Microscopic view of Canine babesiosis

Canine Babesiosis: Unveiling the Mystery of Anemia and Blood Disorders in Dogs

Kai Mendoza in Health & Wellness December 2025 • 4 min read.

"A Deep Dive into Babesia rossi Infections and Their Impact on Canine Hematology"

Canine babesiosis, a disease caused by blood-borne parasites like Babesia canis and B. gibsoni, poses a significant threat to dogs worldwide. Among these, Babesia rossi stands out as particularly virulent. Recently, a novel large Babesia species has emerged, further complicating the landscape of canine babesiosis, especially for immunocompromised dogs.

These parasites trigger anemia through a dual mechanism: direct damage to red blood cells and antibody-mediated destruction. This hemolytic process, occurring both within and outside blood vessels, leads to a decrease in hematocrit levels. Recent studies suggest that even before parasites are detectable in the blood, sequestration, splenomegaly, and hemodilution contribute to the decrease in hematocrit. Acute canine babesiosis is a severe condition characterized by life-threatening hemolytic anemia and shares similarities with other pro-inflammatory states, such as bacterial sepsis and human malaria.

Though current treatments involve anti-babesial drugs and, in severe cases, blood transfusions, comprehensive insights into the hematological changes during a natural Babesia rossi infection are still lacking. A deeper understanding of these changes is critical for making well-informed decisions about treatments.

What Happens to a Dog's Blood During Babesia rossi Infection?

A prospective study followed 32 transfused and 54 non-transfused dogs naturally infected with Babesia rossi, tracking hematological changes over six days post-diagnosis and treatment. The study also considered the effect of age on complete blood counts, analyzing data at presentation, 24 hours, three days, and six days after. All dogs received diminazene aceturate, with blood transfusions administered when clinically necessary.

Throughout the study, all dogs showed mild to moderately regenerative normocytic normochromic anemia. Dogs receiving transfusions were more likely to exhibit inflammatory leukograms at presentation and after 24 hours compared to non-transfused dogs. A notable observation was the presence of normal or decreased segmented neutrophil counts alongside a left shift, which was more common than neutrophilia. Severe thrombocytopenia, resolving within a week, was a common occurrence.

Mild to Moderate Anemia: All dogs experienced anemia that was neither severe nor life-threatening.
Inflammatory Leukogram: Transfused dogs showed more signs of inflammation in their blood.
Neutrophil Count Variations: Many dogs with a left shift (immature neutrophils) had normal or low neutrophil counts, rather than high counts.
Thrombocytopenia: A significant drop in platelet count was noted, but it recovered within a week.

While blood transfusions effectively alleviated anemia, they did not significantly impact white blood cell or platelet responses. Age was also found to have no substantial effect on blood cell responses. Overall, the red and white blood cell responses were less pronounced than expected, given the degree of anemia and inflammation present. The rapid return of platelet counts to normal suggested a possible immune-mediated mechanism for the thrombocytopenia.

What This Means for Dog Owners and Vets

These findings offer valuable insights for veterinarians in evaluating and treating canine babesiosis. Understanding the expected blood cell responses can lead to more informed treatment decisions, especially regarding blood transfusions and managing the associated inflammatory response. The study highlights the importance of monitoring platelet counts and considering immune-mediated mechanisms in thrombocytopenia. Additional research is needed to fully elucidate the underlying factors affecting bone marrow response and to compare these findings with human malaria, potentially leveraging canine babesiosis as a translational model.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.4102/jsava.v82i3.51, Alternate LINK

Title: Serial Haematology Results In Transfused And Non-Transfused Dogs Naturally Infected With Babesia Rossi

Subject: General Veterinary

Journal: Journal of the South African Veterinary Association

Publisher: AOSIS

Authors: E. Scheepers, A. L. Leisewitz, P. N. Thompson, M. M. Christopher

Published: 2011-04-13

Everything You Need To Know

What is Canine Babesiosis and what does it do to a dog's blood?

Canine babesiosis is a disease caused by blood-borne parasites, with Babesia rossi being a particularly virulent type. These parasites damage a dog's red blood cells directly, leading to anemia, a condition where the blood doesn't have enough healthy red blood cells. The impact of this is a reduction in the oxygen-carrying capacity of the blood, which can lead to fatigue and other health problems.

What specific blood changes occur in dogs infected with Babesia rossi?

During a Babesia rossi infection, dogs can experience mild to moderate regenerative normocytic normochromic anemia. This means that the anemia is not usually life-threatening and the body tries to make new red blood cells (regenerative), and the cells are of normal size (normocytic) and color (normochromic). Moreover, dogs may show signs of inflammation in the blood (inflammatory leukograms), particularly if they receive blood transfusions. Additionally, severe thrombocytopenia, a significant drop in platelet count, is a common occurrence, but usually resolves within a week. The neutrophil counts can vary, with a left shift (immature neutrophils) observed in many cases, often with normal or decreased segmented neutrophil counts.

How do blood transfusions affect a dog's blood cell responses in the context of this infection?

The study found that blood transfusions effectively addressed the anemia associated with Babesia rossi infection, but they didn't significantly affect the white blood cell or platelet responses. This suggests that while transfusions can provide immediate relief from anemia, they may not directly influence the underlying immune-mediated processes or inflammatory responses. Furthermore, age did not substantially impact the blood cell responses, indicating that dogs of different ages respond similarly to the infection.

Why is understanding blood cell responses important for vets treating dogs with this disease?

Understanding the blood cell responses in dogs with Babesia rossi infections offers significant value to veterinarians. This knowledge allows for more informed decisions regarding treatments such as blood transfusions and managing the associated inflammatory response. For instance, recognizing the expected degree of anemia or understanding the mechanisms behind thrombocytopenia can help veterinarians tailor treatment plans. Further research is needed to fully explain the bone marrow response, and using canine babesiosis as a translational model to human malaria.

Why is thrombocytopenia a concern in dogs with Babesia rossi, and what is the likely cause?

Thrombocytopenia, a significant drop in platelet count, is common in dogs with Babesia rossi. The rapid recovery of platelet counts within a week suggests a possible immune-mediated mechanism. This means the body's immune system might be attacking the platelets. Platelets are crucial for blood clotting, so a drop in their count can lead to bleeding issues. Monitoring platelet counts is vital in treating the disease to ensure appropriate intervention to manage bleeding risk.