Original Scientific Article
Reticulocyte response in paired blood samples of Babesia canis infected young and adult dogs
Zorana Milanović * ,
Anja Ilić Božović ,
Žanka Bojić-Trbojević ,
Ljiljana Hajduković ,
Jelena Francuski Andrić ,
Milica Kovačević Filipović

Mac Vet Rev 2024; 47 (1): 13 - 21


Received: 29 November 2023

Received in revised form: 07 January 2024

Accepted: 15 January 2024

Available Online First: 31 January 2024

Published on: 15 March 2024

Correspondence: Zorana Milanović, zorana.milanovic@vin.bg.ac.rs


Acute B. canis infection can lead to an acute phase reaction (APR) in dogs. The parasite invades red blood cells causing anemia through immune-mediated hemolysis and possible erythropoietic suppression. A regenerative response of the erythroid lineage during the babesiosis has not been described in extension. This research examines hematologic parameters focusing on the absolute reticulocyte count and apolipoprotein A I (ApoA I) level on the day of admission and 14 days after treatment with imidocarb-dipropionate in young (n=11) and adult (n=11) dogs naturally infected with B. canis. Metabolic and inflammatory processes were characterized by analyzing protein and lipid profiles, as well as ApoA I at specified time points. Automated analyzers were used to determine complete blood count and biochemical parameters, while ApoA I was assessed using radioimmunoassay. The reticulocyte count was determined using a manual method by means of supravital staining. Both young and adult dogs with acute B. canis infection showed non-regenerative anemia without difference. Fourteen days after successful treatment with imidocarb dipropionate, the anemia was corrected and a high reticulocyte count was observed (p<0.05). This indicates that the erythroid regenerative response was efficient in young and adult dogs, although vital signs, leukocyte count and triglyceride concentration suggest a more intense APR in young dogs. A decrease in ApoA I in both groups 14 days after treatment (p<0.01) confirmed that this lipoprotein acts as a positive acute-phase protein in acute B. canis infection in dogs, but further studies are needed to connect its role in erythroid lineage regeneration.

Keywords: Babesia canis, dog, reticulocyte count, paired blood samples, ApoA I


1. Brandão, L.P., Hagiwara, M.K., Myiashiro, S.I. (2003). Humoral immunity and reinfection resistance in dogs experimentally inoculated with Babesia canis and either treated or untreated with imidocarb dipropionate. Vet Parasitol. 114(4): 253-265. https://doi.org/10.1016/S0304-4017(03)00130-4 PMid:12809752
2. Schetters, T.P.M., Kleuskens, J.A.G.M., Van De Crommert, J., De Leeuw, P.W.J., Finizio, A.-L., Gorenflot, A. (2009). Systemic inflammatory responses in dogs experimentally infected with Babesia canis; a haematological study. Vet Parasitol. 162(1-2): 7-15. https://doi.org/10.1016/j.vetpar.2009.02.012 PMid:19269099
3. Bilić, P., Kuleš, J., Barić Rafaj, R., Mrljak, V. (2018). Canine babesiosis: Where do we stand? Acta Vet. 68(2): 127-160. https://doi.org/10.2478/acve-2018-0011 
4. Schetters, T.P.M., Montenegro-James, S. (1995). Vaccines against babesiosis using soluble parasite antigens. Parasitol Today 11(12): 456-462. https://doi.org/10.1016/0169-4758(95)80059-X PMid:15275383
5. Milanović, Z., Vekić, J., Radonjić, V., Ilić Božović, A., Zeljković, A., Janac, J., Spasojević-Kalimanovska, V., et al. (2019). Association of acute Babesia canis infection and serum lipid, lipoprotein, and apoprotein concentrations in dogs. J Vet Intern Med. 33(4): 1686-1694. https://doi.org/10.1111/jvim.15537 PMid:31175698 PMCid:PMC6639482
6. Milanović, Z., Beletić, A., Vekić, J., Zeljković, A., Andrić, N., Božović, A.I., Spariosu, K., et al. (2020). Evidence of acute phase reaction in asymptomatic dogs naturally infected with Babesia canis. Vet Parasitol. 282, 109140. https://doi.org/10.1016/j.vetpar.2020.109140 PMid:32473353
7. Milanović, Z., Ilić, A., Andrić, J.F., Radonjić, V., Beletić, A., Filipović, M.K. (2017). Acute-phase response in Babesia canis and Dirofilaria immitis coinfections in dogs. Ticks Tick Borne Dis. 8(6): 907-914. https://doi.org/10.1016/j.ttbdis.2017.07.009 PMid:28802807
8. Beletić, A., Janjić, F., Radaković, M., Spariosu, K., Francuski Andrić, J., Chandrashekar, R., Tyrrell, P., et al. (2021). Systemic inflammatory response syndrome in dogs naturally infected with Babesia canis: association with the parasite load and host factors. Vet Parasitol. 291, 109366. https://doi.org/10.1016/j.vetpar.2021.109366 PMid:33545559
9. Zygner, W., Gójska, O., Rapacka, G., Jaros, D., Wędrychowicz, H. (2007). Hematological changes during the course of canine babesiosis caused by large Babesia in domestic dogs in Warsaw (Poland). Vet Parasitol. 145(1-2): 146-151. https://doi.org/10.1016/j.vetpar.2006.11.008 PMid:17157987
10. Jacobson, L.S. (2006). The South African form of severe and complicated canine babesiosis: Clinical advances 1994-2004. Vet Parasitol. 138(1-2): 126-139. https://doi.org/10.1016/j.vetpar.2006.01.047 PMid:16503090
11. Zygner, W., Gójska-Zygner, O., Norbury, L.J. (2023). Pathogenesis of anemia in canine babesiosis: possible contribution of pro-inflammatory cytokines and chemokines-a review. Pathogens 12(2): 166. https://doi.org/10.3390/pathogens12020166 PMid:36839438 PMCid:PMC9962459
12. Spariosu, K., Janjić, F., Andrić, J.F., Radaković, M., Beletić, A., Filipović, M.K., Milanović, S. (2021). Relationship between changes in hematological parameters, levels of acute phase proteins and redox homeostasis during acute Babesia canis infection in dogs. Acta Vet. 71(2): 158-169. https://doi.org/10.2478/acve-2021-0014 
13. Pathak, V.A., Ghosh, K. (2016). Erythropoiesis in malaria infections and factors modifying the erythropoietic response. Anemia 2016, 9310905. https://doi.org/10.1155/2016/9310905 PMid:27034825 PMCid:PMC4789361
14. Žvorc, Z., Baric Rafaj, R., Kuleš, J., Mrljak, V. (2010). Erythrocyte and platelet indices in babesiosis of dogs. Vet Arh. 80(2): 259-267.
15. Maegraith, B., Gilles, H., Devakul, K. (1957). Pathological processes in Babesia canis infections. Z Tropenmed Parasitol. 8(4): 485-514.
16. Furlanello, T., Fiorio, F., Caldin, M., Lubas, G., Solano-Gallego, L. (2005). Clinicopathological findings in naturally occurring cases of babesiosis caused by large form Babesia from dogs of northeastern Italy. Vet Parasitol. 134(1-2): 77-85. https://doi.org/10.1016/j.vetpar.2005.07.016 PMid:16112810
17. Reyers, F., Leisewitz, A., Lobetti, R., Milner, R., Jacobson, L., van Zyl, M. (1998). Canine babesiosis in South Africa: more than one disease. Does this serve as a model for falciparum malaria. Ann Trop Med Parasitol. 92(4): 503-511. https://doi.org/10.1080/00034983.1998.11813308 PMid:9683901
18. Scheepers, E., Leisewitz, A.L., Thompson, P.N., Christopher, M.M. (2011). Serial haematology results in transfused and non-transfused dogs naturally infected with Babesia rossi. J S Afr Vet Assoc. 82(3): 136-143. https://doi.org/10.4102/jsava.v82i3.51 PMid:22332296
19. Kelley, K.W., Arkins, S., Minshall, C., Liu, Q., Dantzer, R. (1996). Growth hormone, growth factors and hematopoiesis. Horm Res. 45(1-2): 38-45. https://doi.org/10.1159/000184757 PMid:8742117
20. Soran, H., Schofield, J.D., Durrington, P.N. (2015). Antioxidant properties of HDL. Front Pharmacol. 6, 222. https://doi.org/10.3389/fphar.2015.00222 PMid:26528181 PMCid:PMC4607861
21. Cowgill, E.S., Neel, J.A., Grindem, C.B. (2003). Clinical application of reticulocyte counts in dogs and cats. Vet Clin North Am-Small Anim Pract. 33(6): 1223-1244. https://doi.org/10.1016/S0195-5616(03)00099-8 PMid:14664196
22. Kovačević Filipović, M.M., Beletić, A.D., Ilić Božović, A.V., Milanović, Z., Tyrrell, P., Buch, J., Breitschwerdt, E.B., et al. (2018). Molecular and serological prevalence of Anaplasma phagocytophilum, A. platys, Ehrlichia canis, E. chaffeenses, E. ewingii, Borrelia burgdorferi, Babesia canis, B. gibsoni and B. vogeli among clinically healthy outdoor dogs in Serbia. Vet Parasitol Reg Stud Reports. 14, 117-122. https://doi.org/10.1016/j.vprsr.2018.10.001 PMid:31014716
23. Hodges, J., Christopher, M.M. (2011). Diagnostic accuracy of using erythrocyte indices and polychromasia to identify regenerative anemia in dogs. J Am Vet Med Assoc. 238(11): 1452-1458. https://doi.org/10.2460/javma.238.11.1452 PMid:21627508
24. Golubović, S.J., Bojić-Trobjević, Ž.T. (2006). Human carcinoma-associated and salivary mucins detected by anti-bovine submaxillary mucin antibodies. Biochem (Moscow). 71(Suppl. 1): S9-S17. https://doi.org/10.1134/S0006297906130025 PMid:16487075
25. Solano-Gallego, L., Sainz, Á., Roura, X., Estrada-Peña, A., Miró, G. (2016). A review of canine babesiosis: the European perspective. Parasit Vectors. 9, 336. https://doi.org/10.1186/s13071-016-1596-0 PMid:27289223 PMCid:PMC4902949
26. Davitkov, D., Vucicevic, M., Stevanovic, J., Krstic, V., Tomanovic, S., Glavinic, U., Stanimirovic, Z. (2015). Clinical babesiosis and molecular identification of Babesia canis and Babesia gibsoni infections in dogs from Serbia. Acta Vet Hung. 63(2): 199-208. https://doi.org/10.1556/avet.2015.017 PMid:26051258
27. Giger, U. (2005). Regenerative anemias caused by blood loss or hemolysis. In: S.J. Ettinger, E.C. Feldman (Eds.), Textbook of veterinary internal medicine (pp. 1886-1907), Saunders
28. Alamgir Hossain, M., Yamato, O., Yamasaki, M., Jeong, J.-R., Chang, H.-S., Maede, Y. (2003). Serum from dogs infected with Babesia gibsoni inhibits maturation of reticulocytes and erythrocyte 5’-nucleotidase activity in vitro. J Vet Med Sci. 65(12): 1281-1286. https://doi.org/10.1292/jvms.65.1281 PMid:14709814
29. Kuleš, J., Mrljak, V., Rafaj, R.B., Selanec, J., Burchmore, R., Eckersall, P.D. (2014). Identification of serum biomarkers in dogs naturally infected with Babesia canis canis using a proteomic approach. BMC Vet Res. 10, 111. https://doi.org/10.1186/1746-6148-10-111 PMid:24885808 PMCid:PMC4045879
30. Khovidhunkit, W., Kim, M.S., Memon, R.A., Shigenaga, J.K., Moser, A.H., Feingold, K.R., Grunfeld, C. (2004). Thematic review series: the pathogenesis of atherosclerosis. Effects of infection and inflammation on lipid and lipoprotein metabolism mechanisms and consequences to the host. J Lipid Res. 45(7): 1169-1196. https://doi.org/10.1194/jlr.R300019-JLR200 PMid:15102878


© 2024 Milanović Z. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Conflict of Interest Statement

The authors declared that they have no potential lict of interest with respect to the authorship and/or publication of this article.

Citation Information

Macedonian Veterinary Review. Volume 47, Issue 1, Pages 13-21, e-ISSN 1857-7415, p-ISSN 1409-7621, DOI: 10.2478/macvetrev-2024-0011