Comparison of conventional polymerase chain reaction and routine blood smear for the detection of Babesia canis, Hepatozoon canis, Ehrlichia canis, and Anaplasma platys in Buriram Province, Thailand

Dog blood parasite infection in upland and lowland communities of northern Thailand: The role of environment and care of dog owners

Dogs play an important role as hosts and reservoirs for many zoonotic diseases. Ehrlichiosis, babesiosis and hepatozoonosis are a group of canine vector-borne diseases that can be transmitted via ectoparasites from dog to dog and also from dog to humans. This study focused on three main blood parasites of dog (i.e., Babesia spp., Ehrlichia spp. and Hepatozoon spp.) among two different landscape types of eight villages of Santhong Sub-district, Nan Province, Thailand. In this study, 149 dogs were surveyed and blood samples were collected. Blood parasite infections in dogs were assessed using molecular detection approach. Babesia canis vogeli, Babesia gibsoni, Ehrlichia canis and Hepatozoon canis were detected with prevalence of infection at 10.7%, 8.1%, 3.4% and 0.7%, respectively. In terms of landscape type, prevalence of overall blood parasites, particularly Babesia spp. infections were higher in dogs living in upland forested areas (28.3%) compared to dogs from lowland agricultural areas (12.3%). Data obtained from the questionnaires on perceptions of dog owners showed that dogs raised all the time outside owner's house, and those dogs whose owners have never bathed and cleaned were more likely to be exposed to blood parasites. As infected dogs could play an important role as reservoirs of the blood parasites, attitude of dog owners may affect public health in terms of zoonotic disease transmission. Effective control measures and surveillance program of arthropod vectors and blood parasite infection in dogs still need to be advocated to minimize zoonotic disease transmission.

Metabarcoding using nanopore long-read sequencing for the unbiased characterization of apicomplexan haemoparasites

Apicomplexan haemoparasites generate significant morbidity and mortality in humans and other animals, particularly in many low-to-middle income countries. Malaria caused by Plasmodium remains responsible for some of the highest numbers of annual deaths of any human pathogen, whilst piroplasmids, such as Babesia and Theileria can have immense negative economic effects through livestock loss. Diagnosing haemoparasites via traditional methods like microscopy is challenging due to low-level and transient parasitaemia. PCR-based diagnostics overcome these limitations by being both highly sensitive and specific, but they may be unable to accurately detect coinfections or identify novel species. In contrast, next-generation sequencing (NGS)-based methods can characterize all pathogens from a group of interest concurrently, although, the short-read platforms previously used have been limited in the taxonomic resolution achievable. Here, we used Oxford Nanopore Technologies' (ONT) long-read MinION™ sequencer to conduct apicomplexan haemoparasite metabarcoding via sequencing the near full-length 18S ribosomal RNA gene, demonstrating its ability to detect Babesia, Hepatozoon, Neospora, Plasmodium, Theileria and Toxoplasma species. This method was tested on blood-extracted DNA from 100 dogs and the results benchmarked against qPCR and Illumina-based metabarcoding. For two common haemoparasites, nanopore sequencing performed as well as qPCR (kappa agreement statistics > 0.98), whilst also detecting one pathogen, Hepatozoon felis, missed by the other techniques. The long-reads obtained by nanopore sequencing provide an improved species-level taxonomic resolution whilst the method's broad applicability mean it can be used to explore apicomplexan communities from diverse mammalian hosts, on a portable sequencer that easily permits adaptation to field use.

Molecular occurrence and genetic diversity of Ehrlichia canis in naturally infected dogs from Thailand

Canine monocytic ehrlichiosis is cause by Ehrlichia canis resulting in hematologic disorders and severe clinical signs. The aim of this study was to scrutinize the molecular detection and genetic diversity of E. canis based on the trp36 gene in dogs from Thailand's northern and central regions. A total of 120 dogs blood samples were amplified for trp36 gene of E. canis using the polymerase chain reaction (PCR). Forty-seven out of 120 dog blood samples (39.16%, 47/120) were positive for E. canis the trp36 DNA with 790 bp of PCR amplicon size. The factor significantly associated with E. canis infection is animal housing status (p < 0.05). Sequence and phylogenetic analysis showed that E. canis trp36 gene of Thailand isolates was clustered into 1st clade with similarity ranging from 95.65 to 100% together with the US genogroup. The 14 haplotypes of the trp36 gene shown in TCS network exhibited that haplotype #1-4 was found in Thailand. The entropy analysis of the trp36 gene illustrated 751 polymorphic sites and 271 entropy peaks of nucleic and amino acid sequences, respectively. Hence, these findings are crucial for better understanding the epidemiology of Ehrlichia infection and could be helpful for implementing control measures in Thailand.

Epidemiological and phylogenetic investigation of Babesia spp. in dogs of Hainan Province/Island, China

Babesiosis is a significant tick-borne disease, which is globally prevalent. Many previous research studies have discussed the presence of Babesia gibsoni, Babesia vogeli, and Babesia canis in dogs in China. In the present study, we have used distinct molecular approaches to detect the presence of Babesia spp. in dogs of Hainan Province/Island, China. A total of 1106 dog blood samples were collected from the Island, of which 61 dog samples were found to be positive for Babesia vogeli. The highest infection rate was 56.7% (17/30) detected from Tunchang, followed by 25.0% (3/12) from Baisha and 10.4% (5/48) from Wenchang. There was only one positive case of Babesia gibsoni, and the infection rate was found to be 0.1% (1/1106). The sequencing results showed that the subjected sample sequences were identical and resembled the Babesia vogeli and Babesia gibsoni sequences available in the database. The results derived from this study will be helpful for planning effective strategies for the treatment, control, and prevention of babesiosis in dogs of Hainan Province/Island.

Proteomics identification of overexpressed serum proteins in dogs with Babesiacanis infection

Background and Aim

Canine babesiosis, caused by the protozoan parasite Babesia canis, is characterized by clinical manifestations, including hemolytic anemia, thrombocytopenia, multiple organ failure, and may result in death. This disease is detected using conventional blood smears, which are time-consuming and have low sensitivity. This study aimed to investigate a more rapid and sensitive method for detecting B. canis infection in dogs by examining the expressed serum protein profiles using proteomics.

Materials and Methods

We collected six sera samples from three healthy and three B. canis-infected dogs diagnosed using blood smear and polymerase chain reaction. We analyzed the proteins using two-dimensional gel electrophoresis. The candidate spots from the gel were subjected to protein identification using a nano-liquid chromatography system coupled to an ion-trap mass spectrometer equipped with an electrospray ionization nano-sprayer.

Results

We found that 10 protein spots were overexpressed in the serum samples from infected dogs compared with healthy dogs, which corresponded to three proteins: serotransferrin, serotransferrin isoforms X1, and hemopexin. Furthermore, analysis of the protein-protein interaction network confirmed that they strongly interacted with each other.

Conclusion

This study suggests that high levels of serotransferrin and hemopexin are related to B. canis infection, making these proteins potential candidates for the development of diagnostic molecules or vaccines.

Preliminary study on prevalence of hemoprotozoan parasites harbored by Stomoxys (Diptera: Muscidae) and tabanid flies (Diptera: Tabanidae) in horse farms in Nakhon Si Thammarat province, Southern Thailand

Background and Aim

Stomoxys and tabanid flies are of medical and veterinary importance because they play crucial roles in disease transmission as mechanical vectors of various hemopathogens. However, its role as a hemoprotozoan parasite vector in horse farms has not been studied. Therefore, we investigated the occurrence of hemoprotozoan parasites belonging to the genera Babesia, Theileria, and Trypanosoma in Stomoxys and tabanid flies using conventional polymerase chain reaction (PCR) and DNA sequencing.

Materials and Methods

All samples (Stomoxys and tabanid flies) were collected using an Nzi trap for three consecutive days each month from November 2022 to March 2023. The flies were morphologically identified to the species level and separated according to sex. Individual (for tabanid flies) or pooled samples (consisting of three specimens of Stomoxys flies of the same species and sex collected from the same site) were used for DNA extraction. Conventional PCR was used to screen for hemoprotozoan parasite DNA, followed by Sanger sequencing to identify the species.

Results

In total, 189 biting flies were collected, including four species of Stomoxys (Stomoxys bengalensis, Stomoxys calcitrans, Stomoxys indicus, and Stomoxys sitiens) and five species of tabanids (Atylotus cryptotaxis, Chrysops dispar, Tabanus megalops, Tabanus mesogaeus, and Tabanus rubidus). Stomoxys calcitrans was the most prevalent species, accounting for 58.7% (n = 111) of the collected flies. Ten (12.4%) of the 81 samples (individuals and pools) analyzed by PCR were positive for the 18S rRNA gene of the Theileria/Babesia species. Trypanosoma DNA was not detected in any sample. After performing Basic Local Alignment Search Tool searches and a phylogenetic analysis, only six samples (7.4%), including S. calcitrans (n = 2), S. sitiens (n = 2), T. megalops (n = 1), and A. cryptotaxis (n = 1), were found to be infected with Theileria sinensis. Furthermore, apicomplexan parasites, namely, Mattesia spp. and Colpodella spp., were found on S. indicus, the fungus Meira spp. was found on S. calcitrans, and the pathogenic green alga Helicosporidium spp. was found on A. cryptotaxis.

Conclusion

This study is the first to report a variety of Stomoxys and tabanid flies collected from horse farms in Thailand, which were found to be infected with Theileria and Colpodella species that affect mammals, suggesting that Stomoxys and tabanid flies can be used to confirm the presence of hemoprotozoan parasites in the study area. Understanding the presence of hemoprotozoa in flies could help design vector control programs and manage various diseases in the study area.

RPA/CRISPR-cas12a as a specific, sensitive and rapid method for diagnosing Ehrlichia canis and Anaplasma platys in dogs in Thailand

Rickettsial pathogens including Ehrlichia canis and Anaplasma platys are bacteria that cause parasitic infections in dogs such as canine monocytic ehrlichiosis (CME) and canine cyclic thrombocytopenia (CCT), respectively affecting mortality and morbidity worldwide. An accurate, sensitive, and rapid method to diagnose these agents is essential for effective treatment. In this study, a recombinase polymerase amplification (RPA) coupled with CRISPR-Cas12a methods was established to detect E. canis and A. platys infection in dogs based on the 16S rRNA. The optimal condition for DNA amplification by RPA was 37 °C for 20 min, followed by CRISPR-Cas12a digestion at 37 °C for one hour. A combination of RPA and the cas12a detection method did not react with other pathogens and demonstrated strong sensitivity, detecting as low as 100 copies of both E. canis and A. platys. This simultaneous detection method was significantly more sensitive than conventional PCR. The RPA-assisted cas12a assay provides specific, sensitive, rapid, simple and appropriate detection of rickettsial agents in canine blood at the point-of-care for diagnostics, disease prevention and surveillance.

Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

Detection of ivermectin and fipronil resistance in Rhipicephalus sanguineus sensu lato in Maha Sarakham, Thailand

Background and Aim

Administration is the main strategy for controlling ectoparasites in dogs. Ivermectin and fipronil are most extensively used to prevent and treat Rhipicephalus sanguineus sensu lato infestation in dogs in Thailand. Several researchers have reported resistance to acaricides in R. sanguineus s.l. globally, but documentation of acaricide resistance in the tick population in Thailand is lacking. In this study, we investigated the status of resistance to commonly used acaricides in Thailand in R. sanguineus s.l.

Materials and Methods

Engorged brown dog tick females (10 tick populations) were field-collected directly from parasitized dogs in Maha Sarakham, Thailand, for toxicological bioassays with ivermectin and fipronil. Bioassays were performed in three replicates at 25°C-27°C and 80%-85% relative humidity under a 12-h/12-h photoperiod. The 50% of lethal concentration and its confidence intervals and the slope were estimated for each tick population using probit analysis. Resistance ratios (RRs) of field ticks were characterized based on the relative susceptible population of each acaricide.

Results

Six tick populations (P1-6) were tested for resistance to ivermectin, three of which (P2-4) exhibited low-level resistance to ivermectin (RR = 2.115-2.176). Of four tick populations (P7-10) treated with fipronil, two exhibited moderate-to-severe resistance (P7 and P9, RR = 21.684 and 4.387, respectively). All tick populations deemed resistant to acaricides had a history of exposure.

Conclusion

Based on RR values, four R. sanguineus s.l. tick populations from Maha Sarakham province were resistant to ivermectin and fipronil. To the best of our knowledge, this represents the first documentation of acaricide-resistant populations of R. sanguineus s.l. in Thailand, and recommendations on tick control programs must be formulated with veterinarians and pet owners to prevent the development of further resistance.

Co-infections of major tick-borne pathogens of dogs in Andhra Pradesh, South India

Implementing hemoprotozoan control strategies in dogs has become difficult because of the co-infections. A multiplex polymerase chain reaction (PCR) was carried out for simultaneous detection of the co-infections of Babesia gibsoni, B. vogeli, Hepatozoon canis and Ehrlichia canis from dogs (N = 442) in Andhra Pradesh, South India. The co-infection combinations were classified as (i) B. gibsoni + B. vogeli + E. canis + H. canis (BEH), (ii) B. gibsoni + B. vogeli + E. canis (BE), (iii) B. gibsoni + B. vogeli + H. canis (BH) and (iv) E. canis + H. canis (EH) groups. The parasite-specific multiplex PCR amplified 18S rRNA gene of B. gibsoni, B. vogeli and H. canis and VirB9 gene of E. canis. The age, gender, breed, medium, living condition and region of dogs were studied as risk factors for co-infections using logistic regression model. Among the co-infections, the incidence was 1.81%, 9.28%, 0.69% and 0.90% for BEH, BE, BH and EH infections, respectively. Young age (< one year), females, mongrels, rural dogs, kennel dogs and presence of ticks were the identified risk factors for overall prevalence of tick-borne pathogens. The incidence of infection was less in rainy season, especially in dogs with a previous acaricidal treatment. The study concludes that the multiplex PCR assay could simultaneously detect natural co-infections in dogs, emphasizing the need for the assay in epidemiological studies to reveal the real pattern of pathogens and select pathogen-specific treatment protocols.

Clinical, hematological and molecular evaluation of piroplasma and Anaplasma infections in small ruminants and tick vectors from Kurdistan province, western Iran

Tick-borne haemoparasite infections are a major challenge in small ruminant (SR) production across tropical areas. The present study evaluated the prevalence of Theileria, Babesia and Anaplasma in SRs and their tick vectors and estimated the association between pathogen prevalence with clinical hematological findings among SR populations in Kurdistan province, western Iran. In total, 250 blood samples and 250 tick species (one per animal) were collected from SR populations, along with clinical and hematological examinations. Microscopy of blood smears and molecular analysis were performed to detect potential infection with Theileria, Babesia and Anaplasma. Moreover, haemoparasites were explored in the isolated ticks using semi-nested PCR. Based on microscopy, the prevalence of Theileria, Anaplasma and Babesia infections was 91.2%, 23.2% and 2.4%, respectively. Semi-nested PCR analysis of blood samples demonstrated 86.8%, 78.8% and 14% prevalence for T. ovis, A. ovis and B. ovis, respectively. Dermacentor marginatus and Rhipicephalus turanicus were predominant isolated tick vectors from SR, while D. marginatus was the most contaminated tick in all investigated counties. There were, also, a statistically significant association between the estimated molecular prevalence rates with semi-yellow conjunctiva (A. ovis), body temperature (T. ovis and A. ovis), heart rate (T. ovis and B. ovis), mean white blood cell count (T. ovis and A. ovis), mean red blood cell count (T. ovis and B. ovis), as well as mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration in all haemoparasite infections. Future studies are recommended to reveal the epidemiology of such infections in SRs in Iran.

Hematological analysis of naturally infecting blood parasites in dogs

Background and Aim: Blood parasite infections such as anaplasmosis, babesiosis, and ehrlichiosis are commonly found in domestic dogs, which adversely influence their health. Many dogs are infected with multiple blood parasites that cause more severe diseases than a single infection. This study aimed to investigate the effect of multiple blood parasite infections on the hematological profiles of dogs at a shelter in Southern Thailand. Materials and Methods: The blood samples from 122 dogs were collected to assess the hematology profiles of uninfected, single-infected, and multiple blood parasite-infected dogs. The results were compared using Kruskal-Wallis test and Dwass-Steel-Critchlow-Fligner pairwise comparisons. The infections were confirmed by polymerase chain reaction. Results: The results showed that all the infected dogs had significantly lower red blood cell (RBC) count, hemoglobin (HB), hematocrit (HCT), and platelet count (PLT) than the uninfected dogs. Although the dogs with triple infection had lower RBC, HB, HCT, and PLT than those with double and single infections, the difference was not statistically significant. Conclusion: We proposed that triple blood parasite infection with Anaplasma platys, Babesia vogeli, and Ehrlichia canis caused more severe disease than double and single infections. Evaluating the hematological profiles of dogs naturally infected with single, double, and multiple blood parasite infections without clinical signs can enhance their health and welfare. Keywords: blood parasite, dogs, hematology, multiple blood parasite infection, tick-borne pathogens.

Companion Vector-Borne Pathogens and Associated Risk Factors in Apparently Healthy Pet Animals (Dogs and Cats) in Khukhot City Municipality, Pathum Thani Province, Thailand

Pet animals (dogs and cats) can be infected with several companion vector-borne pathogens (CVBPs). Morbidity and mortality have been reported in pet animals due to CVBP infections. Pet animals living in close proximity to humans are able to transmit zoonotic pathogens. This study used molecular techniques to investigate the prevalence of CVBPs in apparently healthy pet animals (dogs and cats) from Khukhot City Municipality, Pathum Thani province, Thailand. In total, 210 blood samples were randomly collected from 95 dogs and 115 cats for the detection of seven companion vector-borne pathogens (Anaplasma, Babesia, Bartonella, Ehrlichia, Hepatozoon, Mycoplasma, and Rickettsia) using polymerase chain reaction. The results showed that 10.5% (22/210) of apparently healthy pet animals were infected with at least one pathogen, comprising 6 dogs (6.3% of all dogs tested) and 16 cats (13.9% of all cats tested). Ehrlichia (6.3%) was present only in dogs; furthermore, 1.1% of the dogs were positive for Anaplasma. There was one dog case co-infected with two pathogens (1.1%). In cats, Mycoplasma (9.6%) was the predominant CVBP, followed by Rickettsia (4.4%). The DNA sequences of all positive animals were 97–99% homologous to those found in the GenBank™ database for all CVBPs identified, namely Ehrlichia canis, Anaplasma platys, Rickettsia felis, Mycoplasma haemofelis, and Candidatus Mycoplasma haemominutum. Additionally, the risk of infection with CVBPs in pets was significantly associated with age, with young dogs more likely to be infected with CVBPs than adult dogs (OR 8.5, 95% CI 1.4–50.1, p = 0.006), while adult cats were more likely to be infected with CVBPs than young cats (OR 3.8, 95% CI 1.0–14.0, p = 0.038). The detection of CVBPs demonstrated the potential risk of infection that may occur in apparently healthy pet animals in Pathum Thani province. These results confirmed that apparently healthy pet animals may still be at risk of vector-borne infections and could maintain the infection cycle in pet populations. Furthermore, sampling a greater number of apparently healthy pet animals may disclose predictors of CVBP positivity in domesticated animals in this area.

Molecular characterization of Ehrlichia canis and Babesia vogeli reveals multiple genogroups associated with clinical traits in dogs from urban areas of Colombia

Ehrlichia canis and Babesia vogeli are vector-borne pathogens that infect blood cells and produce the diseases Canine Monocytic Ehrlichiosis (CME) and Babesiosis in dogs. Considering the lack of studies on these pathogens in Colombia, this study aims to determine the molecular prevalence and genetic characterization of E. canis and Babesia spp., in dogs from the Metropolitan Area of Bucaramanga (MAB), Santander, a region with one of the greatest pet densities in Colombia. One hundred eighty-five dogs were surveyed and analyzed through molecular, clinical, and hematological approaches. The molecular detection of E. canis and Babesia spp., was performed by conventional PCR targeting the dsb and 18S rRNA genes, respectively. To identify genogroups, E. canis positive samples underwent a hemi-nested PCR of the trp36 gene, and the PCR products were subsequently sequenced. Molecular analyses showed a prevalence of 13% (24/185; CI 95%, 8.1 - 18.0%) and 1.09% (2/185; CI 95,% -0.43 - 2.6%) for E. canis and B. vogeli respectively, as well as the presence of the genogroups US (USA), BR (Brazil), and CR (Costa Rica), in 62.5, 16.6, and 16.6% of E. canis positive samples, respectively. Values of hematocrit, hemoglobin, platelets, erythrocytes, white blood cell (WBC) count, lymphocytes, and eosinophils showed significant differences between animals infected with the different genogroups of E. canis (p< 0.05). In contrast, hematocrit values, hemoglobin, platelets, red blood cells, and creatine kinase MB isoenzyme (CK-MB) were lower in B. vogeli positive animals. Statistical analysis indicated that E. canis infection was associated with specific socioeconomic sectors as well as with some household features (p< 0.05). In conclusion, our results present evidence of the circulation of multiple genogroups of E. canis in the MAB, which is associated with different geographical origins and clinical traits. Epidemiological analyses suggest a need to increase molecular surveillance and prevention campaigns especially in lower socioeconomic sectors.

Ehrlichia canis: Molecular characterization and genetic diversity based on the p28 and trp36 genes

Ehrlichia canis is a common tick-borne intracellular pathogen causing canine monocytic ehrlichiosis (CME) in dogs worldwide. The aims of this study were to investigate the genetic diversity and antigenicity of E. canis based on the p28 and trp36 genes in dogs in Thailand. The E. canis p28 and trp36 genes were amplified by the polymerase chain reaction (PCR) and cloned for sequencing and bioinformatic analyses. 36% (44/120) of dog blood samples were positive for E. canis DNA consisting of p28 (31%, 14/44) and trp36 (69%, 30/44) genes with 792 and 882 bp of PCR products size, respectively. The E. canis TRP36 from all Thailand sequences exhibited encoded nine amino acids (TEDSVSAPA) with 11 copies of tandem repeats along the sequences. The phylogenetic trees of E. canis, using the p28 and trp36 genes, exhibited that the Thailand isolates fell into two clades and one clade with similarity ranging from 55.95 to 100% and 100%, respectively. The results of diversity analysis revealed 10 and 20 haplotypes of the p28 and trp 36 genes, respectively. The entropy analysis of the p28 and trp36 nucleic acid sequences showed 442 and 1321 high entropy peaks respectively, whereas those of the P28 and TRP36 amino acid sequences showed 477 and 388 high entropy peaks, respectively. For B-cell epitopes analysis, the conserved amino acid of P28 and TRP36 sequences has been also demonstrated. Therefore, the results could be utilized to improve the understanding of phylogenetic relationship, genetic diversity and antigenicity of E. canis Thailand isolates.

Detection of Hepatozoon spp. in dogs in Shiraz, southern Iran and its effects on the hematological alterations

Canine hepatozoonosis is a tick-transmitted apicomplexan infection caused by two species of Hepatozoon, H. canis, and H. americanum. The present research aimed at detection of Hepatozoon spp. in dogs and its effects on hematological alterations. Blood samples were taken from 108 dogs to assess Hepatozoon spp. Phylogenetic analysis was performed based on the 18S rDNA marker by PCR assay and Giemsa-stained blood smear examination. Of the 108 blood samples of dogs tested in the present study, eight (7.40%, 95% CI: 3.25-14.07%) were positive by the Hepatozoon-specific PCR assay. However, in the microscopic examination, only one sample (0.93%) was positive. All of the sequenced samples were H. canis. The Hepatozoon sequences obtained from PCR amplicons in the canine-positive cases exhibited 100% similarity to each other and 98.47-100% similarity to other relevant sequences in GenBank. These findings represent the first molecular evidence of H. canis in dog populations in South Iran. Furthermore, according to the hematological analysis, significantly higher average numbers of neutrophils and lymphocytes were found in the infected group compared to the non-infected dogs. In this study, no statistically significant connection (P<0.05) was observed between H. canis infection and the examined risk factors.

Multiple blood pathogen infections in apparently healthy sheltered dogs in southern Thailand

In developing countries such as Thailand, free-ranging dogs are frequently involved in road accidents and contribute to the cost of public healthcare. Shelters play a vital role in communities because they help to control the population of unwanted and free-ranging dogs. This study aimed to investigate blood pathogen infection in sheltered dogs, as it is one of the factors contributing to animal welfare. Blood samples were randomly collected from 141 dogs from the largest shelter (approximately 400–500 dogs in total) in southern Thailand. Blood pathogens were detected using both PCR and light microscopy. Four blood pathogens were identified: Anaplasma platys, Ehrlichia canis, Babesia canis vogeli, and Hepatozoon canis. No trypanosomes were detected. The incidence of blood parasite infection was 56.7% (80/141) by PCR, and 28.4% (40/141) by microscopy. E. canis was the most prevalent pathogen, accounting for 46.1% (65/141) of the cases, while multiple infections accounted for 22% (31/141) of the cases. A triple infection with E. canis, A. platys, and B. canis vogeli was observed in 5.7% (8/141) of the cases. Although PCR is far more sensitive than microscopy, it appears to have equivalent specificity. In conclusion, this study reported a high occurrence of blood pathogen infections in clinically healthy sheltered dogs. Many of them were infected with multiple pathogens and may have been infected before entering the shelter. These findings suggest that a blood test is necessary to screen dogs prior to their admission to the shelter to prevent disease transmission and enhance animal welfare.

Molecular detection and phylogeny of Ehrlichia canis and Anaplasma platys in naturally infected dogs in Central and Northeast Thailand

Background and Aim

Ehrlichia canis and Anaplasma platys are tick-borne, Gram-negative bacteria that cause canine monocytic ehrlichiosis and canine cyclic thrombocytopenia, respectively. These diseases are of great importance and are distributed globally. This study aimed to create new primers for the identification of E. canis and A. platys in naturally infected dogs using polymerase chain reaction (PCR), DNA sequencing, and phylogenetic analysis using the 16S rDNA and gltA genes.

Materials and Methods

In total, 120 blood samples were collected from dogs in three different locations (Saraburi, Buriram, and Nakhon Ratchasima provinces) in Central and Northeast Thailand. The molecular prevalence of E. canis and A. platys was assessed using PCR targeting the 16S rDNA and gltA genes. All positive PCR amplicons were sequenced, and phylogenetic trees were constructed based on the maximum likelihood method.

Results

Ehrlichia canis had an overall molecular prevalence of 15.8% based on the 16S rDNA gene, compared to 8.3% based on the gltA gene. In addition, the overall molecular prevalence of A. platys using the 16S rDNA gene was 10.8%, while the prevalence rate was 5.8% using the gltA gene. Coinfection was 0.8% in Saraburi province. The partial sequences of the 16S rDNA and gltA genes of E. canis and A. platys in dogs in Central and Northeast Thailand showed 96.75%-100% identity to reference sequences in GenBank. Phylogenetic analysis of the 16S rDNA and gltA genes revealed that E. canis and A. platys sequences were clearly grouped into their own clades.

Conclusion

This study demonstrated the molecular prevalence of E. canis and A. platys in Central and Northeast Thailand. The 16S rDNA and gltA genes were useful for the diagnosis of E. canis and A. platys. Based on the phylogenetic analysis, the partial sequences of the 16S rDNA and gltA genes in E. canis and A. platys were related to prior Thai strains and those from other countries.

Sensitive and rapid detection of Babesia species in dogs by recombinase polymerase amplification with lateral flow dipstick (RPA-LFD)

Canine babesiosis is a tick-borne disease caused by Babesia spp., which infects and destroys healthy erythrocytes, leading to mortality and morbidity in dogs. The diagnosis of babesiosis is tedious and time-consuming, especially in latent and chronic infections. Here, a recombinase polymerase amplification combined with a lateral flow dipstick (RPA-LFD) assay was developed for rapid and accurate detection of Babesia spp. in canine blood specimens based on the 18S rRNA region. The RPA-LFD assay using rpaBab264 gave specificity to Babesia spp. in dogs (B. vogeli and B. gibsoni) without cross-amplification to other parasites (apicomplexans and non-apicomplexans), with detection limit of at least 22.5 copies/μl (0.1 fg/µl) at 40 °C for at least 10 min. The whole process of DNA amplification by RPA and readout by LFD did not exceed 30 min. To determine the performance of the RPA-LFD assay, a total of 30 clinical samples was examined and compared with conventional PCR (cPCR) and multiplex HRM (mHRM). Eight dogs (26.67%) were detected as positive by RPA-LFD, while seven and six were found positive by cPCR and mHRM, respectively. RPA-LFD and cPCR showed high agreement with Babesia spp. detection with kappa > 0.9. We confirmed that the dogs were infected by B. vogeli from sequences of positive PCR results. Our findings suggested that RPA-LFD using the rpaBab264 assay offered a rapid, accurate, cost-effective and simple method for Babesia spp. detection that is feasibly applicable to be rapid kit at a pet hospital or point-of-care testing.

Prevalence of Ehrlichia-, Babesia-, and Hepatozoon-infected brown dog ticks in Khon Kaen Province, Northeast Thailand

Background and Aim:

The brown dog tick, Rhipicephalus sanguineus sensu lato, is the most common tick found on domestic dogs in Southeast Asia, including Thailand. Canine tick-borne pathogens are a public health concern worldwide. Tick-borne diseases are diagnosed by identifying pathogens based on the morphological or molecular analyses of dog blood samples. However, the collection of ticks, a non-invasive procedure, is easier than drawing blood. This study aimed to demonstrate the usefulness of collecting brown dog ticks for the diagnosis of tick-borne diseases and for estimating the prevalence of tick-borne pathogens among companion dogs in Khon Kaen, Northeast Thailand.

Materials and Methods:

Seventy brown dog ticks from 70 companion dogs in Khon Kaen Province, Thailand, were evaluated for molecular evidence of tick-borne pathogens, including Babesia spp., Ehrlichia canis, and Hepatozoon canis. Ticks were collected from dogs at a private animal hospital based on the presence of at least one of the three inclusion criteria: fever, anorexia, or lethargy. Molecular diagnosis was performed using conventional polymerase chain reaction for the detection of pathogens.

Results:

Of the 70 ticks collected from 70 sick dogs, 55 (78.57%) were positive for tick-borne pathogens. The most common infection was a single infection with H. canis (65.71%) followed by Babesia spp. (31.43%) and E. canis (30.00%). Coinfection was observed in 14 ticks (20.00%), and coinfection with Babesia spp. and E. canis was the most prevalent double infection (n = 6). The prevalence of coinfection was identical for H. canis mixed with Babesia spp. and H. canis mixed with E. canis (n = 4).

Conclusion:

The present study showed that tick-borne pathogens are highly prevalent among companion dogs in Khon Kaen Province. Therefore, we encourage an increase in tick control or the reduction and prevention of tick-borne diseases in this region. Furthermore, this study revealed that ticks are valuable samples for the molecular detection of tick-borne pathogens.

First study on molecular detection of three major canine tick-borne pathogens in subclinically infected dogs in Chiang Mai, Thailand

Background and Aim:

Canine tick-borne pathogens (CTBPs) are an important cause of morbidity in dogs in Thailand. This study aimed to evaluate the occurrence of three CTBPs in clinically normal, owned dogs to understand the risk for the general canine population. We also examined sex, age, tick infestation, and packed cell volume (PCV) of the animals in association with active infection of the CTBPs.

Materials and Methods:

A total of 139 dogs were included in the study. Blood samples were collected for thin blood smear, PCV and nested polymerase chain reaction (PCR) assay. Statistical analyses were performed to examine the association between individual factors and CTBP infection status determined by PCR. In addition, sensitivity, specificity, and Cohen’s kappa were calculated to assess the utility of routine blood smear.

Results:

The PCR results showed that 31 dogs (22.3%) were infected with at least one of the three pathogens. The occurrence rate for Ehrlichia canis, Anaplasma platys, and Hepatozoon canis was 2.2% (3/139), 18.7% (24/139), and 2.8% (4/139), respectively. There were two cases of coinfection with A. platys and E. canis. The univariate analyses did not yield any associations between recorded variables and the active infection. Microscopic examination showed good sensitivity and agreement only for H. canis (Sn: 75%, 95% confidence interval: 24.9-98.7, k=0.85).

Conclusion:

Our findings confirmed the endemicity of the CTBPs in owned canine population in the study site. In-depth epidemiological investigation would be warranted to elucidate environmental risk factors for CTBP infection.

A newly developed droplet digital PCR for Ehrlichia canis detection: comparisons to conventional PCR and blood smear techniques

Canine monocytic ehrlichiosis caused by Ehrlichia canis infection is a life-threatening vector-borne disease in dogs worldwide. Routine blood smear has very low sensitivity and cannot accurately provide a quantitative result. Conventional PCR (cPCR) and real-time PCR (qPCR) are widely used as molecular methods for E. canis detection. qPCR is quantitative but relies on standard curves of known samples. To overcome this difficulty, this study developed a new E. canis quantitative detection method, using droplet digital polymerase chain reaction (ddPCR). ddPCR was evaluated against cPCR and blood smears. PCR amplicons and genomic DNA (gDNA) from 12 microscopic positive samples were used to identify the limits of detection (LODs) in ddPCR and cPCR. Our ddPCR was assessed in 92 field samples, it was compared with cPCR and blood smears. ddPCR showed LOD = 1.6 copies/reaction, or 78 times more sensitive than cPCR (LOD = 126 copies/reaction), using PCR amplicons as a template, whereas both ddPCR and cPCR had equal LODs at 0.02 ng gDNA/reaction. In addition, ddPCR had 100% sensitivity and 75% specificity for E. canis detection compared to cPCR and no cross-reaction with other blood pathogens was observed. ddPCR identified more positive samples than cPCR and blood smear. ddPCR improved the overall performance of E. canis detection, with a better LOD and comparable sensitivity and specificity to cPCR. The technique might be helpful for diagnosis of E. canis in light infection, evaluating the number of E. canis and follow-up after treatment.

Systematic evaluation of TaqMan real-time polymerase chain reaction assays targeting the dsb and gltA loci of Ehrlichia canis in recombinant plasmids and naturally infected dogs

Background and Aim: Because of the diversity of local genotypes of Ehrlichia canis, genes targeted by TaqMan real-time polymerase chain reaction (RT-PCR) assays should be systematically evaluated. This study evaluated the amplification efficiency, linearity, precision, and sensitivity of two TaqMan RT-PCR assays targeting the dsb and gltA loci of E. canis in recombinant plasmids and naturally infected dogs. Materials and Methods: Thirty blood samples were collected from dogs showing clinical signs of canine monocytic ehrlichiosis at the Kasetsart University Veterinary Teaching Hospital, Bangkok, Thailand. The dsb and gltA genes were amplified by conventional PCRs (cPCRs) on the blood samples and were then sequenced. Meanwhile, RT-PCR was used to detect dsb and gltA genes in 10-fold dilutions of the recombinant plasmids. Results: Both dsb and gltA were amplified with a high degree of linearity (R2≥0.975 and 0.993, respectively) in all dilutions, although the mean percentage of relative standard deviation of gltA was lower, but the difference was non-significant. The detection limits of RT-PCR and cPCR were 10–7 and 10–6, respectively, for both loci. RT-PCR targeting dsb (22/30; 73.3%) and gltA (15/30; 50%) yielded a number of positive results that did not differ significantly (p=0.06). The RT-PCR positive results of the dsb gene (22/30) differed significantly from that of cPCR (11/30) (p=0.004). In contrast, the RT-PCR positive results of the gltA gene (15/30) did not differ significantly from that of cPCR (12/30) (p=0.43). The mean Ct value (30.2) based on dsb RT-PCR of 22 positive cases was higher than that of gltA RT-PCR (Ct=27.4) on 15 positive cases. The Ct values from dsb RT-PCR were >30 in all seven discordant samples that were not detected by the gltA RT-PCR. Conclusion: RT-PCR targeting the dsb gene was more sensitive for detecting E. canis in naturally infected dogs. This study suggested that TaqMan RT-PCR of the dsb gene should be selected for E. canis research in this region.

First report on molecular characteristics and risk factor analysis of Ehrlichia canis in dogs in Khon Kaen, Thailand

Background and Aim:

Ehrlichia canis is a well-known cause of both anemia and thrombocytopenia in dogs. There are insufficient epidemiological data on this blood parasite in Thailand and the association of infections with hematological abnormalities. This study aimed to analyze the molecular characteristics and to identify E. canis as well as the risk factors associated with E. canis infection in dogs in Khon Kaen, Thailand.

Materials and Methods:

Blood samples from 126 dogs that visited animal clinics were subjected to molecular detection using nested polymerase chain reaction for E. canis16S rRNA gene. The risk factors and hematological profiles associated with the infection were analyzed using the logistic regression test in program SPSS version 19.

Results:

Forty-one dogs were infected, indicating a 32.5% molecular infection rate of E. canis. The factors significantly associated with E. canis infection include animal housing status, low packed cell volume, low red blood cell count, and low platelets (p<0.05). Ten positive samples were amplified, sequenced, and phylogenetically analyzed. Sequence and phylogenetic analysis confirmed the current ten samples as E. canis compared with reference sequences in GenBank, using the BLAST program hosted by NCBI, which showed 99.74-100% similarity.

Conclusion:

This study provided the first data of infection rate of E. canis using nested PCR and molecular characteristics of E. canis in randomly selected domestic dogs in Khon Kaen, Thailand.

Retrospective analysis of canine monocytic ehrlichiosis in Thailand with emphasis on hematological and ultrasonographic changes

Background and Aim: Canine monocytic ehrlichiosis (CME) is a tropical endemic tick-borne disease that causes fatality or chronic infection involving many organs in dogs. This study aimed to examine the prevalence, risk factors, and hematological and ultrasonographic changes in the liver, gallbladder, kidneys, and spleen following CME infection. Materials and Methods: This retrospective study used 30,269 samples collected from dogs at the hematology section of the pathology unit of a university veterinary hospital and 35 samples collected from dogs at the diagnostic imaging unit. CME was determined using the buffy coat smear method. Data were analyzed using descriptive statistics and odds ratios. Results: CCl4 The data revealed that the average yearly prevalence of CME was 1.32%. Risk factors contributing to CME infection were a tick on the body during physical examination, lack of ectoparasite control, and outdoor living. All 148 dogs with CME infection had low platelet counts. The percentages of CME-infected dogs with elevated serum alanine aminotransferase, alkaline phosphatase, and both enzymes above the normal range were 33.6%, 65.9%, and 29.8%, respectively. The rates for elevated serum levels of blood urea nitrogen, creatinine, and both compounds were 33.1%, 19.1%, and 17.3%, respectively. The most common ultrasonographic changes were liver abnormalities (hyperechogenicity or hypoechogenicity, hepatomegaly, and hypoechoic nodules), hyperechogenicity of the kidneys, and an enlarged spleen. These ultrasonographic changes were consistent with the hematology results, which showed a greater elevation of serum liver enzyme levels than renal enzymes. Conclusion: Ultrasonographic changes during CME infection and after treatment with doxycycline can help to monitor and identify persistent pathological changes in the target organs resulting from immune response to CME.

Molecular discrimination and genetic diversity of three common tick-borne pathogens in dogs in Thailand

There was little information regarding the occurrence of canine vector-borne disease (CVBDs) in shelter dogs in Thailand. This work is the first report regarding a molecular method used to determine the occurrence and genetic diversity of three canine tick-borne pathogens (TBPs) (Hepatozoon canis, Anaplasma platys and Ehrlichia canis) in blood samples from 275 shelter dogs in the north and central areas of Thailand. The PCR results based on the 18S rRNA and 16S rRNA genes showed that 71 (25.82%) dogs were positive for at least a TBP. The overall occurrence rates of H. canis, A. platys and E. canis infections were 1.81, 16.36 and 7.64%, respectively. For the phylogenetic analysis, A. platys 16S rRNA gene was genetically diverse, while H. canis 18S rRNA and E. canis 16S rRNA genes were conserved. The haplotype diversity exhibited 12 and 2 haplotypes as well as 78 and 178 polymorphic sites of A. platys and E. canis 16S rRNA genes, respectively. Our findings could be used to improve the understanding of phylogeny and genetic diversity of TBP rRNA genes and used to ameliorate the diagnosis and control programmes for the diseases in Thailand.

First report on molecular prevalence and identification of Anaplasma platys in dogs in Khon Kaen, Thailand

Background and Aim:

Anaplasma platys is a blood parasite that infects platelets, causing thrombocytopenia. Rhipicephalus sanguineus ticks are believed to transmit A. platys. To identify A. platys, nested polymerase chain reaction (PCR) has proven to be an effective diagnostic tool. In this study, the molecular prevalence of A. platys infection in dogs was investigated for the 1^st time in the Khon Kaen region of Thailand. The association between risk factors and A. platys infection was also evaluated.

Materials and Methods:

A total of 130 blood samples were collected from dogs in Khon Kaen, Thailand. DNA from the samples was extracted and nested PCR was applied for molecular analysis. Platelet count and packed cell volume (PCV) levels were measured. Platelet counts were categorized into four grades: Non-thrombocytopenia (platelets >200,000 cells/μL), mild thrombocytopenia (platelets 150,000-200,000 cells/μL), moderate thrombocytopenia (platelets 100,000-150,000 cells/μL), and severe thrombocytopenia (platelets <100,000 cells/μL). Four categories for PCV levels of >37%, 30-37%, 20-29%, and <20% were defined as no anemia, mild anemia, moderate anemia, and severe anemia, respectively. DNA sequencing was analyzed using BTSeq™ (Barcode-Tagged Sequencing; CELEMICS, Seoul, South Korea) for similarity index.

Results:

Among the 130 samples, 9 (6.9%) were positive for A. platys infection. There was an association between low platelet count and infection (p<0.05). PCV level was also associated with A. platys infection (p<0.05). DNA sequencing results of the nine positive samples showed similarity to known sequences of A. platys with 99.36-100% nucleotide identity. These results suggested low genetic diversity in A. platys infecting dogs in the Khon Kaen area.

Conclusion:

By amplifying 16S rRNA, A. platys infection was detected in the blood of Thai dogs. Further work should be performed to identify risk factors potentially associated with A. platys infection in dogs in Khon Kaen. Other related factors should also be considered, such as location and breeding, as well as the environmental characteristics of each locality. In addition, sampling a larger number of animals may reveal predictors for the positivity of A. platys in dogs in this region.

Characterization of serum protein electrophoresis patterns and C-reactive protein in canine tick-borne diseases

Background and Aim

Canine tick-borne diseases are important diseases with a worldwide distribution. In Thailand, the most important canine tick-borne diseases are ehrlichiosis, babesiosis, and hepatozoonosis. This study aimed to determine the serum protein electrophoresis patterns (SPEPs) and C-reactive protein (CRP) levels associated with Ehrlichia canis , Babesia canis, or Hepatozoon canis single infections.

Materials and Methods

A total of 650 canine blood samples were collected from animal hospitals and clinics in Bangkok and its vicinity to examine health status and blood parasite infection. Suspected blood parasite infections were examined by buffy coat thin blood smear and confirmed by polymerase chain reaction. Normal dog and positive E. canis , B. canis, and H. canis single infections and serum protein profiles were determined by agarose gel electrophoresis. CRP concentration was measured by fluorescent immunoassay.

Results

In dogs infected with E. canis, B. canis, and H. canis single infections, albumin levels and A/G ratios significantly decreased, whereas β2-globulin levels increased (p<0.05). The γ-globulin level significantly increased in E. canis and H. canis infections (p<0.05). A monoclonal gammopathy pattern wasi observed in E. canis and B. canis sngle infections, whereas β-γ bridging patterns and increased β- and γ-globulin fractions were found in H. canis single infections. The CRP level increased in dogs with blood parasite single infections and may be related to the pathogenesis of the infection.

Conclusion

SPEPs and CRP levels can be used to monitor health status and blood parasite problems in infected dogs.

Molecular detection of tick-borne pathogens in infected dogs associated with Rhipicephalus sanguineus tick infestation in Thailand

Background and Aim:

Tick-borne pathogens (TBPs) are of great concern having the potential to threaten canine health. Dogs infected with Ehrlichia canis, Anaplasma platys, Babesia canis, and Hepatozoon canis are commonly found in Thailand; Rhipicephalus sanguineus tick is the most common vector of diseases. This study aimed to determine the prevalence of common TBPs in dogs and their ticks in Thailand using polymerase chain reaction (PCR) and DNA sequencing methods.

Materials and Methods:

Forty-four blood samples were positively diagnosed with TBPs infection by microscopy. Samples were from animal hospitals in Maha Sarakham, Amnat Charoen, Nakhon Ratchasima, and Bangkok, Thailand, during January-June 2020. Five to six ticks were also taken from infected dogs, and then, both blood and tick were analyzed using PCR and DNA sequencing.

Results:

PCR results showed that R. sanguineus was the only tick species detected in this study. The appearance of single infection with E. canis was the most common infection found in dogs and ticks (64% and 82%, respectively). Correlation of pathogen infection in hosts and their vector was performed by similarity detection of pathogens between blood and tick samples based on PCR analysis in 29 samples (66%) but there was no significant differentiation.

Conclusion:

E. canis appears as the most common canine tick-borne pathogen in Thailand, which was detected in both healthy and sick dogs as well as in R. sanguineus. The findings show the relationships among host dogs, pathogens, and ticks. Veterinarians should be proactive in educating pet owners about the risks associated with ticks and their important pathogens and plan effective control strategies.

A multipronged next-generation sequencing metabarcoding approach unearths hyperdiverse and abundant dog pathogen communities in Cambodia

Recent surveys in Southeast Asia, including Cambodia, have identified canine vector-borne pathogens (VBPs), including those with zoonotic potential, as highly prevalent. The lack of veterinary care alongside the close association semidomesticated dogs have with humans in the region exacerbates these zoonotic risks. Nonetheless, the number of studies investigating such pathogens and the threats they pose to dog and human health is limited. Here, we utilize a next-generation sequencing (NGS)-based metabarcoding protocol to conduct an assumption-free characterization of the bacterial, apicomplexan, and kinetoplastid blood-borne pathogens of free-roaming dogs from across Cambodia. From 467 dogs at five field sites, 62% were infected with one of eight confirmed pathogens, comprising Anaplasma platys (32%), Ehrlichia canis (20%), Hepatozoon canis (18%), Babesia vogeli (14%), Mycoplasma haemocanis (13%), the zoonotic pathogen Bartonella clarridgeiae (3%), Candidatus Mycoplasma haematoparvum (0.2%), and Trypanosoma evansi (0.2%). Coinfections of between two and four VBPs were common with 28% of dogs found to have a mixed infection. Moreover, DNA from putatively infectious agents belonging to the bacterial family and genera Coxiella, Mycobacterium, Neisseria, Rickettsiaceae, Treponema, and two uncharacterized Mycoplasma species were identified, in addition to protozoan genera Colpodella, Parabodo, and Bodo. Using a multiple logistic regression model, the presence of ectoparasites, abnormal mucous membranes, anemia, and total protein were found as predictors of canine VBP exposure. This study represents the first time an NGS metabarcoding technique has been used to holistically detect the bacterial and protozoan hemoparasites communities of dogs through an in-depth survey, highlighting the power of such methods to unearth a wide spectrum of pathogenic organisms in an unbiased manner.

First Molecular Detection of Babesia gibsoni in Stray Dogs from Thailand

In southern Thailand, the increasingly growing population of stray dogs is a concern to public health and environmental safety because of the lack of medical attention and control. More importantly, these animals are considered reservoirs for many zoonotic pathogens. The objective of this study was to molecularly detect canine vector-borne pathogens, and to perform genetic characterization of Babesia gibsoni present in stray dogs from southern Thailand. Blood samples were collected from 174 stray dogs in two provinces (Songkhla and Narathiwat) in southern Thailand. PCR analyses were executed using specific primers based on the Babesia spp. 18S rRNA gene, Babesia gibsoni Internal transcribed spacer 1 (ITS1) region, Ehrlichia canis citrate synthase (gltA) gene, Hepatozoon spp. 18S rRNA gene and Anaplasma platys heat shock protein (groEL) gene. The most common canine vector-borne pathogen found infecting stray dogs in this study was Hepatozoon canis (24.7%) followed by A. platys (14.9%), Babesia vogeli (8.0%), B. gibsoni (6.3%), and E. canis (1.72%). Concurrent infection with more than one pathogen occurred in 72 cases. Phylogenetic analysis based on the ITS1 region and 18S rRNA gene revealed that the B. gibsoni isolates from this study shared a large proportion of their identities with each other and with other reported B. gibsoni genotypes from Asia. This study highlights the molecular detection of B. gibsoni in dogs in Thailand for the first time and presents the genetic characterization by sequencing the ITS1 region and 18S rRNA gene of B. gibsoni from Thailand. Follow-up studies are needed to elucidate the origin, distribution, and vectors of B. gibsoni parasites circulating in dogs in Thailand, as well as to determine to what extent dogs are important reservoir hosts for zoonotic canine vector-borne disease infection in the studied area.

Molecular Detection of Tick-Borne Pathogens in Stray Dogs and Rhipicephalussanguineus sensu lato Ticks from Bangkok, Thailand

Canine tick-borne pathogens (CTBPs) such as Babesia vogeli, Ehrlichia canis, Anaplasma platys, Hepatozoon canis, and Mycoplasma haemocanis are important pathogens in dogs worldwide. Rhipicephalus sanguineus sensu lato, the main vector of several CTBPs, is the most common tick species found on dogs in Thailand. The present study identified CTBPs in dogs and ticks infested dogs. Samples (360 dog blood samples and 85 individual ticks) were collected from stray dogs residing in 37 temples from 24 districts in Bangkok and screened for CTBPs using molecular techniques. The most common CTBP found infecting dogs in this study was Ehrlichia canis (38.3%) followed by Mycoplasma haemocanis (34.2%), Hepatozoon canis (19.7%), Babesia vogeli (18.1%), and Anaplasma platys (13.9%), respectively. Furthermore, A. platys (22.4%) was the most common CTBP in ticks followed by M. haemocanis (18.8%), B. vogeli (9.4%), H. canis (5.9%), and E. canis (2.4%), respectively. The detection of CTBPs from the present study highlights the potential risk of infections that may occur in stray dogs and their ticks residing in Bangkok temples. These findings underline the importance of performing active surveys to understand the complexity of distributions of CTBPs in dogs and their ticks in Thailand.

Hematological profile of blood parasitic infected dogs in Southern Thailand

Background and Aim:

Tick-borne pathogens such as Babesia canis, Hepatozoon canis, and Ehrlichia canis can cause serious disease in canines. Each blood parasite can be associated with different hematological characteristics in infected dogs. Identification of hematological alterations during routine laboratory screening of blood samples from dogs displaying clinical signs is essential for diagnosing blood parasitic infections. This study aimed to evaluate parasitic infections and hematological alterations in blood samples of infected dogs in Southern Thailand.

Materials and Methods:

A total of 474 blood samples were collected from dogs presented at the Veterinary Teaching Hospital of the Prince of Songkla University between 2016 and 2019. An automatic hematology analyzer was used to establish hematological values; peripheral blood films were screened for blood parasites and their detection was associated with hematological alterations to determine the odds ratio (OR).

Results:

This study found that E. canis (n=127) was the most common blood parasite infecting dogs in southern Thailand, followed by H. canis (n=100) and B. canis (n=24). Hematological alterations caused by Ehrlichia infections included anemia, thrombocytopenia, monocytosis, and eosinophilia (OR=14.64, 17.63, 20.34, and 13.43, respectively; p<0.01). The blood samples of Hepatozoon-infected dogs were characterized by anemia, thrombocytopenia, leukocytosis, neutrophilia, and monocytosis (OR=6.35, 3.16, 12.80, 11.11, and 17.37, respectively; p<0.01). Anemia, thrombocytopenia, eosinopenia, and lymphopenia (OR=10.09, 33.00, 20.02, and 66.47 respectively; p<0.01) were associated with B. canis-infected dogs.

Conclusion:

These data support the fact that hematological abnormalities are a hallmark for the identification of tick-borne infections. The hematological values, hereby reported, can be used as a guideline for the clinical diagnosis of canine blood parasitic infections in Southern Thailand.

Anaplasma platys-Like Infection in Goats, Beijing, China

As one of the important tick-borne zoonotic pathogens, Anaplasma has both veterinary and public health significance. Here, we performed a survey of Anaplasma infection in the goats from a farm in Beijing, China, and found 44.6% (41/92) were infected with Anaplasma capra, and 22.8% (21/92) were infected with Anaplasma sp. This Anaplasma sp. bacterium was close to a recently emerging Anaplasma platys strain based on gltA and groEL gene phylogenetic analysis. As to further understand the characteristics of Anaplasma sp., we raised a couple of positive goats (n = 2) in the laboratory with tick-free settings. We observed inappetence, vomiting, high fever, and weakness of limbs in the goat's offspring (n = 3). In addition, the blood samples from all offspring were all positive of this Anaplasma spp. We did not see any intracellular morulae in neutrophils, monocytes, and erythrocytes, but we identified some in the platelets of the blood smears from the positive goats by light microscopy. We named it A. platys-like and suggested it may infect platelets and be transmitted vertically through the placenta of goats. These findings deserve further evaluation.

Molecular Detection of Some Anaplasma Species in Blood of Dogs in Baghdad Province, Iraq

A total of 150 blood samples were collected from dogs and examined by the polymerase chain reaction (PCR) technique, which was used to detect the 16S RNA gene of Anaplasma platys and Anaplasma phagocytophilum. Subsequent analysis of the PCR amplicons was achieved by nucleotides sequencing of some positive samples. Totally, the findings show the presence of PCR products (i.e., Anaplasma spp. infection) in 12/150 (8.0%) of the dogs under study. While 5/150 (3.33%) of the cases were A. platys, 7/150 (4.66%) were A. phagocytophilum. Nucleotide sequencing confirmed the identity of the amplified genes whose sequences were compared with other references belong to 15 of 16S rRNA gene of A. platys and 14 references of 16S rRNA gene of A. phagocytophilum, and the isolate sequences of this study were deposited on the Gene Bank. The identity and similarity scores between the isolates of this study and reference strains ranged from 98 to 99%. In conclusion, canine anaplasmosis prevalence in dogs could be underestimated in Iraq, and the phylogenetic tree of the local A. platys and A. phagocytophilum isolates were found to resemble other worldwide strains of Anaplasma spp. with a high degree of similarity.

A Host-Specific Blocking Primer Combined with Optimal DNA Extraction Improves the Detection Capability of a Metabarcoding Protocol for Canine Vector-Borne Bacteria

Bacterial canine vector-borne diseases are responsible for some of the most life-threatening conditions of dogs in the tropics and are typically poorly researched with some presenting a zoonotic risk to cohabiting people. Next-generation sequencing based methodologies have been demonstrated to accurately characterise a diverse range of vector-borne bacteria in dogs, whilst also proving to be more sensitive than conventional PCR techniques. We report two improvements to a previously developed metabarcoding tool that increased the sensitivity and diversity of vector-borne bacteria detected from canine blood. Firstly, we developed and tested a canine-specific blocking primer that prevents cross-reactivity of bacterial primer amplification on abundant canine mitochondrial sequences. Use of our blocking primer increased the number of canine vector-borne infections detected (five more Ehrlichia canis and three more Anaplasma platys infections) and increased the diversity of bacterial sequences found. Secondly, the DNA extraction kit employed can have a significant effect on the bacterial community characterised. Therefore, we compared four different DNA extraction kits finding the Qiagen DNeasy Blood and Tissue Kit to be superior for detection of blood-borne bacteria, identifying nine more A. platys, two more E. canis, one more Mycoplasma haemocanis infection and more putative bacterial pathogens than the lowest performing kit.