Prevalence of Babesia gibsoni in dogs: A hospital based studyC

Introduction

Dogs (Canis familiaris) are among the most widely domesticated companion animals and play a crucial role in human society. With increasing pet ownership, the incidence of infectious diseases, particularly vector-borne diseases, has gained considerable attention. Canine babesiosis is a tick-borne disease caused by intraerythrocytic protozoa of the genus Babesia (Birkenheuer et al., 2004) [1] . Among the species infecting dogs, Babesia gibsoni is recognized as one of the most pathogenic, leading to significant morbidity and mortality (Irwin, 2009) [5] . In India, B. gibsoni is more prevalent than other species and is widely distributed due to favourable climatic conditions for tick vectors (Selvaraj et al., 2010) [15] . The parasite is primarily transmitted by ticks such as Rhipicephalus sanguineus and Haemaphysalis spp. (Beugnet and Moreau, 2015). However, alternative transmission routes including dog bites, blood transfusion, contaminated instruments, and transplacental transmission have also been documented (Stegeman et al., 2003; Fukumoto et al., 2005) [20,3] . Clinical manifestations of B. gibsoni infection range from mild to severe and include anemia, fever, lethargy, thrombocytopenia, splenomegaly, and in complicated cases, multi-organ dysfunction (Irwin, 2009) [5] . Chronic infections may remain subclinical, contributing to the persistence and spread of the disease. The prevalence of B. gibsoni varies widely depending on geographic location, environmental factors, and diagnostic methods used (Singh et al., 2014) [17] . Therefore, accurate epidemiological studies are essential for understanding disease dynamics and implementing control strategies. The present study was undertaken to determine the prevalence of Babesia gibsoni in dogs and to evaluate the influence of age, breed, sex, and diagnostic methods on disease occurrence.

Materials and Methods

The study was conducted at Krantisinh Nana Patil College of Veterinary Science, Shirwal from May 2025 to January 2026. A total of 74 dogs showing clinical signs suggestive of babesiosis such as Fever, Anemia, Thrombocytopenia, Lethargy, Loss of appetite, Vomition, Diarrhea, Weight loss, Tick infestation, Hemoglobinuria, and Lymphadenopathy were included in the study. Detailed history including age, breed, and sex was recorded. Clinical examination included assessment of temperature, heart rate, respiratory rate, mucous membrane colour, and lymph node enlargement. Blood sample was taken approximately 5 mL collected aseptically from each dog in K 2 EDTA and clot activator vials. Approximately 3 mL was transferred into a K₂EDTA (ethylenediaminetetraacetic acid) vial for hematological analysis, blood smear examination, and genomic DNA extraction for polymerase chain reaction (PCR) testing to detect B. gibsoni DNA. The remaining 2 mL of blood, collected without anticoagulant, was placed in a separate vial for serum separation and subsequent biochemical analysis. Thin blood smears were prepared, stained with Giemsa stain, and examined under oil immersion (100×) for detection of Babesia gibsoni as shown in plate no. 1. The identification of Babesia gibsoni was based on the detection of intraerythrocytic piroplasms exhibiting characteristic morphology as described by Soulsby (1982) [18] . Extracted DNA sample is used as template to amplify the fragment of Babeisa gibsoni for 18S rRNA using the primers described by Inokuma et al. (2004) [4] showed in table no. 1. [6] (9.65%). However, it is lower than reports by Liu et al. (2022) [7] (66.66%) and Senthil (2023) [16] (70.5%). Climatic conditions such as temperature and humidity, along with the abundance of tick vectors, dog population, management of tick population in an area play a crucial role in disease transmission.

Age-wise prevalence

The highest prevalence was recorded in dogs aged 1-3 years (46.66%), followed by dogs above 3 years (30%) and below 1 year (23.33%) as shown in table no. 2. Adult dogs are more likely to be exposed to tick-infested environments due to increased outdoor activity. Similar findings were reported by Ravi et al. (2016) [12] , Soundarya et al. (2023) [19] and Kamdi et al. (2024) [6] . Lower prevalence in younger dogs may be due to limited exposure and protective care by owners. However, contrasting reports (Singh et al., 2014) [17] and Sarma et al. (2019) [14] indicate higher prevalence in younger dogs, suggesting that immunity and environmental exposure both influence disease occurrence.

Breed-wise prevalence

Labrador dogs showed the highest prevalence (30%), followed by German Shepherd (20%) and Golden Retriever (13.33%) Rottweilers, Doberman and Pomerian each exhibited (10%). Non-descript breeds showed the lowest prevalence (6.6%) as shown in table no. 3. Higher prevalence in exotic breeds may be attributed to genetic susceptibility and management practices. These findings are in agreement with Sarma et al. (2019) [14] Obeta et al. (2020) [11] , Soundarya et al. (2023) [19] . Non-descript dogs may possess better adaptability and resistance to infections.

Sex-wise prevalence

Male dogs showed higher prevalence (70%) compared to females (30%) as shown in table no. 4. Higher incidence of B. gibsoni in male dogs as compared to female dogs supporting the previous findings of Liu et al.

(2022) [7] , Soundarya et al. (2023) [19] , Nagarjuna et al. (2024) [10] , Sahiti et al. (2024) but differ from the findings of Singh et al. (2014) [17] , Kamdi et al. (2024) [6] . This may be due to the increased immune reactivity in females as estrogen helps to produce an effective resistance to infection (Taneja, 2018) [21] or due to the behavioral factors of male such as roaming, fighting, and increased exposure to ticks (Matsuu et al., 2004) [8] .

Prevalence based on blood smear examination and PCR.

In the present study 74 clinically suspected dogs were evaluated for Babesia gibsoni infection using blood smear examination and Polymerase Chain Reaction (PCR). Out of 74 suspected dogs 26 were shown positive for Babesia gibsoni infection in Giemsa stained blood smear examination, showed overall prevalence of 35.13% while PCR showed 30 sample positives for Babesia gibsoni infection resulting in higher prevalence of 40.54%. PCR confirmed all positive cases and demonstrated higher sensitivity and specificity compared to blood smear examination. Similar observations were reported by Singh et al. (2014) [17] , Mittal et al. (2019) [9] and Teodorowski et al.

(2020) [22] . PCR is especially useful in detecting chronic and subclinical infections.

Conclusion

The study revealed a moderate prevalence (40.54%) of Babesia gibsoni infection in dogs. Adult dogs, males, and exotic breeds were more susceptible. PCR proved to be a superior diagnostic tool compared to blood smear examination.

The study emphasizes the need for early diagnosis, effective tick control, and use of molecular techniques for better disease management.

References

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