Canine Large Babesia and Small Babesia

Synopsis

Canine babesiosis, caused by the protozoan Babesia, is an emerging infection in dogs. This tick-borne disease is caused by Babesia parasites, which are classified into large and small piroplasms. For example, B. canis, B. rossi, and B. vogeli are considered large piroplasms due to their larger developmental stages, such as trophozoites and merozoites, compared to smaller species like B. gibsoni.

Both types of Babesia can be passed from mother to offspring or through blood transfusions. Small Babesia spp. infections in dogs can spread through tick bites and dog bites during fights, while large Babesia spp. infections are only transmitted by ticks, which limits their geographical occurrence. Different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. Babesia gibsoni can be found in Africa, Asia, Australia, North and South America, and Europe. In a 2020 study, globally Babesia gibsoni accounted for almost 50% of positive Babesia PCR test results in specimens submitted to IDEXX Laboratories; this was followed by B. canis (35%) and B. vogeli (15%).

All Babesia species that infect dogs can cause anemia. The severity, rate at which anemia develops following infection and the strength of association between infection and anemia do, however, seem to vary. Depending on the species of the parasite and the immune status of the host, infection may lead to mild, moderate, or severe disease. 

• B. rossi causes the most severe form of the disease in domestic dogs, and almost always presents with anemia..

• B. vogeli infection may be mild or even subclinical in adult animals, but in young dogs may cause severe anemia.

• B. canis are typically milder than those caused by B. rossi; however, both pathogens can cause acute babesiosis

• B. gibsoni causes mild to moderate anemia in the majority of infected dogs. Severe life-threatening anemia is rare.

Therapy

Many drugs have been used to treat babesiosis, yet very few are consistently reliable. Few, if any, sterilize the infection, and most affected individuals harbour parasites after the treatment is finished. It should be noted that only a few drugs are efficacious against both forms of Babesia. 

Diagnosis

Rapid reporting of results for relevant Babesia species within an hour can enhance therapy and prognosis for canine babesiosis. A tentative diagnosis can be established in dogs with a history of tick exposure and associated clinical signs. The diagnostic goals for babesiosis include:

i) identifying the Babesia parasite(s);
ii) screening for other infectious agents, particularly Ehrlichia spp.;
iii) assessing the severity of anemia; and
iv) evaluating the patient’s overall health status, especially in per-acute cases.

Identification of large and small Babesia parasites is performed through microscopic examination of stained blood smears, which requires technical skill; however, light microscopy cannot differentiate between canine large Babesia species. Serological tests can detect antibodies to B. gibsoni or B. vogeli but may yield false negatives in per-acute or acute primary infections. Alternatively, PCR on whole blood, which offers high sensitivity and specificity, is now widely used in clinical practice.

In conclusion, babesiosis is a frequently encountered infectious disease, and treating it can be prolonged due to the difficulty in eliminating parasites from the blood. Given the high mortality and morbidity rates, a rapid and accurate diagnosis is a crucial first step for veterinarians to save lives affected by Babesia. The Pluslife Minidock is a portable molecular detection system compatible with qPCR, capable of detecting and distinguishing different Babesia genotypes in just 35 minutes from sampling to result. This efficiency enables veterinarians to determine treatment on the same day.

If you are interested in ordering our Babesia gibsoni/Canine Babesia Rapid Nucleic Acid Test Card, please visit or reach out to us through the "Contact Us" section on this website for more information.

Reference

1.  Zygner, W., Gójska-Zygner, O., Bartosik, J., Górski, P., Karabowicz, J., Kotomski, G., & Norbury, L. J. (2023). Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review. Animals : an open access journal from MDPI, 13(16), 2612.
2.  Leisewitz, A. L., Mrljak, V., Dear, J. D., & Birkenheuer, A. (2023). The Diverse Pathogenicity of Various Babesia Parasite Species That Infect Dogs. Pathogens (Basel, Switzerland), 12(12), 1437.
3. TroCCAP: Guidelines for the diagnosis, treatment and control of canine endoparasites in the tropics. Second Edition March 2019.