How do ehrlichiosis and anaplasmosis spread?

They are mainly spread through the bites of infected ticks and other blood-sucking arthropods. In rare cases transmission may occur via blood transfusion or vertically from mother to offspring. Consult your vet if you suspect your pet has been exposed.

What is the difference between PCR and serology testing?

PCR directly detects the pathogen's nucleic acid and is best suited for acute-phase infections. Serology detects antibodies, indicating prior exposure or infection history. The two tests complement each other — follow your vet's recommendation on which to use.

How long does recovery take after treatment?

Recovery time varies depending on disease severity and whether anaemia is present. Follow-up monitoring typically spans several weeks to months. Regular blood tests and vet check-ups are the best way to gauge your pet's progress.

What should I bring to the appointment?

Bring weight and temperature records, a timeline of when symptoms appeared, any stool or vomit samples if available, and a full medication and supplement history — this helps the vet make a faster and more accurate assessment.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Ehrlichiosis & Anaplasmosis in Dogs and Cats: Lethargy, Blood Tests & Supportive Care [2025]

Ehrlichiosis and anaplasmosis are tick-borne blood infections in dogs and cats. Symptoms include fever, loss of appetite, anaemia and thrombocytopenia. Long-term antibiotic treatment is usually required.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek emergency care immediately

•Sudden hind-limb paralysis — unable to stand on their own
•Persistent high fever for more than 24 hours with noticeably declining alertness
•Pale gums or frequent bleeding — requires immediate attention

Schedule a clinic visit soon (within 24–72 hours)

•Noticeably reduced energy and activity, but still able to get up
•Significantly decreased appetite lasting more than two days
•Slower movement or unsteady gait, but still able to walk

01What symptoms indicate something is wrong?

These tick-borne blood parasitic infections commonly cause lethargy, loss of appetite and weight loss, and may be accompanied by fever or signs of anaemia.

Lethargy or noticeably reduced activity
Loss of appetite or significantly reduced food intake
Noticeable weight loss over days or weeks
Recurring fever or elevated temperature measured at home
Slowed gait or decreased activity level
Localised or generalised swelling, or abdominal distension

Seek emergency care immediately if you notice the following symptoms:

⚠️ Sudden weakness or inability to stand in the hind limbs
⚠️ Persistent high fever lasting more than 24 hours with obvious deterioration in condition
⚠️ Pale gums or frequent unexplained bleeding — seek emergency care immediately

02What should you watch for at home? Monitoring tips and when to seek urgent care

Observations recorded at home before the visit can help your vet quickly assess the progression and determine which tests are needed.

Note when symptoms first appeared and track any changes over time
Weigh your pet at the same time each day and record the values
Monitor body temperature and record results consistently
Track changes in appetite, food intake or refusal to eat
Note any changes in frequency, volume or colour of urine and stools
If possible, take short videos of your pet's movement or gait to share with the vet
Bring all records to the appointment to help the vet make a faster assessment

03How will the vet make a diagnosis? Common tests and examinations

Common in-clinic workups include haematology, molecular testing and imaging to identify the pathogen, assess organ function and check for co-infections.

Complete blood count (CBC)

assesses red blood cells, white blood cells and platelet status

Blood biochemistry

evaluates liver, kidney and other organ function, plus electrolytes

PCR (nucleic acid testing)

directly detects the pathogen — ideal for acute-phase diagnosis

Serology (antibody testing)

determines prior exposure or infection history

Parasite or bacterial culture and imaging as needed to rule out co-infections

04What treatment and care are needed after diagnosis? Medications, diet and home care guide

Treatment focuses on eliminating the pathogen and providing supportive care. Regular blood monitoring is needed to track recovery and detect any side effects.

Choose appropriate medications based on test results and provide supportive care
Blood transfusion may be required in cases of severe anaemia or significant blood loss
Regular blood tests to monitor treatment response and detect any drug side effects
Adjust diet to maintain caloric and nutritional intake and support weight recovery
Attend all follow-up appointments to evaluate recovery and consider specialist referral if needed

05What should you prepare before the vet visit? Key information to speed up diagnosis

Bring a written record or photos of when symptoms first appeared and how they have changed

List all current and past medications, vaccinations and supplements

Bring recent weight and temperature records or screenshots from your tracking app

If available, bring stool samples, vomit samples or any collected parasites to the appointment

Call ahead to book and describe the suspected symptoms to reduce waiting time

If possible, choose a clinic or laboratory with in-house PCR testing capability

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.