemoglobin passes into the urine and colors it dark red or brown: this is the sign which gave the disease its popular name red urine.
A separate sheet exists for canine piroplasmosis: these are different parasites, and a disease is not transmitted from one species to another.
Key point
Veterinary emergency: dark urine associated with fever requires a call the same day.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
High fever, often the first sign, before the breeder even notices anything else.
Dark urine, dark red to brown, in a large proportion of affected animals.
Mucous membranes of the eyes and gums initially pale, then sometimes yellow.
Dejection, loss of appetite, cessation of rumination, sudden drop in milk production.
Rapid breathing, animal that runs out of breath at the slightest effort.
Abortion in pregnant females.
In certain forms, nervous signs appear: staggering gait, restlessness, animal turning or lying down without being able to get up.
Ticks are often visible on the animal.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The culprit is a microscopic parasite of the Babesia genus, inoculated by the bite of a tick.
It multiplies in red blood cells and causes their destruction, resulting in anemia and discoloration of urine.
Several species of babesia affect cattle; some also cause nervous disorders by obstruction of the small vessels of the brain.
Adult cattle which have never encountered the parasite: imported animals, animals coming from a region free of ticks, or from a farm previously protected from ticks.
Selected dairy breeds, generally more susceptible than local breeds.
Conversely, calves exposed very early become immunized by developing mild forms: this explains why local herds live with the parasite without visible cases.
Bushy pastures and hot periods, where ticks abound.
The stress of transport and the change of environment, which often causes the disease to appear in a newly arrived animal.
Transmission
Only by ticks. There is no direct contagion between cattle, neither through milk nor through contact.
The tick transmits the parasite during its blood meal; certain species of ticks transmit it to their own offspring, which maintains the infection on a plot from one year to the next.
The disease therefore follows the tick season: it appears mainly from late spring to fall.
A cured animal can remain a carrier of the parasite without being sick.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
Inform the veterinarian as soon as you notice a fever with dark urine: this is an emergency.
The clinical examination assesses anemia, temperature, circulation status, and looks for ticks on the animal.
The diagnosis is confirmed by a blood smear observed under a microscope, where the parasite is visible in the red blood cells. More in-depth laboratory analyzes exist.
Dark urine can have other causes: only the veterinarian can tell the difference, never treat yourself based on this sign alone.
Avoid moving or exciting a very anemic animal.
Treatment
There are specific antiparasitic treatments for babesiosis, reserved for prescription and follow-up by the veterinarian.
The earlier the treatment, the better the result: a few hours can count in acute forms.
Supportive care is essential: rehydration, complete rest, shelter, water and palatable fodder within immediate reach.
A blood transfusion can be lifesaving in a very anemic animal.
Any ticks present must be eliminated with a suitable acaricide, without crushing them with bare hands.
Withdrawal periods for milk and meat apply to all these products: ask the prescribing veterinarian and respect them.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Prevention involves above all controlling ticks: regular inspections of animals in the hot season, removal of ticks with a hook or pliers, acaricide treatments for the herd according to a schedule established with the veterinarian.
Pasture management: maintenance of brushy areas, rotation of plots, caution with plots known to be infested.
Closely monitor newly introduced animals during their first tick season, when they are most vulnerable.
Quarantine and examination of any purchased animal.
Alternation of acaricide families on veterinary advice: systematic use of the same product ends up selecting resistant ticks.
Live vaccines exist in some countries, but they are not available everywhere; the fight against ticks remains the basis.
Possible complications
Profound anemia with lying animal that no longer gets up.
Kidney damage linked to massive destruction of red blood cells.
Nervous form, with a very poor prognosis, with gait disorders and convulsions.
Abortion in pregnant females.
Long-lasting drop in milk production and weight loss in cured animals.
When to see a veterinarian
A cow's urine is red, brown or abnormally dark: call the veterinarian immediately.
An animal has a fever, stops eating and becomes out of breath while walking during tick season.
The mucous membranes of the eyes or gums are pale or yellow.
A bovine staggers, turns in circles or remains lying down without getting up: absolute emergency.
A recently purchased or imported animal shows any of these signs.
Prognosis
Treated at the first signs, the disease cures in a good proportion of cases, with convalescence lasting several weeks.
Discovered late, in an animal collapsed or showing nervous signs, it often remains fatal.
Local cattle exposed young develop robust immunity and have few serious cases.
A cured animal is generally protected for a time, but this protection is not permanent.
Frequently asked questions
My cow's urine is red: is it necessarily babesiosis?
No. Several diseases can discolor urine, and the treatment is not the same. This is a major warning sign that requires calling the veterinarian the same day, but the diagnosis is made by a blood test.
My dog had piroplasmosis: can it contaminate my cows?
No. The parasites responsible are not the same and each remains in its own species. On the other hand, the presence of ticks on the dog indicates that ticks are circulating on the farm, which also concerns the herd.
Why are my local cows never sick while the imported ones are?
Because they encountered the parasite very young, at an age when the disease remains mild, and they have become immune to it. An adult animal that discovers the parasite develops an acute form.
Should the entire herd be treated preventively every year?
No, not blindly. Systematic treatment without reason selects resistant parasites and ticks and costs a lot of money for nothing. The control schedule is decided with the veterinarian, depending on the tick pressure and the breeding history.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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