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J Vet Clin 2022; 39(5): 207-216

https://doi.org/10.17555/jvc.2022.39.5.207

Published online October 31, 2022

Clinical and Subclinical Cases of Canine Babesiosis Caused by Babesia gibsoni in the Republic of Korea

Evelyn Alejandra Miranda1 , Sun-Woo Han1 , Ji-Min Rim1 , Yoon-Kyoung Cho1 , DoHyeon Yu2 , Kyoung-Seong Choi3 , Joon-Seok Chae1

1Laboratory of Veterinary Internal Medicine, BK21 FOUR Future Veterinary Medicine Leading Education and Research Center, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
2College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea
3College of Ecology and Environmental Science, Kyungpook National University, Sangju 37224, Korea

Correspondence to:*jschae@snu.ac.kr

Received: June 16, 2022; Revised: September 12, 2022; Accepted: September 20, 2022

Copyright © The Korean Society of Veterinary Clinics.

Canine babesiosis has been scarcely investigated in the Republic of Korea (ROK). Although it is known that Babesia gibsoni is its primary causative agent, its clinical presentation has not been completely clarified in the ROK. Consequently, the aim of this study was to evaluate the clinical appearance of this parasitic infection based on the anamnesis of the patient and compare of hematological and biochemical test results. Four hundred whole blood samples from patients with a presumptive diagnosis of tick-borne disease were analyzed by polymerase chain reaction (PCR) to amplify the Babesia spp. 18S rRNA gene and by a rapid diagnostic test kit (VetAll Laboratories®) to detect B. gibsoni seroreactive animals. Thirty-six (9.0%) dogs were PCR-positive but only 24 (6.0%) were seropositive. The investigation revealed that all the courses of the disease are present in the ROK, with the acute course being predominant. The acute course tends to consist of inappetence, lethargy, pyrexia, gastrointestinal symptoms, and occasionally hematuria. It also occurs with common hematological abnormalities, such as thrombocytopenia and anemia, and to a lesser extent biochemical abnormalities, such as hyperbilirubinemia, hypoalbuminemia, and elevated liver enzymes. This research shows that B. gibsoni is an endemic hemoparasite capable of producing a variety of clinical manifestations in dogs. For its accurate diagnosis, a descriptive history of the clinical signs, hematology, and biochemical profile of the patient, along with a well-performing PCR assay, are essential. These findings will help in planning pragmatic preventive strategies against this potent threat in the ROK.

Keywords: canine babesiosis, Babesia gibsoni, dog, PCR, seroprevalence.

Babesiosis is an emerging tick-borne hemolytic disease caused by intraerythrocytic protozoan parasites of the genus Babesia (10). To date, there are over 100 Babesia species that can infect various vertebrate hosts, occasionally including humans (13). Canine babesiosis is mainly caused by Babesia canis, B. gibsoni, and B. canis vogeli (32). B. gibsoni was first identified in 1910 in India (8), and it has since been reported in the Middle East, Africa, Asia, Europe, the United States, and in some Latin American and Caribbean countries (5,20). Dogs become infected when ticks feed and release sporozoites, which then enter the red blood cells usually within two to three days (29). The clinical manifestation of babesiosis typically occurs after an incubation period of 10 to 28 days (12), and it varies widely from hyper-acute or acute to chronic, and it can even present as a subclinical infection (23). Babesia species are mainly transmitted by tick vectors; however, they can alternatively be transmitted via dog bites, blood transfusions, and transplacental transmission (10). The four genera of ticks that have been reported as vectors of Babesia species are: Rhipicephalus, Ixodes, Haemaphysalis, and Hyalomma, all of which belong to the family Ixodidae (9).

In the Republic of Korea (ROK), the tick species most commonly infected with Babesia species are Haemaphysalis longicornis and H. flava, which can be collected from grass, vegetation, and human patients (11). According to a survey, H. longicornis, H. flava, Ixodes nipponensis, and Rhipicephalus sanguineus sensu late were found to be the tick species that most frequently infest domestic dogs in Korea (6); however, the main tick vector of B. gibsoni in the ROK has not yet been elucidated, especially considering that there have been few surveys of B. gibsoni infection in canines in the ROK. The first molecular detection was performed in German Shepherd dogs in 2004, in which an infection rate of 1.8% (9/501) was identified (27). Subsequently, in 2009, an infection rate of 24.8% (29/117) was reported (14). In 2017, B. gibsoni DNA was identified in 23/440 (5.2%) strictly outdoor dogs using a real-time polymerase chain reaction (PCR) assay (28). Moreover, one of the most recent studies carried out in the country demonstrated the effectiveness of using the ultra fast real-time PCR, giving an accurate diagnosis of babesiosis. In this study it was identified an infection rate of 38.3% (62/162) (33). Currently, there has only been one instance of B. gibsoni in serological evidence from Korean domestic dogs. This evidence was obtained using ELISA and indirect fluorescence immunoassay (IFA) kits, and a seroprevalence of 1.7% (38/2,215) was identified (15).

The present study aimed to investigate the molecular and serological prevalence of B. gibsoni in Korean domestic dogs, as well as to understand the clinical occurrence of the infection through the classification and evaluation of patients according to different courses of the disease. The results of this study may help in elucidating the common clinical presentation, geographical distribution, and risk factors associated with canine babesiosis in the ROK.

Sampling methodology and patient data collection

A total of 400 whole blood samples were collected from companion dogs at different veterinary hospitals and clinical centers located in seven metropolitan cities and nine provinces within the ROK (Fig. 1). The samples were then sent to the Laboratory of Veterinary Internal Medicine, Seoul National University, ROK, between April 2019 and December 2020. The samples were collected in sterile blood collection tubes containing EDTA anticoagulant and submitted to the laboratory in an icepack container. The criteria for referring the sample to the laboratory was based on the presumptive diagnosis of tick-borne disease given by a veterinarian. Such diagnoses were based on clinical symptoms alongside the hematological and biochemical abnormalities presented by the patient on the day of its visit to the veterinary hospital or clinic. Along with the whole blood sample, the patient data, its clinical records, and the hematological and blood chemistry results were provided to the laboratory team for further analysis and interpretation.

Figure 1.Map of the Republic of Korea showing the sampled sites for the detection of B. gibsoni infection in companion dogs in 2019-2020. The gray color indicates sampled provinces, and the purple color represents sampled metropolitan cities. The number of samples analyzed per site are shown in circles.

DNA extraction and PCR amplification

Genomic DNA was extracted from 200 µL of the whole blood sample using the commercial LaboPass DNA Purification Kit (Cosmo Genetech, Seoul, ROK) according to the manufacturer’s instructions. The extracted DNA was stored at –20°C until further analysis. For the detection of Babesia species, a single PCR assay was conducted to amplify its partial 18S rRNA gene (641 bp) using the primer pair BabgenF 5’-GAAACTGCGAATGGCTCATTA-3’ and Babesiarev1 5’-CCATGCTGAAGTATTCAAGAC-3’ (22). These reactions were performed in a total volume of 30 µL, containing 10 pmol of each primer, 15 µL of 2x Taq PCR Pre-mix (BioFACT, Daejeon, ROK), and 50 to 100 ng of genomic DNA samples. The reactions were conducted in a SimpliAmp Thermal Cycler (Thermo Fisher Scientific; Foster City, CA) under optimal cycling conditions. The cycling conditions used in this study for successful amplification consisted of 30 cycles, each of 1 min at 94°C for denaturation, followed by annealing for 1 min at 55°C and extension for 1 min at 72°C. The PCR products were visualized under UV light after 1.5% agarose gel electrophoresis using a 100 bp ladder (Sizer-100 DNA Marker Solution, iNtRON Biotechnology, Seongnam, ROK) as a DNA size marker.

Rapid antibody test for B. gibsoni

The SensPERT Canine Babesia gibsoni Ab Test Kit (sensitivity of 91.8% and specificity of 93.5% vs. IFA) (VetAll Laboratories®, Goyang, ROK) was used to detect seroreactive dogs. The serological test procedure consisted of adding one drop (10 µL) of whole blood to the specimen well using a dropper as a pipette. Two drops (80 µL) of buffer were dispensed onto the whole blood drop until it was completely absorbed. The results were interpreted 10 min later according to the manufacturer’s instructions.

DNA sequencing and phylogenetic analysis

Positive PCR products were purified using the DNA Gel Extraction S & V Kit (BIONICS, Daejeon, ROK) and sequenced using an Applied Biosystems 3730xl capillary DNA Analyzer (Thermo Fisher Scientific; Foster City, CA). Nucleotide sequences were evaluated and confirmed using Chromas software. They were then compared with reference sequences downloaded from the National Center of Biotechnology Information (NCBI) to determine the accuracy of the PCR. Multiple sequence alignment was performed with the program ClustalX 2.1 and corrected with BioEdit software (v 7.2.5). Finally, a similarity matrix was constructed to determine the percentage of similarity between sequences. Phylogenetic analysis was performed based on the maximum likelihood method in MEGA 6.06 software. The stability of the obtained tree was estimated by bootstrap analysis with 1,000 replicates.

Nucleotide sequence accession numbers

The representative sequences obtained in this study of the B. gibsoni partial 18S rRNA gene have been submitted and deposited in the GenBank database under accession numbers MW485704 to MW485725.

Statistical analysis

The statistical analysis was performed using the analytical software package GraphPad Prism (v 5.04; GraphPad Software, Inc., La Jolla, CA). To analyze the significant differences that might exist between regions, genders, age groups, and breeds of dogs, the Chi-square test or Fisher’s exact test was performed. Differences were considered statistically significant if the p value was less than 0.05.

Ethics approval and consent to participate

The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Ethics Committee of Seoul National University Animal Care and Use Committee (No. SNU-190524-2-1). Informed consent was obtained from the owners of all animals involved in the study.

Molecular and serological prevalence

Out of the 400 dogs, 36 (9.0%) were PCR-positive, while only 24 (6.0%) were B. gibsoni seropositive. Dogs from the metropolitan cities of Busan, Incheon, and Seoul were not only PCR-positive, but also antibody-positive, with prevalence rates of 40.0% vs. 13.3%, 12.5% vs. 12.5%, and 11.5% vs. 7.6%, respectively (Table 1). The same pattern of results was observed in Gyeongsangnam-do and Gyeonggi-do provinces, where animals tested positive in both the PCR and antibody tests (Table 1). The highest Babesia spp. infection rate was identified in male dogs (8.9%, 17/192), whereas female dogs were found to be the most seroreactive to B. gibsoni (6.8%, 12/176) (Table 1). The age group classification revealed the highest infection rate in dogs aged 2-4 years (12.9%, 15/116), whereas the highest seroprevalence rate was identified in dogs within the age range of 5-7 years (8.9%, 8/90). Out of the 44 dog breeds, 17 were PCR-positive and 11 were antibody-positive, as shown in Supplementary Table 1. Despite the differences observed between the molecular and serological prevalence analyzed per risk factor, the differences were not statistically significant (Table 1, Supplementary Table 1).

Table 1 Comparison between antigen and antibody prevalence of Babesia gibsoni in companion dogs in 2019-2020 in the Republic of Korea

Risk factorNo. testedPCR positiveSeropositive


No.IR (%)p-valueNo.IR (%)p-value
Region0.96930.6922
Metropolitan cities
Seoul1311511.5107.6
Incheon8112.5112.5
Daejeon70000
Daegu310026.5
Ulsan800112.5
Busan15640.0213.3
Gwangju30000
Provinces
Gyeonggi-do125108.064.8
Gangwon-do90000
Chungbuk-do100000
Chungnam-do10110.000
Gyeongsangbuk-do10000
Gyeongsangnam-do14214.3213.3
Jeollabuk-do190000
Jeollanam-do80000
Jeju-do11100.000
Total400369.0246.0
Sex0.58520.6607
Male192178.9105.2
Female176158.5126.8
NS32412.526.3
Total400369.0246.0
Age0.13750.4628
≤1 year old5123.923.9
2-4 years old1161512.976.0
5-7 years old9088.988.9
8-10 years old57610.558.8
≥11 years old4912.012.0
NS3742.712.7
Total400369.0246.0

IR, Infection Rate; NS, not specified (sex and age not specified in the clinical record).

p ≤ 0.05 considered statistically significant.



Sequencing and phylogenetic analysis

The alignment of the Babesia spp. 18S rRNA nucleotide sequences generated in the present study revealed that all sequences had a fragment length of 641 bp and were 100% identical to each other. Through the Basic Local Alignment Search Tool (BLAST) and the phylogenetic analysis based on the 18S rRNA gene fragment of Babesia species, the genetic relationships between our sequences and the reference sequences downloaded from the GenBank database were confirmed. The sequences were 100% identical to previously sequenced B. gibsoni obtained from dogs, cats, and masked palm civets from several countries, as shown in Supplementary Fig. 1 and Supplementary Table 2.

Clinical signs

To evaluate the common clinical presentation of B. gibsoni infection, 34 clinical records out of the 36 B. gibsoni PCR-positive dogs were classified into three different groups according to their clinical signs, as follows: dogs manifesting symptoms of the complicated form of canine babesiosis (Group I – acute infection), dogs with mild to non-specific symptoms (Group II – chronic infection), and apparently healthy dogs (Group III – subclinical infection) (Table 2). Inappetence (61.8%, 21/34), lethargy (50.0%, 17/34), pyrexia (47.1%, 16/34), gastrointestinal symptoms including diarrhea and vomiting (29.4%, 10/34), and hematuria (23.5%, 8/34) were found to be the most common clinical symptoms (Fig. 2). Other clinical complications are shown in Table 2. In terms of tick exposure, only 22 (64.7%) out of 36 PCR-positive dogs had a history of tick bites (Table 2). Considering the three forms of canine babesiosis, 55.8% (19/34) of the dogs presented an acute infection, 32.4% (11/34) a chronic infection, and 11.8% (4/34) a subclinical infection; the latter dogs were considered as carriers of B. gibsoni (Table 2).

Table 2 Clinical findings observed in dogs infected with B. gibsoni

No.Patient dataTick exposureAnamnesisOther complications

BreedAgeSex
Group I. Acute infection (n = 19)
1Yorkshire Terrier4 yFYesPale gums, lethargy, hematuriaNone
2Yorkshire TerrierNSFYesInappetence, hematuriaNone
3Bichon2 yMNoPyrexia, lethargy, inappetenceIMHA
4PomeranianNSM-Lethargy, inappetence, splenomegalyNone
5Great Pyrenees10 yFYesPyrexia, lethargy, inappetenceNone
6Poodle8 yMYesPyrexia, lethargy, inappetence, GSNone
7Maltese6 yF-Lethargy, inappetence, hematuriaNone
8Poodle10 yNS-Pale gums, lethargy, inappetence, weight loss, depression, hematuriaPancreatitis,hepatic compromise
9Dachshund5 yMYesPyrexia, GS, splenomegaly, hepatomegalyColitis
10Poodle10 yFNoEye edema, jaundice, hematuriaNone
11Mixed6 yM-Pyrexia, lethargy, inappetence, hematuria, splenomegalyCholangiohepatitis, urolithiasis
12Mixed13 yMYesPyrexia, inappetence, weight loss, GSNone
13Maltese8 yMYesPyrexia, lethargy, inappetence, GSNone
14Irish Terrier3 yMYesPyrexia, pale gums, lethargy, GSIMHA
15Pompitz3 yMYesPyrexia, pale gums, inappetence, GS,
jaundice, hematuria, splenomegaly
Pancreatitis
16Poodle3 yMYesPyrexia, inappetence, hematuriaNone
17Bichon Frise6 mM-Lethargy, inappetence, splenomegalyNone
18Mixed6 yF-Pyrexia, pale gums, lethargy, GS, RS, splenomegalyOvarian cysts, chronic bronchitis
19Miniature Pinscher3 yFYesPyrexia, inappetence, depressionNone
Group II. Chronic infection (n = 11)
20Beagle3 yFYesLethargy, inappetenceNone
21Mixed6 yMYesPyrexiaIMHA
22Beagle10 yFYesLethargy, inappetenceNone
23Bichon1 yMYesLethargy, inappetenceNone
24Jindo2 yNSYesPyrexia, inappetenceNone
25Italian Greyhound4 yMYesPyrexiaNone
26Poodle6 yF-Inappetence, GSNone
27Pomeranian5 yFYesLethargy, inappetenceNone
28Mixed2 yMYesGSNone
29Pomeranian4 yMYesLethargy, inappetenceNone
30Poodle4 yMYesPyrexia, GSIMHA
Group III. Subclinical infection (n = 4)
31Mixed3 yFNoApparently healthyNone
32Schnauzer7 yF-Apparently healthyNone
33Jindo2 yF-Apparently healthyNone
34American Pitbull Terrier2 yFYesApparently healthyNone

NS, not specified (age and sex not specified in the clinical record); GS, gastrointestinal symptoms; RS, respiratory symptoms; IMHA, immune-mediated hemolytic anemia; y, years old; m, months; F, female; M, male; Dash, unknown data.


Figure 2.Case of complicated canine babesiosis in the Republic of Korea. (A) A 3-year-old Pompitz (Pomeranian plus Japanese spitz) male dog was presented at the Gyeongsang National University Veterinary Teaching Hospital with a history of pyrexia, jaundice in the (a) skin of the abdomen and at the base of the (b) ears, inappetence, (c) gastrointestinal symptoms such as diarrhea and vomiting, (d) hematuria, pancreatitis, and tick exposure. The hemogram findings were normocytic normochromic regenerative moderate anemia, leukopenia (neutropenia 2.78 109/L, RR: 3.9-8.0), and thrombocytopenia (17 109/L, RR: 148-484). Chemistry results indicated hyperbilirubinemia (1.0 mg/dL, RR: 0.1-0.7). (B) The microscopic examination (1,000×) of the blood smear revealed pleomorphic intraerythrocytic B. gibsoni piroplasms. The clinical record and a whole blood sample from the patient were submitted to the Laboratory of Veterinary Internal Medicine of Seoul National University for further analysis. The patient was (C) PCR-positive to B. gibsoni and (D) seropositive to B. gibsoni antibodies (SensPERT Canine Babesia gibsoni Ab Test Kit, VetAll Laboratories®). The patient was urgently hospitalized, subjected to blood transfusion treatment, and maintained on oral Atovaquone (13.4 mg/kg three times daily) and Azithromycin (10 mg/kg once daily) for 10 days. Response to treatment was monitored by hematocrit and CBC tests along with repeated PCR testing for B. gibsoni at 30 and 60 days.

Hematologic and biochemical test results

Complete blood count (CBC) and biochemistry test results were available for 26 of the 36 B. gibsoni PCR-positive dogs, including 15 acutely infected, 8 chronically infected, and 3 subclinically infected dogs. When comparing the hematology and blood chemistry test results between the three courses of the disease, it was identified that the acute course commonly tended to include the following abnormalities: thrombocytopenia (93.3%, 14/15), anemia (86.7%, 13/15), hyperbilirubinemia (53.3%, 8/15), hypoalbuminemia (40.0%, 6/15), increased aspartate aminotransferase (AST) enzyme activity (26.7%, 4/15), neutropenia (26.7%, 4/15), lymphocytopenia (26.7%, 4/15), and lymphocytosis (26.7%, 4/15). For both the chronic and subclinical courses, thrombocytopenia and anemia were primarily found (Table 3).

Table 3 Comparison of hematologic and biochemical test results of B. gibsoni PCR-positive dogs in 2019-2020 in the Republic of Korea

Blood testParametersUnitReference valuesResults (No. of dog patients)


MinMaxLowNormalHigh



Disease courseTotalDisease courseTotalDisease courseTotal






ACSNo. (%)ACSNo. (%)ACSNo. (%)
Hemogram (n = 26)PCV%37.157.0136221 (80.8)2215 (19.2)0000 (0)
RBC10 × 12/L5.78.8116320 (76.9)4206 (23.1)0000 (0)
Hbg/dL12.918.4136221 (80.8)2215 (19.2)0000 (0)
RDW%11.914.51102 (7.7)115218 (69.2)3216 (23.1)
PLT10 × 9/L148.0484.0147223 (88.5)1012 (7.7)0101 (3.8)
WBC10 × 9/L5.213.92204 (15.4)105318 (69.2)3104 (15.4)
NEUT10 × 9/L3.98.04004 (15.4)107219 (73.1)1113 (11.5)
LYMPH10 × 9/L1.34.14004 (15.4)76316 (61.5)4206 (23.1)
MONO10 × 9/L0.21.12002 (7.7)126321 (80.8)1203 (11.5)
EOS10 × 9/L0.061.232204 (15.4)135321 (80.8)0101 (3.8)
BASO10 × 9/L00.10101 (3.8)156324 (92.3)0101 (3.8)
Biochemistry (n = 26)ALTU/L10.0100.00000 (0)138223 (88.5)2013 (11.5)
ASTU/L11.742.50000 (0)117321 (80.8)4105 (19.2)
BUNmg/dL5.030.00000 (0)148325 (96.2)1001 (3.8)
Creatininemg/dL0.41.60000 (0)148325 (96.2)1001 (3.8)
Total bilirubinmg/dL0.10.70000 (0)76316 (61.5)82010 (38.5)
Albuming/dL2.33.96118 (30.8)97218 (69.2)0000 (0)
Total proteing/dL4.97.22002 (7.7)127322 (84.6)1102 (7.7)

A, acute (n = 15); C, chronic (n = 8); S, subclinical (n = 3); PCV, packed-cell volume; RBC, red blood cell count; Hb, hemoglobin; RDW, red cell distribution width; PLT, platelet count; WBC, white blood cell count; NEUT, neutrophils; LYMPH, lymphocytes; MONO, monocytes; EOS, eosinophils; BASO, basophils; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen.


In the present investigation, there was a notable difference between the total number of PCR-positive animals and the total number of antibody-positive animals [n = 36 (9.0%) vs. n = 24 (6.0%), respectively]. This pattern of results is consistent with previous studies suggesting that it is perfectly feasible for a dog to be seronegative but positive to Babesia infection, as infections by species such as B. canis and B. gibsoni manifest acutely (26). This idea is further supported by the analysis of the clinical history of each PCR-positive dog, which revealed that a large portion of the dogs exhibited the acute course of the disease.

Regarding host susceptibility, age is one of the factors that may predispose dogs to infection and determine the severity of infection, with young dogs being the most prone to severe babesiosis (1). The findings of the present study highlight this theory. It was found that younger dogs, specifically within the age range of 2-4 years old, are the most affected by B. gibsoni infection, whereas older animals (8-10 years old) are the most seroreactive. Poor humoral response and maternal antibody protection are suspected to directly influence the lower seroprevalence rate observed in younger patients (1). Although the differences observed in the infection rates among the breeds tested in this study were not statistically significant, a breed predisposition has been suggested in the USA (5). Specifically, the American Pitbull Terrier is particularly vulnerable to the development of B. gibsoni infection owing to their frequent use as fighting dogs. No significant sex predisposition to the disease was observed in the current study; however, the proportion of male dogs infected with B. gibsoni was relatively high compared to female dogs. This pattern is consistent with the results obtained in the studies performed by Song et al. (27) and Lee et al. (14), who suggested that male dogs are more likely to be kept outdoors as guard dogs or used as fighting dogs. This also explains why there is a higher risk of tick exposure for male dogs in the ROK.

Additionally, our study demonstrates that the clinical expression of canine babesiosis in the ROK ranges from subclinical to acute, the latter being the most common. This result differs from results reported in the USA, in which the subclinical course was found to be the most predominant (3). In the present investigation, the acute course is characterized by pyrexia, pale gums, lethargy, depression, inappetence, weight loss, vomiting, diarrhea, hematuria, jaundice, splenomegaly, and hepatomegaly. Regarding jaundice, there were only two (5.9%) icteric patients in this study, thus supporting the evidence that clinical icterus is rare in Babesia infection (4). Interestingly, 17.6% of the B. gibsoni-infected dogs presented splenomegaly, which is an abnormality considered as a risk factor for the development of natural and potentially fatal babesiosis (25). Other organ dysfunctions found in the acutely infected patients were pancreatitis, liver failure, and chronic bronchitis. Goris and colleagues considered that multiple organ dysfunction syndrome (MODS) develops as a consequence of the dysregulation of proinflammatory and anti-inflammatory mechanisms, resulting in overwhelming auto-destructive inflammation (7). In addition, another study has also demonstrated a correlation between the number of affected organs and mortality (31). The clinical presentation of the chronic course varied greatly in this study from mild symptoms, such as pyrexia, lethargy, inappetence, diarrhea, and vomiting, to completely asymptomatic cases. In general, subclinical carriers were observed to be apparently healthy; however, it is important to keep in mind that there is the possibility that an individual can remain as an infected carrier for many months, possibly even for life (23). This leads to a potential risk for the rapid spread of the disease.

The most common hematological abnormalities found in the current investigation were anemia (80.8%) and thrombocytopenia (88.5%). The pathogenesis of anemia in canine babesiosis is not dependent on the intensity of parasitism (19). Onishi et al. (19) demonstrated the presence of hemolytic factors in the serum of B. gibsoni-infected dogs and the correlation between the activity of the infection and anemia. Therefore, it seems that the hemolytic factors in the serum of B. gibsoni-infected dogs play an important role in the development of anemia in the infection. Thrombocytopenia is considered as the hallmark symptom associated with canine babesiosis, which may result from immune-mediated platelet destruction, platelet sequestration in the spleen, elevated body temperatures, or disseminated intravascular coagulation (DIC) (2). The severity and rapid recovery of the platelet counts have led to the suggestion that immune-mediated mechanisms are involved (21).

Patients in our study also presented alterations in the white blood cell count, with values occurring above the normal range as well as below the normal range. These findings are further supported by previous research that suggests that the leukocyte count is extremely variable in dogs with babesiosis and can range from leukopenic to leukemoid (16).

Biochemical abnormalities revealed that hepatic enzyme activities, including alanine aminotransferase (ALT) and AST, as well as bile acids and albumin levels could be altered in a patient infected with B. gibsoni. This pattern of results is consistent with previous studies (3,18). Consequently, it is of crucial importance to assess liver biofunction while measuring cholinesterase activity in cases of canine babesiosis (24). Blood urea nitrogen (BUN) and creatine levels were elevated in only one patient. A possible reason for this elevated level in some dogs may be due to the non-renal accumulation of ammonia in serum as a result of hemolytic anemia (17). Azotemia appears to be a common complication of B. microti-like piroplasm (Theileria annae) infection. However, our findings, along with those previously reported in the USA (30), suggest the possibility of also finding cases of canine babesiosis due to B. gibsoni with azotemia and proteinuria.

In conclusion, it can be concluded that B. gibsoni is endemic in the ROK, as PCR-positive and seroreactive animals have been identified across the whole country. In the ROK, the disease occurs in its three courses, with its acute course being the most predominant, thus representing a great challenge for veterinary clinicians due to the severity of clinical signs. The classification of patients according to the clinical presentation of the disease favors the identification of the pattern of symptoms and hematological and biochemical abnormalities found in acutely, chronically, and subclinically infected animals.

This research was supported by the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, and Forestry (IPET) through the Animal Disease Management Technology Development Program, which is funded by the Ministry of Agriculture, Food, and Rural Affairs (MAFRA) (119053).

The authors wish to thank VetAll Laboratories® for providing the SensPERT Ab Test Kits for this study. Evelyn Alejandra Miranda expresses her deep gratitude to the National Institute of International Education (NIIED) and the Global Korea Scholarship (GKS) program for the scholarship granted for her graduate studies for 2018-2021.

Conceptualization: Miranda EA, Chae JS; Data curation: Miranda EA; Formal analysis: Miranda EA; Funding acquisition: Chae JS; Investigation: Miranda EA; Methodology: Miranda EA, Chae JS; Project administration: Chae JS; Resources: Han SW, Rim JM, Cho YK, Yu DH, Choi KS, Chae JS; Software: Miranda EA; Supervision: Han SW, Cho YK, Chae JS; Validation: Miranda EA, Choi KS, Yu DH, Chae JS; Visualization: Miranda EA, Chae JS; Writing-original draft: Miranda EA; Writing-review & editing: Miranda EA.

  1. Ayoob AL, Hackner SG, Prittie J. Clinical management of canine babesiosis. J Vet Emerg Crit Care (San Antonio) 2010; 20: 77-89.
    Pubmed CrossRef
  2. Barić Rafaj R, Kuleš J, Selanec J, Vrkić N, Zovko V, Zupančič M, et al. Markers of coagulation activation, endothelial stimulation, and inflammation in dogs with babesiosis. J Vet Intern Med 2013; 27: 1172-1178.
    Pubmed CrossRef
  3. Birkenheuer AJ, Correa MT, Levy MG, Breitschwerdt EB. Geographic distribution of babesiosis among dogs in the United States and association with dog bites: 150 cases (2000-2003). J Am Vet Med Assoc 2005; 227: 942-947.
    Pubmed CrossRef
  4. Boozer AL, Macintire DK. Canine babesiosis. Vet Clin North Am Small Anim Pract 2003; 33: 885-904, viii.
    CrossRef
  5. Boozer L, Macintire D. Babesia gibsoni: an emerging pathogen in dogs. Compend Contin Educ Pract Vet 2005; 2: 33-42.
  6. Choe HC, Fudge M, Sames WJ, Robbins RG, Lee IY, Chevalier NA, et al. Tick surveillance of dogs in the Republic of Korea. Syst Appl Acarol 2011; 16: 215-222.
    CrossRef
  7. Goris RJ, te Boekhorst TP, Nuytinck JK, Gimbrère JS. Multiple-organ failure. Generalized autodestructive inflammation? Arch Surg 1985; 120: 1109-1115.
    Pubmed CrossRef
  8. Groves MG, Yap LF. Babesia gibsoni (Patton, 1910) from a dog in Kuala Lumpur. Med J Malaya 1968; 22: 229.
  9. Hamšíková Z, Kazimírová M, Haruštiaková D, Mahríková L, Slovák M, Berthová L, et al. Babesia spp. in ticks and wildlife in different habitat types of Slovakia. Parasit Vectors 2016; 9: 292.
    Pubmed KoreaMed CrossRef
  10. He L, Miao X, Hu J, Huang Y, He P, He J, et al. First molecular detection of Babesia gibsoni in dogs from Wuhan, China. Front Microbiol 2017; 8: 1577.
    Pubmed KoreaMed CrossRef
  11. Hong SH, Kim SY, Song BG, Rho JR, Cho CR, Kim CN, et al. Detection and characterization of an emerging type of Babesia sp. similar to Babesia motasi for the first case of human babesiosis and ticks in Korea. Emerg Microbes Infect 2019; 8: 869-878.
    Pubmed KoreaMed CrossRef
  12. Köster LS, Lobetti RG, Kelly P. Canine babesiosis: a perspective on clinical complications, biomarkers, and treatment. Vet Med (Auckl) 2015; 6: 119-128.
    Pubmed KoreaMed CrossRef
  13. Krause PJ. Human babesiosis. Int J Parasitol 2019; 49: 165-174.
    Pubmed CrossRef
  14. Lee MJ, Yu DH, Yoon JS, Li YH, Lee JH, Chae JS, et al. Epidemiologic and clinical surveys in dogs infected with Babesia gibsoni in South Korea. Vector Borne Zoonotic Dis 2009; 9: 681-686.
    Pubmed CrossRef
  15. Lee S, Lee H, Park JW, Yoon SS, Seo HJ, Noh J, et al. Prevalence of antibodies against Anaplasma spp., Borrelia burgdorferi sensu lato, Babesia gibsoni, and Ehrlichia spp. in dogs in the Republic of Korea. Ticks Tick Borne Dis 2020; 11: 101412.
    Pubmed CrossRef
  16. Meinkoth JH, Kocan AA, Loud SD, Lorenz MD. Clinical and hematologic effects of experimental infection of dogs with recently identified Babesia gibsoni-like isolates from Oklahoma. J Am Vet Med Assoc 2002; 220: 185-189.
    Pubmed CrossRef
  17. Mittal M, Kundu K, Chakravarti S, Mohapatra JK, Singh VK, Raja Kumar B, et al. Canine babesiosis among working dogs of organised kennels in India: a comprehensive haematological, biochemical, clinicopathological and molecular epidemiological multiregional study. Prev Vet Med 2019; 169: 104696.
    Pubmed KoreaMed CrossRef
  18. Myburgh EC, Goddard A. The effect of pyridoxal-5-phosphate on serum alanine aminotransferase activity in dogs suffering from canine babesiosis. Onderstepoort J Vet Res 2009; 76: 327-333.
    CrossRef
  19. Onishi T, Ueda K, Horie M, Kajikawa T, Ohishi I. Serum hemolytic activity in dogs infected with Babesia gibsoni. J Parasitol 1990; 76: 564-567.
    Pubmed CrossRef
  20. Panti-May JA, Rodríguez-Vivas RI. Canine babesiosis: a literature review of prevalence, distribution, and diagnosis in Latin America and the Caribbean. Vet Parasitol Reg Stud Reports 2020; 21: 100417.
    Pubmed CrossRef
  21. Petra B, Josipa K, Renata BR, Vladimir M. Canine babesiosis: where do we stand? Acta Vet Beogr 2018; 68: 127-160.
    CrossRef
  22. Santos F, Coppede JS, Pereira AL, Oliveira LP, Roberto PG, Benedetti RB, et al. Molecular evaluation of the incidence of Ehrlichia canis, Anaplasma platys and Babesia spp. in dogs from Ribeirão Preto, Brazil. Vet J 2009; 179: 145-148.
    Pubmed CrossRef
  23. Schoeman JP. Canine babesiosis. Onderstepoort J Vet Res 2009; 76: 59-66.
    Pubmed CrossRef
  24. Shabani B, Esmaeilnejad B, Tavassoli M, Imani M. Assessment of cholinesterase activity and hepatic biofunction in dogs naturally infected with Babesia gibsoni. Comp Clin Pathol 2020; 29: 1265-1269.
    CrossRef
  25. Solano-Gallego L, Baneth G. Babesiosis in dogs and cats--expanding parasitological and clinical spectra. Vet Parasitol 2011; 181: 48-60.
    Pubmed CrossRef
  26. Solano-Gallego L, Sainz Á, Roura X, Estrada-Peña A, Miró G. A review of canine babesiosis: the European perspective. Parasit Vectors 2016; 9: 336.
    Pubmed KoreaMed CrossRef
  27. Song KH, Kim DH, Hayasaki M. The PCR-based detection of Babesia gibsoni infection in dogs (German shepherds) reared in South Korea. Ann Trop Med Parasitol 2004; 98: 149-153.
    Pubmed CrossRef
  28. Suh GH, Ahn KS, Ahn JH, Kim HJ, Leutenegger C, Shin S. Serological and molecular prevalence of canine vector-borne diseases (CVBDs) in Korea. Parasit Vectors 2017; 10: 146.
    Pubmed KoreaMed CrossRef
  29. Taboada J, Merchant SR. Babesiosis of companion animals and man. Vet Clin North Am Small Anim Pract 1991; 21: 103-123.
    CrossRef
  30. Ullal T, Birkenheuer A, Vaden S. Azotemia and proteinuria in dogs infected with Babesia gibsoni. J Am Anim Hosp Assoc 2018; 54: 156-160.
    Pubmed CrossRef
  31. Welzl C, Leisewitz AL, Jacobson LS, Vaughan-Scott T, Myburgh E. Systemic inflammatory response syndrome and multiple-organ damage/dysfunction in complicated canine babesiosis. J S Afr Vet Assoc 2001; 72: 158-162.
    Pubmed CrossRef
  32. Wozniak EJ, Barr BC, Thomford JW, Yamane I, McDonough SP, Moore PF, et al. Clinical, anatomic, and immunopathologic characterization of Babesia gibsoni infection in the domestic dog (Canis familiaris). J Parasitol 1997; 83: 692-699.
    Pubmed CrossRef
  33. Yang YS, Mun MJ, Yun YM. Ultra fast real-time PCR for detection of Babesia gibsoni as point of care test. J Vet Clin 2020; 37: 23-27.
    CrossRef

Article

Original Article

J Vet Clin 2022; 39(5): 207-216

Published online October 31, 2022 https://doi.org/10.17555/jvc.2022.39.5.207

Copyright © The Korean Society of Veterinary Clinics.

Clinical and Subclinical Cases of Canine Babesiosis Caused by Babesia gibsoni in the Republic of Korea

Evelyn Alejandra Miranda1 , Sun-Woo Han1 , Ji-Min Rim1 , Yoon-Kyoung Cho1 , DoHyeon Yu2 , Kyoung-Seong Choi3 , Joon-Seok Chae1

1Laboratory of Veterinary Internal Medicine, BK21 FOUR Future Veterinary Medicine Leading Education and Research Center, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
2College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea
3College of Ecology and Environmental Science, Kyungpook National University, Sangju 37224, Korea

Correspondence to:*jschae@snu.ac.kr

Received: June 16, 2022; Revised: September 12, 2022; Accepted: September 20, 2022

This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial 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.

Abstract

Canine babesiosis has been scarcely investigated in the Republic of Korea (ROK). Although it is known that Babesia gibsoni is its primary causative agent, its clinical presentation has not been completely clarified in the ROK. Consequently, the aim of this study was to evaluate the clinical appearance of this parasitic infection based on the anamnesis of the patient and compare of hematological and biochemical test results. Four hundred whole blood samples from patients with a presumptive diagnosis of tick-borne disease were analyzed by polymerase chain reaction (PCR) to amplify the Babesia spp. 18S rRNA gene and by a rapid diagnostic test kit (VetAll Laboratories®) to detect B. gibsoni seroreactive animals. Thirty-six (9.0%) dogs were PCR-positive but only 24 (6.0%) were seropositive. The investigation revealed that all the courses of the disease are present in the ROK, with the acute course being predominant. The acute course tends to consist of inappetence, lethargy, pyrexia, gastrointestinal symptoms, and occasionally hematuria. It also occurs with common hematological abnormalities, such as thrombocytopenia and anemia, and to a lesser extent biochemical abnormalities, such as hyperbilirubinemia, hypoalbuminemia, and elevated liver enzymes. This research shows that B. gibsoni is an endemic hemoparasite capable of producing a variety of clinical manifestations in dogs. For its accurate diagnosis, a descriptive history of the clinical signs, hematology, and biochemical profile of the patient, along with a well-performing PCR assay, are essential. These findings will help in planning pragmatic preventive strategies against this potent threat in the ROK.

Keywords: canine babesiosis, Babesia gibsoni, dog, PCR, seroprevalence.

Introduction

Babesiosis is an emerging tick-borne hemolytic disease caused by intraerythrocytic protozoan parasites of the genus Babesia (10). To date, there are over 100 Babesia species that can infect various vertebrate hosts, occasionally including humans (13). Canine babesiosis is mainly caused by Babesia canis, B. gibsoni, and B. canis vogeli (32). B. gibsoni was first identified in 1910 in India (8), and it has since been reported in the Middle East, Africa, Asia, Europe, the United States, and in some Latin American and Caribbean countries (5,20). Dogs become infected when ticks feed and release sporozoites, which then enter the red blood cells usually within two to three days (29). The clinical manifestation of babesiosis typically occurs after an incubation period of 10 to 28 days (12), and it varies widely from hyper-acute or acute to chronic, and it can even present as a subclinical infection (23). Babesia species are mainly transmitted by tick vectors; however, they can alternatively be transmitted via dog bites, blood transfusions, and transplacental transmission (10). The four genera of ticks that have been reported as vectors of Babesia species are: Rhipicephalus, Ixodes, Haemaphysalis, and Hyalomma, all of which belong to the family Ixodidae (9).

In the Republic of Korea (ROK), the tick species most commonly infected with Babesia species are Haemaphysalis longicornis and H. flava, which can be collected from grass, vegetation, and human patients (11). According to a survey, H. longicornis, H. flava, Ixodes nipponensis, and Rhipicephalus sanguineus sensu late were found to be the tick species that most frequently infest domestic dogs in Korea (6); however, the main tick vector of B. gibsoni in the ROK has not yet been elucidated, especially considering that there have been few surveys of B. gibsoni infection in canines in the ROK. The first molecular detection was performed in German Shepherd dogs in 2004, in which an infection rate of 1.8% (9/501) was identified (27). Subsequently, in 2009, an infection rate of 24.8% (29/117) was reported (14). In 2017, B. gibsoni DNA was identified in 23/440 (5.2%) strictly outdoor dogs using a real-time polymerase chain reaction (PCR) assay (28). Moreover, one of the most recent studies carried out in the country demonstrated the effectiveness of using the ultra fast real-time PCR, giving an accurate diagnosis of babesiosis. In this study it was identified an infection rate of 38.3% (62/162) (33). Currently, there has only been one instance of B. gibsoni in serological evidence from Korean domestic dogs. This evidence was obtained using ELISA and indirect fluorescence immunoassay (IFA) kits, and a seroprevalence of 1.7% (38/2,215) was identified (15).

The present study aimed to investigate the molecular and serological prevalence of B. gibsoni in Korean domestic dogs, as well as to understand the clinical occurrence of the infection through the classification and evaluation of patients according to different courses of the disease. The results of this study may help in elucidating the common clinical presentation, geographical distribution, and risk factors associated with canine babesiosis in the ROK.

Materials and Methods

Sampling methodology and patient data collection

A total of 400 whole blood samples were collected from companion dogs at different veterinary hospitals and clinical centers located in seven metropolitan cities and nine provinces within the ROK (Fig. 1). The samples were then sent to the Laboratory of Veterinary Internal Medicine, Seoul National University, ROK, between April 2019 and December 2020. The samples were collected in sterile blood collection tubes containing EDTA anticoagulant and submitted to the laboratory in an icepack container. The criteria for referring the sample to the laboratory was based on the presumptive diagnosis of tick-borne disease given by a veterinarian. Such diagnoses were based on clinical symptoms alongside the hematological and biochemical abnormalities presented by the patient on the day of its visit to the veterinary hospital or clinic. Along with the whole blood sample, the patient data, its clinical records, and the hematological and blood chemistry results were provided to the laboratory team for further analysis and interpretation.

Figure 1. Map of the Republic of Korea showing the sampled sites for the detection of B. gibsoni infection in companion dogs in 2019-2020. The gray color indicates sampled provinces, and the purple color represents sampled metropolitan cities. The number of samples analyzed per site are shown in circles.

DNA extraction and PCR amplification

Genomic DNA was extracted from 200 µL of the whole blood sample using the commercial LaboPass DNA Purification Kit (Cosmo Genetech, Seoul, ROK) according to the manufacturer’s instructions. The extracted DNA was stored at –20°C until further analysis. For the detection of Babesia species, a single PCR assay was conducted to amplify its partial 18S rRNA gene (641 bp) using the primer pair BabgenF 5’-GAAACTGCGAATGGCTCATTA-3’ and Babesiarev1 5’-CCATGCTGAAGTATTCAAGAC-3’ (22). These reactions were performed in a total volume of 30 µL, containing 10 pmol of each primer, 15 µL of 2x Taq PCR Pre-mix (BioFACT, Daejeon, ROK), and 50 to 100 ng of genomic DNA samples. The reactions were conducted in a SimpliAmp Thermal Cycler (Thermo Fisher Scientific; Foster City, CA) under optimal cycling conditions. The cycling conditions used in this study for successful amplification consisted of 30 cycles, each of 1 min at 94°C for denaturation, followed by annealing for 1 min at 55°C and extension for 1 min at 72°C. The PCR products were visualized under UV light after 1.5% agarose gel electrophoresis using a 100 bp ladder (Sizer-100 DNA Marker Solution, iNtRON Biotechnology, Seongnam, ROK) as a DNA size marker.

Rapid antibody test for B. gibsoni

The SensPERT Canine Babesia gibsoni Ab Test Kit (sensitivity of 91.8% and specificity of 93.5% vs. IFA) (VetAll Laboratories®, Goyang, ROK) was used to detect seroreactive dogs. The serological test procedure consisted of adding one drop (10 µL) of whole blood to the specimen well using a dropper as a pipette. Two drops (80 µL) of buffer were dispensed onto the whole blood drop until it was completely absorbed. The results were interpreted 10 min later according to the manufacturer’s instructions.

DNA sequencing and phylogenetic analysis

Positive PCR products were purified using the DNA Gel Extraction S & V Kit (BIONICS, Daejeon, ROK) and sequenced using an Applied Biosystems 3730xl capillary DNA Analyzer (Thermo Fisher Scientific; Foster City, CA). Nucleotide sequences were evaluated and confirmed using Chromas software. They were then compared with reference sequences downloaded from the National Center of Biotechnology Information (NCBI) to determine the accuracy of the PCR. Multiple sequence alignment was performed with the program ClustalX 2.1 and corrected with BioEdit software (v 7.2.5). Finally, a similarity matrix was constructed to determine the percentage of similarity between sequences. Phylogenetic analysis was performed based on the maximum likelihood method in MEGA 6.06 software. The stability of the obtained tree was estimated by bootstrap analysis with 1,000 replicates.

Nucleotide sequence accession numbers

The representative sequences obtained in this study of the B. gibsoni partial 18S rRNA gene have been submitted and deposited in the GenBank database under accession numbers MW485704 to MW485725.

Statistical analysis

The statistical analysis was performed using the analytical software package GraphPad Prism (v 5.04; GraphPad Software, Inc., La Jolla, CA). To analyze the significant differences that might exist between regions, genders, age groups, and breeds of dogs, the Chi-square test or Fisher’s exact test was performed. Differences were considered statistically significant if the p value was less than 0.05.

Ethics approval and consent to participate

The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Ethics Committee of Seoul National University Animal Care and Use Committee (No. SNU-190524-2-1). Informed consent was obtained from the owners of all animals involved in the study.

Results

Molecular and serological prevalence

Out of the 400 dogs, 36 (9.0%) were PCR-positive, while only 24 (6.0%) were B. gibsoni seropositive. Dogs from the metropolitan cities of Busan, Incheon, and Seoul were not only PCR-positive, but also antibody-positive, with prevalence rates of 40.0% vs. 13.3%, 12.5% vs. 12.5%, and 11.5% vs. 7.6%, respectively (Table 1). The same pattern of results was observed in Gyeongsangnam-do and Gyeonggi-do provinces, where animals tested positive in both the PCR and antibody tests (Table 1). The highest Babesia spp. infection rate was identified in male dogs (8.9%, 17/192), whereas female dogs were found to be the most seroreactive to B. gibsoni (6.8%, 12/176) (Table 1). The age group classification revealed the highest infection rate in dogs aged 2-4 years (12.9%, 15/116), whereas the highest seroprevalence rate was identified in dogs within the age range of 5-7 years (8.9%, 8/90). Out of the 44 dog breeds, 17 were PCR-positive and 11 were antibody-positive, as shown in Supplementary Table 1. Despite the differences observed between the molecular and serological prevalence analyzed per risk factor, the differences were not statistically significant (Table 1, Supplementary Table 1).

Table 1 . Comparison between antigen and antibody prevalence of Babesia gibsoni in companion dogs in 2019-2020 in the Republic of Korea.

Risk factorNo. testedPCR positiveSeropositive


No.IR (%)p-valueNo.IR (%)p-value
Region0.96930.6922
Metropolitan cities
Seoul1311511.5107.6
Incheon8112.5112.5
Daejeon70000
Daegu310026.5
Ulsan800112.5
Busan15640.0213.3
Gwangju30000
Provinces
Gyeonggi-do125108.064.8
Gangwon-do90000
Chungbuk-do100000
Chungnam-do10110.000
Gyeongsangbuk-do10000
Gyeongsangnam-do14214.3213.3
Jeollabuk-do190000
Jeollanam-do80000
Jeju-do11100.000
Total400369.0246.0
Sex0.58520.6607
Male192178.9105.2
Female176158.5126.8
NS32412.526.3
Total400369.0246.0
Age0.13750.4628
≤1 year old5123.923.9
2-4 years old1161512.976.0
5-7 years old9088.988.9
8-10 years old57610.558.8
≥11 years old4912.012.0
NS3742.712.7
Total400369.0246.0

IR, Infection Rate; NS, not specified (sex and age not specified in the clinical record)..

p ≤ 0.05 considered statistically significant..



Sequencing and phylogenetic analysis

The alignment of the Babesia spp. 18S rRNA nucleotide sequences generated in the present study revealed that all sequences had a fragment length of 641 bp and were 100% identical to each other. Through the Basic Local Alignment Search Tool (BLAST) and the phylogenetic analysis based on the 18S rRNA gene fragment of Babesia species, the genetic relationships between our sequences and the reference sequences downloaded from the GenBank database were confirmed. The sequences were 100% identical to previously sequenced B. gibsoni obtained from dogs, cats, and masked palm civets from several countries, as shown in Supplementary Fig. 1 and Supplementary Table 2.

Clinical signs

To evaluate the common clinical presentation of B. gibsoni infection, 34 clinical records out of the 36 B. gibsoni PCR-positive dogs were classified into three different groups according to their clinical signs, as follows: dogs manifesting symptoms of the complicated form of canine babesiosis (Group I – acute infection), dogs with mild to non-specific symptoms (Group II – chronic infection), and apparently healthy dogs (Group III – subclinical infection) (Table 2). Inappetence (61.8%, 21/34), lethargy (50.0%, 17/34), pyrexia (47.1%, 16/34), gastrointestinal symptoms including diarrhea and vomiting (29.4%, 10/34), and hematuria (23.5%, 8/34) were found to be the most common clinical symptoms (Fig. 2). Other clinical complications are shown in Table 2. In terms of tick exposure, only 22 (64.7%) out of 36 PCR-positive dogs had a history of tick bites (Table 2). Considering the three forms of canine babesiosis, 55.8% (19/34) of the dogs presented an acute infection, 32.4% (11/34) a chronic infection, and 11.8% (4/34) a subclinical infection; the latter dogs were considered as carriers of B. gibsoni (Table 2).

Table 2 . Clinical findings observed in dogs infected with B. gibsoni.

No.Patient dataTick exposureAnamnesisOther complications

BreedAgeSex
Group I. Acute infection (n = 19)
1Yorkshire Terrier4 yFYesPale gums, lethargy, hematuriaNone
2Yorkshire TerrierNSFYesInappetence, hematuriaNone
3Bichon2 yMNoPyrexia, lethargy, inappetenceIMHA
4PomeranianNSM-Lethargy, inappetence, splenomegalyNone
5Great Pyrenees10 yFYesPyrexia, lethargy, inappetenceNone
6Poodle8 yMYesPyrexia, lethargy, inappetence, GSNone
7Maltese6 yF-Lethargy, inappetence, hematuriaNone
8Poodle10 yNS-Pale gums, lethargy, inappetence, weight loss, depression, hematuriaPancreatitis,hepatic compromise
9Dachshund5 yMYesPyrexia, GS, splenomegaly, hepatomegalyColitis
10Poodle10 yFNoEye edema, jaundice, hematuriaNone
11Mixed6 yM-Pyrexia, lethargy, inappetence, hematuria, splenomegalyCholangiohepatitis, urolithiasis
12Mixed13 yMYesPyrexia, inappetence, weight loss, GSNone
13Maltese8 yMYesPyrexia, lethargy, inappetence, GSNone
14Irish Terrier3 yMYesPyrexia, pale gums, lethargy, GSIMHA
15Pompitz3 yMYesPyrexia, pale gums, inappetence, GS,
jaundice, hematuria, splenomegaly
Pancreatitis
16Poodle3 yMYesPyrexia, inappetence, hematuriaNone
17Bichon Frise6 mM-Lethargy, inappetence, splenomegalyNone
18Mixed6 yF-Pyrexia, pale gums, lethargy, GS, RS, splenomegalyOvarian cysts, chronic bronchitis
19Miniature Pinscher3 yFYesPyrexia, inappetence, depressionNone
Group II. Chronic infection (n = 11)
20Beagle3 yFYesLethargy, inappetenceNone
21Mixed6 yMYesPyrexiaIMHA
22Beagle10 yFYesLethargy, inappetenceNone
23Bichon1 yMYesLethargy, inappetenceNone
24Jindo2 yNSYesPyrexia, inappetenceNone
25Italian Greyhound4 yMYesPyrexiaNone
26Poodle6 yF-Inappetence, GSNone
27Pomeranian5 yFYesLethargy, inappetenceNone
28Mixed2 yMYesGSNone
29Pomeranian4 yMYesLethargy, inappetenceNone
30Poodle4 yMYesPyrexia, GSIMHA
Group III. Subclinical infection (n = 4)
31Mixed3 yFNoApparently healthyNone
32Schnauzer7 yF-Apparently healthyNone
33Jindo2 yF-Apparently healthyNone
34American Pitbull Terrier2 yFYesApparently healthyNone

NS, not specified (age and sex not specified in the clinical record); GS, gastrointestinal symptoms; RS, respiratory symptoms; IMHA, immune-mediated hemolytic anemia; y, years old; m, months; F, female; M, male; Dash, unknown data..


Figure 2. Case of complicated canine babesiosis in the Republic of Korea. (A) A 3-year-old Pompitz (Pomeranian plus Japanese spitz) male dog was presented at the Gyeongsang National University Veterinary Teaching Hospital with a history of pyrexia, jaundice in the (a) skin of the abdomen and at the base of the (b) ears, inappetence, (c) gastrointestinal symptoms such as diarrhea and vomiting, (d) hematuria, pancreatitis, and tick exposure. The hemogram findings were normocytic normochromic regenerative moderate anemia, leukopenia (neutropenia 2.78 109/L, RR: 3.9-8.0), and thrombocytopenia (17 109/L, RR: 148-484). Chemistry results indicated hyperbilirubinemia (1.0 mg/dL, RR: 0.1-0.7). (B) The microscopic examination (1,000×) of the blood smear revealed pleomorphic intraerythrocytic B. gibsoni piroplasms. The clinical record and a whole blood sample from the patient were submitted to the Laboratory of Veterinary Internal Medicine of Seoul National University for further analysis. The patient was (C) PCR-positive to B. gibsoni and (D) seropositive to B. gibsoni antibodies (SensPERT Canine Babesia gibsoni Ab Test Kit, VetAll Laboratories®). The patient was urgently hospitalized, subjected to blood transfusion treatment, and maintained on oral Atovaquone (13.4 mg/kg three times daily) and Azithromycin (10 mg/kg once daily) for 10 days. Response to treatment was monitored by hematocrit and CBC tests along with repeated PCR testing for B. gibsoni at 30 and 60 days.

Hematologic and biochemical test results

Complete blood count (CBC) and biochemistry test results were available for 26 of the 36 B. gibsoni PCR-positive dogs, including 15 acutely infected, 8 chronically infected, and 3 subclinically infected dogs. When comparing the hematology and blood chemistry test results between the three courses of the disease, it was identified that the acute course commonly tended to include the following abnormalities: thrombocytopenia (93.3%, 14/15), anemia (86.7%, 13/15), hyperbilirubinemia (53.3%, 8/15), hypoalbuminemia (40.0%, 6/15), increased aspartate aminotransferase (AST) enzyme activity (26.7%, 4/15), neutropenia (26.7%, 4/15), lymphocytopenia (26.7%, 4/15), and lymphocytosis (26.7%, 4/15). For both the chronic and subclinical courses, thrombocytopenia and anemia were primarily found (Table 3).

Table 3 . Comparison of hematologic and biochemical test results of B. gibsoni PCR-positive dogs in 2019-2020 in the Republic of Korea.

Blood testParametersUnitReference valuesResults (No. of dog patients)


MinMaxLowNormalHigh



Disease courseTotalDisease courseTotalDisease courseTotal






ACSNo. (%)ACSNo. (%)ACSNo. (%)
Hemogram (n = 26)PCV%37.157.0136221 (80.8)2215 (19.2)0000 (0)
RBC10 × 12/L5.78.8116320 (76.9)4206 (23.1)0000 (0)
Hbg/dL12.918.4136221 (80.8)2215 (19.2)0000 (0)
RDW%11.914.51102 (7.7)115218 (69.2)3216 (23.1)
PLT10 × 9/L148.0484.0147223 (88.5)1012 (7.7)0101 (3.8)
WBC10 × 9/L5.213.92204 (15.4)105318 (69.2)3104 (15.4)
NEUT10 × 9/L3.98.04004 (15.4)107219 (73.1)1113 (11.5)
LYMPH10 × 9/L1.34.14004 (15.4)76316 (61.5)4206 (23.1)
MONO10 × 9/L0.21.12002 (7.7)126321 (80.8)1203 (11.5)
EOS10 × 9/L0.061.232204 (15.4)135321 (80.8)0101 (3.8)
BASO10 × 9/L00.10101 (3.8)156324 (92.3)0101 (3.8)
Biochemistry (n = 26)ALTU/L10.0100.00000 (0)138223 (88.5)2013 (11.5)
ASTU/L11.742.50000 (0)117321 (80.8)4105 (19.2)
BUNmg/dL5.030.00000 (0)148325 (96.2)1001 (3.8)
Creatininemg/dL0.41.60000 (0)148325 (96.2)1001 (3.8)
Total bilirubinmg/dL0.10.70000 (0)76316 (61.5)82010 (38.5)
Albuming/dL2.33.96118 (30.8)97218 (69.2)0000 (0)
Total proteing/dL4.97.22002 (7.7)127322 (84.6)1102 (7.7)

A, acute (n = 15); C, chronic (n = 8); S, subclinical (n = 3); PCV, packed-cell volume; RBC, red blood cell count; Hb, hemoglobin; RDW, red cell distribution width; PLT, platelet count; WBC, white blood cell count; NEUT, neutrophils; LYMPH, lymphocytes; MONO, monocytes; EOS, eosinophils; BASO, basophils; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen..


Discussion

In the present investigation, there was a notable difference between the total number of PCR-positive animals and the total number of antibody-positive animals [n = 36 (9.0%) vs. n = 24 (6.0%), respectively]. This pattern of results is consistent with previous studies suggesting that it is perfectly feasible for a dog to be seronegative but positive to Babesia infection, as infections by species such as B. canis and B. gibsoni manifest acutely (26). This idea is further supported by the analysis of the clinical history of each PCR-positive dog, which revealed that a large portion of the dogs exhibited the acute course of the disease.

Regarding host susceptibility, age is one of the factors that may predispose dogs to infection and determine the severity of infection, with young dogs being the most prone to severe babesiosis (1). The findings of the present study highlight this theory. It was found that younger dogs, specifically within the age range of 2-4 years old, are the most affected by B. gibsoni infection, whereas older animals (8-10 years old) are the most seroreactive. Poor humoral response and maternal antibody protection are suspected to directly influence the lower seroprevalence rate observed in younger patients (1). Although the differences observed in the infection rates among the breeds tested in this study were not statistically significant, a breed predisposition has been suggested in the USA (5). Specifically, the American Pitbull Terrier is particularly vulnerable to the development of B. gibsoni infection owing to their frequent use as fighting dogs. No significant sex predisposition to the disease was observed in the current study; however, the proportion of male dogs infected with B. gibsoni was relatively high compared to female dogs. This pattern is consistent with the results obtained in the studies performed by Song et al. (27) and Lee et al. (14), who suggested that male dogs are more likely to be kept outdoors as guard dogs or used as fighting dogs. This also explains why there is a higher risk of tick exposure for male dogs in the ROK.

Additionally, our study demonstrates that the clinical expression of canine babesiosis in the ROK ranges from subclinical to acute, the latter being the most common. This result differs from results reported in the USA, in which the subclinical course was found to be the most predominant (3). In the present investigation, the acute course is characterized by pyrexia, pale gums, lethargy, depression, inappetence, weight loss, vomiting, diarrhea, hematuria, jaundice, splenomegaly, and hepatomegaly. Regarding jaundice, there were only two (5.9%) icteric patients in this study, thus supporting the evidence that clinical icterus is rare in Babesia infection (4). Interestingly, 17.6% of the B. gibsoni-infected dogs presented splenomegaly, which is an abnormality considered as a risk factor for the development of natural and potentially fatal babesiosis (25). Other organ dysfunctions found in the acutely infected patients were pancreatitis, liver failure, and chronic bronchitis. Goris and colleagues considered that multiple organ dysfunction syndrome (MODS) develops as a consequence of the dysregulation of proinflammatory and anti-inflammatory mechanisms, resulting in overwhelming auto-destructive inflammation (7). In addition, another study has also demonstrated a correlation between the number of affected organs and mortality (31). The clinical presentation of the chronic course varied greatly in this study from mild symptoms, such as pyrexia, lethargy, inappetence, diarrhea, and vomiting, to completely asymptomatic cases. In general, subclinical carriers were observed to be apparently healthy; however, it is important to keep in mind that there is the possibility that an individual can remain as an infected carrier for many months, possibly even for life (23). This leads to a potential risk for the rapid spread of the disease.

The most common hematological abnormalities found in the current investigation were anemia (80.8%) and thrombocytopenia (88.5%). The pathogenesis of anemia in canine babesiosis is not dependent on the intensity of parasitism (19). Onishi et al. (19) demonstrated the presence of hemolytic factors in the serum of B. gibsoni-infected dogs and the correlation between the activity of the infection and anemia. Therefore, it seems that the hemolytic factors in the serum of B. gibsoni-infected dogs play an important role in the development of anemia in the infection. Thrombocytopenia is considered as the hallmark symptom associated with canine babesiosis, which may result from immune-mediated platelet destruction, platelet sequestration in the spleen, elevated body temperatures, or disseminated intravascular coagulation (DIC) (2). The severity and rapid recovery of the platelet counts have led to the suggestion that immune-mediated mechanisms are involved (21).

Patients in our study also presented alterations in the white blood cell count, with values occurring above the normal range as well as below the normal range. These findings are further supported by previous research that suggests that the leukocyte count is extremely variable in dogs with babesiosis and can range from leukopenic to leukemoid (16).

Biochemical abnormalities revealed that hepatic enzyme activities, including alanine aminotransferase (ALT) and AST, as well as bile acids and albumin levels could be altered in a patient infected with B. gibsoni. This pattern of results is consistent with previous studies (3,18). Consequently, it is of crucial importance to assess liver biofunction while measuring cholinesterase activity in cases of canine babesiosis (24). Blood urea nitrogen (BUN) and creatine levels were elevated in only one patient. A possible reason for this elevated level in some dogs may be due to the non-renal accumulation of ammonia in serum as a result of hemolytic anemia (17). Azotemia appears to be a common complication of B. microti-like piroplasm (Theileria annae) infection. However, our findings, along with those previously reported in the USA (30), suggest the possibility of also finding cases of canine babesiosis due to B. gibsoni with azotemia and proteinuria.

In conclusion, it can be concluded that B. gibsoni is endemic in the ROK, as PCR-positive and seroreactive animals have been identified across the whole country. In the ROK, the disease occurs in its three courses, with its acute course being the most predominant, thus representing a great challenge for veterinary clinicians due to the severity of clinical signs. The classification of patients according to the clinical presentation of the disease favors the identification of the pattern of symptoms and hematological and biochemical abnormalities found in acutely, chronically, and subclinically infected animals.

Source of Funding

This research was supported by the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, and Forestry (IPET) through the Animal Disease Management Technology Development Program, which is funded by the Ministry of Agriculture, Food, and Rural Affairs (MAFRA) (119053).

Supplemental Material

Acknowledgements

The authors wish to thank VetAll Laboratories® for providing the SensPERT Ab Test Kits for this study. Evelyn Alejandra Miranda expresses her deep gratitude to the National Institute of International Education (NIIED) and the Global Korea Scholarship (GKS) program for the scholarship granted for her graduate studies for 2018-2021.

Conflicts of Interest

The authors have no conflicting interests.

Author Contributions

Conceptualization: Miranda EA, Chae JS; Data curation: Miranda EA; Formal analysis: Miranda EA; Funding acquisition: Chae JS; Investigation: Miranda EA; Methodology: Miranda EA, Chae JS; Project administration: Chae JS; Resources: Han SW, Rim JM, Cho YK, Yu DH, Choi KS, Chae JS; Software: Miranda EA; Supervision: Han SW, Cho YK, Chae JS; Validation: Miranda EA, Choi KS, Yu DH, Chae JS; Visualization: Miranda EA, Chae JS; Writing-original draft: Miranda EA; Writing-review & editing: Miranda EA.

Fig 1.

Figure 1.Map of the Republic of Korea showing the sampled sites for the detection of B. gibsoni infection in companion dogs in 2019-2020. The gray color indicates sampled provinces, and the purple color represents sampled metropolitan cities. The number of samples analyzed per site are shown in circles.
Journal of Veterinary Clinics 2022; 39: 207-216https://doi.org/10.17555/jvc.2022.39.5.207

Fig 2.

Figure 2.Case of complicated canine babesiosis in the Republic of Korea. (A) A 3-year-old Pompitz (Pomeranian plus Japanese spitz) male dog was presented at the Gyeongsang National University Veterinary Teaching Hospital with a history of pyrexia, jaundice in the (a) skin of the abdomen and at the base of the (b) ears, inappetence, (c) gastrointestinal symptoms such as diarrhea and vomiting, (d) hematuria, pancreatitis, and tick exposure. The hemogram findings were normocytic normochromic regenerative moderate anemia, leukopenia (neutropenia 2.78 109/L, RR: 3.9-8.0), and thrombocytopenia (17 109/L, RR: 148-484). Chemistry results indicated hyperbilirubinemia (1.0 mg/dL, RR: 0.1-0.7). (B) The microscopic examination (1,000×) of the blood smear revealed pleomorphic intraerythrocytic B. gibsoni piroplasms. The clinical record and a whole blood sample from the patient were submitted to the Laboratory of Veterinary Internal Medicine of Seoul National University for further analysis. The patient was (C) PCR-positive to B. gibsoni and (D) seropositive to B. gibsoni antibodies (SensPERT Canine Babesia gibsoni Ab Test Kit, VetAll Laboratories®). The patient was urgently hospitalized, subjected to blood transfusion treatment, and maintained on oral Atovaquone (13.4 mg/kg three times daily) and Azithromycin (10 mg/kg once daily) for 10 days. Response to treatment was monitored by hematocrit and CBC tests along with repeated PCR testing for B. gibsoni at 30 and 60 days.
Journal of Veterinary Clinics 2022; 39: 207-216https://doi.org/10.17555/jvc.2022.39.5.207

Table 1 Comparison between antigen and antibody prevalence of Babesia gibsoni in companion dogs in 2019-2020 in the Republic of Korea

Risk factorNo. testedPCR positiveSeropositive


No.IR (%)p-valueNo.IR (%)p-value
Region0.96930.6922
Metropolitan cities
Seoul1311511.5107.6
Incheon8112.5112.5
Daejeon70000
Daegu310026.5
Ulsan800112.5
Busan15640.0213.3
Gwangju30000
Provinces
Gyeonggi-do125108.064.8
Gangwon-do90000
Chungbuk-do100000
Chungnam-do10110.000
Gyeongsangbuk-do10000
Gyeongsangnam-do14214.3213.3
Jeollabuk-do190000
Jeollanam-do80000
Jeju-do11100.000
Total400369.0246.0
Sex0.58520.6607
Male192178.9105.2
Female176158.5126.8
NS32412.526.3
Total400369.0246.0
Age0.13750.4628
≤1 year old5123.923.9
2-4 years old1161512.976.0
5-7 years old9088.988.9
8-10 years old57610.558.8
≥11 years old4912.012.0
NS3742.712.7
Total400369.0246.0

IR, Infection Rate; NS, not specified (sex and age not specified in the clinical record).

p ≤ 0.05 considered statistically significant.


Table 2 Clinical findings observed in dogs infected with B. gibsoni

No.Patient dataTick exposureAnamnesisOther complications

BreedAgeSex
Group I. Acute infection (n = 19)
1Yorkshire Terrier4 yFYesPale gums, lethargy, hematuriaNone
2Yorkshire TerrierNSFYesInappetence, hematuriaNone
3Bichon2 yMNoPyrexia, lethargy, inappetenceIMHA
4PomeranianNSM-Lethargy, inappetence, splenomegalyNone
5Great Pyrenees10 yFYesPyrexia, lethargy, inappetenceNone
6Poodle8 yMYesPyrexia, lethargy, inappetence, GSNone
7Maltese6 yF-Lethargy, inappetence, hematuriaNone
8Poodle10 yNS-Pale gums, lethargy, inappetence, weight loss, depression, hematuriaPancreatitis,hepatic compromise
9Dachshund5 yMYesPyrexia, GS, splenomegaly, hepatomegalyColitis
10Poodle10 yFNoEye edema, jaundice, hematuriaNone
11Mixed6 yM-Pyrexia, lethargy, inappetence, hematuria, splenomegalyCholangiohepatitis, urolithiasis
12Mixed13 yMYesPyrexia, inappetence, weight loss, GSNone
13Maltese8 yMYesPyrexia, lethargy, inappetence, GSNone
14Irish Terrier3 yMYesPyrexia, pale gums, lethargy, GSIMHA
15Pompitz3 yMYesPyrexia, pale gums, inappetence, GS,
jaundice, hematuria, splenomegaly
Pancreatitis
16Poodle3 yMYesPyrexia, inappetence, hematuriaNone
17Bichon Frise6 mM-Lethargy, inappetence, splenomegalyNone
18Mixed6 yF-Pyrexia, pale gums, lethargy, GS, RS, splenomegalyOvarian cysts, chronic bronchitis
19Miniature Pinscher3 yFYesPyrexia, inappetence, depressionNone
Group II. Chronic infection (n = 11)
20Beagle3 yFYesLethargy, inappetenceNone
21Mixed6 yMYesPyrexiaIMHA
22Beagle10 yFYesLethargy, inappetenceNone
23Bichon1 yMYesLethargy, inappetenceNone
24Jindo2 yNSYesPyrexia, inappetenceNone
25Italian Greyhound4 yMYesPyrexiaNone
26Poodle6 yF-Inappetence, GSNone
27Pomeranian5 yFYesLethargy, inappetenceNone
28Mixed2 yMYesGSNone
29Pomeranian4 yMYesLethargy, inappetenceNone
30Poodle4 yMYesPyrexia, GSIMHA
Group III. Subclinical infection (n = 4)
31Mixed3 yFNoApparently healthyNone
32Schnauzer7 yF-Apparently healthyNone
33Jindo2 yF-Apparently healthyNone
34American Pitbull Terrier2 yFYesApparently healthyNone

NS, not specified (age and sex not specified in the clinical record); GS, gastrointestinal symptoms; RS, respiratory symptoms; IMHA, immune-mediated hemolytic anemia; y, years old; m, months; F, female; M, male; Dash, unknown data.


Table 3 Comparison of hematologic and biochemical test results of B. gibsoni PCR-positive dogs in 2019-2020 in the Republic of Korea

Blood testParametersUnitReference valuesResults (No. of dog patients)


MinMaxLowNormalHigh



Disease courseTotalDisease courseTotalDisease courseTotal






ACSNo. (%)ACSNo. (%)ACSNo. (%)
Hemogram (n = 26)PCV%37.157.0136221 (80.8)2215 (19.2)0000 (0)
RBC10 × 12/L5.78.8116320 (76.9)4206 (23.1)0000 (0)
Hbg/dL12.918.4136221 (80.8)2215 (19.2)0000 (0)
RDW%11.914.51102 (7.7)115218 (69.2)3216 (23.1)
PLT10 × 9/L148.0484.0147223 (88.5)1012 (7.7)0101 (3.8)
WBC10 × 9/L5.213.92204 (15.4)105318 (69.2)3104 (15.4)
NEUT10 × 9/L3.98.04004 (15.4)107219 (73.1)1113 (11.5)
LYMPH10 × 9/L1.34.14004 (15.4)76316 (61.5)4206 (23.1)
MONO10 × 9/L0.21.12002 (7.7)126321 (80.8)1203 (11.5)
EOS10 × 9/L0.061.232204 (15.4)135321 (80.8)0101 (3.8)
BASO10 × 9/L00.10101 (3.8)156324 (92.3)0101 (3.8)
Biochemistry (n = 26)ALTU/L10.0100.00000 (0)138223 (88.5)2013 (11.5)
ASTU/L11.742.50000 (0)117321 (80.8)4105 (19.2)
BUNmg/dL5.030.00000 (0)148325 (96.2)1001 (3.8)
Creatininemg/dL0.41.60000 (0)148325 (96.2)1001 (3.8)
Total bilirubinmg/dL0.10.70000 (0)76316 (61.5)82010 (38.5)
Albuming/dL2.33.96118 (30.8)97218 (69.2)0000 (0)
Total proteing/dL4.97.22002 (7.7)127322 (84.6)1102 (7.7)

A, acute (n = 15); C, chronic (n = 8); S, subclinical (n = 3); PCV, packed-cell volume; RBC, red blood cell count; Hb, hemoglobin; RDW, red cell distribution width; PLT, platelet count; WBC, white blood cell count; NEUT, neutrophils; LYMPH, lymphocytes; MONO, monocytes; EOS, eosinophils; BASO, basophils; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen.


References

  1. Ayoob AL, Hackner SG, Prittie J. Clinical management of canine babesiosis. J Vet Emerg Crit Care (San Antonio) 2010; 20: 77-89.
    Pubmed CrossRef
  2. Barić Rafaj R, Kuleš J, Selanec J, Vrkić N, Zovko V, Zupančič M, et al. Markers of coagulation activation, endothelial stimulation, and inflammation in dogs with babesiosis. J Vet Intern Med 2013; 27: 1172-1178.
    Pubmed CrossRef
  3. Birkenheuer AJ, Correa MT, Levy MG, Breitschwerdt EB. Geographic distribution of babesiosis among dogs in the United States and association with dog bites: 150 cases (2000-2003). J Am Vet Med Assoc 2005; 227: 942-947.
    Pubmed CrossRef
  4. Boozer AL, Macintire DK. Canine babesiosis. Vet Clin North Am Small Anim Pract 2003; 33: 885-904, viii.
    CrossRef
  5. Boozer L, Macintire D. Babesia gibsoni: an emerging pathogen in dogs. Compend Contin Educ Pract Vet 2005; 2: 33-42.
  6. Choe HC, Fudge M, Sames WJ, Robbins RG, Lee IY, Chevalier NA, et al. Tick surveillance of dogs in the Republic of Korea. Syst Appl Acarol 2011; 16: 215-222.
    CrossRef
  7. Goris RJ, te Boekhorst TP, Nuytinck JK, Gimbrère JS. Multiple-organ failure. Generalized autodestructive inflammation? Arch Surg 1985; 120: 1109-1115.
    Pubmed CrossRef
  8. Groves MG, Yap LF. Babesia gibsoni (Patton, 1910) from a dog in Kuala Lumpur. Med J Malaya 1968; 22: 229.
  9. Hamšíková Z, Kazimírová M, Haruštiaková D, Mahríková L, Slovák M, Berthová L, et al. Babesia spp. in ticks and wildlife in different habitat types of Slovakia. Parasit Vectors 2016; 9: 292.
    Pubmed KoreaMed CrossRef
  10. He L, Miao X, Hu J, Huang Y, He P, He J, et al. First molecular detection of Babesia gibsoni in dogs from Wuhan, China. Front Microbiol 2017; 8: 1577.
    Pubmed KoreaMed CrossRef
  11. Hong SH, Kim SY, Song BG, Rho JR, Cho CR, Kim CN, et al. Detection and characterization of an emerging type of Babesia sp. similar to Babesia motasi for the first case of human babesiosis and ticks in Korea. Emerg Microbes Infect 2019; 8: 869-878.
    Pubmed KoreaMed CrossRef
  12. Köster LS, Lobetti RG, Kelly P. Canine babesiosis: a perspective on clinical complications, biomarkers, and treatment. Vet Med (Auckl) 2015; 6: 119-128.
    Pubmed KoreaMed CrossRef
  13. Krause PJ. Human babesiosis. Int J Parasitol 2019; 49: 165-174.
    Pubmed CrossRef
  14. Lee MJ, Yu DH, Yoon JS, Li YH, Lee JH, Chae JS, et al. Epidemiologic and clinical surveys in dogs infected with Babesia gibsoni in South Korea. Vector Borne Zoonotic Dis 2009; 9: 681-686.
    Pubmed CrossRef
  15. Lee S, Lee H, Park JW, Yoon SS, Seo HJ, Noh J, et al. Prevalence of antibodies against Anaplasma spp., Borrelia burgdorferi sensu lato, Babesia gibsoni, and Ehrlichia spp. in dogs in the Republic of Korea. Ticks Tick Borne Dis 2020; 11: 101412.
    Pubmed CrossRef
  16. Meinkoth JH, Kocan AA, Loud SD, Lorenz MD. Clinical and hematologic effects of experimental infection of dogs with recently identified Babesia gibsoni-like isolates from Oklahoma. J Am Vet Med Assoc 2002; 220: 185-189.
    Pubmed CrossRef
  17. Mittal M, Kundu K, Chakravarti S, Mohapatra JK, Singh VK, Raja Kumar B, et al. Canine babesiosis among working dogs of organised kennels in India: a comprehensive haematological, biochemical, clinicopathological and molecular epidemiological multiregional study. Prev Vet Med 2019; 169: 104696.
    Pubmed KoreaMed CrossRef
  18. Myburgh EC, Goddard A. The effect of pyridoxal-5-phosphate on serum alanine aminotransferase activity in dogs suffering from canine babesiosis. Onderstepoort J Vet Res 2009; 76: 327-333.
    CrossRef
  19. Onishi T, Ueda K, Horie M, Kajikawa T, Ohishi I. Serum hemolytic activity in dogs infected with Babesia gibsoni. J Parasitol 1990; 76: 564-567.
    Pubmed CrossRef
  20. Panti-May JA, Rodríguez-Vivas RI. Canine babesiosis: a literature review of prevalence, distribution, and diagnosis in Latin America and the Caribbean. Vet Parasitol Reg Stud Reports 2020; 21: 100417.
    Pubmed CrossRef
  21. Petra B, Josipa K, Renata BR, Vladimir M. Canine babesiosis: where do we stand? Acta Vet Beogr 2018; 68: 127-160.
    CrossRef
  22. Santos F, Coppede JS, Pereira AL, Oliveira LP, Roberto PG, Benedetti RB, et al. Molecular evaluation of the incidence of Ehrlichia canis, Anaplasma platys and Babesia spp. in dogs from Ribeirão Preto, Brazil. Vet J 2009; 179: 145-148.
    Pubmed CrossRef
  23. Schoeman JP. Canine babesiosis. Onderstepoort J Vet Res 2009; 76: 59-66.
    Pubmed CrossRef
  24. Shabani B, Esmaeilnejad B, Tavassoli M, Imani M. Assessment of cholinesterase activity and hepatic biofunction in dogs naturally infected with Babesia gibsoni. Comp Clin Pathol 2020; 29: 1265-1269.
    CrossRef
  25. Solano-Gallego L, Baneth G. Babesiosis in dogs and cats--expanding parasitological and clinical spectra. Vet Parasitol 2011; 181: 48-60.
    Pubmed CrossRef
  26. Solano-Gallego L, Sainz Á, Roura X, Estrada-Peña A, Miró G. A review of canine babesiosis: the European perspective. Parasit Vectors 2016; 9: 336.
    Pubmed KoreaMed CrossRef
  27. Song KH, Kim DH, Hayasaki M. The PCR-based detection of Babesia gibsoni infection in dogs (German shepherds) reared in South Korea. Ann Trop Med Parasitol 2004; 98: 149-153.
    Pubmed CrossRef
  28. Suh GH, Ahn KS, Ahn JH, Kim HJ, Leutenegger C, Shin S. Serological and molecular prevalence of canine vector-borne diseases (CVBDs) in Korea. Parasit Vectors 2017; 10: 146.
    Pubmed KoreaMed CrossRef
  29. Taboada J, Merchant SR. Babesiosis of companion animals and man. Vet Clin North Am Small Anim Pract 1991; 21: 103-123.
    CrossRef
  30. Ullal T, Birkenheuer A, Vaden S. Azotemia and proteinuria in dogs infected with Babesia gibsoni. J Am Anim Hosp Assoc 2018; 54: 156-160.
    Pubmed CrossRef
  31. Welzl C, Leisewitz AL, Jacobson LS, Vaughan-Scott T, Myburgh E. Systemic inflammatory response syndrome and multiple-organ damage/dysfunction in complicated canine babesiosis. J S Afr Vet Assoc 2001; 72: 158-162.
    Pubmed CrossRef
  32. Wozniak EJ, Barr BC, Thomford JW, Yamane I, McDonough SP, Moore PF, et al. Clinical, anatomic, and immunopathologic characterization of Babesia gibsoni infection in the domestic dog (Canis familiaris). J Parasitol 1997; 83: 692-699.
    Pubmed CrossRef
  33. Yang YS, Mun MJ, Yun YM. Ultra fast real-time PCR for detection of Babesia gibsoni as point of care test. J Vet Clin 2020; 37: 23-27.
    CrossRef

Vol.39 No.5 2022-10-31

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