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Bovine anaplasmosis
Anaplasmosis is a blood disease of cattle. A microorganism settles inside the red blood cells; the body then destroys them en masse, which sometimes causes brutal anemia. It is transmitted by ticks and biting flies, but also, and this is pa...
What is it?
Anaplasmosis is a blood disease of cattle. A microorganism settles inside the red blood cells; the body then destroys them en masse, which sometimes causes brutal anemia.
It is transmitted by ticks and biting flies, but also, and this is particular, by any material soiled with blood passed from one animal to another.
Unlike many diseases, it is all the more serious the older the animal: calves develop discreet forms, adult cows have severe forms.
Key point
Potentially fatal disease in adult cattle. The speed of support makes the difference.
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:
Fever, then progressive pallor of the mucous membranes of the eyes and gums.
Marked depression, animal which stays behind the herd and runs out of steam at the slightest movement.
Loss of appetite, cessation of rumination, sharp drop in milk production.
Rapid breathing and a fast heartbeat, the body trying to compensate for the lack of red blood cells.
Yellow discoloration of the mucous membranes in some animals.
The urine remains normal in color: this is a point that helps the veterinarian distinguish anaplasmosis from babesiosis.
Abortion in pregnant females.
In severe forms, the animal can suddenly become agitated or aggressive due to lack of oxygen: approach it with caution.
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 disease is caused by a very small bacteria that parasitizes inside red blood cells.
It is not the globules destroyed by the bacteria itself that explain anemia, but their massive elimination by the animal's defenses.
The time between contamination and the first signs is long, often several weeks: the disease therefore appears well after exposure to ticks or after handling the herd.
Age: adult cattle have much more serious illnesses than calves.
Animals introduced from a disease-free region into an area where the disease is circulating.
Seasons of high activity for ticks and biting flies.
Group interventions on the herd carried out without changing the needle or disinfecting the equipment.
Stress: transport, calving, change of diet, other ongoing illness.
Transmission
By ticks, which are the main natural vector.
By biting flies and horseflies, which carry blood from one animal to another.
By equipment soiled with blood: reused needles, dehorning equipment, castration, tattooing, trimming. It is a frequent and completely avoidable route of contamination.
From mother to calf during gestation in some cases.
Cured animals remain carriers for life and constitute a silent reservoir for the rest of the herd.
There is no contagion through simple contact, nor through consumed milk, nor to humans.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian first assesses the severity of the anemia: pallor of the mucous membranes, heart and respiratory rate, the animal's ability to move.
A blood smear observed under a microscope allows you to see the bacteria inside the red blood cells. Additional blood tests exist to detect carriers.
A blood test measures the degree of anemia and monitors its progress.
Handle a very anemic animal as little as possible: simply making it walk can cause it to collapse.
Report to the veterinarian recent interventions on the herd (dehorning, vaccinations, blood tests): they guide the investigation.
Treatment
Treatment is based on antibiotics from the tetracycline family, prescribed and monitored by the veterinarian.
Supportive care is decisive: strict rest, clean water and quality fodder within reach, shelter in the shade, handling reduced to a minimum.
A blood transfusion can save a very anemic animal when possible.
Early treatment gives much better results: waiting until the animal is lying down greatly reduces the chances.
Waiting times for milk and meat must be respected; only the prescribing veterinarian can specify them for you.
A cured animal generally remains a carrier: it will not become sick again, but it can be a source of contamination for others.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Fight against ticks and biting flies: treatment of the herd on veterinary advice, management of manure and stagnant water points where flies develop.
One needle per animal. This is the simplest and most effective measure to cut off a major contamination route.
Cleaning and disinfection of dehorning, castration and trimming equipment between each animal.
Quarantine of animals purchased, with veterinary examination before introduction.
Vaccines exist in some countries, but they are not available everywhere and do not provide hygiene and vector control measures. Ask your veterinarian what is available in your area.
Possible complications
Severe anemia with animal lying down, unable to get up.
Significant mortality in adult cattle not treated in time.
Abortion and temporary infertility in females.
Fall in milk production which continues for several weeks after recovery.
Long-lasting weight loss and slow recovery.
When to see a veterinarian
The mucous membranes of a cow's eyes or gums are pale or yellow.
An adult animal is brutally slaughtered, becomes out of breath while walking and has stopped eating.
Several animals in the group show the same signs a few weeks after a group intervention on the herd.
A pregnant cow aborts without obvious cause.
A bovine remains lying down and never gets up: it's an emergency, don't force it to walk.
Prognosis
Treated early, most cattle recover, but recovery and production takes several weeks.
In an adult animal discovered at the lying stage, the prognosis is guarded despite treatment.
Calves almost always recover and become immune carriers.
In a breeding farm where the hygiene of the interventions and the fight against vectors are serious, the cases remain isolated.
Frequently asked questions
My cows got sick after dehorning: is it a coincidence?
Probably not. Anaplasmosis is transmitted very well through blood-stained equipment, including needles. As the signs appear several weeks later, the link with the intervention often goes unnoticed. One needle per animal and disinfected equipment eliminate this risk.
Why aren't calves sick but cows are?
This is a particularity of this disease: young cattle develop discreet forms and become immunized, while adults who encounter the bacteria for the first time develop serious forms. A herd exposed young is therefore more solid.
How to distinguish it from babesiosis?
Both cause fever and anemia, but babesiosis is typically accompanied by very dark urine, while anaplasmosis is not. Only a blood examination under a microscope allows you to decide: do not treat randomly, the treatments are not the same.
Is a cured cow permanently freed?
She will generally not get sick again, but she remains a carrier and can contaminate other animals through ticks, flies or a reused needle.
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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