Anaplasmosis in dogs (also called canine anaplasmosis) is an infectious tick-borne disease caused by bacteria of the genus Anaplasma. These tiny, obligate intracellular bacteria invade either white blood cells or platelets, depending on the species, and trigger illness in dogs.
What Is Anaplasmosis in Dogs?
Anaplasmosis is essentially a tick-borne illness. When an infected tick bites your dog, it can transmit Anaplasma bacteria into the bloodstream. There are two main species of Anaplasma that affect dogs: Anaplasma phagocytophilum and Anaplasma platys. The former invades neutrophils (a type of white blood cell), causing canine granulocytic anaplasmosis, while the latter infects platelets (blood-clotting cells), leading to a condition called cyclic thrombocytopenia.
Some dogs infected with anaplasmosis never become sick at all; their immune system keeps the infection silent. Others develop symptoms ranging from mild (fever, lethargy) to severe (bleeding disorders). In either case, anaplasmosis is treatable.
What Causes Anaplasmosis in Dogs?
Anaplasmosis is a type of tick fever caused by the Anaplasma bacteria. In dogs, two main species are involved: Anaplasma phagocytophilum, which infects neutrophils and can also infect humans, and Anaplasma platys, which infects platelets and causes periodic drops in platelet count.
The bacteria are spread through tick bites, as they live in tick saliva and enter the dog’s bloodstream during feeding.
Worldwide, A. phagocytophilum is mainly spread by black-legged ticks, while A. Platys is spread by the brown dog tick. In India, the brown dog tick is common and is likely the main carrier. Rarely, the infection can also spread through blood transfusions.
Understanding the causes of anaplasmosis starts with proper testing at our dog diagnostics.
Types of Anaplasmosis in Dogs
There are two clinically important forms of canine anaplasmosis, each caused by a different Anaplasma species.
Anaplasma Phagocytophilum (Granulocytic Anaplasmosis)
This species infects neutrophils (a type of white blood cell) and can also infect humans. It is more common in the U.S. and Europe and is reported less often in dogs in India. Dogs usually show signs about 1–2 weeks after a tick bite.
Anaplasma Platys (Cyclic Thrombocytopenia)
This species infects platelets and causes periodic drops in platelet count, typically every 1–2 weeks. In many dogs, the infection is mild or causes no obvious illness, especially when it occurs alone.
How Is Anaplasmosis Transmitted?
Dogs get anaplasmosis mainly through tick bites. In India’s warm climate, ticks can be active all year, with the brown dog tick (Rhipicephalus sanguineus) being the most common carrier. Other ticks, like Ixodes and Dermacentor, are present but play a smaller role.
An infected tick must stay attached for about 24–48 hours to transmit the bacteria. Regular tick checks and quick removal (pulling the tick straight out, close to the skin) can greatly reduce the risk.
Rarely, anaplasmosis can also spread through infected blood transfusions, which is why donor dogs are screened.
What Are the Symptoms of Anaplasmosis in Dogs?
Signs and symptoms of anaplasmosis can range from none to obvious illness and usually appear 1–2 weeks after infection. Many dogs show only mild signs, so careful observation is important.
Common Symptoms:
- Fever
- Lethargy and poor appetite
- Joint pain or shifting lameness
- Swollen lymph nodes or spleen
- Bleeding signs (mainly with A. platys): bruising, nosebleeds, or bleeding gums
These signs can look like other tick-borne diseases, so vets often test for several infections together.
Less Common or Severe Symptoms:
- Vomiting or diarrhoea
- Coughing or breathing difficulty
- Rarely, neurological signs such as twitching or seizures
- Severe bleeding if platelets drop very low
If your dog shows symptoms of anaplasmosis, book a dog consultation.
Can Some Dogs Be Asymptomatic?
Yes, many dogs infected with Anaplasma show no outward illness. In other words, your dog might carry the bacteria and have antibodies, yet never lose appetite or energy.
When Should You Contact a Veterinarian?
If you notice any of the above symptoms in your dog, especially fever, lethargy, loss of appetite, unexplained lameness, or bleeding, contact your vet right away. Also, see a vet if you find a tick bite on your dog and the dog starts acting sick within the next couple of weeks.
Even without noticeable symptoms, mention any recent tick exposure to the veterinarian, so they can consider anaplasmosis in their evaluation.
A simple rule of thumb: fever or dullness lasting more than 24 hours is a good reason for a check-up.
When in doubt about your dog’s health, get help at our dog emergency care.
How Is Anaplasmosis Diagnosed in Dogs?
Anaplasmosis is diagnosed using a mix of history, clinical signs, and blood tests.
- Physical exam & history: The vet checks for fever and swollen lymph nodes and asks about tick exposure or recent travel.
- Blood tests (CBC): Often show low platelets, especially with A. platys. White blood cells may be low or normal.
- Blood smear: May show Anaplasma within cells, but this is not always visible and is not very reliable on its own.
- Antibody tests (ELISA/IFA): Rapid tests can detect exposure, but they cannot tell if the infection is current or past.
- PCR testing: Confirms active infection by detecting bacterial DNA and can identify the species.
Vets often use a rapid test first and follow up with lab tests if needed. Timing matters because very early testing can miss the infection, so repeat or PCR testing may be advised if suspicion remains.
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How Is Anaplasmosis Treated in Dogs?
Main Treatment:
- Canine anaplasmosis is treated with a specific antibiotic prescribed by the veterinarian.
- The usual dose is given once or twice daily for about 2–4 weeks, depending on the case.
Response to Treatment:
- Most dogs begin to improve within 1–2 days of starting medication.
- It is important to complete the full course (usually 14–28 days) to fully clear the infection.
Alternatives:
- If the first-choice medicine is not suitable, the vet may prescribe a similar antibiotic for the same duration.
Supportive Care:
- Pain relief or anti-inflammatory medicines may be given for joint pain or lameness.
- Fluids may be needed if the dog is dehydrated or not drinking well.
- Blood transfusion is required only in rare, severe cases with serious bleeding.
Overall Outlook:
- Most infections are mild.
- Clinical signs usually resolve quickly once treatment begins.
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What Is the Prognosis for Dogs With Anaplasmosis?
Generally speaking, the prognosis for dogs with anaplasmosis is excellent. Most dogs recover fully with prompt treatment.
There are exceptions: a dog with multiple co-infections (for example, Ehrlichia or Babesia) or one that is very young, old, or immunocompromised may have a more serious illness. Without treatment, severe complications like bleeding or organ damage might occur. However, in modern veterinary care, these extreme cases are uncommon.
After recovery, some dogs may carry low levels of the bacterium for a short time or remain antibody-positive. This does not necessarily mean the dog is still sick.
Your vet may recommend regular follow-up blood work.
What If a Dog Tests Positive But Has No Symptoms?
This situation is common. Many healthy dogs in tick-prone areas have antibodies to Anaplasma without ever getting sick, and they usually do not need treatment.
Veterinary guidelines recommend treating only dogs with symptoms or abnormal blood test results, not healthy dogs that are antibody-positive. Treating symptom-free dogs can lead to unnecessary antibiotic use.
The focus should be on prevention and monitoring. Use year-round tick control, watch for changes in appetite, energy, or fever, and seek testing or treatment only if signs appear. A positive antibody result mainly means tick prevention should be strengthened.
Can Anaplasmosis Be Prevented?
There is no vaccine for canine anaplasmosis, so prevention depends entirely on tick control.
- Regular Tick Prevention:
- Use a vet-recommended tick control product consistently (spot-on, tablet, or collar).
- Choose one suitable for your dog’s age and health, and renew it on time.
- Daily Tick Checks:
- Check your dog after outdoor activity, especially ears, neck, chest, between toes, and under the legs.
- Remove any tick immediately using tweezers or a tick hook, as close to the skin as possible.
- Environmental Control:
- Keep grass trimmed and remove leaf litter.
- Clean sleeping areas, wash bedding, and vacuum regularly.
- Use tick sprays in heavily infested areas if advised.
- Lifestyle Precautions:
- Avoid heavily tick-infested areas when possible.
- Stay on clear paths during walks and clean your dog after bushy outings.
- Quick Tick Removal:
- Ticks usually need about 24 hours to transmit disease, so early removal lowers risk.
Natural repellents may help but are less reliable than veterinary products and should only be used after consulting a vet.
Can Humans Get Anaplasmosis From Dogs?
No, humans cannot get anaplasmosis directly from dogs. The disease is not spread by touch or close contact. Both dogs and people get infected only through the bite of an infected tick.
However, dogs can carry ticks into the home. If a tick drops off and later bites a person, infection can occur. That is why tick control on pets is important.
To stay safe, remove ticks promptly from your dog, wash your hands, and use repellents when in tick-prone areas. Dogs with anaplasmosis do not directly infect people; the shared risk is the tick.
Frequently Asked Questions (FAQs)
Is anaplasmosis fatal in dogs?
Fatal cases are very rare with treatment. Most dogs recover fully if seen early. Serious problems usually happen only if the disease is untreated or the dog has other illnesses.
How long does treatment take?
Treatment usually lasts 2-4 weeks. Even if your dog improves quickly, the full course must be completed to clear the infection.
Can dogs get anaplasmosis more than once?
Yes. There is no lasting immunity. Dogs can be reinfected if bitten again by an infected tick, so ongoing tick prevention is important.
Does anaplasmosis cause long-term health problems?
Usually no. Most dogs return to normal health. Long-term effects are uncommon, though mild fatigue may persist briefly in some cases.
Should all tick bites be tested?
No. Testing every bite is not practical. Focus on tick prevention and watch for symptoms. If signs such as fever or lethargy appear, testing is needed.
References:
Abd Rani, P. A. M., Irwin, P. J., Coleman, G. T., Gatne, M., & Traub, R. J. (2011). A survey of canine tick-borne diseases in India. Parasites & Vectors, 4, 141. https://doi.org/10.1186/1756-3305-4-141
El Hamiani Khatat, S., Daminet, S., Duchateau, L., Elhachimi, L., Kachani, M., & Sahibi, H. (2021). Epidemiological and clinicopathological features of Anaplasma phagocytophilum infection in dogs: A systematic review. Frontiers in Veterinary Science, 8, 686644. https://doi.org/10.3389/fvets.2021.686644
Palerme, J.-S. (2025). Anaplasmosis in dogs. In Merck Veterinary Manual. Merck & Co., Inc. Retrieved from https://www.merckvetmanual.com/infectious-diseases/rickettsial-diseases-in-dogs/anaplasmosis-in-dogsWeir, M., Llera, R., & Ward, E. (2022). Anaplasmosis in dogs. VCA Animal Hospitals. https://vcahospitals.com/know-your-pet/anaplasmosis-in-dogs
