Search Results (77)

This study aimed to assess the emergence and/or re-emergence of Tick-borne Diseases (TBD) in Portugal by linking the hemoparasite burden in companion animals to vector-borne disease dynamics through a One Health approach. Between 2015 and 2024, 1169 clinically suspected animals with hemoparasite infections, treated at the Hospital Veterinário de Santarém (HVS), underwent serological confirmation for Rickettsia conorii, Babesia canis, Ehrlichia spp., and Haemobartonella spp. A total of 3791 serological tests (3.2 tests per animal) were performed and 437 animals tested positive for at least one of the four hemoparasites under investigation. From 2020 to 2024, tests nearly tripled from 894 to 2883, raising positive cases and prevalence from 29.5% to 39.9%, especially for rickettsiosis and hemobartonellosis, indicating an increased circulation of their vectors. A national vector surveillance initiative identified Hyalomma spp., Rhipicephalus sanguineus, Ixodes ricinus, and Dermacentor sp. as primary tick vectors in Portugal for the hemoparasites mentioned above and for other agents like arbovirus, such as Crimean-Congo Hemorrhagic Fever Virus (CCHFV) and tick-borne encephalitis virus (TBEV). This study found that the vectors responsible for transmitting hemoparasitosis, given the high number of serologically positive cases detected in the HVS, represent an increasing risk for TBD. These findings highlight the relevance of companion animal monitoring as an early-warning component within a One Health surveillance approach. Full article

Ehrlichia canis is a tick-transmitted zoonotic pathogen in dogs. We conducted a molecular survey for screening of E. canis infection in Rhipicephalus sanguineus ticks infesting dogs and identified its genetic identity in Taiwan. A total of 1195 R. sanguineus ticks were collected and examined for Ehrlichia infection by nested-PCR assay targeting the 16S ribosomal RNA (rRNA) gene. In general, Ehrlichia infection was detected in 1.5% of examined ticks, and was detected in nymph, male and female stages with infection rates of 0.6%, 1.31% and 2.76%, respectively. The highest monthly prevalence was observed in August with an infection rate of 5.91%. Genetic identity was analyzed by comparing the 16S rRNA gene sequences obtained from 11 Taiwan strains and 15 other strains representing five genospecies of Ehrlichia spp., including two outgroups (Anaplasma phagocytophilum and Rickettsia rickettsii). Results revealed that all Taiwan strains were genetically affiliated to the same clade within various E. canis strains documented in GenBank with a high sequence similarity (99.7–100%) and that they can be clearly distinguished from other genospecies of Ehrlichia. This study provides the first evidence of E. canis identified in R. sanguineus ticks and highlights the potential threat for human infections in Taiwan. Full article

Canine monocytic ehrlichiosis (CME) is a highly infectious disease with zoonotic potential. Ehrlichia canis, the causative agent, is primarily transmitted by Rhipicephalus sanguineus. Tick infestation and tick-borne diseases (TBDs) are serious human and veterinary health problems due to the lack of efficient control measures. This review aims to provide information about CME, detailing epidemiology, pathogenesis, clinical manifestations, and current strategies for diagnosis, treatment, and prevention. The review delves into the biology of R. sanguineus, exploring its lifecycle, habitat, and mechanisms of E. canis transmission. Ehrlichia canis infection follows a three-phase transition: acute, subclinical, and chronic, with distinct clinical signs, from mild to severe and even life-threatening in some cases, with the potential for asymptomatic long-term carriers acting as reservoirs. Pathogenesis involves complex interactions between the pathogen and host immune responses, influencing disease severity and progression. Additionally, the review highlights challenges in controlling CME due to the widespread distribution of R. sanguineus. Genetic diversity within R. sanguineus populations and their varying vector competence further complicate control efforts. The role of environmental changes in tick distribution aligns the control of CME within the One Health concept, integrating approaches to improve outcomes for humans, animals, and the environment. Preventive measures on tick control and potential vaccine development are also reviewed. Full article

Ticks and tick-borne pathogens pose a significant threat to human and animal health, yet the diversity and prevalence of tick-borne microorganisms in karst regions remains inadequately explored. In October 2023, a total of 274 Rhipicephalus microplus ticks were collected from livestock in Guizhou Province, which boasts the largest karst area in China. Pathogen identification was subsequently performed using PCR amplification, Sanger sequencing, and phylogenetic analysis. High microbial diversity was noted, with five bacterial species from the order Rickettsiales detected, including those from the genera Rickettsia (family Rickettsiaceae), Anaplasma, and Ehrlichia (family Anaplasmataceae). The overall prevalence of infection with at least one pathogen was remarkably high at 94.5%. The highest positive rate was observed for Candidatus Rickettsia jingxinensis at 90.9%. A novel Ehrlichia species, provisionally designated as Candidatus Ehrlichia carsus, was identified with a positive rate of 16.8%. In addition, Anaplasma marginale, Ehrlchia minasensis and Ehrlichia canis were detected in 15.3%, 4.7% and 1.5%, respectively. The co-infections involving two or three rickettsial species were observed in 34.3% ticks. These findings highlight the high diversity and prevalence of tick-borne rickettsial agents in the karst area, underscoring the need for enhanced surveillance and effective tick control to mitigate disease risks to both humans and livestock. Full article

Canine monocytic ehrlichiosis (CME) is a globally prevalent disease transmitted by the tick Rhipicephalus sanguineus and caused by the Gram-negative bacterium Ehrlichia spp. Following an incubation period, the infection is categorized based on the progression of the disease into acute, subclinical, and chronic stages. Besides hematological alterations, the cardiovascular system is significantly impacted by the hemodynamic effects of the disease, as persistent anemia can lead to myocardial hypoxia and the activation of inflammatory processes, potentially causing myocarditis. It is known that in dogs infected with Ehrlichia canis, there is a higher occurrence of arrhythmias and a predominance of sympathetic activity. This study assessed arrhythmogenic parameters, including P wave dispersion (Pd), QT dispersion (QTd), and QT instability, along with heart rate variability (HRV) analysis from 24 h Holter monitoring in naturally infected dogs during the acute phase (n = 10) and chronic phase (n = 10) compared to a control group (n = 10). The Pd and QTd values were higher in the infect group, confirming the arrhythmogenic character. Instability parameters (TI, LTI, and STI) were higher in sick animals, but no worsening was observed in the chronic phase. All HRV metrics in the time domain were higher in the control group, indicating a balanced sympathovagal activity throughout the day in healthy dogs. Additionally, parameters linked to parasympathetic activity (rMSSD and pNN50) were reduced in the sick groups, confirming the dominance of sympathetic activity. These findings indicate a decrease in HRV in sick individuals and reinforce this useful marker for assessing the influence of the autonomic nervous system on the cardiovascular system. In conclusion, CME exhibits arrhythmogenic activity characterized by the deterioration of predictive parameters for ventricular arrhythmias and increased activity of the sympathetic autonomic nervous system in the heart. This is likely secondary to myocarditis, myocardial hypoxia, and structural damage to cardiomyocytes. Full article

A conventional PCR (cPCR) remains an effective molecular technique for the diagnosis of canine monocytic ehrlichiosis. However, agarose gel electrophoresis requires additional time after thermal cycling. In the present study, we developed a PCR-based lateral flow biosensor (PCR-LFB) to detect Ehrlichia canis (E. canis). Lateral flow strips allow for the simple and rapid detection of PCR products and provide an alternative to gel electrophoresis. The sensitivity, specificity, and detection limit of PCR-LFB were compared to those of TaqMan probe-based real-time PCRs (qPCRs). The PCR-LFB was performed with 5′ 6-FITC and biotin-labeled primers specific to E. canis, targeting the dsb gene. The detection limit of the PCR-LFB assay was 10⁻⁶ for the target DNA sequence in a 10-fold dilution of the recombinant plasmid, which is 10 times lower than that of qPCR. Among the confirmed qPCR results in the 30 dog samples, false-positive results were not detected by the PCR-LFB. Compared to qPCR, the sensitivity and specificity of PCR-LFB were 63.6% (95% CI; 42.9–80.2%) and 100% (95% CI; 67.5–100%), respectively. The Kappa value of the PCR-LFB is in moderate agreement with the qPCR (κ = 0.483). Perfect agreement (κ = 1) was observed between cPCR and PCR-LFB. Lower cost and shorter time consumption were demonstrated using PCR-LFB. Full article

Glomerulonephritis, caused by the deposition of immune complexes, can lead to kidney damage in dogs with canine monocytic ehrlichiosis (CME). The early diagnosis of renal insult is important to prevent severe kidney disease in infected dogs by Ehrlichia canis. This study aimed to investigate urinary biomarkers of renal function, neutrophil gelatinase (uNGAL), and kidney injury molecule-1 (uKIM-1) using the Luminex^® xMAP^® platform, and the proportion of mixed or high molecular weight proteinuria in dogs with CME. This study included blood samples of thirty dogs with clinical signs of CME and amplified DNA for E. canis (CME group) and six dogs of different breeds and both sexes, aged 3 to 7 years, that showed no clinical-laboratory alterations or tick parasitism and were tested negative for E. canis via PCR (control group). The total calcium, phosphorus (p < 0.05), urea (p < 0.001), creatinine (p < 0.05), urinary density (p < 0.05), urinary protein creatinine ratio (p < 0.001), uNGAL (p < 0.05), and uKIM-1 (p > 0.05), as well as the proportion of high molecular weight proteinuria and mixed proteinuria (p < 0.01), were measured. Elevated serum concentrations of creatinine, urea, and phosphorus combined with reduced urinary density, increased urinary creatinine–protein ratio, urinary NGAL, and mixed proteinuria detected renal damage in dogs with CME, while KIM -1 remained unchanged. uNGAL can detect early renal lesions, reflecting renal damage before a significant increase in serum creatinine occurs, and appears to be an early diagnostic biomarker in renal disease in dogs with CME. Full article

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. Full article

Vector-borne diseases represent a serious threat to human and animal health, especially where environmental conditions favor pathogen-carrying vectors. Dogs serve as natural hosts for two tick-borne pathogens: Ehrlichia canis, which causes canine monocytic ehrlichiosis, and spotted fever group (SFG) Rickettsia spp., a zoonotic threat in the Mediterranean region. Rhipicephalus sanguineus is the primary vector for these pathogens. Shelter dogs, due to increased exposure to ticks and confined living conditions, facilitate the spread of vector-borne pathogens, raising the risk of zoonotic transmission. This study conducted a serological survey of 1287 dogs from two shelters, assessing exposure to Rickettsia spp. and E. canis and examining the influence of demographic and environmental factors. Seroprevalence rates were 41.8% for Rickettsia spp. and 24.5% for E. canis, with 14% of dogs positive for both pathogens. No significant association was found with sex or breed. A higher seroprevalence was observed in dogs older than 12 months and in those from the shelter on the Mediterranean coast compared to those from the Tyrrhenian coast, likely due to climatic differences. The study highlights the role of climate in disease spread and the need for public health interventions, supporting One Health initiatives to prevent zoonotic disease transmission. Full article

Infection of dogs with the tick-borne rickettsiae Ehrlichia and Anaplasma provokes an immune response mediating the pathology and bacterial resistance. IL-10 is the main anti-inflammatory cytokine and plays a multifaceted role in host protection. The study aimed to investigate circulating IL-10 in 32 dogs naturally infected with A. phagocytophilum and E. canis, identified by PCR positivity, and 33 PCR-negative animals which tested positive for antibodies against these pathogens, as well as 22 healthy animals. The highest quantity of IL-10, measured by ELISA, was observed among dogs positive simultaneously for anti-E. canis and anti-A. phagocytophilum IgG antibodies, followed by dogs positive for anti-E. canis only. The concentration of IL-10 in PCR-positive dogs was almost three and a half times higher than that measured in the control group (77.09 ± 23.61 pg./mL vs. 21.55 ± 4.61 pg./mL; p = 0.0015) and five times higher than the concentration of interleukin in PCR-negative animals (77.09 ± 23.61 pg./mL vs. 14.86 ± 3.01 pg./mL; p = 0.000016). The highest level of IL-10 was observed in PCR-positive dogs with mixed infection (120.54 ± 44.18), followed by the level in PCR-positive dogs for E. canis only (78.81 ± 16.92). The lowest level of IL-10 was observed in PCR-positive dogs for A. phagocytophilum only (56.32 ± 12.68). We may suggest that infection with E. canis and A. phagocytophilum stimulates the IL-10 production in dogs, which may facilitate specific antibody responses. Full article

Canine monocytic ehrlichiosis (CME) is an infectious disease caused by Ehrlichia canis, a globally recognized obligate intracellular bacterium. In addition to dogs, other animals, including humans, may be affected. Despite its epidemiological importance and impact on public health, there is currently no commercial vaccine against E. canis. This study aimed to present relevant aspects of the challenges and advances encountered in the development of vaccines for CME and highlight perspectives for future investigations. High genetic variability, along with the various evasion mechanisms employed by E. canis, has hindered the identification of an antigen that targets Th1 cells and is immunogenic to most E. canis isolates, considering their genotypic and phenotypic characteristics. The vaccine must predominantly confer cellular and humoral immunity to achieve robust immune responses. Early production efforts have been challenging due to low immunogenicity, difficulties in establishing long-term protection, and limitations of the techniques used. However, with the refinement of bioinformatic tools, research in this area will be facilitated, thereby accelerating the development of effective vaccines for CME. According to these authors, this vaccine should consist of multiple epitopes. Full article

In captive environments, mammals are frequently exposed to various parasitic protozoa and other vector-borne pathogens that can impact both animal health and public health. Monitoring these pathogens is essential for animal welfare and zoonotic disease control. This study aimed to investigate the prevalence of parasitic protozoa and other vector-borne pathogens in captive mammals through molecular detection methods at the Belo Horizonte Zoo, Brazil. Between November 2021 and March 2023, whole blood samples were collected from 40 mammals. Molecular analyses identified piroplasms, Leishmania spp., granulocytic/platelet Anaplasma/Ehrlichia spp., monocytic Ehrlichia spp., Bartonella spp. and hemotropic Mycoplasma spp. with a 72.5% positivity rate. Piroplasms were found in 22.5% (two Pantanal cats, two gorillas, one white rhinoceros, one spider monkey, one jaguar, one tufted capuchin and one hippo) and Leishmania spp. in 12.9% (four maned wolves). Granulocytic/platelet Anaplasma/Ehrlichia spp. were found in 12.5% of the samples (one gorilla and four maned wolves), Ehrlichia canis in 2.5% of the animals (one maned wolf), Bartonella spp. in 42.5% (six howler monkeys, two maned wolves, one gorilla, one white rhino, one southern tamandua, one common woolly monkey, one tufted capuchin, one brown brocket deer, one agouti, one cougar and one hippo), hemotropic Mycoplasma spp. in 17.5% (one gorilla, one maned wolf, one white rhino, one howler monkey, two common woolly monkeys and one European fallow deer). Five Artiodactyla members tested negative for A. marginale. Coinfections occurred in 34.5% of the positive samples. Sequencing revealed that Theileria spp. and Cytauxzoon spp. are closely related to Theileria bicornis and Cytauxzoon felis; Ehrlichia canis and Bartonella spp. are closely related to B. clarridgeiae and B. henselae; and hemotropic Mycoplasma spp. are closely related to Candidatus Mycoplasma haemominutum. Our results showed a high occurrence of vector-borne pathogens in captive animals, including zoonotic species, which may pose a risk to animal and human public health. Full article

Ticks are important vectors of pathogenic bacteria that cause diseases in both humans and animals. Analysis of tick microbiota via massive sequencing allows rapid and comprehensive identification of almost all bacteria inhabiting ticks. This has improved the detection of emerging pathogens and has helped define their relationship with public health. In Mexico, the brown dog tick (Rhipicephalus sanguineus sensu lato) is a public health problem, especially in northeast Durango. In the present study, the bacterial microbiota of this tick was determined using third-generation massive sequencing (PacBio, V1–V9 region of the 16S rRNA gene); bacteria with pathogenic potential that are transmitted by salivation and those that can be transmitted by accidental regurgitation of the parasite were also identified. In 2024, 60 dogs were searched for unfed ticks; then, 15 groups of female ticks and 15 groups of male ticks were formed, with each group consisting of 30 individuals. DNA was extracted from each tick pool, and the complete 16S rRNA gene was amplified (PacBio). Bioinformatics analysis was performed in QIIME2 (Quantitative Insights into Microbial Ecology) to obtain amplicon sequence variants (ASVs). Alpha and beta diversity metrics, as well as statistical analyses, were performed to test for differences between the microbiota of females and males. The bacterial taxa were classified into 21 phyla, 24 classes, 81 orders, 137 families, 339 genera, and 565 species. The male microbiota presented a significantly greater number of ASVs and a greater phylogenetic diversity index (FaithPD). Additionally, the unweighted UniFrac metric was significantly different between the sexes. The endosymbiont Coxiella mudrowiae was significantly more abundant in females, and Ehrlichia canis was more abundant in males. The pathogens E. canis and Anaplasma platys (transmitted by salivation) were detected, as well as 75 species of potential pathogens recorded in this tick that could enter the host in case of accidental regurgitation of the parasite (e.g., Staphylococcus, Streptococcus, Acinetobacter, Corynebacterium, Proteus, Clostridum, Klebsiella, Bacillus, Escherichia, Fusobacterium, and Pasteurella). It is necessary to continue analyzing the microbiota of ticks through massive sequencing for the benefit of public health and to establish new alternatives for controlling these parasites. Full article

The present study aimed to investigate pathological epidemiology and molecular confirmation of Ehrlichia canis among pet dogs in Bhubaneswar, Odisha, a state in eastern India. A total of 178 dogs were screened for Ehrlichiosis based on history, clinical signs, blood, and buffy coat smear examination, resulting in only 56 dogs (31.46%) screening positive. The epidemiological study recorded a non-significant (p ≥ 0.05) increase in incidences among male dogs (68%), German Shepherds (25%), dogs more than 20 kg body weight (75%), in the summer months (55%), and dogs housed in pukka houses with exposure to the outside (59%). The majority of the infected dogs had a history of tick infestation (79%) at some point in their lives. Clinical signs showed non-typical manifestations like fever, lethargy, diarrhoea, epistaxis, hind limb edema, and corneal opacity. Haematological studies revealed anaemia and thrombocytopenia along with neutrophilia with relative lymphopenia and monocytosis. A decreasing trend was observed in the levels of total protein and albumin, with an increase in the levels of globulin, alanine aminotransferase, alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, and creatinine. The ultrasonography studies revealed hepatosplenomegaly along with hyper-echogenicity in various organs. Proteinuria and haematuria were consistent, along with the presence of bile salts in the urine of affected dogs. Molecular confirmation from n-type PCR data using Ehrlichia-specific primers targeting the p28 gene (843 bp) was done, and the identified gene sequences submitted to NCBI databases have accession numbers OQ383671-OQ383674 and OP886674-OP886677. Ticks collected from dogs were identified morphologically through microscopy and scanning electron microscopy as Rhipicephalus sanguineus. Full article

Anaplasmataceae bacteria are emerging infectious agents transmitted by ticks. The aim of this study was to identify the molecular diversity of this bacterial family in ticks and hosts, both domestic and wild, as well as blood meal sources of free-living ticks in northeastern Paraguay. The bacteria were identified using PCR-HRM, a method optimized for this purpose, while the identification of ticks and their blood meal was performed using conventional PCR. All amplified products were subsequently sequenced. The bacteria detected in the blood hosts included Ehrlichia canis, Anaplasma platys, and Anaplasma phagocytophilum, Candidatus Anaplasma boleense, and Wolbachia spp., which had not been previously reported in the country. Free-living and parasitic ticks on dogs (Canis lupus familiaris) and wild armadillos (Dasypus novemcinctus) were collected and identified as Rhipicephalus sanguineus and Amblyomma spp. The species E. canis, A. platys, A. phagocytophilum, and Ca. A. boleense were detected in domestic dog ticks, and E. canis and A. platys were found for the first time in armadillos and free-living ticks. Blood feeding sources detected in free-living ticks were rodents, humans, armadillos and dogs. Results show a high diversity of tick-borne pathogens circulating among domestic and wild animals in the northeastern region of Paraguay. Full article