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

Exploring tick-borne pathogens in community dogs in Nepal

Tick-borne pathogens (TBPs) in dogs are a major global health concern, with their zoonotic importance often being neglected in developing countries due to a lack of surveillance. This study aimed to highlight the incidence of six important TBPs belonging to the genera Babesia, Theileria, Hepatozoon, Anaplasma, Ehrlichia, and Rickettsia in a total of 230 community dogs from two sites: Lumbini and the Kathmandu Valley, of Nepal. A total of 75 (32.6 %) dogs were found to be infected with at least one TBP, with 11 (4.7 %) being co-infected with more than one TBP. The detection rates of TBPs were 13.9 % (n = 32) for Ehrlichia canis, 9.1 % (n = 21) for Anaplasma platys, 8.6 % (n = 20) for Babesia vogeli, and 6.5 % (n = 15) for Babesia gibsoni. None of the samples were positive for Theileria, Hepatozoon, or Rickettsia. There was a significant association between A. platys and E. canis infections, respectively, with the locations from which the samples were collected. Infections of TBPs in community dogs might be the source of infection for pet dogs or even humans in shared habitats. Further studies are needed to determine the prevalence and diversity of TBPs in dogs in other regions of Nepal. As some of these parasites are zoonotic, concerted efforts are required to raise awareness of, and control efforts for, these tick-borne pathogens.

Improvements in Blood Profiles of Canines Naturally Infected with Triple Blood Pathogens (Babesia vogeli, Ehrlichia canis, and Anaplasma platys) Subsequent to Doxycycline Monotherapy

Multiple blood pathogen infections are increasingly found in many areas, particularly in tropical regions. This study aimed to investigate the effectiveness and safety of using doxycycline monotherapy to treat triple blood pathogen infection in sheltered dogs. A total of 375 sheltered dogs were screened for blood pathogen using polymerase chain reaction technique (PCR). There were 34 dogs with triple infection (Babesia vogeli, Ehrlichia canis, and Anaplasma platys), and most dogs displayed anemia and thrombocytopenia. These dogs were treated with doxycycline (10 mg/kg/day) orally for four weeks, and their blood profiles were monitored. Almost all pathogens were undetectable by PCR by day 14 and pathogens were all cleared by day 28. Most blood profiles significantly improved after 14 days. The improvement continued after 28 days. The red blood cell and platelet count (PLT) were increased in similar trends between mild-to-moderate and severe thrombocytopenia groups. The average PLT in the mild-to-moderate thrombocytopenia group raised to normal level by day 14, whereas in the severe group, it was gradually increased to normal level by day 70. We propose using doxycycline monotherapy for 28 days to eliminate all pathogens, and facilitate recovery and welfare in dogs suffering with triple blood pathogen infections.

Frequency of Anaplasma platys in dogs from the municipality of Veracruz, Mexico

Infectious canine cyclic thrombocytopenia or canine anaplasmosis is an infectious disease caused by Anaplasma platys. In Mexico, cases of human infection have been reported. The present cross-sectional study aimed to determine the frequency of A. platys infection in the municipality of Veracruz, Mexico, by nested polymerase chain reaction method. A total of 100 blood samples from dogs living in the municipality were collected and analyzed between March and June 2022. A descriptive analysis of blood samples for hemoparasites frequencies was performed with the free online software VassarStats. The evaluated variables were sex, street access, usage of ticks control methods, and living environment. The free online software WinEpi software was used to calculate odds ratio (OR) and confidence interval (CI: 95.00%). Out of 100 analyzed blood samples, 27 were confirmed positive for A. platys. The only risk factor found was the absence of tick prevention methods (OR = 9.81; 95.00% CI: 23.00 - 44.50). In conclusion, the frequency of A. platys was 27.00% and no risk factors were identified.

Severe fever with thrombocytopenia syndrome (SFTS) in Thailand: using a one health approach to respond to novel zoonosis and its implications in clinical practice

Severe fever with thrombocytopenia syndrome (SFTS), a tick-borne disease caused by Dabie bandavirus (SFTSV) is an emerging infectious disease of substantial concern in East Asia. In 2019, Ongkittikul S et al. reported the first case of SFTS in Thailand. Our report describes a One Health investigation of SFTS zoonosis examining the index case and suspected animal reservoirs using real-time RT-PCR and immunoassays. We add to the report on the first confirmed case of SFTSV infection in a human in Thailand by conducting a limited but informative One Health surveillance study. Dogs and cats tested positive for SFTSV antibody using IgG ELISA. We conclude that domestic dogs and cats might serve as potential reservoirs for SFTSV spread due to their closer proximity to the index case than other non-domestic animals. Notably, we did not detect SFTSV in synanthropic cats or dogs-nor did we detect SFTSV in Rhipicephalus sanguineus ticks-using RT-PCR. We propose that One Health investigations coupling genomic and serologic assays in response to new SFTS cases could play a pivotal role in preventing and managing SFTS among humans and animals in East Asia. As such, we are establishing a collaborative response to SFTS in Thailand through human outbreak investigations that align with principles of One Health, through environmental surveys and animal RT-PCR and immunoassays. Our investigation highlights the importance of coupling RT-PCR with seroprevalence assays as principal elements of One Health surveillance for SFTS in order to shed light on potential animal reservoirs and track emerging zoonosis.

Molecular detection of Rickettsia species in ectoparasites collected from two southern provinces of Cambodia

Arthropod-borne rickettsioses comprise a wide variety of subtypes that are endemic in Cambodia, but there remains very little data on the geographic distribution of the pathogens or their vectors. Surveys were conducted in Koh Kong and Preah Sihanouk Provinces between September 2017 and June 2018 to collect ectoparasites from peridomestic animals and the environment using dragging and flagging methods. Collected ectoparasites were sorted and identified morphologically, then pooled by species, host, and location for molecular detection using Rickettsia genus- and species-specific qPCR and/or multilocus sequence typing (MLST) assays. A total of 14,254 ectoparasites were collected including seven new locality records. Rickettsia species were detected in 35.5% (174/505) of the pools screened representing 3,149 randomly selected ectoparasites from the total collected. Rickettsia asembonensis was detected in 89.6% (147/164) of Rickettsia-positive flea pools and 3.6% (6/164) of the flea pools were positive for both R. asembonensis and Rickettsia felis. Candidatus Rickettsia senegalensis from Ctenocephalides orientis fleas and Rickettsia sp. close to Rickettsia japonica and Rickettsia heilongjiangensis from Haemaphysalis ticks were identified by MLST. This appears to be the first report of these new ectoparasite records and rickettsial species in southern Cambodia, suggesting a potential health risk to military and civilians in this region.

The detection of zoonotic microorganisms in Rhipicephalus sanguineus (brown dog ticks) from Vietnam and the frequency of tick infestations in owned dogs

Dog owners are greatly concerned about tick infestations in their pets. The prevalence and dispersion of ticks and their disease-causing microorganisms have been limited from the viewpoint of dog owners in Vietnam. This study investigated the presence of tick infestation and the pathogens associated with it in canines that were brought to veterinary hospitals in Vietnam. In the survey, 1,423 dogs participated from February to October 2022. Molecular and morphological methods were utilized to identify ticks and the associated pathogens. In addition,risk variables linked to tick infestation were documented and analyzed using statistical methods. The total exposure to the brown dog tick (Rhipicephalus sanguineus sensu lato) was 29.01%. Nam Dinh has the highest tick prevalence among the research areas. Tick infestation reached its highest point between June and September in the northern region of the country, with distinct seasons showing a strong correlation with tick infestation in dogs. Out of 177 tick pools examined, 146(82.49%) tested positive for at least one infection. Mycoplasma spp. (78.53%) was the most common, followed by Anaplasma spp. (37.29%), Rickettsia felis (5.08%), Babesia vogeli, and Hepatozoon canis (2.82%). In the current study, there was a statistically significant link between tick infestation and characteristics such as age, breed, body size, lifestyle, and bathing frequency. Understanding the seasonal behavior of vector ticks is crucial for identifying individuals or animals susceptible to tick-borne diseases. Studying the distribution of ticks and their ability to carry and disseminate zoonotic germs in specific places could assist veterinarians and policymakers in implementing effective strategies to manage zoonotic infections.

Survey of dog owners' and veterinarians' attitudes regarding the selection of flea and tick prevention products in Thailand

Background and Aim

Tick and flea infestations in dogs are significant concerns for both dog owners and veterinarians in Thailand. The country's climate provides an optimal environment for the proliferation of ticks and fleas, thereby increasing the risk of diseases transmitted by these parasites. At present, a diverse range of tick and flea prevention products is available on the market. This study aimed to investigate the factors influencing the choice of tick and flea prevention products among dog owners and veterinarians in Thailand.

Materials and Methods

Questionnaires were distributed both online and in-person to collect data from dog owners and veterinarians. The data collection period spanned from September 1, 2022, to August 31, 2023. A total of 994 respondents, consisting of 828 dog owners and 166 veterinarians, participated in the questionnaire and were included in this study. The data were then subjected to descriptive statistics and Chi-square test.

Results

The results indicated that most dog owners consider chewable products to be the most effective form of tick and flea prevention, followed by sprays and spot-on treatments. Statistically significant factors (p < 0.05) affecting the frequency of use of tick and flea prevention products were identified, including dog breed, number of owned dogs, and owners' awareness of tick and flea issues in dogs. Most dog owners tend to use these products when their dogs are infected with ticks or fleas. In addition, owners of a single dog tended to use these products regularly compared to those with multiple dogs. Notably, some dog owners (10.99%) used unregistered products. Among veterinarians, it was observed that dog owners followed the recommendations provided by veterinarians (80.12%). In most cases, veterinarians recommend various tick and flea prevention products (74.10%). The most influential factor affecting product selection is suitability for the individual animal.

Conclusion

This study provides insights for veterinarians and relevant stakeholders regarding the factors and attitudes that influence dog owners' selection of tick and flea prevention products. This knowledge can contribute to better planning for ectoparasite prevention. In addition, effective communication from veterinarians can increase owner awareness of the importance of tick and flea prevention, thereby reducing the incidence of diseases transmitted by ticks and fleas.

Seroprevalence study in humans and molecular detection in Rhipicephalus sanguineus ticks of severe fever with thrombocytopenia syndrome virus in Thailand

Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne virus with a mortality rate of up to 30%. First identified in China in 2009, it was later reported in other Asian countries, including Thailand in 2020. SFTSV has been detected in several tick species, including Rhipicephalus sanguineus, known for infesting dogs. We conducted a seroprevalence study of SFTSV in Bangkok and Nong Khai, Thailand, by analyzing 1162 human samples collected between 2019 and 2023. The testing method relied on IgG detection using ELISA and confirmed though a virus seroneutralization test. The results indicated that out of the participants, 12 (1.1%) tested positive for anti-SFTSV IgG antibodies; however, none exhibited positive results in the seroneutralization assay. Additionally, molecular detection of SFTSV, Crimean-Congo hemorrhagic fever (CCHF), Coxiella spp., Bartonella spp., and Rickettsia spp. was performed on 433 Rh. sanguineus ticks collected from 49 dogs in 2023 in Chachoengsao Province, Thailand. No evidence of these pathogens was found in ticks. These findings highlight the importance of exploring viral cross-reactivity. Furthermore, it is important to conduct additional studies to isolate SFTSV from animals and ticks in order to identify the potential transmission routes contributing to human and animal infections in Thailand.

Seroprevalence of melioidosis and its association with blood profiles and pathogens in sheltered dogs in southern Thailand

Background and Aims

Melioidosis is a notable zoonotic disease in Thailand that can affect both humans and animals. Although dogs are one of the most popular pets worldwide, there is a remarkable lack of information on the prevalence and knowledge of canine melioidosis. This study aimed to estimate the seroprevalence of melioidosis in sheltered dogs and its relationship with the blood profile and blood pathogens.

Materials and Methods

Melioidosis in 156 dogs was analyzed using an indirect hemagglutination assay. Hematology and serum biochemistry tests were performed using an automated system. Blood pathogens (e.g., Ehrlichia, Anaplasma, Hepatozoon, and Babesia) were diagnosed using conventional polymerase chain reaction.

Results

The seroprevalence rates of canine melioidosis and blood pathogen infection were 5.77% (9/156) and 50.64% (79/156), respectively. Seropositive dogs generally have higher lymphocyte counts and aspartate aminotransferase levels but lower total white blood cell, neutrophil, and platelet (PLT) counts than seronegative dogs. No statistically significant difference (p > 0.05) was observed between the seropositive and seronegative dogs' hematology and serum biochemistry findings. Neither the correlation between melioidosis and blood pathogen infection nor the association between melioidosis and thrombocytopenia was statistically significant (p > 0.05). Remarkably, dogs that had coinfections with both melioidosis and blood pathogens demonstrated a significantly reduced PLTcount (49,167 ± 7,167) compared with dogs that tested positive for melioidosis but negative for blood pathogens (139,333 ± 29,913) (p < 0.01).

Conclusion

In southern Thailand, the prevalence of canine melioidosis was low but the prevalence of blood pathogens was high. Coinfection with blood pathogens can significantly reduce PLT counts, which may have a potentially serious impact. Future research should focus on conducting seroprevalence studies in the general dog population.

First report of dog ticks and tick-borne pathogens they are carrying in Malawi

Ticks are vectors for transmitting tick-borne pathogens (TBPs) in animals and humans. Therefore, tick identification is necessary to understand the distribution of tick species and the pathogens they carry. Unfortunately, data on dog ticks and the TBPs they harbor in Malawi are incomplete. This study aimed to identify dog ticks and the TBPs they transmit in Malawi. One hundred thirty-two ticks were collected from 87 apparently healthy but infested domestic dogs in four districts of Malawi, which were pooled into 128 tick samples. The ticks were morphologically identified under a stereomicroscope using identification keys, and species identification was authenticated by polymerase chain reaction (PCR) through the amplification and sequencing of 12S rRNA and cytochrome c oxidase subunit I (CO1) genes. The tick species identified were Rhipicephalus sanguineus sensu lato (58.3%), Haemaphysalis elliptica (32.6%), and Hyalomma truncatum (9.1%). Screening for TBPs using species-specific PCR assays revealed that 48.4% of the ticks were infected with at least one TBP. The TBP detection rates were 13.3% for Anaplasma platys, 10.2% for Babesia rossi, 8.6% for B. vogeli, 6.3% for Ehrlichia canis, 3.9% for A. phagocytophilum, 3.1% for B. gibsoni, 2.3% for B. canis and 0.8% for Hepatozoon canis. Co-infections of up to three pathogens were observed in 48.4% of the positive samples. This is the first study to identify dog ticks and the TBPs they harbor in Malawi. These findings provide the basis for understanding dog tick distribution and pathogens they carry in Malawi. This study necessitates the examination of ticks from more study locations to have a better picture of tick challenge, and the development of ticks and tick-borne disease control methods in Malawi.

First report on tick-borne pathogens detected in ticks infesting stray dogs near butcher shops

Public health is a major concern for several developing countries due to infectious agents transmitted by hematophagous arthropods such as ticks. Health risks due to infectious agents transmitted by ticks infesting butcher-associated stray dogs (BASDs) in urban and peri-urban regions have been neglected in several developing countries. To the best of the authors' knowledge, this is the first study assessing public health risks due to ticks infesting BASDs in Pakistan's urban and peri-urban areas. A total of 575 ticks (390 from symptomatic and 183 from asymptomatic BASDs) were collected from 117 BASDs (63 symptomatic and 54 asymptomatic); the ticks belonged to 4 hard tick species. A subset of each tick species' extracted DNA was subjected to polymerase chain reaction (PCR) to amplify the 16S rDNA and cox1 sequences of the reported tick species, as well as bacterial and protozoal agents. The ticks' 16S rDNA and cox1 sequences showed 99-100% identities, and they were clustered with the sequence of corresponding species from Pakistan and other countries in phylogenetic trees. Among the screened 271 ticks' DNA samples, Anaplasma spp. was detected in 54/271 (19.92%) samples, followed by Ehrlichia spp. (n = 40/271, 14.76%), Rickettsia spp. (n = 33/271, 12.17%), Coxiella spp. (n = 23/271, 4.48%), and Hepatozoon canis (n = 9/271, 3.32%). The obtained sequences and phylogenetic analyzes revealed that the pathogens detected in ticks were Ehrlichia minasensis, Ehrlichia sp., Hepatozoon canis, Coxiella burnetii, Coxiella sp., Anaplasma capra, Anaplasma platys, Anaplasma sp., Rickettsia massiliae, "Candidatus Rickettsia shennongii" and Rickettsia aeschlimannii. Tick-borne pathogens such as E. minasensis, H. canis, A. capra, A. platys, and R. aeschlimannii, were detected based on the DNA for the first time in Pakistan. This is the first report on public health risks due to ticks infesting BASDs. These results not only provided insights into the occurrence of novel tick-borne pathogens in the region but also revealed initial evidence of zoonotic threats to both public health and domestic life.

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.

Genetic diversity of tick (Acari: Ixodidae) populations and molecular detection of Anaplasma and Ehrlichia infesting beef cattle from upper-northeastern Thailand

Genetic diversity, genetic structure and demographic history of the ticks infesting beef cattle in Thailand were examined based on mitochondrial cytochrome c oxidase I (cox1) sequences. Tick samples were collected in 12 provinces in upper-northeastern Thailand. Three species were found; Rhipicephalus microplus, R. sanguineus, and Haemaphysalis bispinosa. Of these, R. microplus was by far the most abundant species in beef cattle and was widely distributed throughout the area. No cox1 sequence variation was found in the R. sanguineus or H. bispinosa specimens collected. Low nucleotide diversity but high haplotype diversity was observed in R. microplus. All collected R. microplus specimens belonged to lineage A. Mismatch-distribution analysis, as well as Tajima's D and Fu's Fs tests, provided evidence of recent demographic expansion. A subsample of tick specimens was investigated for presence of Anaplasma and Ehrlichia using a fragment of the 16S rRNA gene. Three species of Anaplasma were detected from R. microplus; Anaplasma marginale (19.08%), Anaplasma platys (1.97%) and unidentified Anaplasma strain (0.66%). The infection rate of Ehrlichia was 7.24% (two ticks were infected with E. minasensis (1.97%) and eight with an unidentified Ehrlichia strain (5.26%). No infections were found in R. sanguineus or H. bispinosa. This is the first report of A. platys and E. minasensis in cattle ticks in Thailand, providing information for future epidemiological surveys and control strategies in this region.

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.

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.

The Bacterial Community in Questing Ticks From Khao Yai National Park in Thailand

Ticks are known vectors for a variety of pathogens including bacteria, viruses, fungi, and parasites. In this study, bacterial communities were investigated in active life stages of three tick genera (Haemaphysalis, Dermacentor, and Amblyomma) collected from Khao Yai National Park in Thailand. Four hundred and thirty-three questing ticks were selected for pathogen detection individually using real-time PCR assays, and 58 of these were subjected to further metagenomics analysis. A total of 62 ticks were found to be infected with pathogenic bacteria, for a 14.3% prevalence rate, with Amblyomma spp. exhibiting the highest infection rate (20.5%), followed by Haemaphysalis spp. (14.5%) and Dermacentor spp. (8.6%). Rickettsia spp. were the most prevalent bacteria (7.9%) found, followed by Ehrlichia spp. (3.2%), and Anaplasma spp. and Borrelia spp. each with a similar prevalence of 1.6%. Co-infection between pathogenic bacteria was only detected in three Haemaphysalis females, and all co-infections were between Rickettsia spp. and Anaplasmataceae (Ehrlichia spp. or Anaplasma spp.), accounting for 4.6% of infected ticks or 0.7% of all examined questing ticks. The prevalence of the Coxiella-like endosymbiont was also investigated. Of ticks tested, 65.8% were positive for the Coxiella-like endosymbiont, with the highest infection rate in nymphs (86.7%), followed by females (83.4%). Among tick genera, Haemaphysalis exhibited the highest prevalence of infection with the Coxiella-like endosymbiont. Ticks harboring the Coxiella-like endosymbiont were more likely to be infected with Ehrlichia spp. or Rickettsia spp. than those without, with statistical significance for Ehrlichia spp. infection in particular (p-values = 0.003 and 0.917 for Ehrlichia spp. and Rickettsia spp., respectively). Profiling the bacterial community in ticks using metagenomics revealed distinct, predominant bacterial taxa in tick genera. Alpha and beta diversities analyses showed that the bacterial community diversity and composition in Haemaphysalis spp. was significantly different from Amblyomma spp. However, when examining bacterial diversity among tick life stages (larva, nymph, and adult) in Haemaphysalis spp., no significant difference among life stages was detected. These results provide valuable information on the bacterial community composition and co-infection rates in questing ticks in Thailand, with implications for animal and human health.

Epidemiology, Diagnosis, and Control of Canine Infectious Cyclic Thrombocytopenia and Granulocytic Anaplasmosis: Emerging Diseases of Veterinary and Public Health Significance

This review highlights the diagnostic methods used, the control strategies adopted, and the global epidemiological status of canine cyclic thrombocytopenia and granulocytic anaplasmosis at the animal–human interface. Canine anaplasmosis is an important worldwide disease, mainly caused by Anaplasma platys and A. phagocytophilum with zoonotic implications. A. platys chiefly infects platelets in canids, while A. phagocytophilum is the most common zoonotic pathogen infecting neutrophils of various vertebrate hosts. Diagnosis is based on the identification of clinical signs, the recognition of intracellular inclusions observed by microscopic observation of stained blood smear, and/or methods detecting antibodies or nucleic acids, although DNA sequencing is usually required to confirm the pathogenic strain. Serological cross-reactivity is the main problem in serodiagnosis. Prevalence varies from area to area depending on tick exposure. Tetracyclines are significant drugs for human and animal anaplasmosis. No universal vaccine is yet available that protects against diverse geographic strains. The control of canine anaplasmosis therefore relies on the detection of vectors/reservoirs, control of tick vectors, and prevention of iatrogenic/mechanical transmission. The control strategies for human anaplasmosis include reducing high-risk tick contact activities (such as gardening and hiking), careful blood transfusion, by passing immunosuppression, recognizing, and control of reservoirs/vectors.

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.