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Objective: To establish a rapid detection method for canine brucellosis using recombinase-aided amplification (RAA) technology. Methods: The outer membrane protein 25 gene fragment (Omp25) of Brucella canis was targeted. Primers and fluorescent probes were designed and synthesized, and recombinant plasmids were constructed as standards. The RAA assay was optimized by screening primers and establishing a fluorescent reaction system. Sensitivity was analyzed using plasmid standards with varying copy numbers. Specificity was tested using genomes from Brucella canis, Brucella suis, Brucella melitensis, Brucella abortus, Staphylococcus aureus, pathogenic Escherichia coli, Salmonella enteritidis, Shigella spp. , Proteus mirabilis, and Listeria monocytogenes. Reproducibility was evaluated using plasmid standards from the same and different batches. Results: The optimized RAA system used primers bOmp25-F2/bOmp25-R2 and probe bOmp25-P, with a constant reaction temperature of 39°C for 15 minutes. The detection sensitivity was 1 copy/μL. No cross-reaction was observed with other Brucella species or pathogenic bacteria, indicating high specificity. Intra-batch variability was below 1.00%, and inter-batch variability was below 2.00%. The positive detection coincidence rate of RAA was significantly higher than that of commercial real-time fluorescence quantitative PCR (100% VS 86.96%, P<0.05). Conclusion: The RAA-based rapid detection method for Brucella canis is suitable for clinical rapid testing. It offers advantages such as quick detection, high sensitivity, strong specificity, and good reproducibility. This method provides new insights for the rapid detection of canine brucellosis and the precise diagnosis of other pet diseases, making it suitable for promotion and application. [ABSTRACT FROM AUTHOR]

ObjectiveTo establish a rapid detection method for canine brucellosis using recombinase-aided amplification (RAA) technology.MethodsThe outer membrane protein 25 gene fragment (Omp25) of Brucella canis was targeted. Primers and fluorescent probes were designed and synthesized, and recombinant plasmids were constructed as standards. The RAA assay was optimized by screening primers and establishing a fluorescent reaction system. Sensitivity was analyzed using plasmid standards with varying copy numbers. Specificity was tested using genomes from Brucella canis, Brucella suis, Brucella melitensis, Brucella abortus, Staphylococcus aureus, pathogenic Escherichia coli, Salmonella enteritidis, Shigella spp., Proteus mirabilis, and Listeria monocytogenes. Reproducibility was evaluated using plasmid standards from the same and different batches.ResultsThe optimized RAA system used primers bOmp25-F2/bOmp25-R2 and probe bOmp25-P, with a constant reaction temperature of 39°C for 15 minutes. The detection sensitivity was 1 copy/μL. No cross-reaction was observed with other Brucella species or pathogenic bacteria, indicating high specificity. Intra-batch variability was below 1.00%, and inter-batch variability was below 2.00%. The positive detection coincidence rate of RAA was significantly higher than that of commercial real-time fluorescence quantitative PCR (100% VS 86.96%, P

Background: Although Brucella abortus, Brucella suis, and Brucella canis may infect humans and dogs worldwide, no study to date has assessed and compared owners and their dogs between island and mainland seashore areas. Materials and Methods: Accordingly, the study herein has applied serological tests, including Microplate Agglutination Test with 2-Mercaptoethanol, immunochromatographic assay, and Rose Bengal Test, and a Brucella genus-specific PCR assay to 195 owners and their 148 dogs living on 1 mainland seashore area and three nearby oceanic islands of southern Brazil. Results: No seropositivity to B. abortus and B. suis was detected in owner or dog sera. Anti-B. canis seropositivity was observed in 3/148 (2.0%) dogs, but no owner sample was seropositive to B. canis. In addition, all blood samples from both owners and dogs were negative on Brucella genus-specific PCR assay. Conclusions: The seropositive dogs were not related and lived on the seashore mainland area of Guaraqueçaba city. The absence of seropositivity on the islands and the low seropositivity on the seashore mainland could be attributed to geographic isolation, and suggest the low impact of the disease in the region. Despite being a zoonotic disease, brucellosis by B. canis is not included in the National Program for Control and Eradication of Brucellosis, and its diagnosis and notification are not mandatory. The presence of seropositive dogs highlights the risk to human health and the importance of epidemiological surveillance actions in the region, as well as the need for the implantation of preventive measures to avoid the transmission of the pathogen. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the effectiveness of analysis of the high resolution melting curves obtained after amplification of VNTR loci for the identification and differentiation of Brucella strains.Materials and methods. 16 strains of Brucella species – B. canis (n=1), B. abortus (n=9), B. melitensis (n=2), B. suis (n=4) – of different geographical origin were used as objects of the research. The MLVA-typing was performed using conventional PCR followed by separation of amplicons in agarose gel and real-time PCR with post-amplification analysis of the curves of VNTR loci melting in the presence of intercalating dye SybrGreen. Bioinformatics analysis was conducted with the help of Vector NTI 9.1, Mega 11 software (MUSCLE algorithm). Phylogenetic analysis was carried out applying UPGMA method using the Mega 11 program.Results and discussion. MLVA approach based on the analysis of the melting point curves of the obtained after amplification of VNTR-loci PCR fragments has shown that each of the 16 strains of Brucella is characterized by a unique melting temperature profile. PCR followed by electrophoresis has demonstrated that despite the high variability of the used VNTR sequences (h=0.48…0.74), only post-amplification melting curves of the Bru7, Bru9, Bru18, Bru21 loci had sufficient information content to determine the genetic polymorphism of the studied Brucella strains. Based on the results of phylogenetic analysis of the Bru7, Bru9, Bru18, Bru21 sequences, it has been found that the majority of the studied Brucella strains are distributed in the dendrogram in accordance with their taxonomic and geographical position. Thus, HRM analysis of melting curves obtained after amplification of the Bru7, Bru9, Bru18, Bru21 loci has the potential to be used for differentiating Brucella strains.

Canine brucellosis is an infectious disease caused by Brucella canis. Dogs can be infected by other Brucella species such as B. abortus, by ingestion of tissues or contaminated material from other animal hosts. The objective of the study was to identify the presence of B. abortus and B. canis, and to analyze the risk factors associated with Brucella spp. in canines from municipalities in northern Antioquia during 2019. 214 serum samples obtained from a neutering program sponsored by the Government of Antioquia were used. Immunochromatography and Rose Bengal tests were performed to detect the presence of antibodies against Brucella canis and B. abortus, respectively. 89 samples were randomly selected for detection of Brucella spp. DNA by PCR. A seroprevalence of 0% was obtained for B. canis, and 7% (15/214) for B. abortus. The positivity by PCR to Brucella spp. was 2.25% (2/89). Contact with bovine cattle, spend most of the time outside the house and have dirt floor inside the house were associated as risk factors. This study reports for Colombia the presence of B. abortus in dogs inside dairy production areas and suggests that dogs may participate as accidental or bridge hosts of B. abortus in epidemiologically active areas for Brucelosis, facilitating its dissemination and making eradication difficult in the national territory. [ABSTRACT FROM AUTHOR]

Brucella canis, a zoonotic agent primarily infects dogs and wild Canidae. Infection is notably suspected in dogs exhibiting epididymitis, infertility or disco-spondylitis. Recent reports indicate a growing incidence of Brucella canis infections in dogs, particularly among those imported into the UK from Eastern Europe. In India, the first reported case of Brucella canis infection was documented by in 1992.Although human infections by B. canis are relatively uncommon, clinical manifestations are typically mild, yet severe cases can potentially lead to septicemia. The disease in humans is incurable and spreads through contact with fluids from infected animals. Various diagnostic protocols, including Real-time PCR, Rapid slide agglutination test (RSAT), and Complement fixation test (CFT), are employed for the diagnosis of canine brucellosis. Brucella canis-specific quantitative polymerase chain reaction (qPCR) from non-invasive samples (vaginal swab or urine sample) allows its early detection. These diagnostic tests play a crucial role in diagnosing canine brucellosis. The "gold standard" for diagnosing brucellosis involves culture of Brucella isolated from body fluids (such as blood, cerebrospinal fluid, and urine) or tissues. Given the potential zoonotic risks, it is imperative to consistently include B. canis in diagnostic algorithms for canine diseases. Veterinary professionals play a vital role in this integrated approach, contributing to the prevention and management of Brucella canis infections in both animals and humans. [ABSTRACT FROM AUTHOR]

A 2-year-old, spayed female, Bichon Frise dog was presented with reluctance to exercise, back pain, and frequent sitting down. Multiple osteolysis, periosteal proliferation, and sclerosis of the vertebral endplates of T11-13 were observed in the radiography, computed tomography, and magnetic resonance imaging. The bacterial culture of the urine specimen, the polymerase chain reaction (PCR) of the blood, and the antibody tests were positive for Brucella canis. Accordingly, discospondylitis caused by B. canis was diagnosed and doxycycline was administered. The clinical signs resolved and the culture and PCR results were negative afterwards. Doxycycline was discontinued after 6 months. The clinical signs recurred 2 weeks later, and the combination treatment of doxycycline and enrofloxacin was initiated. Though no clinical signs were observed after 9 months and the bacterial cultures and PCR were negative, the antibody titre remained at 1:200 or more. The dog will continue taking antibiotics until the antibody titre drops. To the best of our knowledge, this is the first case report of a clinical infection of B. canis associated with canine discospondylitis in the Republic of Korea. Although the clinical signs of brucellosis might improve with antibiotic treatment, the disease cannot be cured due to Brucella's various strategies to evade host immune systems. Specifically, it can proliferate and replicate within the host cells, resulting in an environment that makes treatment less effective. Furthermore, owing to its zoonotic potential, owners and veterinarians should consider lifelong management or euthanasia.

Nuestro enfoque de servicio está orientado hacia el inmunodiagnóstico de la brucelosis en humanos y animales, abarcando pruebas serológicas, microbiológicas y moleculares para todas las variantes del género. Recibimos muestras derivadas de colegas en práctica privada y del Hospital de Enseñanza de la Facultad. A continuación, presentamos un análisis retrospectivo de solicitudes de diagnóstico de brucelosis canina, que abarca un período de 9 años, evaluado segú

O presente artigo objetiva relatar um caso de brucelose de um cão adotado bem como alertar o clínico veterinário acerca do subdiagnóstico da doença, o que impacta diretamente a maneira pela qual o clínico avalia as condutas a serem seguidas.

Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Canine brucellosis caused by Brucella canis, is an infectious disease affecting dogs and wild Canidae. Clinical diagnosis is challenging, and laboratory testing is crucial for a definitive diagnosis. Various serological methods have been described, but their accuracy is uncertain due to limited validation studies. The present study aimed to evaluate the performances of three serological tests for the diagnosis of B. canis in comparison with bacterial isolation (gold standard), in order to establish a protocol for the serological diagnosis of canine brucellosis. A panel of sera from naturally infected dogs (n = 61), from which B. canis was isolated, and uninfected dogs (n = 143), negative for B. canis isolation, were tested using microplate serum agglutination (mSAT), complement fixation performed using the Brucella ovis antigen (B. ovis-CFT), and a commercial immunofluorescence assay (IFAT). The sensitivity and specificity of the three serological methods were, respectively, the following: 96.7% (95% CI 88.8–98.7%) and 92.3 (95% CI 86.7–95.1%) for mSAT; 96.7% (95% CI 88.8–98.7%) and 96.5 (95% CI 92.1–98.2%) for B. ovis-CFT; 98.4% (95% CI 91.3–99.4%) and 99.3 (95% CI 96.2–99.8%) for IFAT. The use in of the three methods in parallel, combined with bacterial isolation and molecular methods, could improve the diagnosis of the infection in dogs. [ABSTRACT FROM AUTHOR]

Background and Aim: Given the rise in stray and imported dogs in Egypt over the past 5 years, it is surprising that no report of Brucella canis infection in dogs or humans has been documented in Egypt's published papers. This study aimed to detect the presence of antibodies against the rough (B. canis) and smooth Brucellae among dogs in Egypt and to characterize the Brucella species circulating in dogs. Materials and Methods: Blood samples (n = 449) were collected from owned and stray dogs in the Greater Cairo region (n = 309) and Damietta governorate (n = 140). The apparent, true, and total seroprevalence of canine brucellosis caused by B. canis infection were calculated using the 2-mercaptoethanol tube agglutination test (2-ME TAT) and rapid slide agglutination test (RSAT). We used the rose Bengal test (RBT) and the buffered acidified plate antigen test (BAPAT) to check the serum samples from dogs for the presence of antibodies against smooth Brucellae. Three polymerase chain reaction (PCR) assays - Bruce-ladder PCR, B. canis species-specific PCR (BcSS-PCR), and Abortus Melitensis Ovis Suis (AMOS)-PCR - were used to determine the Brucella species in the buffy coats of the serologically positive dogs. Results: The overall apparent and true prevalence of B. canis infection in dogs were estimated to be 3.8% and 13.2%. The estimated true prevalence in stray dogs (15%) was higher than in owned dogs (12.5%). The BAPAT and the RBT using smooth antigens revealed that 11 (2.4%) and 9 (2%) were positive. Bruce-ladder PCR targeting eryC, ABC, and Polysaccharide deacetylase genes was able to identify B. canis in nine out of 17 buffy coat samples. AMOS-PCR identified the eight undetermined Brucella species by Bruce-ladder PCR as Brucella abortus (n = 4) and Brucella melitensis (n = 4). To exclude the presence of Brucella suis, a one-step species-specific BcSS-PCR was performed and specifically amplified all B. canis DNA (n = 9) the same as did the Bruce-ladder PCR. Conclusion: To the best of our knowledge, this is the first report of B. canis detection in dogs in Egypt. Molecular identification of B. abortus and B. melitensis in the Egyptian canines highlights the role of stray dogs in brucellosis remerging in Brucellosis-free dairy farms. Brucella canis infection can be diagnosed specifically with the one-step BcSS-PCR. The obtained results set-an-alarm to the veterinary authorities to launch plans to control this disease in dogs.

A 2-year-old, spayed female, Bichon Frise dog was presented with reluctance to exercise, back pain, and frequent sitting down. Multiple osteolysis, periosteal proliferation, and sclerosis of the vertebral endplates of T11–13 were observed in the radiography, computed tomography, and magnetic resonance imaging. The bacterial culture of the urine specimen, the polymerase chain reaction (PCR) of the blood, and the antibody tests were positive for Brucella canis. Accordingly, discospondylitis caused by B. canis was diagnosed and doxycycline was administered. The clinical signs resolved and the culture and PCR results were negative afterwards. Doxycycline was discontinued after 6 months. The clinical signs recurred 2 weeks later, and the combination treatment of doxycycline and enrofloxacin was initiated. Though no clinical signs were observed after 9 months and the bacterial cultures and PCR were negative, the antibody titre remained at 1: 200 or more. The dog will continue taking antibiotics until the antibody titre drops. To the best of our knowledge, this is the first case report of a clinical infection of B. canis associated with canine discospondylitis in the Republic of Korea. Although the clinical signs of brucellosis might improve with antibiotic treatment, the disease cannot be cured due to Brucella’s various strategies to evade host immune systems. Specifically, it can proliferate and replicate within the host cells, resulting in an environment that makes treatment less effective. Furthermore, owing to its zoonotic potential, owners and veterinarians should consider lifelong management or euthanasia. [ABSTRACT FROM AUTHOR]

Brucella canis infection is an often neglected but important zoonotic disease. This study aims to determine its seroprevalence in Pit Bull dogs from the Western Region of the Turkish Anatolian Peninsula. In the Province of Manisa, 2 mL blood samples were taken from the antebrachial region of 35 Pit Bull dogs using sterile K2EDTA (3.6 mg) blood tubes, and the samples were analyzed using both the mercaptoethanol (ME) microagglutination test and B. canis–specific PCR techniques. Of the 35 dogs tested by 2–ME RSAT, 13 (37.14%) tested positive and 22 (63%) tested negative. Of the 13 dogs that tested positive for 2–ME RSAT, 8 (22.85%) were female, and 5 (14.28%) were male. Subsequent PCR analysis of all samples revealed that 7 (20%; 7/35) of the samples that tested positive for 2–ME RSAT were actually B. canis–specific PCR positive. These findings suggest that B. canis is present in Pit Bull dogs, although they provide a general idea of the disease's prevalence of the disease in the region. Multicentre studies with larger numbers of cases in different groups of Pit Bulls, such as healthy, patient and risk groups, are needed to provide comprehensive evidence.

Copyright of Revista Cientifica de la Facultade de Veterinaria is the property of Universidad del Zulia, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The incidence of Brucella canis (B. canis) in humans is unknown in Northern Cyprus. In this study, we investigated the prevalence of B. canis and Brucella abortus (B. abortus) infection in human sera and evaluated the results obtained by agglutination-based techniques using standardized antigens made from B. canis comparatively. All of the subjects were negative in terms of Rose-Bengal plate test. Undiluted serum samples were initially screened by rapid slide agglutination test (RSAT), and those which were found positive were retested in the dilution of 1/25-1/200. Confirmation of the positive results was performed by using 2-mercaptoethanol standard agglutination test (SAT). The test antigen was prepared from the less mucoid M (-) variant of B. canis, and 1/1,048 titered dog antiserum was used as positive control. In 225 serum samples, 3.6% (8/225) was positive by B. canis M (-) RSAT, 4.4 % (10/225) was positive by B. canis M (-) indirect enzyme-linked immunosorbent assay (iELISA). 5.3% (12/225) was positive by B. abortus S99 RSAT and 9.8% (22/225) was positive by B. abortus S99 iELISA. Nine samples were positive by both B. abortus S99 RSAT and B. abortus S99 iELISA. Seven samples were positive by both B. canis M (-) RSAT and B. canis M (-) iELISA. One patient was positive by all methods. It is important to evaluate patient samples with RSAT and iELISA. Until the notification system gives better results to the Ministry of Health, in order to reach the real data for Northern Cyprus, multicenter prevalence determination studies should be done for future. [ABSTRACT FROM AUTHOR]

Canine brucellosis caused by Brucella canis, is an infectious disease affecting dogs and wild Canidae. Clinical diagnosis is challenging, and laboratory testing is crucial for a definitive diagnosis. Various serological methods have been described, but their accuracy is uncertain due to limited validation studies. The present study aimed to evaluate the performances of three serological tests for the diagnosis of B. canis in comparison with bacterial isolation (gold standard), in order to establish a protocol for the serological diagnosis of canine brucellosis. A panel of sera from naturally infected dogs (n = 61), from which B. canis was isolated, and uninfected dogs (n = 143), negative for B. canis isolation, were tested using microplate serum agglutination (mSAT), complement fixation performed using the Brucella ovis antigen (B. ovis-CFT), and a commercial immunofluorescence assay (IFAT). The sensitivity and specificity of the three serological methods were, respectively, the following: 96.7% (95% CI 88.8–98.7%) and 92.3 (95% CI 86.7–95.1%) for mSAT; 96.7% (95% CI 88.8–98.7%) and 96.5 (95% CI 92.1–98.2%) for B. ovis-CFT; 98.4% (95% CI 91.3–99.4%) and 99.3 (95% CI 96.2–99.8%) for IFAT. The use in of the three methods in parallel, combined with bacterial isolation and molecular methods, could improve the diagnosis of the infection in dogs.

Brucella canis is the cause of canine brucellosis, a globally distributed, zoonotic pathogen which primarily causes disease in dogs. B. canis is unique amongst the zoonotic Brucella spp. with its rough lipopolysaccharide, a trait typically associated with attenuation in gram-negative bacteria. Unfortunately, no vaccine is available against B. canis, and vaccine development is hampered by a limited understanding of the immune response required to combat it and the course of infection following a physiologically relevant, mucosal route of inoculation. To address these concerns and analyze the impact of the rough phenotype on the immune response, we infected mice intratracheally with rough B. canis or smooth B. melitensis or B. abortus. Bacterial colonization and histologic lesions were assessed in systemic target organs as well as locally in the lungs and draining mediastinal lymph node. Mice were also reinfected with Brucella following antibiotic treatment and cytokine production by T lymphocytes in the lung and spleen was assessed by flow cytometry to investigate the memory immune response. Despite its rough phenotype, B. canis established a persistent infection at the same level of colonization as the smooth strains. However, B. canis induced significantly less granulomatous inflammation in the spleen as well as a lack of bronchial-associated lymphoid tissue (BALT) hyperplasia in the lungs. These differences coincided with increased IL-10 and decreased IFN-g in the spleen of B. canis-infected mice. Previous exposure to all Brucella strains provided protection against colonization following secondary challenge, although induction of IFN-g by T lymphocytes was seen only in the lungs during B. canis infection while the smooth strains induced this cytokine in the spleen as well. Neither Brucella strain induced significant polyfunctional T lymphocytes, a potential immunomodulatory mechanism that appears to be independent of lipopolysaccharide phenotype. [ABSTRACT FROM AUTHOR]

Brucellosis is one of the most important and widespread bacterial zoonoses worldwide. Cases are reported annually across the range of known infectious species of the genus Brucella. Globally, Brucella melitensis, primarily hosted by domestic sheep and goats, affects large proportions of livestock herds, and frequently spills over into humans. While some species, such as Brucella abortus, are well controlled in livestock in areas of North America, the Greater Yellowstone Ecosystem supports the species in native wild ungulates with occasional spillover to livestock. Elsewhere in North America, other Brucella species still infect domestic dogs and feral swine, with some associated human cases. Brucella spp. patterns vary across space globally with B. abortus and B. melitensis the most important for livestock control. A myriad of other species within the genus infect a wide range of marine mammals, wildlife, rodents, and even frogs. Infection in humans from these others varies with geography and bacterial species. Control in humans is primarily achieved through livestock vaccination and culling and requires accurate and rapid species confirmation; vaccination is Brucella spp.-specific and typically targets single livestock species for distribution. Traditional bacteriology methods are slow (some media can take up to 21 days for bacterial growth) and often lack the specificity of molecular techniques. Here, we summarize the molecular techniques for confirming and identifying specific Brucella species and provide recommendations for selecting the appropriate methods based on need, sensitivity, and laboratory capabilities/technology. As vaccination/culling approaches are costly and logistically challenging, proper diagnostics and species identification are critical tools for targeting surveillance and control. [ABSTRACT FROM AUTHOR]

Three adult littermates were diagnosed with Brucella canis, two of which were diagnosed with discospondylitis. The first littermate, a 2-year-old spayed-female Labrador Retriever, was evaluated for progressive episodes of cervical pain, lethargy, reported circling to the right, and a right-sided head tilt. Magnetic resonance imaging (MRI) of the cervical spine revealed changes consistent with discospondylitis at C6-C7. MRI of the brain was unremarkable and cerebrospinal fluid analysis was declined. Brucella spp. was isolated from aerobic and Brucella blood cultures. PCR performed on the isolate identified Brucella canis and indirect fluorescent antibody (IFA) testing for Brucella canis also confirmed the species. Patient #1 was treated with doxycycline and marbofloxacin for 1 year. Clinical signs returned 2-years after diagnosis. Following the diagnosis of patient #1, a known littermate (patient #2) was tested for Brucella canis. Patient #2 was 2 years old and asymptomatic at the time of diagnosis. Aerobic and Brucella spp. cultures, PCR, and IFA were obtained and were diagnostic for Brucella canis. A 6-month course of marbofloxacin and doxycycline was implemented. The patient remained PCR positive following 4 months of treatment and repeat cultures were planned following 6 months of treatment; however, the patient was lost to follow-up. A third littermate (patient #3) was identified by the family of patient #1. Patient #3 was evaluated at 18 months of age for a 6-month history of progressive lumbosacral pain. Spinal radiographs revealed discospondylitis of the C3-C4, T12-T13, and L7-S1 vertebral endplates. Computed tomography (CT) of the lumbosacral spine was also consistent with discospondylitis at L7-S1. Brucella canis serologic testing consisting of rapid slide agglutination test, 2ME-rapid slide agglutination test, and cytoplasmic agar gel immunodiffusion was positive. Enrofloxacin was administered for 7 months and was discontinued thereafter based on radiographic evidence of healing and resolution of clinical signs. Although Brucella canis is not a rare disease in dogs, the documentation of two out of three adult littermates with associated discospondylitis is an interesting feature. In addition, this report highlights available diagnostic and treatment options, as each patient was managed differently based on clinical signs and the preference of the managing clinician.

Brucella canis is the cause of canine brucellosis, a globally distributed, zoonotic pathogen which primarily causes disease in dogs. B. canis is unique amongst the zoonotic Brucella spp. with its rough lipopolysaccharide, a trait typically associated with attenuation in gram-negative bacteria. Unfortunately, no vaccine is available against B. canis, and vaccine development is hampered by a limited understanding of the immune response required to combat it and the course of infection following a physiologically relevant, mucosal route of inoculation. To address these concerns and analyze the impact of the rough phenotype on the immune response, we infected mice intratracheally with rough B. canis or smooth B. melitensis or B. abortus. Bacterial colonization and histologic lesions were assessed in systemic target organs as well as locally in the lungs and draining mediastinal lymph node. Mice were also reinfected with Brucella following antibiotic treatment and cytokine production by T lymphocytes in the lung and spleen was assessed by flow cytometry to investigate the memory immune response. Despite its rough phenotype, B. canis established a persistent infection at the same level of colonization as the smooth strains. However, B. canis induced significantly less granulomatous inflammation in the spleen as well as a lack of bronchial-associated lymphoid tissue (BALT) hyperplasia in the lungs. These differences coincided with increased IL-10 and decreased IFN-γ in the spleen of B. canis-infected mice. Previous exposure to all Brucella strains provided protection against colonization following secondary challenge, although induction of IFN-γ by T lymphocytes was seen only in the lungs during B. canis infection while the smooth strains induced this cytokine in the spleen as well. Neither Brucella strain induced significant polyfunctional T lymphocytes, a potential immunomodulatory mechanism that appears to be independent of lipopolysaccharide phenotype.

Brucella canis had not been isolated in the Netherlands until November 2016, when it was isolated from a dog imported from Romania. Including this case, 16 suspected cases were notified to the authorities during the following 25 months. Of these 16 dogs, 10 were seropositive; tracking investigations found another 8 seropositive littermates. All seropositive animals were rescue dogs imported from Eastern Europe. B. canis was cultured from urine, blood, and other specimens collected from the dogs. Genotyping of isolates revealed clustering by litter and country. Isolating B. canis in urine indicates that shedding should be considered when assessing the risk for zoonotic transmission. This case series proves introduction of B. canis into a country to which it is not endemic through import of infected dogs from B. canis–endemic areas, posing a threat to the naive autochthonous dog population and humans.

Brucella canis is a zoonotic pathogen and the main causative agent of canine brucellosis. In the Netherlands, B. canis had previously only been detected in individual cases of imported dogs. However, an outbreak of B. canis occurred for the first time in a cohort of autochthonous dogs in a breeding kennel in 2019. The outbreak began with a positive serological test result of an imported intact male dog showing clinical symptoms of brucellosis. Consequently, urine and blood samples were collected and tested positive for B. canis by culture, matrix-assisted laser desorption/ionization – time of flight mass spectrometry (MALDI-TOF MS) and whole-genome-sequencing (WGS). Screening of the contact dogs in the kennel where the index case was kept, revealed that antibodies against B. canis could be detected in 23 out of 69 dogs (34 %) by serum agglutination test (SAT). Of the 23 seropositive dogs, B. canis could be cultured from the urine and/or heparin samples of 19 dogs (83 %). This outbreak represents the first documented case of transmission of B. canis to autochthonous contact dogs in the Netherlands. WGS revealed all B. canis isolates belonged to the same cluster, which means the transmission of B. canis in the breeding kennel was most likely caused by the introduction of one infected dog. Comparing this cluster with data from other B. canis isolates, it also appears that characteristic clusters of B. canis are present in several endemic countries. These clusters seem to remain stable over time and may help in locating the origin of new isolates found. This outbreak showed that the international movement of dogs from endemic countries poses a threat to the canine population, while serological screening and WGS proved to be valuable tools for respectively screening and the epidemiological investigation. • We describe the transmission of Brucella canis in a canine kennel following the introduction of an infected dog. • We draw attention to the diagnostic challenges during an outbreak of B. canis and the usefulness of serological screening. • We present data that indicates that characteristic clusters of B. canis are present in several endemic countries. • We explain how novel tools like whole-genome-sequencing and phylogenetic analysis contribute to the control of B. canis. [ABSTRACT FROM AUTHOR]

Brucellosis is a contagious disease caused by bacteria of the genus Brucella, which can affect different animal species. Dogs may occasionally be infected with B. abortus, B. melitensis or B. suis, or by the endemic form of the disease, caused by B. canis. Among the brucellosis‑affecting domestic animals, that of the dog is certainly the least frequent, but also the least studied. Canine brucellosis due to B. canis represents the dog‑specific brucellosis, both because it is the main susceptible animal species, and because it constitutes its fundamental reservoir of infection. The disease can also affect humans, although its course does not assume the characteristics of severity typical of the infection determined by the ‘classical’ species of the genus Brucella. In Italy, there are frequent imports of dogs from countries where the disease is present, often with non‑controlled movements and without sanitary controls. Considering that the zoonotic potential of the disease can be favored by the close cohabitation between man and dog, which occurs especially in urban environments, canine brucellosis has to be regarded as a public health problem susceptible to introduction and spread in the Italian territory.

Background: Brucella canis is the etiological agent of canine brucellosis, a worldwide neglected zoonosis that constitutes one of the major infectious causes of infertility and reproductive failure in dogs. Although genomic information available for this pathogen has increased in recent years, here we report the first genome sequencing of a B. canis strain in Chile, and the differences in virulence genes with other B. canis strains. Results: Genome assembly produced a total length of 3,289,216 bp, N50 of 95,163 and GC% of 57.27, organized in 54 contigs in chromosome I, and 21 contigs in chromosome II. The genome annotation identified a total of 1981 CDS, 3 rRNA and 36 tRNA in chromosome I, and 1113 CDS and 10 tRNA in chromosome II. There is little variation between the different strains and the SCL isolate. Phylogenetic analysis showed that the Chilean SCL strain is closely related to B. canis and B. suis strains. Small differences were found when compared to the Serbian isolate, but all strains shared the same recent common ancestor. Finally, changes in the sequence of some virulence factors showed that the SCL strain is similar to other South American B. canis strains. Conclusions: This work sequenced and characterized the complete genome of B. canis strain SCL, evidencing the complete presence of all the genes of the virB operon, and minor changes in outer membrane proteins and in the urease operon. Our data suggest that B. canis was introduced from North America and then spread throughout the South American continent.How to cite: Borie C, Bravo C, Dettleff P, et al. First genome sequence of Chilean Brucella canis SCL strain provides insights on the epidemiology and virulence factors, explaining differences between geographical origins Electron J Biotechnol 2020;49. https://dx.doi.org/10.1016/j.ejbt.2020.10.002.

Brucellosis is a bacterial disease, caused by the genus Brucella, which compromises several species of domestic mammals, among which the canine species stands out. One of the major sources of contamination is direct contact with expelled tissue or genital secretions of bitches that have recently aborted. Brucella infection in dogs causes several clinical manifestations. In infected pregnant bitches, it can result in embryonic death, abortion and subsequent prolonged vaginal discharge. In males, infection is associated with epididymitis, scrotal dermatitis, testicular atrophy and infertility. Although many infected dogs are clinically normal, there may be impairment of the reproductive function, thus being a negative factor for the animals that make up breeding programs. The most commonly used diagnostic method is serology, in which whey tests can be cited rapid plaque agglutination, tube agglutination and immunodiffusion on agar gel. Treatment alternatives include concomitant and repeated courses of antimicrobial therapy and also castration of seropositives. Among the measures of prevention and control, we can mention the serological control of breeding dogs and animals that are to be introduced in kennels, as well as the use of disinfectants to eliminate the infectious agent, the excretions of the seropositive, present in the environment. In the context of public health, the dog has long been neglected as a source of infection for the human species, although it has a proven zoonotic potential, as well as a negative reflection on the economy. [ABSTRACT FROM AUTHOR]

A patient was diagnosed with Brucella canis following exposure to infected dogs in her breeding facility. Transboundary spread of B. canis through (illegal) import of infected dogs to non-endemic countries in Europe suggest that B. canis infection should be considered in European patients with occupational exposure to dogs. [ABSTRACT FROM AUTHOR]

Members of the bacterial genus Brucella cause brucellosis, a zoonotic disease that affects both livestock and wildlife. Brucella are category B infectious agents that can be aerosolized for biological warfare. As part of the structural genomics studies at the Seattle Structural Genomics Center for Infectious Disease (SSGCID), FolM alternative dihydrofolate reductases 1 from Brucella suis and Brucella canis were produced and their structures are reported. The enzymes share ∼95% sequence identity but have less than 33% sequence identity to other homologues with known structure. The structures are prototypical NADPH‐dependent short‐chain reductases that share their highest tertiary‐structural similarity with protozoan pteridine reductases, which are being investigated for rational therapeutic development. [ABSTRACT FROM AUTHOR]

The aims of this study was to evaluate a PCR for detecting Brucella canis in the blood of dogs, using a primer pair designed for Brucella spp. A study was conducted on 150 blood sample collected from dogs suspected to Veterinary Hospital in Baghdad / Aden Square. All blood samples (150) were tested by PCR technique using a common primer of the 23S ribosomal RNA (23s RNA) gene and specific primer for brucella canis (B0548). The genomic DNA was extracted and PCR was applied. Our study recorded 5.3% of brucellosis in common primer and 3.3% in specific primer for brucella canis in dog in Baghdad city, the sequences of Brucella canis in dog in different isolates in our study recorded 99% compatibility recording to National Center Biotechnology Information (NCBI). Following correspondence from National Center for Biotechnology Information, the 23S ribosomal RNA gene was registered, given an agreement number, and became a resource for Iraq and Middle East, as well as the rest of the world. As more type strains are published, this set will grow, and it can be download from NCBI at: https://www.ncbi.nlm. nih.gov/nuccore/. From this study we can conclude that, the percentage of Brucellosis in dogs in Baghdad city is 5.3% and 3.3% in a common and specific primer, respectively and the molecular method (PCR), is a good idea for confirmation of diagnosis of Brucella canis infection in dog. [ABSTRACT FROM AUTHOR]

Brucella canis has been isolated for the first time in Italy in a commercial breeding kennel. It was diagnosed after a deep investigation related to the onset of reproductive disorders. Animals were tested with direct and indirect techniques. The agent was first detected in two Chihuahua aborted foetuses by direct culture. Further, it was also isolated from blood samples of dogs hosted in the kennel, which also showed reaction to conventional serological tests (microplate serum agglutination test). The isolates were identified as B. canis by standard microbiological methods and a Bruce‑ladder multiplex PCR. To investigate the genomic diversity, whole genome sequencing was used, applying the core genome Multilocus Sequence Typing (cgMLST ). In a first round of serological testing performed on 598 animals, 269 (46.1%) tested positive. In the second round of laboratory testing carried out 4‑5 weeks apart, the number of serologically positive dogs was 241 out of 683 tested (35.3%), while the number of dogs positive to isolation was 68 out of 683 tested (10.0%). The PCR showed a lack of sensitivity when compared to direct isolation. The epidemiological investigation did not identify the source of the infection, given the time elapsed from the onset of abortions to the definitive diagnosis of B. canis infection in the kennel. The genomic analyses featured the strains as ST21 and, according to the cgMLST, revealed the presence of a tight cluster with a maximum diversity of four allelic differences. The observed limited genomic variation, largely within the known outbreak cut‑offs, suggests that the outbreak herein described was likely caused by a single introduction. Moreover, in a broader scale comparison using the public available genomes, we found that the closest genome, isolated in China, differed by more than 50 alleles making not possible to find out the likely origin of the outbreak. The lack of updated data on B. canis genome sequences in the public databases, together with the limited information retrieved from the epidemiological investigations on the outbreak, hampered identification of the source of B. canis infection.

Brucellosis is one of the most important and widespread bacterial zoonoses worldwide. Cases are reported annually across the range of known infectious species of the genus Brucella. Globally, Brucella melitensis, primarily hosted by domestic sheep and goats, affects large proportions of livestock herds, and frequently spills over into humans. While some species, such as Brucella abortus, are well controlled in livestock in areas of North America, the Greater Yellowstone Ecosystem supports the species in native wild ungulates with occasional spillover to livestock. Elsewhere in North America, other Brucella species still infect domestic dogs and feral swine, with some associated human cases. Brucella spp. patterns vary across space globally with B. abortus and B. melitensis the most important for livestock control. A myriad of other species within the genus infect a wide range of marine mammals, wildlife, rodents, and even frogs. Infection in humans from these others varies with geography and bacterial species. Control in humans is primarily achieved through livestock vaccination and culling and requires accurate and rapid species confirmation; vaccination is Brucella spp.-specific and typically targets single livestock species for distribution. Traditional bacteriology methods are slow (some media can take up to 21 days for bacterial growth) and often lack the specificity of molecular techniques. Here, we summarize the molecular techniques for confirming and identifying specific Brucella species and provide recommendations for selecting the appropriate methods based on need, sensitivity, and laboratory capabilities/technology. As vaccination/culling approaches are costly and logistically challenging, proper diagnostics and species identification are critical tools for targeting surveillance and control.

The transcriptional regulator MucR is related to normal growth, stress responses and Brucella virulence, and affects the expression of various virulence-related genes in smooth-type Brucella strains. However, the function of MucR in the rough-type Brucella canis remains unknown. In this study, we discovered that MucR protein was involved in resistance to heat stress, iron-limitation, and various antibiotics in B. canis. In addition, the expression level of various bacterial flagellum-related genes was altered in mucR mutant strain. Deletion of this transcriptional regulator in B. canis significantly affected Brucella virulence in RAW264.7 macrophage and mice infection model. To gain insight into the genetic basis for distinctive phenotypic properties exhibited by mucR mutant strain, RNA-seq was performed and the result showed that various genes involved in translation, ribosomal structure and biogenesis, signal transduction mechanisms, energy production, and conversion were significantly differently expressed in ΔmucR strain. Overall, these studies have not only discovered the phenotype of mucR mutant strain but also preliminarily uncovered the molecular mechanism between the transcriptional regulator MucR, stress response and bacterial virulence in B. canis.

Brucella canis had not been isolated in the Netherlands until November 2016, when it was isolated from a dog imported from Romania. Including this case, 16 suspected cases were notified to the authorities during the following 25 months. Of these 16 dogs, 10 were seropositive; tracking investigations found another 8 seropositive littermates. All seropositive animals were rescue dogs imported from Eastern Europe. B. canis was cultured from urine, blood, and other specimens collected from the dogs. Genotyping of isolates revealed clustering by litter and country. Isolating B. canis in urine indicates that shedding should be considered when assessing the risk for zoonotic transmission. This case series proves introduction of B. canis into a country to which it is not endemic through import of infected dogs from B. canis-endemic areas, posing a threat to the naive autochthonous dog population and humans. [ABSTRACT FROM AUTHOR]

Canine brucellosis is an infectious and zoonotic disease caused by Brucella canis, which has been reported worldwide, and is a major public health concern due to close contact between dogs and humans. In dogs, canine brucellosis manifests with abortion outbreaks, reproductive failure, enlargement of lymph nodes, and occasionally affects the osteoarticular system, although the occurrence of asymptomatic infections in dogs are not uncommon. In humans, the disease is associated with a febrile syndrome, commonly with non-specific symptoms including splenomegaly, fatigue, and weakness. Infection of dogs occurs mostly by the oronasal route when in contact with contaminated tissues such as aborted fetuses, semen, urine, and vaginal secretions. In humans, contact with contaminated fluids from infected dogs is an important source of infection, and it is an occupational risk for veterinarians, breeders, laboratory workers, among other professionals who deal with infected animals or biological samples. The diagnosis in dogs is largely based on serologic methods. However, serologic diagnosis of canine brucellosis remains very challenging due to the low accuracy of available tests. Molecular diagnostic methods have been increasingly used in the past few years. Treatment of infected dogs is associated with a high frequency of relapse, and should be employed only in selected cases. Currently there are no commercially available vaccines for prevention of canine brucellosis. Therefore, development of novel and improved diagnostic methods as well as the development of efficacious and safe vaccination protocols are needed for an effective control of canine brucellosis and its associated zoonotic risk.

Research has been undertaken to understand the host immune response to Brucella canis infection because of the importance of the disease in the public health field and the clinical field. However, the previous mechanisms governing this infection have not been elucidated. Therefore, in vitro models, which mimic the in vivo infection route using a canine epithelial cell line, D17, and a canine macrophage, DH82, were established to determine these mechanisms by performing an analysis of the transcriptomes in the cells. In this study, a coculture model was constructed by using the D17 cell line and DH82 cell line in a transwell plate. Also, a single cell line culture system using DH82 was performed. After the stimulation of the cells in the two different systems infected with B. canis, the gene expression in the macrophages of the two different systems was analyzed by using RNA-sequencing (RNA-seq), and a transcriptomic analysis was performed by using the Ingenuity Pathway Analysis (IPA). Gene expression patterns were analyzed in the DH82 cell line at 2, 12, and 24 h after the stimulation with B. canis. Changes in the upregulated or downregulated genes showing 2-fold or higher were identified at each time point by comparing with the non-stimulated group. Differentially expressed genes (DEGs) between the two culture models were identified by using the IPA program. Generally, the number of genes expressed in the single cell line culture was higher than the number of genes expressed in the coculture model for all-time points. The expression levels of those genes were higher in the single cell line culture (p < 0.05). This analysis indicated that the immune response-related pathways, especially, the dendritic cell maturation, Triggering receptor expression on myeloid cells 1 (TREM1) signaling, and Toll-like receptor (TLR) signaling pathway, were significantly induced in both the culture systems with higher p-values and z-scores. An increase in the expression level of genes related to the pathways was observed over time. All pathways are commonly associated with a manifestation of pro-inflammatory cytokines and early immune responses. However, the Peroxisome proliferator-activation receptor (PPAR) signaling and Liver X Receptor/Retinoid X Receptor (LXR/RXR) signaling associated with lipid metabolism were reduced. These results indicate that early immune responses might be highly activated in B. canis infection. Therefore, these results might suggest clues to reveal the early immune response of the canine to B. canis infection, particularly TLR signaling.

Brucella canis is a worldwide infectious disease of dogs and a zoonotic infection. Until now the disease has not been diagnosed or documented in Israel. Recently, an outbreak of canine brucellosis in Northern Israel has been documented and confirmed for the first time in Israel using bacteriological, serological and molecular methods. The exact source of the infection was not determined but was possibly associated with a single female dog which was imported into Israel from abroad or with more than one imported dog. It was expected that the extent of the outbreak would be limited by taking the necessary measures described in this document and by renewing the vigilance and awareness of Israeli veterinarians. [ABSTRACT FROM AUTHOR]

In male dogs, Brucella canis frequently causes epididymitis, ultimately resulting in testicular atrophy and infertility. Although B. canis predominantly affects the epididymis, the misleading term "orchitis" is still commonly used by clinicians. Of additional concern, diagnosis in dogs remains challenging because of variable sensitivity and specificity of serologic assays and fluctuations in bacteremia levels in infected dogs, reducing the sensitivity of blood culture. We describe here the histologic lesions in the scrotal contents of 8 dogs suspected of being infected with B. canis and clinically diagnosed with orchitis. We explored the possibility of using immunohistochemistry (IHC) and real-time PCR (rtPCR) in formalin-fixed, paraffin-embedded (FFPE) tissues to detect the presence of B. canis. Epididymitis of variable chronicity was identified in all 8 dogs, with only 3 also exhibiting orchitis. Using rtPCR, the presence of B. canis was identified in 4 of 8 dogs, with 3 of these 4 dogs also positive by IHC. These results suggest that rtPCR and IHC are promising techniques that can be used in FFPE tissues to detect B. canis when other detection techniques are unavailable. Additionally, accurate recognition of epididymitis rather than orchitis in suspect cases could aid in accurate diagnosis. [ABSTRACT FROM AUTHOR]

Canine brucellosisis an infectious disease caused by bacteria of the genus Brucella, with world wide distribution and zoonotic impact, and in humans and animals is a neglected disease. In the present study, the sero prevalence of B. canis and B. abortus were determined in a probabilistic sample of housed dogs from the Atlantic Rainforest area of the state of Paraíba, Brazil, and the factors associated with sero positivity. A total of 386 dogs over three months of age were used. For the search for anti-B.canis antibodies the agar gel immune diffusion test (IDGA) was used as a screening and IDGA+2ME as confirmatory test, and to search for anti-B. abortus antibodies the Rose Bengal test (RBT) test was used. Apparent and real prevalences were calculated, and robust Poisson regression was used to identify factors associated with prevalence. The real prevalence fB. Canis was 12.6% and of B. abortus was 22.8%. The factors associated with sero positivity for B. canis were age greater than 10 years (prevalence ratio; PR = 6.38; P = 0.024) and dogs reared in they ard (PR = 5.20; P = 0.035) and for B. abortus was no treplacement of water of animals everyday (PR = 1.48; P = 0.033). It can be concluded that the prevalence of B. canis and B. Abortus in the region is high, which warns to the adopting of control and prevention measures, as well as greater care in the management of animals, especially for elderly dogs. [ABSTRACT FROM AUTHOR]

Human brucellosis, one of the most common zoonoses worldwide, is rare in Japan. Brucella canis is the specific pathogen of human brucellosis carried by dogs. According to an epidemiological study of B. canis infection in Japan, B. canis is the specific pathogen of human brucellosis in dogs. We herein report a rare case of meningoencephalomyelitis caused by B. canis in a 68-year-old Japanese man. Neurobrucellosis was diagnosed based on a serum tube agglutination test and abnormal cerebrospinal fluid findings. The patient was started on targeted treatment with a combination of doxycycline and streptomycin. Although extremely rare, neurobrucellosis should be considered in patients with a fever of unknown origin and unexplained neurological symptoms.

ABSTRACT Brucella canis is a Gram-negative, facultative intracellular bacterium and the causative agent of canine brucellosis, a highly contagious disease of dogs that can be transmitted to humans. Unfortunately, no vaccine is available to prevent infection. We recently characterized the kinetics of B. canis infection in the mouse model, establishing the required dose necessary to achieve systemic infection. The objective of this study was to investigate the utility of the mouse model in assessing canine brucellosis vaccine candidates and to subsequently investigate the safety and efficacy of a live attenuated vaccine, the B. canis RM6/66 ΔvjbR strain. Mice vaccinated with a dose of 109 CFU of the vaccine strain by both intraperitoneal and subcutaneous routes were afforded significant protection against organ colonization and development of histopathologic lesions following intraperitoneal challenge. Addition of an adjuvant or a booster dose 2 weeks following initial vaccination did not alter protection levels. Vaccination also resulted in a robust humoral immune response in mice, and B. canis RM6/66 ΔvjbR was capable of activating canine dendritic cells in vitro. These data demonstrate that the B. canis RM6/66 ΔvjbR strain shows promise as a vaccine for canine brucellosis and validates the mouse model for future vaccine efficacy studies. IMPORTANCE Canine brucellosis, caused by Brucella canis, is the primary cause of reproductive failure in dogs and represents a public health concern due to its zoonotic nature. Cases in dogs in the United States have been increasing due to the persistent nature of the bacterium, deficiencies in current diagnostic testing, and, most importantly, the lack of a protective vaccine. Current estimates place the seroprevalence of B. canis in the southern United States at 7% to 8%, but with the unprecedented rates of animals moving across state and international borders and the lack of federal regulations in regard to testing, the true seroprevalence of B. canis in the United States may very well be higher. Vaccination represents the most effective method of brucellosis control and, in response to the demand for a vaccine against B. canis, we have developed the live attenuated B. canis RM6/66 ΔvjbR vaccine strain capable of protecting mice against challenge.

Brucella canis infects dogs and humans. In dogs, it can cause reproductive failure; in humans, it can cause fever, chills, malaise, peripheral lymphadenomegaly, and splenomegaly. B. canis infection in dogs is underrecognized. After evaluating serologic data, transmission patterns, and regulations in the context of brucellosis in dogs as an underrecognized zoonosis, we concluded that brucellosis in dogs remains endemic to many parts of the world and will probably remain a threat to human health and animal welfare unless stronger intervention measures are implemented. A first step for limiting disease spread would be implementation of mandatory testing of dogs before interstate or international movement.

Abstract Background Canine brucellosis, due to Brucella canis, is a worldwide zoonosis that remains endemic in South America, including Brazil. Implementation of powerful whole-genome sequencing approaches allowed exploring the Brucella genus considered as monomorphic, with, to date, more than 500 genomes available in public databases. Nevertheless, with under-representation of B. canis genomes −only twenty complete or draft genomes−, lack of knowledge about this species is still considerable. This report describes a comparative genomics-based phylogeographic investigation of 53 B. canis strains, including 28 isolates paired-end sequenced in this work. Results Obtained results allow identifying a SNP panel species-specific to B. canis of 1086 nucleotides. In addition, high-resolution analyses assess the epidemiological relationship between worldwide isolates. Our findings show worldwide strains are distributed among 2 distinct lineages. One of them seems to be specific to South American strains, including Brazil. B. canis South American strains may be identified by a SNP panel of 15 nucleotides, whereas a 22 SNP panel is sufficient to define contamination origin from Brazil. These results lead to the proposal of a possible spread route for dog brucellosis through South America. Additionally, whole-genome analyses highlight the remarkable genomic stability of B. canis strains over time and the sustainability of the infection in São Paulo over 12 year-period. Conclusions Significant increase of B. canis genomes available in public databases provides new insights into B. canis infection in South America, including Brazil, as well as in the world, and also offers new perspectives for the Brucella genus largo sensu.

Aim: This study aimed to compare the sensitivity (S), specificity (Sp), and positive likelihood ratios (LR+) of four polymerase chain reaction (PCR) assays for the detection of Brucella spp. in dog's clinical samples. Materials and Methods: A total of 595 samples of whole blood, urine, and genital fluids were evaluated between October 2014 and November 2016. To compare PCR assays, the gold standard was defined using a combination of different serological and microbiological test. Bacterial isolation from urine and blood cultures was carried out. Serological methods such as rapid slide agglutination test, indirect enzyme-linked immunosorbent assay, agar gel immunodiffusion test, and buffered plate antigen test were performed. Four genes were evaluated: (i) The gene coding for the BCSP31 protein, (ii) the ribosomal gene coding for the 16S-23S intergenic spacer region, (iii) the gene coding for porins omp2a/omp2b, and (iv) the gene coding for the insertion sequence IS711. Results: The results obtained were as follows: (1) For the primers that amplify the gene coding for the BCSP31 protein: S: 45.64% (confidence interval [CI] 39.81-51.46), Sp: 95.62% (CI 93.13-98.12), and LR+: 10.43 (CI 6.04-18); (2) for the primers that amplify the ribosomal gene of the 16S-23S rDNA intergenic spacer region: S: 69.80% (CI 64.42-75.18), Sp: 95.62 % (CI 93.13-98.12), and LR+: 11.52 (CI 7.31-18.13); (3) for the primers that amplify the omp2a and omp2b genes: S: 39.26% (CI 33.55-44.97), Sp: 97.31% (CI 95.30-99.32), and LR+ 14.58 (CI 7.25-29.29); and (4) for the primers that amplify the insertion sequence IS711: S: 22.82% (CI 17.89 - 27.75), Sp: 99.66% (CI 98.84-100), and LR+ 67.77 (CI 9.47-484.89). Conclusion: We concluded that the gene coding for the 16S-23S rDNA intergenic spacer region was the one that best detected Brucella spp. in canine clinical samples.

Dogs can act as intermediary hosts, reservoirs, and sentinel animals for zoonotic diseases such as brucellosis, toxoplasmosis and leptospirosis, and human contact with domestic animals can spread these infections. These diseases are globally distributed, and are a uniquely severe health issue, since they can infect a great range of animals, including humans. The purpose of this work was to determine the prevalence of anti-Leptospira spp., anti-Brucella spp., and anti-Toxoplasma gondii antibodies in stray dogs. Blood samples were collected from 181 stray dogs and used for serological diagnosis. Of the analyzed samples, 36.46%, 16.57%, and 9.39% were positive for T. gondii, Leptospira spp., and B. canis. The results indicate that these zoonotic diseases are highly prevalent in stray dogs in the northwestern region of the state of Paraná. The high infection rates for these zoonotics in the canine population is an indication that the environment is contaminated with a variety of different microorganisms, exposing both humans and dogs to different sources of infection.

Canine brucellosis is a cause of reproductive failure and early detection in infected dogs remains a challenge. The aim of the present study was to test two antigens to be used in two different immunoassays for the detection of Brucella canis infection in dogs: one from Brucella canis RM6/66 sonicated crude antigen (CA-iELISA) and the other using the immunodominant protein GroEL (GroEL-iELISA). The cut-off point was determined using sera from infected dogs; subsequently, reproducibility was measured and a coefficient of variation (CV) below 15 % was obtained for negatives and positives with the CA-iELISA, whereas, for the GroEL-iELISA they were higher than 15 %. In the robustness test, there were significant differences for the GroEL-iELISA, but not for the CA-iELISA. The selectivity test showed cross-reactivity with Leptospira interrogans in the CA-iELISA, and with L. interrogans and Salmonella spp. in the GroEL-iELISA. From the sample stability tests, it was demonstrated that samples should be stored at room temperature for no more than 2 hours, at 4 °C for no more than 24 hours and can be kept at -20 °C for up to 30 days. Finally, sensitivity and specificity were calculated, resulting in 100 % for both CA-iELISA; sensitivity of 44 % and specificity of 67 % for GroEL-iELISA. In conclusion, the CA-iELSA proved to be better at detecting Brucella canis than the GroEL-iELISA. [ABSTRACT FROM AUTHOR]