Bovine Brucellosis Research Articles

Accuracy of molecular diagnostic methods for the detection of bovine brucellosis: A systematic review and meta-analysis.

Bovine brucellosis is a disease of global socio-economic importance caused by Brucella abortus. Diagnosis is mainly based on bacterial culture and serology. However, these methods often lack sensitivity and specificity. A range of molecular diagnostic methods has been developed to address these challenges. Therefore, this study aims to investigate the diagnostic accuracy of molecular tools, in comparison to gold standard bacterial isolation and serological assays for the diagnosis of bovine brucellosis. The systematic review and meta-analysis were conducted based on analyses of peer-reviewed journal articles published between January 1, 1990, and June 6, 2020, in the PubMed, Science Direct, Scopus, and Springer Link databases. Data were extracted from studies reporting the use of molecular diagnostic methods for the detection of B. abortus infections in animals according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The quality of included journal articles was assessed using the quality assessment of diagnostic-accuracy studies assessment tool and meta-analysis was carried out using Review Manager. From a total of 177 studies, only 26 articles met the inclusion criteria based on PRISMA guidelines. Data from 35 complete studies were included in the meta-analysis and used to construct 2 × 2 contingency tables. Improved diagnostic performance was observed when tissue (sensitivity 92.7% [95% confidence interval (CI) 82.0-98.0%]) and serum samples (sensitivity 91.3% [95% CI 86.0-95.0%]) were used, while the BruAb2_0168 locus was the gene of preference for optimal assay performance (sensitivity 92.3% [95% CI 87.0-96.0%] and specificity 99.3% [95% CI 98.0-100.0%]). Loop-mediated isothermal amplification (LAMP) had a higher diagnostic accuracy than polymerase chain reaction (PCR) and real-time quantitative PCR with sensitivity of 92.0% (95% CI 78.0-98.0%) and specificity of 100.0% (95% CI 97.0-100.0%). The findings of this study assign superior diagnostic performance in the detection of B. abortus to LAMP. However, due to limitations associated with decreased specificity and a limited number of published articles on LAMP, the alternative use of PCR-based assays including those reported in literature is recommended while the use of LAMP for the detection of bovine brucellosis gains traction and should be evaluated more comprehensively in future.

Seroprevalence of Cattle Brucellosis in Al Gadarif State – Eastern Sudan

Aims: This study was conducted to determine the seroprevalence of bovine brucellosis in Al Gadarif state -Eastern Sudan- and to evaluate the sensitivity of RBPT, mRBPT, and milk ring test for serodiagnosis of bovine brucellosis.
 Study Design: Collect serum and milk samples and apply the recommended tests for diagnosis.
 Place and Duration of Study: This study was carried out in Al Gadarif state regional laboratory and Central Veterinary Research Laboratory (CVRL) in 2015.
 Methodology: A total of 367 serum samples were collected from 12 localities which include: Al Fao, Fashaga, Baldiat Al Gadarif, Wasat Gadarif, West Gadarif, Basonda, Al Gorisha, Al rhad,Mafaza , Butana, East Galapat and Gla nahl. Also, 100 bulk milk samples have been collected from Baldiat Al Gadarif, West Gadarif, Wasat Gadarif, and Fashaga and subjected to the milk ring test. All collected sera samples were tested for Brucella antibodies using the following serological tests: Rose Bengal Plate Test (RBPT), modified Rose Bengal Plate test (mRBT 1:2 and 1:3) and, c.ELISA test, the last test was done for 143 serum samples only.
 Results: The overall seroprevalence was 35.7%, 38.4%, 42.2% and 8.4% using RBPT, mRBPT (1:2), mRBPT (1:3) and c.ELISA tests respectively. According to this study the lowest seroprevalence was observed in Al Fao locality (11.1%), and the highest seroprevalence was in Al Gorisha Locality (71.4%).There was similarity in seroprevalence rate results using RBPT (1:2) and RBPT (1:3) in Al rahd (43.6%), Al Gorisha (85.7%) and Mafaza (50%) localities. Seroprevalence rate showed 10.9% and 9.1% in males and females respectively. There was no association between sex-as risk factor- and cattle brucellosis. Using the milk ring test the overall prevalence of positive milk samples was 39% (39/100). The highest prevalence was in Fashaga (60%), followed by Wasat Gadarif (46.7%). Baldiat Al Gadarif showed the lowest prevalence (22.9%).
 Conclusion: The serological investigation proved the occurrence of bovine brucellosis in Al Gadarif state -Eastern Sudan - using the recommended tests.

Determining the Extent of IBR, BVD and Bovine Brucellosis Based on Abortion History of Dairy Cattle’s Reared at College of Wondo Genet Forestry and Natural Resources, Sidama, Ethiopia

The study was conducted in the Wondo Genet district of the Sidama region of Ethiopia to identify the cause of sporadic abortion occurrence in dairy cattle kept in the college. Serum samples were collected for the test from a total of 101 cattle with essential epidemiological data. Disease investigations were carried out on IBR gB ELISA for BoHV-1 antibody detection, BVD for antibody and antigen detection ELISA, and Rose Bengal plate test for Bovine brucellosis antibody detection. Of 101 serum samples examined for these diseases; IBR was found 28.7% (29/101) seropositive for bovine herpesvirus-1 antibody detection and the other two diseases (i.e. bovine brucellosis and BVD) showed negative (0%). Out of, 16 cows with a history of abortion, 10 (62.5%) were positive for the antibody detection of BoHV-1 which was statistically significant when compared to non-aborted groups (p=0.003). The farm had used bulls for breeding purposes and was positive upon examination for IBR. So that the seropositivity of this bull had a direct causal effect on the breeding cows on the farm as the disease was majorly transmitted through the reproductive tract. The result of the present study revealed that IBR is the most important disease in the area which is causing a significant economic loss on the dairy farm. Therefore, it requires further detailed studies on the level of antigen detection using some sophisticated test methods like real-time PCR.

Rapid diagnosis of bovine brucellosis by peptide nucleic acid-fluorescence in situ hybridization assay

Brucellosis is a major economical disease of livestock and an important zoonotic disease. Rapid and accurate diagnosis is a fundamental prerequisite in the quest for control and elimination of brucellosis. The current study was conducted to evaluate a rapid molecular technique, peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) assay for the diagnosis of brucellosis. Samples, including fetal stomach contents, vaginal discharges, and placenta collected from cattle and buffaloes experiencing abortion and other reproductive disorders were processed for isolation. Brucella isolates obtained were confirmed by biochemical tests and polymerase chain reaction (PCR), thereby subjected to PNA-FISH which yielded positive fluorescence. The clinical samples were processed and subjected directly to PNA-FISH. On performing PNA-FISH directly on the clinical samples, this test reduces the time spent on processing the sample for isolation, avoiding the risk of handling the infectious organism while going through the process of isolation. Hence, PNA FISH can be considered as a rapid and efficient diagnostic method for Brucellosis.

First report and whole-genome sequencing of Pseudochrobactrum saccharolyticum in Latin America

The Brucellaceae family comprises microorganisms similar both phenotypically and genotypically, making it difficult to identify the etiological agent of these infections. This study reports the first isolation, identification, and characterization of Pseudochrobactrum saccharolyticum (strain 115) from Latin America. Strain 115 was isolated in 2007 from a bovine in Brazil and was initially classified as Brucella spp. by classical microbiological tests and bcsp31 PCR. The antimicrobial susceptibility of strain 115 was tested against drugs used to treat human brucellosis by minimal inhibitory concentration test. Subsequently, the whole genome of the strain was sequenced, assembled, and characterized. Phylogenetic trees built from 16S rRNA and recA gene sequences enabled the classification of strain 115 as Pseudochrobactrum spp. Phylogenomic analysis using Single Nucleotide Polymorphisms and Average Nucleotide Identity allowed the classification of the strain as P. saccharolyticum. Additionally, a Tetra Correlation Search identified one related genome from the same species, which was compared with strain 115 by analyzing genomic islands. This is the first identification and whole-genome sequence of P. saccharolyticum in Latin America and highlights a challenge in the diagnosis of bovine brucellosis, which could be solved by including the sequencing of 16S rRNA and recA genes in routine diagnostics.

Brucellosis: Trends in the Development of Situation in the World and Forecast for 2022 in the Russian Federation

An analysis of trends in the development of situation on brucellosis in the world over past decade and the data on the main risk factors for the occurrence of epidemiological complications regarding this infection in various regions of the world are provided in the paper. An expert assessment of the current epizootiological and epidemiological situation on brucellosis, the coverage of population and animals with immunization in the Russian Federation is given. Over 9 months of 2021, 210 potentially hazardous as regards brucellosis in cattle areas and 24 sites – as regards brucellosis in small ruminants – were registered in Russia. Compared to the same period in 2020, there was a decrease in the number of newly identified hazardous sites for bovine brucellosis by 35.8 % (117 areas). However, long-term upward trend in epizootiological adversity for bovine brucellosis in Russia persists. The epidemiological situation on brucellosis in the country for the period of 2012–2021 is characterized as unfavorable. Decrease in the number of newly detected human brucellosis cases (by 25.1 % of long-term average values) is observed against the background of persistent unfavorable epizootic conditions for brucellosis among epidemiologically significant species of small ruminants and cattle in regions with developed animal husbandry. In 2021, clusters of human cases were registered in the Republic of Dagestan and Penza Region. In the Republic of Dagestan, against the background of aggravation of epizootiological and epidemiological situation on brucellosis, there was also an alarming trend towards prevalence of a relatively high incidence among minors. The proportion of cases of brucellosis among children under the age of 17 in the Republic amounted to 60.3 % of the total number of minors with newly diagnosed brucellosis in Russia over the past 10 years. Taking into account current epizootic, epidemic situations and the long-term dynamics of the development of situation on brucellosis in the Russian Federation, the incidence of brucellosis among the population is predicted to be 10–15 % lower than the average long-term values – 0.18–0.20 per 100000 of the population – in 2022. The number of human cases of brucellosis can range from 250 to 300.

Cross-Sectional Study of Seroprevalence and Associated Risk Factors of Bovine Brucellosis in Selected Districts of Jimma Zone, South Western Oromia, Ethiopia.

Bovine brucellosis is one of the most widespread but neglected zoonotic diseases in developing countries where it is an endemic and growing problem causing public health impacts. Developing a cost-effective control strategy of the disease can only be guaranteed by knowledge of the disease epidemiology that defines its risk profiles. Hence, this study was designed to evaluate epidemiological aspects of bovine brucellosis in selected districts of Jimma zone. A cross-sectional study with multistage sampling techniques was conducted on 424 cattle to evaluate its seroprevalence. Likewise, 114 households were included for the investigation of risk factors. SPSS version 20 for data analysis and C-ELISA test for antibody detection were used. Moreover, the chi-square test for univariable analysis and logistic regression model for multivariable analysis were employed to assess association between seropositivity and risk factors. From this study, 3.3% (95% CI: 1.82-5.48) and 12.3% (95% CI: 6.88-19.75) seroprevalence of the disease was detected with the highest proportion found at Kersa district (6.5 (95% CI: 1.37-17.90) and (21.4 (95% CI: 4.66-50.80)) followed by Seka Chokorsa (1.76 (95% CI: 0.37-5.07) and (6.7 (95% CI: 1.40-18.27)) and Mana (1.75 (95% CI: 0.21-6.20) and (7.1 (95% CI: 0.88-23.50)) at individual animals and herd levels, respectively. Cattle of poor body condition, pregnant, and cows with history of abortion and repeat breeding were found 4.8 (95% CI: 2.00-22.74), 4.3 (95% CI: 1.43-13.04), 3.3 (95% CI: 1.07-10.21), and 2.7 (95% CI: 1.86-8.15) times more likely seropositive than their counterparts, respectively. Besides these, mixed feeding style was highly associated with seropositive reactors than separate feeding (AOR = 8.3; 95% CI: 1.76-38.99). These findings depicted substantial areas to be addressed in implementation of appropriate and immediate control actions and establishment of intervention mechanisms of bovine brucellosis.

Seroprevalence of brucellosis in cattle in abia state

Bovine brucellosis caused by the organism Brucella abortus is a chronic infectious disease of public health and economic significance. Studies on prevalence of bovine brucellosis in Abia State are scarce. Therefore, a cross-sectional study was conducted to determine the prevalence of bovine brucellosis in the State. Blood samples were collected from 212 cattle from various parts of the State and sera subjected to Rose Bengal Plate Test (RBPT) to detect antibodies against Brucella. Overall sero-prevalence of 13.7% was reported. The prevalence was higher in female cattle (24.2%) than in males (11%). Red Bororo showed higher seropositivity (26.7%) than other breeds screened. Sero-prevalence was higher in the semi-intensively managed animals (27.8%) than in extensively reared cattle. Similarly, cattle aged 2 to 3 years recorded a higher prevalence (25%) than others. However, there was no statistically significant association between the seroprevalence of brucellosis and sex (P= 0.05), age (P=0.82), breed (P=0.25), and management system (P=0.07 ). The detection of brucellosis in cattle poses a very significant public health risk in Abia state, and so it is important to carry out awareness campaigns to enlighten cattle handlers and the general public of its public health significance.

Sero Prevalence and Associated Risk Factors of Bovine Brucellosis in Cross Breed Dairy Cattle in Selected districts of Gamo Zone, Southwesten Ethiopia

Sero Prevalence and Associated Risk Factors of Bovine Brucellosis in Cross Breed Dairy Cattle in Selected districts of Gamo Zone, Southwesten Ethiopia

Some Serological Analytic Approaches and Test Execution in Determination of Bovine Brucellosis: Overview

Bovine brucellosis is a highly contagious, zoonotic, and economically significant bacterial disease. The purpose of this paper was to review available scientific data on serological tests for the diagnosis of bovine brucellosis and compare test performance based on assay sensitivity (Se) and specificity (Sp) values. Abortion, placentitis, epididymitis, and orchitis are symptoms of the disease. The clinical picture of brucellosis is not pathognomonic, and the patient's clinical history, particularly the occurrence of abortion, is crucial for diagnosis. Although the causative agent is isolated and identified for a definitive diagnosis of bovine brucellosis, serological tests are usually preferred. The host defense mechanism against Brucella is functionally divided into innate or non-specific immunity and adaptive or specific immunity. The pathogenic brucella organism has evolved a slew of mechanisms for evading and/or modulating both innate and adaptive immune responses in its host. Serological assays are based on the fact that Brucella abortus and other smooth Brucella have a unique O-polysaccharide that induces a humoral response with the production of IgM first, followed by IgG1, and then IgG2/IgA. Screening serological tests (Milk ring test, Rose Bengal Test (RBT), and Buffered plate agglutination test (BPAT)) and confirmatory serological tests (complement fixation test (CFT), serum agglutination test (SAT), 2-mercaptoethanol test (2ME), indirect-enzyme-linked immunosorbent assay (iELISA), and, more recently, competitive-ELISA (cELISA) and Brucella fluorescent pol (FPA). CFT, RBT, and iELISA tests are currently used in EU legislation for intra-community cattle trade and show comparable Se and Sp. The new FPA test demonstrated Se and Sp levels comparable to standard tests and was proposed for inclusion as a standard test in EU legislation. Similarly, the OIE considers the four tests to be a mandatory requirement for international trade. Several methods, however, produce both false-positive and false-negative results. There is no single serological test that is 100% accurate and applicable in all epidemiological situations. In general, confirmatory serological procedures involve testing each serum with multiple tests, usually a screening test with high sensitivity followed by a confirmatory test with high specificity. As a result, the development of rapid, low-cost serological tests with high sensitivity and specificity for brucellosis detection is a major issue that requires further investigation. Keywords: Bovine Brucellosis; Brucella Abortus; Diagnosis; Sensitivity; Specificity; Serological Tests, Test Performance DOI: 10.7176/JNSR/13-12-03 Publication date: June 30 th 2022

Bovine brucellosis serological survey in small dairy herds in Lushnja district, Albania

Bovine brucellosis is an important zoonotic disease in Albania. Both B. abortus and B. melitensis have been isolated from ruminants. National control and eradication programs for brucellosis are applied on sheep and goat farms and larger dairy cattle farms. However, the current control programs for brucellosis do not cover small dairy cattle farms, and there is no valid data on the prevalence of the disease in this category; this prevents formulating evidence-based and effective strategies for control of the disease in this population subset. Therefore, the current study aimed to assess the herd and within-herd prevalence of bovine brucellosis in small bovine herds and provide scientific evidence for establishing an evidence-based approach to control the disease in this subset of the population not previously included in the national eradication program. To achieve this objective, a statistical survey was designed and implemented in small dairy herds in the Lushnja district, where samples from statistically selected herds were serologically tested in parallel with Rose Bengal Test (RBT), Fluorescence Polarization Assay (FPA) and Enzyme-Linked Immunosorbent Assay (ELISA). In total, 120 dairy herds were randomly selected from a list of 1,955 registered herds: from these selected herds, 368 blood samples were collected from all animals older than 12 months, and their sera were tested using RBT, FPA, and c-ELISA. The test results revealed no positive or suspect cases. Based on these results, we are confident (P0.05) that Brucella spp is not circulating in this subpopulation of cattle in the Lushja district. This deduction is supported by analyses of the main risk factors, other epidemiological data, and the perceptions of official and private veterinarians. This is the first structured survey of bovine brucellosis in small dairy herds in Albania. In conclusion, our study results and our findings show that the epidemiological status of bovine brucellosis in the Lushnja district is encouraging. Therefore, a test and slaughter control program appears appropriate in smaller herds. Furthermore, the approach used in this pilot study could be extended to establish the prevalence of brucellosis in other districts, the result of which would establish the basis for rational control measures in the smaller herds of cattle.

A Seroprevalence Study of Brucellosis in Boran (Zebu) Breeds of Pastoral Area.

PurposeThe economic and health implications of brucellosis are of particular concern in developing countries, primarily in the vulnerable sector of rural herders. A cross-sectional study was done in Boran breeds to estimate the seroprevalence of bovine brucellosis, identify risk variables and assess public health implications in Borena zone, Oromia region, Ethiopia in the questionnaire survey.MethodsThe sampling animals were chosen from smallholders using a simple random sampling procedure. The study involved a total of 788 animals. Animals of both sex and different age groups with the age of 6 months or above found during the study interval were included. The Rose Bengal plate test was used to screen sera, and positive samples were subsequently retested using a Direct Enzyme-Linked Immunosorbent Assay for confirmation.ResultsThe overall seroprevalence of bovine brucellosis was 7.6% (60/788) in the Direct Enzyme-Linked Immunosorbent Assay test. Herd size, age, history of abortion, testicular hygroma, and retained fetal membrane were statistical significance for the Brucella seropositivity (P<0.05). Whereas, district, sex, body condition score, and management did not influence the disease occurrence (P>0.05). The majority of the participants, 91.7% (55/60) did not aware of the zoonotic implications of brucellosis. Only 10% (6/60) of interviewed respondents disposed of aborted fetuses and retained fetal membrane properly and the rest 90% (54/60) left in the environment. Ninety percent and 83.3% of the respondents revealed that they consumed raw milk and meat, respectively.ConclusionThe presence of Brucella infection is highly correlated with age, history of abortion, and testicular hygroma. According to the collected data: sex, body condition score, district, and management had no statistically significant effect on Brucella occurrence. The majority of respondents were unaware of the disease’s zoonotic consequences. Finally, creating community awareness about its transmission, zoonotic significance, and hygienic practices were recommended.

Development of a novel glycoprotein-based immunochromatographic test for the rapid serodiagnosis of bovine brucellosis.

Bovine brucellosis is a worldwide zoonotic disease that causes important economic losses and public health concerns. Because control of the disease depends on vaccination, serodiagnosis and isolation of the infected animals, affordable, rapid and accurate point of care (POC) tests are needed. We developed and evaluated a novel glycoprotein-based immunochromatographic test for the detection of IgG antibodies against the O-polysaccharide of Brucella in bovine serum samples. Brucella GlycoStrip combines the power of immunochromatographic and bacterial glycoengineering technologies for the diagnosis of bovine brucellosis. The analysis of positive and negative reference samples indicated that the test has a diagnostic sensitivity and specificity of 96.9% (95% CI: 92.7%-100.0%) and 100%, respectively. Due to the recombinant glycoprotein-based antigen OAg-AcrA, which consists of the O-side chain of Brucella smooth lipopolysaccharide (sLPS) covalently linked to the carrier protein AcrA, the test is highly accurate, allows the differentiation of infected animals from those vaccinated with a rough strain or with a single dose of a smooth strain and fulfil the minimum diagnostic requirements established by the national and international regulations. This strip test could provide a rapid (10min) and accurate diagnosis of bovine brucellosis in the field contributing to the control of the disease.

Seroprevalence of Brucellosis in Cattle in Abia State

Bovine brucellosis caused by the organism Brucella abortus is a chronic infectious disease of public health and economic significance. Studies on prevalence of bovine brucellosis in Abia State are scarce. Therefore, a cross-sectional study was conducted to determine the prevalence of bovine brucellosis in the State. Blood samples were collected from 212 cattle from various parts of the State and sera subjected to Rose Bengal Plate Test (RBPT) to detect antibodies against Brucella. Overall sero-prevalence of 13.7% was reported. The prevalence was higher in female cattle (24.2%) than in males (11%). Red Bororo showed higher seropositivity (26.7%) than other breeds screened. Sero-prevalence was higher in the semi-intensively managed animals (27.8%) than in extensively reared cattle. Similarly, cattle aged 2 to 3 years recorded a higher prevalence (25%) than others. However, there was no statistically significant association between the seroprevalence of brucellosis and age (P=0.82)/ breed (P=0.25), while a significant association was recorded for seroprevalence of brucellosis and sex (P= 0.05)/ management system (P=0.07). The detection of brucellosis in cattle poses a very significant public health risk in Abia state, and so it is important to carry out awareness campaigns to enlighten cattle handlers and the general public of its public health significance.

Bacteriological and etiological investigation of bovine brucellosis in South Korea with importance on control strategies

Bacteriological and etiological investigation of bovine brucellosis in South Korea with importance on control strategies

A Mathematical Model of the Transmission Dynamics and Control of Bovine Brucellosis in Cattle

Brucellosis is one of the most serious diseases that wreaks havoc on the production of livestock. Despite various efforts made to curb the spread of brucellosis, the disease remains a major health concern to both humans and animals. In this work, a deterministic model is developed to investigate the transmission dynamics and control of bovine brucellosis in a herd of cattle. The disease-free equilibrium point of the model is shown to be locally asymptotically stable whenever basic reproduction number R 0 ≤ 1 and unstable if R 0 &gt; 1 . Also, the endemic equilibrium point of the model is shown to be locally asymptotically stable whenever R 0 &gt; 1 and unstable otherwise. Numerical simulations of the model suggest that vaccination is the most efficient single control intervention. Also, the most efficient pair of control interventions is vaccination and culling of seropositive cattle. However, the best way to control bovine brucellosis in cattle is the combination of the three control interventions (vaccination, culling of seropositive cattle, and observation of comprehensive biosecurity protocols).

Situating zoonotic diseases in peacebuilding and development theories: Prioritizing zoonoses in Jordan.

Zoonotic diseases are projected to be a serious public threat in the coming decades. In 2016, the World Health Organization (WHO) recommended that Jordan prioritize their list of zoonoses, partially in response to the influx of Syrian refugees. We write this paper to expand the One Health framework by situating zoonotic diseases in peacebuilding and development theories in order to prioritize zoonotic diseases in Jordan. We employ an explanatory sequential mixed methods approach to create a modified version of the Center for Disease Control's (CDC) One Health Zoonotic Disease Prioritization (OHZDP) tool. We use an integrative literature review to develop a list of zoonoses to be prioritized. We expand the One Health framework by arguing health inequity is a form of violence, and thus promotion of health equity is a form of peacebuilding. We undertake thematic and statistical analyses to assess the 12 previously published OHZDP tools to evaluate necessity for change to the process given COVID-19 and the refugee situation in Jordan. In these analyses we use drivers of health indicators as measurements for peacebuilding and development, given these drivers are related to health inequities, to guide weighting of the criteria in our tool for Jordan. We apply our modified OHZDP tool to prioritize our disease list. We find it necessary to give socioeconomic factors greater consideration and to distribute weighting more evenly among all criteria within the tool when prioritizing zoonotic diseases in better reflect the Jordanian context and incorporate the refugee population. We find the priority zoonoses within Jordan to be bovine tuberculosis, brucellosis, and COVID-19, with most having a disproportionately negative impact on refugees. In Jordan's case, zoonotic diseases represent an area where promoting social equity for individuals is essential to the larger society. In this sense managing zoonoses is an area uniquely suited for peacebuilding.

Development And Validation of An In-House Brucella Smooth Lipopolysaccharide as A Coating Antigen in ELISA For Serodiagnosis of Bovine Brucellosis

Development And Validation of An In-House Brucella Smooth Lipopolysaccharide as A Coating Antigen in ELISA For Serodiagnosis of Bovine Brucellosis

Design and Characterization of a Recombinant Brucella abortus RB51 Vaccine That Elicits Enhanced T Cell-Mediated Immune Response.

Brucella abortus vaccines help control bovine brucellosis. The RB51 strain is a live attenuated vaccine with low side effects compared with other live attenuated brucellosis vaccines, but it provides insufficient protective efficacy. Cell-mediated immune responses are critical in resistance against intracellular bacterial infections. Therefore, we hypothesized that the listeriolysin O (LLO) expression of Listeria monocytogenes, BAX, and SMAC apoptotic proteins in strain RB51 could enhance vaccine efficacy and safety. B. abortus RB51 was transformed separately with two broad-host-range plasmids (pbbr1ori-LLO and pBlu–mLLO-BAX-SMAC) constructed from our recent work. pbbr1ori-LLO contains LLO, and pBlu–mLLO-BAX-SMAC contains the mutant LLO and BAX-SMAC fusion gene. The murine macrophage-like cell line J774A.1 was infected with the RB51 recombinant strain containing pBlu-mLLO-BAX-SMAC, RB51 recombinant strain containing LLO, and RB51 strain. The bacterial cytotoxicity and survival and apoptosis of host cells contaminated with our two strain types—RB51 recombinants or the parental RB51—were assessed. Strain RB51 expressing mLLO and BAX-SMAC was tested in BALB/c mice and a cell line for enhanced modulation of IFN-γ production. LDH analysis showed that the RB51-mLLO-BAX-SMAC and RB51-LLO strains expressed higher cytotoxicity in J774A.1 cells than RB51. In addition, RB51 recombinants had lower macrophage survival rates and caused higher levels of apoptosis and necrosis. Mice vaccinated with the RB51 recombinant containing mLLO-BAX-SMAC showed an enhanced Th1 immune response. This enhanced immune response is primarily due to bacterial endosome escape and bacterial antigens, leading to improved apoptosis and cross-priming. This potentially enhanced TCD8+- and T cell-mediated immunity leads to the increased safety and potency of the RB51 recombinant (RB51 mLLO-BAX-SMAC) as a vaccine candidate against B. abortus.

Seroprevalence and risk behaviors of bovine brucellosis in the south-western prefecture of Haho, Togo, January to April 2020

Seroprevalence and risk behaviors of bovine brucellosis in the south-western prefecture of Haho, Togo, January to April 2020