Anaplasmosis in Dogs: Symptoms, Diagnosis & Treatment
Anaplasmosis in dogs: symptoms, diagnosis & treatment
What is anaplasmosis in dogs?
Anaplasmosis is a tick-borne bacterial infectious disease. The most common pathogen in dogs in Germany is Anaplasma phagocytophilum, the cause of granulocytic anaplasmosis — it infects white blood cells (granulocytes) and causes a broad spectrum of clinical signs. It is transmitted mainly by the castor bean tick (Ixodes ricinus). A second form, thrombocytopenic anaplasmosis caused by Anaplasma platys, is less common in Germany.
Anaplasmosis is not an exotic tropical disease, but a domestic disease risk: in Germany, the detection rate in the dog population has risen steadily over more than a decade.
Background + scientific classification
Schafer et al. (2023, Animals, PubMed 36830507) analyzed 13 years of laboratory data from German dogs (2008–2020): of 27,368 dogs tested by PCR, 4.9% were positive; of 90,376 dogs tested serologically, 27.4% had positive IFAT/ELISA results. The study documents a statistically significant increase in cases over the observation period — correlating with Ixodes ricinus activity periods. Male and older dogs showed higher seroprevalence.
Chirek et al. (2018, Journal of Small Animal Practice, PubMed 29171663) clinically described 63 confirmed cases from German veterinary practices: the most common symptoms were lethargy/reduced activity (83%), fever (67%), and loss of appetite (63%). In the blood count, thrombocytopenia (86%) was the main finding. With doxycycline therapy, 97% of dogs recovered; fever and clinical signs typically resolved within 3–5 days.
Yancey et al. (2018, Journal of Small Animal Practice, PubMed 29280490) prospectively confirmed that a 28-day doxycycline protocol led to complete pathogen elimination in all 16 PCR-positive dogs (blood PCR negative after 28 days).
Vitomalia position
Anaplasmosis is a real and increasing concern in Germany — tick prevention is not excessive caution, but medically sound prevention. We consider it important that dog owners know: positive serology alone (antibody detection) only shows contact with the pathogen, not an acute disease. Clinical signs + a positive PCR are the indication for treatment, not antibody detection alone. This distinguishes anaplasmosis from Lyme disease, where the classification is similar.
When does anaplasmosis become relevant in dogs?
- After a known tick bite, especially April–October (main activity period of Ixodes ricinus)
- In cases of sudden fever, lethargy, and loss of appetite without any obvious other cause
- As an incidental finding: thrombocytopenia in the blood count in asymptomatic dogs
- In dogs without ongoing tick prevention
- In dogs that live in areas with a high tick density or have vacationed there
Practical application
Symptoms of granulocytic anaplasmosis (according to Chirek et al. 2018):
| Symptom | Frequency |
|---|---|
| Lethargy, reduced activity | 83 % |
| Fever (>39.5 °C) | 67 % |
| Loss of appetite | 63 % |
| Thrombocytopenia in the blood count | 86 % |
| Lameness / joint pain | ~30 % |
| Vomiting, diarrhea | ~20 % |
Diagnostics:
- Blood count: Thrombocytopenia (low platelet count) is the most common laboratory finding — not proof on its own, but a warning sign
- PCR (blood): Gold standard for acute infection; results are usually available within 24–48 hours
- Serology (IFAT/ELISA): Shows only antibody contact, not acute disease — not sufficient on its own for making a diagnosis
- Blood smear: Morulae (inclusion bodies in granulocytes) — if visible, conclusive; but rare and difficult to detect
Treatment:
Doxycycline is the treatment of choice — oral, 28 days, with a rapid clinical response typically within 3–5 days. No response after 72 hours requires the diagnosis to be reviewed.
Common mistakes & myths
- “My dog has antibodies — he has to be treated.” Seropositivity without clinical signs is common and only shows previous contact with the pathogen. Antibiotic treatment is indicated only in cases of clinical disease + laboratory diagnostic confirmation.
- “Anaplasmosis and Lyme disease are the same.” Both are transmitted by Ixodes ricinus and can occur at the same time — but the pathogens, disease mechanisms, and changes in the blood count are different. Co-infections are possible.
- “After treatment, my dog is immune.” Having had anaplasmosis does not leave reliable immunity. Reinfections are possible — tick prevention remains important even after recovery.
Scientific status 2026
Anaplasmosis is an increasingly relevant zoonosis in Germany — humans can also become infected through tick bites (granulocytic anaplasmosis, the human form). The rising seroprevalence in dogs correlates with an expansion of the Ixodes ricinus distribution area. Open research questions: the role of persistent subclinical infection, interaction with other tick-borne pathogens (Borrelia, Ehrlichia) in co-infections.
Frequently asked questions
How dangerous is anaplasmosis for dogs?
With early diagnosis and doxycycline treatment, 97% of dogs recover fully. If left untreated, anaplasmosis can lead to a tendency to bleed and life-threatening complications due to thrombocytopenia. Early veterinary assessment after a tick bite with clinical signs is crucial.
How is anaplasmosis diagnosed in dogs?
Through a combination of clinical signs, blood count (thrombocytopenia), and PCR detection from blood. Serology alone is not sufficient — positive antibodies only indicate previous contact, not an active infection.
Can I prevent anaplasmosis in dogs?
Yes — through consistent tick prevention (spot-on treatments, Collars, tablets) during the active season (April–October). Complete protection cannot be guaranteed, but the risk of infection is significantly reduced. Check your dog after every stay in tick-rich areas.
Related terms
- Ticks in dogs
- Lyme disease in dogs
- Blood count in dogs
- Fever in dogs
- Infectious diseases in dogs
- TBE in dogs
Sources & further reading
-
Chirek, A., Silaghi, C., Pfister, K., & Kohn, B. (2018). Granulocytic anaplasmosis in 63 dogs: clinical signs, laboratory results, therapy and course of disease. Journal of Small Animal Practice, 59(2), 112–120. https://pubmed.ncbi.nlm.nih.gov/29171663/
-
Schafer, I., Kohn, B., Silaghi, C., Fischer, S., Marsboom, C., Hendrickx, G., & Muller, E. (2023). Molecular and serological detection of Anaplasma phagocytophilum in dogs from Germany (2008–2020). Animals, 13(4), 720. https://pubmed.ncbi.nlm.nih.gov/36830507/
-
Yancey, C. B., Diniz, P. P. V. P., Breitschwerdt, E. B., Hegarty, B. C., Wiesen, C., & Qurollo, B. A. (2018). Doxycycline treatment efficacy in dogs with naturally occurring Anaplasma phagocytophilum infection. Journal of Small Animal Practice, 59(5), 286–293. https://pubmed.ncbi.nlm.nih.gov/29280490/