Economics of brucellosis impact and control in low-income countries

Diagnosis and control of brucellosis through food: The contribution of omics sciences

More than 60 percent of emerging infectious diseases in humans are zoonoses, and about 70 percent of these come from wildlife. In this context, infectious diseases in animals are no longer a problem confined to the livestock and animal health sector but have important repercussions in public health-related risk assessment and management. One of the most relevant risks in the transmission of zoonoses is certainly the consumption of food contaminated with pathogens, especially because of the potential epidemiological relevance of foodborne outbreaks. Brucellosis represents one of the most prevalent zoonoses worldwide and one of the most important foodborne zoonoses, particularly in the Mediterranean and developing countries; The European Union has funded numerous eradication and control programs in at-risk herds. This review aims to analyze current diagnostic methods used in the detection of Brucella in food matrices. It will highlight issues related to the timing and specificity of classical diagnostic methods while also analyzing new diagnostic methods in the current literature. The focus of this work is on emphasizing the potential that integrated omics sciences have in developing early and highly sensitive diagnostic tools. It analyzes strengths and weaknesses and underscores, through a review of recent scientific articles in the "PubMed" and "Google Scholar" databases, the importance of current and future research, especially those based on an omics approach, in providing fundamental biological data and knowledge. This, in turn, could play a crucial role in designing innovative diagnostic tests to complement those currently in use.

Brucella NyxA and NyxB dimerization enhances effector function during infection

Brucella abortus is the cause of one of the most prevalent zoonoses worldwide. We have recently discovered two translocated effectors, NyxA and NyxB, that contribute to the late stages of the infectious cycle. Although their structure was solved, the importance of their interactions and dimeric states remains unknown. We found that NyxA and NyxB directly interact and that their dimerization is essential for their function during infection. We show that monomeric forms of the Nyx effectors still interact with their host cellular target, the deSUMOylase sentrin-specific protease 3 (SENP3) but are less able than the dimers to delocalize SENP3 from the nucleoli. This study provides new insights into the intra- and inter-effector molecular interactions during Brucella pathogenesis.

Gender and cultural aspects of brucellosis transmission and management in Nakasongola cattle corridor in Uganda

BACKGROUND

Brucellosis is a zoonotic disease with significant public health and economic effects on societies. In Uganda, brucellosis is endemic and a primary contributor in livestock productivity losses. This is more worrisome for populations in the cattle corridor with high reliance on cattle and milk for nutritional value and symbol in social relations and identity. The community's social construction may affect comprehension of brucellosis hence leading to exposure and increased vulnerability to transmission. Despite brucellosis' high prevalence in the cattle corridor, little attention has been paid to its social construction. Hence, this study explored the interplay between gender dynamics, vulnerability and social construction of brucellosis transmission, in consideration of the unique socio-cultural context that characterizes cattle corridor populations.

METHODS

Using an exploratory qualitative approach, the study was conducted in Nakasongola cattle corridor within three sub counties; Nabiswera, Nakitoma and Wabinyonyi using key informant interviews (KIIs) and focus group discussions (FGDs). Purposive sampling was used to identify participants for the four FGD [8-12] each from a subcounty though one was combined and 15 KIIs. Data were collected using face -to -face interviews with an interview guide that was structured using the Socio Ecological Model of Human Behaviour framework (SEMHB) constructs. Thematic analysis was conducted in NVivo 12 Pro incorporating both deductive (guided by the SEMHB) and inductive approaches (guided by the data).

FINDINGS

The study identified important themes under each SEMHB influence level (Individual, Interpersonal, Community and Societal level). The study indicates that social composition and role distribution are driven by social and cultural expectations and significantly contribute to exposure and vulnerability to infection in the cattle corridor. For instance, it is paramount that women undergoing marriage preparations to be fed on raw milk for a certain period prior to their ceremony to enhance beauty. Also, important to note that use of personal protection to assist births is viewed by the community as opposing cultural norms, creating a perception of detachment from the highly valued cattle. Another noteworthy finding is the level of knowledge on brucellosis in terms of symptoms, transmission route, prevention and treatment at the interpersonal level. Furthermore, findings show practices such as the consumption of raw milk and assisted births, as being rooted in the social cultural norms, hence critical for transmission of brucellosis. At the community and organizational levels, the findings indicate an inadequate level of knowledge sharing and reluctance towards preventive measures as structural factors for the transmission of brucellosis and are ingrained in family and power relations.

CONCLUSION

The findings highlight that the social construction of brucellosis transmission is rooted in gender roles, social- cultural and power structures highlighting the influence of living process and spaces, at the different societal levels. Such complex dynamics play a critical role in determining individuals' susceptibility to infection as well as transmission potential of the disease-causing agent in cattle keeping communities. The gendered induced vulnerabilities related to the socio-cultural norms and familial roles, also play an important role in the exposure and spill over at the individual, interpersonal and community levels. The insufficient knowledge-sharing and reluctance to adopt preventive measures emerge as structural contributors to the persistence of brucellosis and other emerging zoonoses. These factors, intertwined with family dynamics and power relations, call for targeted interventions that address both individual behaviors and broader socio-cultural and institutional barriers to effective disease management and prevention. Conversely, policies that align with the community's social construction, gender and context are more likely to be feasible, adopted and sustained by the affected population.

Malaria misdiagnosis substantially contributes to the underestimation of global human brucellosis incidence

BACKGROUND

Brucellosis is a neglected and re-emerging zoonotic disease of nearly worldwide distribution. Recently, a new model utilizing publicly available data, voluntarily provided by countries to the World Organization for Animal Health (WOAH), estimated a global annual incidence of at least 1.62-2.10 million cases. However, global and regional knowledge gaps, partially attributed to lack of diagnostic capability and disease unawareness, result in misdiagnosis.

METHODS

This study incorporated misdiagnosis to assess the potential impact on incidence estimates. Specifically, we examined the potential impact of misdiagnosing brucellosis as malaria. Incidence rates modeled from WOAH data comprised a baseline estimate for brucellosis rates. A range of potential misdiagnosis rates based on World Bank malaria data and scientific literature were utilized to estimate the number of misdiagnosed cases. We assumed a conservative misdiagnosis range of 0.25-4.00% based on clinical studies that reported a 4-11% misdiagnosis rate.

RESULTS

We show that malaria misdiagnosis can significantly impact global annual incidence estimation of brucellosis. Rates of 0.25% increase brucellosis incidence by 0.34-5.4 M cases, while rates of 4% increase these estimates by 2.43-7.45 M cases.

CONCLUSIONS

Human brucellosis misdiagnosed as malaria can significantly impact global annual incidence estimates. Enhanced efforts are needed to identify misdiagnosed cases in countries where both diseases are endemic.

A novel IgG-Fc-Fused multiepitope vaccine against Brucella: robust immunogenicity

Brucellosis is one of the most common zoonotic diseases caused by Brucella spp. However, there is currently no Brucella vaccine available for humans. Although some attenuated live vaccines have been approved for animals, their protective efficacy is suboptimal. In previous studies, we utilized an epitope- and structure-based vaccinology platform to identify the immunodominant epitopes of Brucella antigens OMP19, OMP16, OMP25, and L7/L12, and constructed the multi-epitope vaccine MEV-Fc against Brucella. In this study, OMP19, OMP16, OMP25, and L7/L12, and MEV-Fc was expressed and purified via an Escherichia coli expression system, which validated that MEV-Fc possesses high immunological efficacy and exerts a significant protective effect in BALB/c mice within the Brucella infection model. MEV-Fc enhanced Th1 and Th2 immune responses and strongly induced the production of the pro-inflammatory cytokine IFN-γ. Furthermore, MEV-Fc protected mice against Brucella infection compared to control group (PBS). In conclusion, our results provide new insights and data support for the development of human Brucella vaccines.

Risk perception, seroprevalence, and real-time PCR detection of Brucella among pyretic patients and domestic animals in Kwara State, Nigeria

Brucellosis is a neglected, reportable, and under-reported zoonosis that poses a significant public health challenge in endemic countries like Nigeria. In this study, the risk perception was assessed and 103 pyretic patients from three local government areas of Kwara State, Nigeria were screened by using Rose Bengal plate test (RBPT) and confirmed the analytical sensitivity through real-time PCR (qPCR). We further screened 150 cattle and 52 goats from within a 1-km radius of pyretic patients to determine disease burden in domestic animal reservoirs. Our findings revealed that most of the farmers have heard of brucellosis (89.3%, n = 92/103) while 38.8% (n = 40/103) reported they could identify the symptoms of brucellosis in their herds. The most important risk factors were the consumption of raw milk (92.2%, n = 95/103) and animal abortion within the last year (19.4%, n = 20/103). Also, most study participants (94.2%, n = 97/103) did not believe that they could be infected with the disease. The seroprevalence of brucellosis in humans was 5.8% (n = 6/103) and there was 100% concordance between the results of the RBPT and qPCR in humans. The seroprevalence was 18% and 25% in cattle and goats respectively. The qPCR revealed a lower prevalence rate of 11.3% and 15.4% in cattle and goats respectively. There was high discordance in sensitivity between the RBPT and qPCR in animal samples screened, although both tests had an analytical specificity of 100%. There was no association between awareness and positivity for brucellosis among the study participants and none of the sociodemographic variables significantly influenced the brucellosis positivity rate of humans. Public health physicians and community health workers should consider brucellosis as a differential diagnosis when clerking pyretic patients. In addition, we advocate for mass animal vaccinations and public education with an emphasis on identified risks.

Social network analysis of key stakeholders in Brucellosis prevention in Western Iran

BACKGROUND

Brucellosis remains a persistent public health challenge in Iran, particularly in rural regions such as Lorestan province, due to systemic, economic, and cultural barriers. Effective disease control requires multisectoral collaboration among stakeholders. This study aimed to map the stakeholder network involved in brucellosis prevention in Lorestan province, identify gaps in coordination, and provide actionable recommendations for improving control strategies.

METHODS

This cross-sectional study employed social network analysis (SNA) to explore the relationships among key stakeholders in brucellosis prevention. Data were collected through a structured questionnaire administered to 75 experts from various sectors, including health, veterinary, agriculture, and non-governmental organizations. The SNA evaluated network density, clustering coefficient, and centrality metrics to determine the levels of collaboration and influence among stakeholders.

RESULTS

The analysis revealed a moderately dense network (density: 0.2745; clustering coefficient: 0.2839) with central roles played by the Veterinary Organization of Lorestan Province, Lorestan University of Medical Sciences, and the Ministry of Agriculture. These organizations exhibited high levels of influence, support, and interest in brucellosis prevention. However, limited involvement of community-based organizations and environmental agencies was identified, highlighting a critical gap in grassroots engagement. Fragmented coordination was particularly evident in rural areas, where traditional livestock practices, inadequate veterinary services, and the consumption of unpasteurized dairy products perpetuate disease transmission. Economic constraints, such as the high cost of vaccines, along with limited public awareness, further hinder effective control efforts.

CONCLUSIONS

Brucellosis prevention in Lorestan province requires a comprehensive, multisectoral approach. The adoption of a One Health framework can improve collaboration among stakeholders, enhance resource allocation, and address systemic barriers. Community engagement and intersectoral coordination are essential for improving public awareness and compliance with preventive measures. These findings provide a foundation for developing a National Brucellosis Control Program and inform strategies to mitigate zoonotic diseases in similar high-risk regions.

A One Health Approach to Reducing Livestock Disease Prevalence in Developing Countries: Advances, Challenges, and Prospects

Challenges in livestock production in developing countries are often linked to a high disease prevalence and may be related to poor husbandry, feeding, and nutrition practices, as well as to inadequate access to preventive veterinary care. Structural barriers including chronic poverty, gender roles, inadequate supply chains, and limitations in surveillance infrastructure further complicate progress. Despite many challenges, the livestock sector substantially contributes to agricultural GDP, and reducing livestock disease prevalence is a goal for many countries. One Health initiatives that work across disciplines and sectors to reduce livestock diseases are underway around the world and use integrated approaches that consider the connections between humans, animals, and their shared environments. The growing recognition of the role livestock play in sustainability and livelihoods, as well as their involvement in zoonotic disease transmission and global health security, has highlighted the need for disease reduction strategies as described in this review.

Change point detection in brucellosis time series from 2010 to 2023 in Xinjiang China using the BEAST algorithm

Brucellosis is a significant global challenge, but there has been a lack of epidemiological studies on brucellosis in Xinjiang from a change point perspective. This study aims to bridge this gap by employing sequence decomposition and identifying significant change points, with datasets sourced from the Xinjiang Disease Prevention and Control Information System. This study employed the BEAST algorithm to decompose the brucellosis time series in Xinjiang from 2010 to 2023, while simultaneously identifying change points in the decomposed seasonal and trend components. The probability of four change points occurring within the seasonal component is 0.8950. And the locations where these four change points occur and the probabilities associated with each change point are August 2013 ([Formula: see text]), August 2017 ([Formula: see text]), February 2022 ([Formula: see text]), and May 2023 ([Formula: see text]), respectively. The probability of the existence of five change points in the trend factors of brucellosis in Xinjiang is highest ([Formula: see text]). The times at which these five change points occur, along with the probabilities of change at those moments, are as follows: March 2013 ([Formula: see text]), August 2015 ([Formula: see text]), July 2017 ([Formula: see text]), February 2020 ([Formula: see text]), and May 2023 ([Formula: see text]). Change point analysis holds significant utility within the field of epidemiology. These discoveries furnish pivotal insights for epidemiological investigations and the development of early warning systems tailored to brucellosis.

Molecular Testing of Zoonotic Bacteria in Cattle, Sheep, and Goat Abortion Cases in Botswana

Abortion is one of the major causes of economic losses in livestock production worldwide. Because several factors can lead to abortion in cattle, sheep and goats, laboratory diagnosis, including the molecular detection of pathogens causing abortion, is often necessary. Bacterial zoonotic diseases such as brucellosis, coxiellosis, leptospirosis, and listeriosis have been implicated in livestock abortion, but they are under diagnosed and under-reported in most developing countries, including Botswana. This study applied a recently developed multiplex high-resolution melting analysis technique, coupled with singleplex qPCR assays, to investigate abortions in livestock in Botswana, using 152 samples from cattle, sheep, and goat abortion cases. Brucella spp. were the most frequent pathogen detected, with an overall frequency of 21.1%, followed by Coxiella burnetii with 19.1%. Listeria monocytogenes and Leptospira spp. were not detected in any of specimens samples investigated. Mixed infections with Brucella spp. and C. burnetii were observed in 35% specimes examined. There was a good agreement between the multiplex qPCR-HRM and singleplex qPCR for detecting Brucella spp. and C. burnetii. This study is the first report on the syndromic testing of abortion-causing pathogens in Botswana. It shows the importance of molecular methods in the differential diagnosis of abortion-causing diseases in domestic ruminants.

Human and animal brucellosis and risk factors for human infection in Ethiopia: a systematic review and meta-analysis (2015-2024)

BACKGROUND AND OBJECTIVE

Brucellosis is a neglected zoonotic disease caused by Brucella species. Unlike most developed nations, the problem of brucellosis in Ethiopia remains a public and animal health concern. This study was conducted to determine the magnitude of brucellosis in animals (mainly cattle, sheep, goats, dogs and camels) and humans, and to identify the risk factors for human brucellosis.

METHODOLOGY

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to conduct this systematic review and meta-analysis, which was performed from May 2024 to July 2024. Academic databases such as PubMed, ScienceDirect, Scopus, PubMed Central, Web of Science, and Google Scholar were searched to identify articles focusing on brucellosis in humans and animals in Ethiopia. Data extraction was performed according to predefined inclusion and exclusion criteria. The included articles were appraised using the appraisal tool for cross-sectional studies to assess study quality. Publication bias and small study effects were examined using funnel plot observation and Egger's test, respectively. Statistical analysis was conducted using R software version 4.4.1.

RESULTS

Thirty-nine articles published between 2015 and 2024 were included in the final analysis from a total of 1,427 identified articles. The overall pooled seroprevalence of brucellosis was 5.0% (95% CI: 3.0, 6.0). The seroprevalence of brucellosis was higher in humans at 6.9% (95% CI: 4.9, 8.8) and lower in cattle at 3.5% (95% CI: 2.2, 4.7). There was high heterogeneity in the reports of brucellosis seroprevalence between studies (τ² = 0.0038, H² = 255.9, I² = 99.61%, Q-test = 1954.99, df = 56, p ≤ 0.001). Laboratory tests and study location were identified as factors contributing to potential sources of variation in the pooled seroprevalence. Drinking raw milk from aborted animals, touching aborted materials or fetuses, and occupation were among the risk factors for human brucellosis. No publication bias or small study effects were detected.

CONCLUSION

The findings indicate that brucellosis continues to pose a significant zoonotic threat, particularly to humans, where the seroprevalence is notably higher than in animals. These results highlight the need for targeted public health interventions and greater awareness to reduce the incidence of brucellosis, especially among high-risk populations.

Molecular epidemiology of brucellosis in Asia: insights from genotyping analyses

Brucellosis infects humans and animals worldwide but is particularly prevalent in Asia. In many Asian countries, molecular diagnostic tools for accurate molecular diagnostics and molecular epidemiology are lacking. Nonetheless, some countries have conducted in-depth molecular epidemiological studies. The objective of this study was to reveal the genetic relationships, geographic origins, and distributions of Brucella strains across Asia for two primary species, B. abortus and B. melitensis. For this, we systematically searched genotyping data from published studies on the molecular epidemiology of Brucella species for both humans and livestock in Asia. We used data from multilocus sequence typing (MLST), multiple-locus variable-number tandem repeat analysis (MLVA), and whole genome sequencing analysis of Brucella strains. We also analyzed the MLVA genotypes of 129 B. abortus isolates and 242 B. melitensis isolates with known origins in Asia from an online MLVA database using MLVA-11 data in minimum spanning trees and MLVA-16 data in neighbor-joining trees. We found that the B. melitensis East Mediterranean lineage is predominant across the continent, with only a small number of samples from the Africa and Americas lineages, and none from the West Mediterranean lineage. The "abortus C" genotype was the most common group of B. abortus in Asia, with limited genetic variation for this species. Several studies also reported that Near Eastern countries frequently encounter human brucellosis cases of B. abortus from genotypes 42 and 43. Our study highlights the inconsistent collection of genetic data for Brucella species across Asia and a need for more extensive sampling in most countries. Finally, a consistent nomenclature is necessary to define various groupings of strains within a lineage (i.e., clade) so uniform terminology should denote particular genetic groups that are understood by all researchers.

Spatial prediction of human brucellosis susceptibility using an explainable optimized adaptive neuro fuzzy inference system

Brucellosis, a zoonotic disease caused by Brucella bacteria, poses significant risks to human, livestock, and wildlife health, alongside economic losses from livestock morbidity and mortality. This study improves Human Brucellosis Susceptibility Mapping (HBSM) by integrating the Adaptive Neuro-Fuzzy Inference System (ANFIS) with meta-heuristic algorithms, including Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Boruta-XGBoost identified key covariates, while VIF and tolerance tests addressed collinearity, and Shapley additive explanation (SHAP) values enhanced model interpretability. In Mazandaran province, Iran (2012-2018), the hybrid ANFIS-PSO model demonstrated superior performance (RMSE: 0.5076; R2: 0.6980). SHAP analysis highlighted mean elevation, NDVI, and relative humidity as the most impactful covariates, while max evaporation and precipitation had minimal influence. ANFIS-based models outperformed Support Vector Regression (SVR), offering a robust framework for brucellosis control. This approach enables effective interventions and resource allocation, with potential for improvement through advanced algorithms and greater interpretability.

Rapid detection of Brucella cells using a gold nanoparticle-based aptasensor via a simple colorimetric method

BACKGROUND

Brucellosis is a major worldwide zoonotic disease that is caused by Brucella spp. and threatens the health of communities. Novel methods for rapid detection of Brucella bacteria are beneficial and necessary in preventing infection and subsequent economic losses. Constructing biosensors with nanoparticles is a promising approach for identification of pathogenic bacteria in a short time. This study aimed to introduce a new detection method of Brucella cells using a biosensor, based on gold nanoparticles and a specific aptamer, via a colorimetric reaction. In this work, gold nanoparticles (GNPs) were synthesized and attached to the aptamer through electrostatic bonding. The binding of aptamer to gold nanoparticles was confirmed by Uv/vis spectrophotometry, FT-IR, transmission electron microscope (TEM) and zeta sizer (DLS).

RESULTS

In the presence of the bacterial cells, aptamers were bound to their targets, and the surfaces of the nanoparticles were depleted from aptamers resulting in intensified peroxidation activity of GNPs, and with the addition of 3, 3', 5, 5'-tetramethylbenzidine (TMB), the color of the solution was changed from red to purple, which indicated the presence of Brucella. The sensitivity of the aptasensor was investigated using different concentrations of Brucella cells and its specificity was confirmed against several species of bacteria. The results showed that the designed aptasensor was more sensitive compared to PCR assay method with the ability to detect 1.5 × 101 CFU/mL of the bacterial cells.

CONCLUSION

These findings indicate that the designed aptasensor can be used as a simple and rapid diagnostic tool to detect Brucella cells without need to experts and expensive laboratory equipment.

Disruption of Erythritol Catabolism via the Deletion of Fructose-Bisphosphate Aldolase (Fba) and Transaldolase (Tal) as a Strategy to Improve the Brucella Rev1 Vaccine

Brucellosis is a bacterial zoonosis caused by the genus Brucella, which mainly affects domestic animals. In these natural hosts, brucellae display a tropism towards the reproductive organs, such as the placenta, replicating in high numbers and leading to placentitis and abortion, an ability also exerted by the B. melitensis live-attenuated Rev1 strain, the only vaccine available for ovine brucellosis. It is broadly accepted that this tropism is mediated, at least in part, by the presence of certain preferred nutrients in the placenta, particularly erythritol, a polyol that is ultimately incorporated into the Brucella central carbon metabolism via two reactions dependent on transaldolase (Tal) or fructose-bisphosphate aldolase (Fba). In the light of these remarks, we propose that blocking the incorporation of erythritol into the central carbon metabolism of Rev1 by deleting the genes encoding Tal and Fba may impair the ability of the vaccine to proliferate massively in the placenta. Therefore, a Rev1ΔfbaΔtal double mutant was generated and confirmed to be unable to use erythritol. This mutant exhibited a reduced intracellular fitness both in BeWo trophoblasts and THP-1 macrophages. In the murine model, Rev1ΔfbaΔtal provided comparable protection to the Rev1 reference vaccine while inducing fewer adverse reproductive events in pregnant animals. Altogether, these results postulate the Rev1ΔfbaΔtal mutant as a reproductively safer Rev1-derived vaccine candidate to be studied in the natural host.

Development and Bayesian validation of a competitive inhibition ELISA for detection of antibodies against Brucella abortus in cattle

Bovine brucellosis is a zoonotic disease caused by Brucella abortus, responsible for abortions in cows. It is endemic in low- and middle-income countries, where the brucellosis control and eradication programs are based on compulsory vaccination, detection of infected cattle through serologic assays, and culling of infected animals at slaughterhouses. The development of high sensitivity and specificity, and low-cost serologic assays guarantee their implementation in countries where the disease is endemic. The aim of the present study was to develop and validate a competitive inhibition enzyme-linked immune assay (ciELISA) to detect anti-B. abortus antibodies in sera from cattle. The developed ciELISA was validated using 2833 serum samples from dairy and beef cattle. From these, 1515 sera were from uninfected cows that belonged to free of brucellosis herds and 1318 were from infected cows that belonged positive to brucellosis herds. Sera were analyzed with the developed ciELISA, the buffer plate antigen (BPA) test, and the complement fixation test (CFT). The brucellosis status of the herds was officially established according to the country legislation and consistent for at least 5 years and was defined for each cow using the CFT as gold standard. The cutoff for the ciELISA was calculated using a ROC curve and its sensitivity and specificity were analyzed using the Bayesian Latent Class Model (BLCM) approach. The agreement among tests was calculated using the kappa (κ) value. In addition, 15 calves were vaccinated with 3 × 1010 viable cells of B. abortus Strain 19 vaccine, and the dynamics of antibodies were measured by CFT, buffered plate antigen (BPA) test, and the developed ciELISA. The obtained cutoff for ciELISA was ≥ 47 percentage of inhibition (% I), at the BLCM approach the sensitivity was 99.01 % (95 % CI: 97.55-100) and the specificity 98.74 % (95 % CI: 97.68-99.8). The κ between the ciELISA and BPA was κ = 0.88 and between the ciELISA and CFT κ = 0.95. Antibodies against B. abortus were detected in all the vaccinated calves 7 days after vaccination (AV) by the three assays, at day 135 AV all the calves were negative to CFT (15/15), 93.3 % (14/15) to ciELISA and 73.3 % (11/15) to BPA, and at day 190 AV all the calves were negative to the three assays. The developed ciELISA showed a very good performance, could detect the majority of vaccinated animals as negative after 135 days and could be used for the detection of anti-B. abortus antibodies in serum samples for the brucellosis control and eradication program.

Seroprevalence and molecular detection of Brucella infection in livestock in the United Arab Emirates

Small ruminants and camels are important livestock species in the United Arab Emirates (UAE), although Brucella infection can limit their productivity. This study aimed to investigate the seroprevalence of Brucella infection and its associated risk factors in small ruminants and camels in the Emirate of Abu Dhabi. Additionally, seropositive animals were tested for the DNA of Brucella. Multispecies competitive enzyme-linked immunosorbent assay (c-ELISA) and multispecies indirect (i-ELISA) were used to test 3,086 animals from 2022 to 2023. Brucella cell surface 31 kDa protein (bcsp31) gene-based real-time polymerase chain reaction (q-PCR) was used to detect Brucella DNA. Multivariate logistic regression was used to assess the association between seroprevalence and potential risk factors. The overall seroprevalences of Brucella infection were 1.7% (95% confidence interval [CI], 1.2%-2.2%) and 5.8% (95% CI, 5.0%-6.7%) based on serial and parallel testing, respectively. The DNA of Brucella was detected in 13 of the 51 seropositive animals. The overall seroprevalence of Brucella infection was associated with the region, type of animal holding, species, and age of the animals. In conclusion, this study documented Brucella infection in small ruminants and camels in the Emirate of Abu Dhabi, warranting necessary intervention strategies to eliminate Brucella infections in livestock populations.

Understanding brucellosis: knowledge, perceptions, and self-reported prevalence among agro-pastoralists in Nakasongola, Uganda

BACKGROUND

Brucellosis is an infectious zoonotic disease that poses serious health threats around the world including Uganda. Brucellosis is caused by Brucella spp., the bacteria being transmitted via contact through skin breaks, via inhalation, or orally through the consumption of raw milk and other dairy products. The aim of this study was to investigate self-reported prevalence, knowledge, and perceptions towards brucellosis transmission, within agro-pastoralist communities in the Nakasongola district, central Uganda.

METHODS

This study employed a cross-sectional survey design. A semi-structured questionnaire was developed and administered to 398 participants selected through convenience sampling method. The survey gathered information on socio-demographic characteristics, knowledge of brucellosis transmission, symptoms, preventive measures, and self-reported prevalence of brucellosis. Qualitative data involved the use of six focus group discussions, identifying factors for transmission based on their perceived level of risk or impact using ranking by proportional piling.

RESULTS

A majority (99.2%, n = 398) had heard about brucellosis and 71.2% were aware of the zoonotic nature of the disease. There were varied responses regarding transmission routes, symptoms, and preventive measures. Self-reported prevalence was relatively high (55.5%). Following adjusted analysis, factors such as subcounty, source of income, knowledge about symptoms of brucellosis, whether brucellosis is treatable, perception, and living close to animals were statistically significant. Participants from Wabinyonyi had 2.7 higher odds of reporting brucellosis than those from Nabiswera, aOR = 2.7, 95%CI 1.4-5.5. Crop farming and livestock had much higher odds of reporting brucellosis than those earning from casual sources, aOR = 8.5, 95%C 1.8-40.1 and aOR = 14.4, 95%CI 3.1-67.6, respectively. Those who had knowledge about symptoms had 6.9 higher odds of reporting brucellosis than who mentioned fever, aOR = 4.5, 95%CI 2.3-18.3. Likewise, living close with animals and handling aborted fetuses (aOR = 0.4, 95%CI: 0.17-0.86), (aOR = 0.2,95% CI: 0.07-0.0.42,) had significantly lower odds for self-reported prevalence compared to those who believed did not cause brucellosis. Risk factors identified included, handling of aborted fetuses and living in close proximity with animals. Overall, there was a moderate statistical agreement in the ranking across the focus groups discussion (Wc = 0.48, p < 0.01; n = 6).

CONCLUSION

While awareness of brucellosis is high in the community, understanding of the transmission routes, clinical symptoms, and preventive measures varied. Investigating the understanding and assessing knowledge, perceptions and self-reported prevalence in this region indicated a necessity for risk communication strategies and community-based interventions to better control brucellosis transmission.

The Economic Burden of Brucellosis Care in China: Socioeconomic Status Inequality

The economic burden of brucellosis care on patients can lead to significant financial strain, despite partial coverage by medical insurance. However, there is limited research on the out-of-pocket costs faced by brucellosis patients. Therefore, our study aimed to investigate the costs and out-of-pocket expenses of brucellosis care, specifically examining the varying socioeconomic status of patients in Xinjiang, China. We collected cost and demographic data from 563 respondents and their hospital bills and employed latent variable analysis to assess socioeconomic status. The majority of patients belonged to the middle and lower socioeconomic status categories (85.97%), and they were primarily farmers and herders (82.77%). The median direct cost per brucellosis episode was USD 688.65, with out-of-pocket expenses amounting to USD 391.44. These costs exceeded both the 2020 Xinjiang and national per capita health expenditures (USD 233.66 and USD 267.21, respectively). Notably, the overall medical reimbursement rate was 48.60%, and for outpatient costs, it was merely 12.82%. Despite higher out-of-pocket costs among high socioeconomic status patients, the percentage of income spent was higher (37.23%) for patients in the lower socioeconomic status group compared to other groups (16.25% and 12.96%). In conclusion, our findings highlight that brucellosis patients are predominantly from the middle and lower socioeconomic status, with high out-of-pocket expenses placing them under significant financial pressure. Moreover, there is notable inequity in economic consequences across different socioeconomic status groups. These results call for policy interventions aimed at reducing brucellosis-related poverty and promoting equitable access to care.

Molecular typing methods to characterize Brucella spp. from animals: A review

Brucellosis is an infectious disease of animals that can infect humans. The disease causes significant economic losses and threatens human health. A timely and accurate disease diagnosis plays a vital role in the identification of brucellosis. In addition to traditional diagnostic methods, molecular methods allow diagnosis and typing of the causative agent of brucellosis. This review will discuss various methods, such as Bruce-ladder, Suiladder, high-resolution melt analysis, restriction fragment length polymorphism, multilocus sequence typing, multilocus variable-number tandem repeat analysis, and whole-genome sequencing single-nucleotide polymorphism, for the molecular typing of Brucella and discuss their advantages and disadvantages.

Seroprevalence of brucellosis and associated risk factors in camels and its herders in selected districts of Somali Pastoral Region, Eastern Ethiopia

Brucellosis poses a major public and animal health problem in many parts of the world, particularly in pastoral settings, however, seroepidemological studies are scarce. A cross-sectional study was conducted from December 2021 to April 2022 to estimate the prevalence of brucellosis and to identify the associated risk factors for camels and occupational individuals from three purposively selected districts of the Somali pastoral region in Eastern Ethiopia. Serum samples were serially diluted using the Rose Bengal Plate Test (RBPT) as a screening test and a competitive Enzyme-Linked Immunosorbent Assay (cELISA) test as a confirmatory test. From a total of 450 camels and 250 human serum samples tested, the overall seroprevalence was confirmed to be 2.9 % (95 % CI, 1.5-4.9) in camels and 2.0 % (95 % CI, 0.2-3.7) in humans. In camels, abortion and retained fetal membrane (RFM) were significant risk factors for Brucella seropositivity (p<0.05). However, in humans, RFM disposal differed significantly (p<0.05). The fact that brucellosis is found in both camels and humans highlights the importance of implementing a coordinated One Health approach to control and eliminate the disease. This would ensure improved public health and increased livestock productivity.

Genome-wide analysis of Brucella melitensis growth in spleen of infected mice allows rational selection of new vaccine candidates

Live attenuated vaccines (LAVs) whose virulence would be controlled at the tissue level could be a crucial tool to effectively fight intracellular bacterial pathogens, because they would optimize the induction of protective immune memory while avoiding the long-term persistence of vaccine strains in the host. Rational development of these new LAVs implies developing an exhaustive map of the bacterial virulence genes according to the host organs implicated. We report here the use of transposon sequencing to compare the bacterial genes involved in the multiplication of Brucella melitensis, a major causative agent of brucellosis, in the lungs and spleens of C57BL/6 infected mice. We found 257 and 135 genes predicted to be essential for B. melitensis multiplication in the spleen and lung, respectively, with 87 genes common to both organs. We selected genes whose deletion is predicted to produce moderate or severe attenuation in the spleen, the main known reservoir of Brucella, and compared deletion mutants for these genes for their ability to protect mice against challenge with a virulent strain of B. melitensis. The protective efficacy of a deletion mutant for the plsC gene, implicated in phospholipid biosynthesis, is similar to that of the reference Rev.1 vaccine but with a shorter persistence in the spleen. Our results demonstrate that B. melitensis faces different selective pressures depending on the organ and underscore the effectiveness of functional genome mapping for the design of new safer LAV candidates.

Efficacy of antibiotic prophylaxis to preventing brucellosis in accidental exposure: A systematic review

BACKGROUND

Antibiotic prophylaxis to prevent brucellosis after accidental exposure to Brucella is an important topic in public health. This study aimed to systematically review the efficacy of antibiotic prophylaxis following accidental exposure to Brucella in preventing human brucellosis disease.

METHODS

The study protocol was registered in PROSPERO (CRD42023456812). The outcomes included the incidence of brucellosis disease, adverse events rate, and antibiotic prophylaxis adherence. A comprehensive literature search, conducted until 20 November, 2023, involved Medline, Embase, Cochrane Library, and LILACS databases. Descriptive analysis and meta-analysis using R software were performed, risk of bias was assessed using JBI Critical appraisal tools, and certainty of evidence was assessed using the GRADE tool.

RESULTS

Among 3102 initially identified records, eight studies involving 97 individuals accidentally exposed, all focused on high-risk accidental exposure to Brucella in laboratory settings, were included in the review. All studies reported the prophylactic treatment comprising doxycycline at a dosage of 100 mg twice daily, combined with rifampicin at 600 mg, both administered over 21 days. Prophylaxis adherence was reported in 86% of cases, and incidence of brucellosis post-treatment was 0.01. Adverse events, mainly gastrointestinal, occurred in 26% of cases. Critical appraisal revealed limitations in reporting demographics and clinical information. The certainty of evidence was rated as 'very low,' emphasising the need for caution in interpreting the observed outcomes due to study design constraints and the absence of comparative groups.

CONCLUSIONS

PEP is an alternative practice reported in the literature, used in accidents with high-risk exposure to Brucella. The currently available evidence of the efficacy of antibiotic prophylaxis is insufficient to support a recommendation for or against the widespread use of antibiotic prophylaxis, so caution is needed in interpreting results due to the very low certainty of evidence, primarily stemming from case series and lack of comparative groups.

Seroprevalence of brucellosis in sheep and goats from Al Jufrah district in Libya

Introduction

brucellosis is a global neglected zoonotic disease affecting mainly livestock, causing communicable and zoonotic infections. This study aimed to investigate the seroprevalence and determine epidemiological risk factors associated with Brucella infection in sheep and goats in Al Jufrah central district of Libya.

Methods

sera samples from 555 animals (goats (n=320) and sheep (n=235)) sheep) were obtained and subjected to the Rose Bengal Plate Test (RBPT) then further confirmed by a validated Enzyme Linked Immunosorbent assay (ELISA). Collected data was analyzed using Statistical Package for the Social Sciences (SPSS).

Results

in total, 2.7% were ELISA seropositive for brucellosis with the highest seropositivity rate among the studied animals from Sokna with 5.8% (n=13/225) followed by 0.7% (n=2/285) in Waddan and 0% (n=0/45) in Houn. Only location was identified as a significant risk and no significant differences were identified between seropositivity and the age studied groups, species of animals, gender, and size of farms (p-value>0.05).

Conclusion

the present study provides important information on the epidemiological status of Brucella infection in an important region in North Africa. Prevention control systems adopting "One Health" concept, and regional and international collaboration are important to control brucellosis and other zoonotic and transboundary diseases.

Concomitant Treatment with Doxycycline and Rifampicin in Balb/c Mice Infected with Brucella abortus 2308 Fails to Reduce Inflammation and Motor Disability

Brucellosis is an infection widely distributed around the world, and in some countries it is considered a public health problem. Brucellosis causes insidious symptoms that make it difficult to diagnose. Infection can also trigger chronic pain and neuropsychiatric complications. Antibiotics are not always effective to eradicate infection, contributing to chronicity. We aimed to investigate the effects of antibiotic treatment on proinflammatory cytokines, neurotransmitters, corticosterone, and behavior in a murine model of infecrion of B. abortus strain 2308. Four study groups were created: (a) control; (b) antibiotic control; (c) infected with B. abortus 2308; and (d) infected and treated with rifampicin and doxycycline. We determined B. abortus 2308 colony-forming units (CFUs), the count of dendritic cells, and macrophages in the spleen; serum levels of cytokines and corticosterone; levels of serotonin, dopamine, epinephrine, and norepinephrine in the brain; and equilibrium, physical strength, anxiety, and hopelessness tests. The infected and treated mice group was compared with the control and infected mice to assess whether treatment is sufficient to recover neuroimmunoendocrine parameters. Our results showed that despite the treatment of brucellosis with rifampicin and doxycycline, antibiotic-treated mice showed a persistence of B. abortus 2308 CFUs, an increased count in macrophage number, and higher circulating levels of corticosterone. Furthermore, the levels of IL-12, IL-6, and TNF-α remained higher. We found a decrease in muscular strength and equilibrium concomitant to changes in neurotransmitters in the hippocampus, cerebellum, and frontal cortex. Our data suggest that the remaining bacterial load after antibiotic administration favors inflammatory, neurochemical, and behavioral alterations, partly explaining the widespread and paradoxical symptomatology experienced by patients with chronic brucellosis.

A Review on the Methodology and Use of the Pregnant Mouse Model in the Study of Brucella Reproductive Pathogenesis and Its Abortifacient Effect

Brucellosis is one of the most common and widespread bacterial zoonoses and is caused by Gram-negative bacteria belonging to the genus Brucella. These organisms are able to infect and replicate within the placenta, resulting in abortion, one of the main clinical signs of brucellosis. Although the mouse model is widely used to study Brucella virulence and, more recently, to evaluate the protection of new vaccines, there is no clear consensus on the experimental conditions (e.g., mouse strains, doses, routes of inoculation, infection/pregnancy time) and the natural host reproducibility of the pregnant mouse model for reproductive brucellosis. This lack of consensus calls for a review that integrates the major findings regarding the effect of Brucella wild-type and vaccine strains infections on mouse pregnancy. We found sufficient evidence on the utility of the pregnant mouse model to study Brucella-induced placentitis and abortion and propose suitable experimental conditions (dose, time of infection) and pregnancy outcome readouts for B. abortus and B. melitensis studies. Finally, we discuss the utility and limitations of the pregnant mouse as a predictive model for the abortifacient effect of live Brucella vaccines.

Endovascular Repair and Prognosis of Patients with Brucella abortus Infection-Induced Aorto-Iliac Aneurysm

Objective

To establish the endovascular repair and prognosis of patients with aorto-iliac aneurysm and Brucella abortus infection.

Methods

From September 2018 to September 2021, seven cases of Brucella abortus infection with aorto-iliac aneurysm were treated by the endovascular aneurysm repair (EVAR) procedure. Clinical and imaging data were collected to evaluate the therapeutic results, including body temperature, blood culture, imaging manifestations, stent patency and endoleak during the postoperative and follow-up periods.

Results

Except for one patient who died of acute hematemesis and hematochezia just after the admission, seven patients were treated successfully. The aneurysms were completely excluded, and all stent grafts were patent. Patients were followed up for 12-32 months, with an average follow-up of 18.5 ± 9.1 months. There were no cases of endoleak, infection recurrence, gluteal muscle ischemia or spinal cord ischemia during the follow-up period.

Conclusion

It is feasible to treat Brucella abortus-infected aneurysms with the EVAR procedure. The results were optimistic in the short and medium-term. The application of sensitive antibiotics before and after the operation is the cornerstone of endovascular therapy. However, the long-term results require further follow-up.

Seroprevalence of brucellosis antibodies and associated risk factors among the hospitalized patient, Aleppo, Syria: a hospital-based cross-sectional study

Introduction and importance

Brucellosis is one of the most common infectious diseases in the world, especially in developing countries. Recent reports show that Syria is among the top ten countries where brucellosis is most prevalent. The purpose of this study is to estimate the seroprevalence of brucellosis antibodies among the hospitalized patients, in one of the largest hospitals in northern Syria.

Materials and methods

A cross-sectional study was conducted among the hospitalized patients. The authors used a questionnaire to collect sociodemographic and brucellosis-related data from the patients. The authors also collected blood samples from these patients to be screened for brucellosis antibodies using Wright Coombs Agglutination and 2-mercaptoethanol tests, during the period from November 2021 and March 2022.

Results

Among the 776 patients who were recruited in the study, the seroprevalence of brucellosis antibodies was 13.1% (n=776). The highest prevalence was among the female sex (16.7%, n=298), middle aged group 12-40 years (24.1%, n=116), and patients with history of brucellosis (30.1%, n=53). Among the positive samples, the findings of 2-mercaptoethanol tests show that (14.7%, n=102) were positive (presence of IgG Antibodies), and (75.5%, n=102) were negative.

Conclusion

This study is the first to describe the epidemiology of brucellosis in northern Syria. It clearly shows high rates of positivity, which reflects immense challenges facing the public health sector in Syria. The best next step in light of this crisis is to raise awareness among population about brucellosis and its risk factor.

A novel gluconeogenic route enables efficient use of erythritol in zoonotic Brucella

Brucellosis is a worldwide extended zoonosis caused by pathogens of the genus Brucella. While most B. abortus, B. melitensis, and B. suis biovars grow slowly in complex media, they multiply intensely in livestock genitals and placenta indicating high metabolic capacities. Mutant analyses in vitro and in infection models emphasize that erythritol (abundant in placenta and genitals) is a preferred substrate of brucellae, and suggest hexoses, pentoses, and gluconeogenic substrates use in host cells. While Brucella sugar and erythritol catabolic pathways are known, growth on 3-4 carbon substrates persists in Fbp- and GlpX-deleted mutants, the canonical gluconeogenic fructose 1,6-bisphosphate (F1,6bP) bisphosphatases. Exploiting the prototrophic and fast-growing properties of B. suis biovar 5, we show that gluconeogenesis requires fructose-bisphosphate aldolase (Fba); the existence of a novel broad substrate bisphosphatase (Bbp) active on sedoheptulose 1,7-bisphosphate (S1,7bP), F1,6bP, and other phosphorylated substrates; that Brucella Fbp unexpectedly acts on S1,7bP and F1,6bP; and that, while active in B. abortus and B. melitensis, GlpX is disabled in B. suis biovar 5. Thus, two Fba-dependent reactions (dihydroxyacetone-phosphate + glyceraldehyde 3-phosphate ⇌ F1,6bP; and dihydroxyacetone-phosphate + erythrose 4-phosphate ⇌ S1,7bP) can, respectively, yield fructose 6-phosphate and sedoheptulose 7-phosphate for classical gluconeogenesis and the Pentose Phosphate Shunt (PPS), the latter reaction opening a new gluconeogenic route. Since erythritol generates the PPS-intermediate erythrose 4-phosphate, and the Fba/Fbp-Bbp route predicts sedoheptulose 7-phosphate generation from erythrose 4-phosphate, we re-examined the erythritol connections with PPS. Growth on erythritol required transaldolase or the Fba/Fbp-Bbp pathway, strongly suggesting that Fba/Fbp-Bbp works as a PPS entry for both erythritol and gluconeogenic substrates in Brucella. We propose that, by increasing erythritol channeling into PPS through these peculiar routes, brucellae proliferate in livestock genitals and placenta in the high numbers that cause abortion and infertility, and make brucellosis highly contagious. These findings could be the basis for developing attenuated brucellosis vaccines safer in pregnant animals.

A spatiotemporal analysis of bovine brucellosis cases in Minas Gerais state, Brazil, from 2011 to 2018

Our study explored the patterns of bovine brucellosis dissemination in Minas Gerais state, Brazil, by examining data on passive surveillance of bovine brucellosis cases from the Instituto Mineiro de Agropecuaria (IMA) (Animal Health Authority), as well as cattle population and bovine brucellosis testing, from 2011 to 2018 by means of a spatiotemporal analysis. We plotted cases, populations and testing distributions and performed spatial autocorrelation (Moran's I test) and local indicators of spatial autocorrelation (LISA) analyses. Moreover, we assessed the correlation of the spatial distribution and the compiled data (brucellosis cases, cattle populations, and brucellosis testing) by Lee's test. Our results showed that bovine brucellosis cases occurred mainly in the Triângulo Mineiro, Alto Paranaíba and Northwest regions, which reported cases in all analyzed years (2011 to 2018). The cattle population of Minas Gerais was concentrated in the same regions as bovine brucellosis cases, and the performed tests through the analyzed years (2011 to 2018). Moran's I test results of the case data showed significant spatial autocorrelation in 2011, 2015 and 2018 (p value < 0.05), and from 2011 to 2018, the population and testing data were also significant in Moran's I test (p value < 0.01). The results of cluster analysis (LISA) of cases showed clusters mainly in the Triângulo Mineiro, Alto Paranaíba, Northwest and South regions in 2011, 2015 and 2018. The local clusters for cattle populations and brucellosis testing were also observed in the same regions as bovine brucellosis cases in all years (2011 to 2018). The correlation results between clusters (Lee's test) were 0.22 (p value < 0.01) in 2011, 0.15 (p value < 0.01) in 2015 and 0.43 (p value <0.01) in 2018 between cases and populations, and 0.25 (p value <0.01) in 2011, 0.14 (p value <0.01) in 2015 and 0.38 (p value < 0.01) in 2018 for testing and cases. Therefore, our results showed that brucellosis cases were distributed together with cattle populations and brucellosis testing data, indicating that brucellosis in cattle in Minas Gerais state is being identified where there are more animals and where more tests are performed.

Sero-prevalence and risk factors associated with occurrence of anti-Brucella antibodies among slaughterhouse workers in Uganda

INTRODUCTION

Brucellosis is a febrile zoonosis occurring among high-risk groups such as livestock keepers and abattoir workers and is a public health priority in Uganda. The technical complexities of bacteriological and molecular methods make serological approaches the cornerstone of diagnosis of human brucellosis in resource limited settings. Therefore, proper application and interpretation of serological tests is central to achieve a correct diagnosis.

MATERIALS AND METHODS

We conducted a cross-sectional study to estimate the seroprevalence and factors associated with anti-Brucella antibodies among slaughterhouse workers processing ruminants and pigs in three regions of the country with serial testing using a combination of the Rose Bengal Test (RBT) and the BrucellaCapt test. An authorized clinician collected 543 blood samples from consenting abattoir workers as well as attribute medical and social demographic data. Univariable and multivariable logistic regression were used to determine factors associated with anti-Brucella sero-positivity.

RESULTS AND DISCUSSION

The sero-prevalence among ruminant slaughterhouse workers ranged from 7.3% (95% CI: 4.8-10.7) using BrucellaCapt to 9.0% (95% CI: 6.3-12.7) using RBT. Slaughterhouse workers from the Eastern regions (AOR = 9.84, 95%CI 2.27-69.2, p = 0.006) and those who graze animals for alternative income (AOR = 2.36, 95% CI: 1.91-6.63, p = 0.040) were at a higher risk of exposure to Brucella. Similarly, those who wore Personal Protective Equipment (AOR = 4.83, 95%CI:1.63-18.0, p = 0.009) and those who slaughter cattle (AOR = 2.12, 95%CI: 1.25-6.0, p = 0.006) were at a higher risk of exposure to Brucella. Those who slaughter small ruminants (AOR = 1.54, 95%CI: 1.32-4.01, p = 0.048) were also at a higher risk of exposure to Brucella.

CONCLUSIONS AND RECOMMENDATIONS

Our study demonstrates the combined practical application of the RBT and BrucellaCapt in the diagnosis of human brucellosis in endemic settings. Both pharmaceutical (e.g., routine testing and timely therapeutic intervention), and non-pharmaceutical (e.g., higher index of suspicion of brucellosis when investigating fevers of unknown origin and observation of strict abattoir hygiene) countermeasures should be considered for control of the disease in high-risk groups.

Exposure to Brucella Species, Coxiella burnetii, and Trichinella Species in Recently Imported Camels from Sudan to Egypt: Possible Threats to Animal and Human Health

Brucellosis and coxiellosis/Q fever are bacterial infections caused by Brucella species and Coxiella burnetii, respectively; camels are highly susceptible to both pathogens. Trichinellosis is a parasitic infection caused by various Trichinella nematode species. Reportedly, camels are susceptible to experimental infection with Trichinella spp., but information on this potential host species is scarce. All three infections are of zoonotic nature and thus of great public health concern. The current study aimed to determine antibodies against the three pathogens in recently imported camels (n = 491) from Sudan at the two main ports for the entrance of camels into southern Egypt using commercial indirect ELISAs. Samples were collected in two sampling periods. The seropositivity rates of Brucella spp., C. burnetii, and Trichinella spp. were 3.5%, 4.3%, and 2.4%, respectively. Mixed seropositivity was found in 1% for Brucella spp. and C. burnetii. Marked differences were found between the two study sites and the two sampling periods for Brucella. A higher rate of seropositivity was recorded in the Red Sea/older samples that were collected between 2015 and 2016 (4.3%, 17/391; odds ratio = 9.4; p < 0.030) than in those collected in Aswan/recent samples that were collected between 2018 and 2021 (0/100). Concerning C. burnetii, samples collected during November and December 2015 had a significantly higher positivity rate than the other samples (13%, 13/100; OD = 4.8; p < 0.016). The same effect was observed for antibodies to Trichinella spp., with samples collected during November and December 2015 showing a higher positivity rate than the other samples (7%, 7/100; OD = 10.9; p < 0.001). This study provides valuable information on the seroprevalence of Brucella spp. and additional novel information on C. burnetii and Trichinella spp. in recently imported camels kept in quarantine before delivery to other Egyptian regions. This knowledge can be utilized to reduce health hazards and financial burdens attributable to brucellosis, Q fever, and trichinellosis in animals and humans in Egypt.

Use of recombinant malate dehydrogenase (MDH) and superoxide dismutase (SOD) [CuZn] as antigens in indirect ELISA for diagnosis of bovine brucellosis

The objective of this study was to validate an indirect enzyme-linked immunoassay (iELISA) using the recombinant proteins, malate dehydrogenase (MDH) and superoxide dismutase (SOD) [CuZn], as antigens and to evaluate its ability to discriminate antibodies produced by vaccination from those induced by infection in the diagnosis of bovine brucellosis. Sera from six groups were evaluated: G1 - culture-positive animals (52 serum samples) (naturally infected); G2 - non-vaccinated animals (28 serum samples) positive in RBT (Rose Bengal test) and 2ME (2-mercaptoethanol test) selected from brucellosis-positive herds; G3 - animals from a brucellosis-free area (32 serum samples); G4 - S19 vaccinated heifers (114 serum samples); G5 - RB51 vaccinated heifers (60 serum samples); G6 - animals inoculated with inactivated Yersinia enterocolitica O:9 (42 serum samples). Diagnostic sensitivity (DSe) and diagnostic specificity (DSp) were estimated using the frequentist approach and the confidence interval (CI) (95%) calculated by the Clopper-Pearson (exact) method. The DSe for iELISA_MDH in the G1 group was 71.7% (CI 95%: 57.6-83.2%) and for the G2 100.0% (CI 95%: 87.7-100.0%), whereas the DSp was 84.4% in the G3 (CI 95%: 67.2-94.7%). For the iELISA_SOD the DSe was estimated 67.3% for the G1 (CI 95%: 52.9-79.7%) and 71.4% for G2 (CI 95%: 51.3-86.8%), while the DSp for G3 was 87.5% (CI 95%: 71.0-96.5%). iELISA_MDH and iELISA_SOD showed potential to be used in the diagnosis of infected animals, increasing the range of serological tests available for the diagnosis of bovine brucellosis, with the advantage of being S-LPS-free. However, none of the tests could differentiate between infection and vaccination.

Parenteral Vaccination with a Live Brucella melitensis Mutant Protects against Wild-Type B. melitensis 16M Challenge

Susceptibility to brucellosis remains prevalent, even in herds vaccinated with conventional vaccines. Efforts are underway to develop an improved brucellosis vaccine, and possibly a universal vaccine, given that Brucella species are highly homologous. To this end, two B. melitensis mutants were developed, znBM-lacZ (znBMZ) and znBM-mCherry (znBM-mC), and were tested for their ability to confer systemic immunity against virulent B. melitensis challenge. To assess the extent of their attenuation, bone-marrow-derived macrophages and human TF-1 myeloid cells were infected with both mutants, and the inability to replicate within these cells was noted. Mice infected with varying doses of znBM-mC cleared the brucellae within 6-10 weeks. To test for efficacy against systemic disease, groups of mice were vaccinated once by the intraperitoneal route with either znBMZ or B. abortus S19 vaccine. Relative to the PBS-dosed mice, znBMZ vaccination greatly reduced splenic brucellae colonization by ~25,000-fold compared to 700-fold for S19-vaccinated mice. Not surprisingly, both znBMZ and S19 strains induced IFN-γ+ CD4+ T cells, yet only znBMZ induced IFN-γ+ CD8+ T cells. While both strains induced CD4+ effector memory T cells (Tems), only znBMZ induced CD8+ Tems. Thus, these results show that the described znBM mutants are safe, able to elicit CD4+ and CD8+ T cell immunity without a boost, and highly effective, rendering them promising vaccine candidates for livestock.

Brucellosis Seropositivity Using Three Serological Tests and Associated Risk Factors in Abattoir Workers in Gauteng Province, South Africa

Abattoir workers are liable to zoonotic infections from animals and animal products, primarily to diseases with asymptomatic and chronic clinical manifestations in animals, such as brucellosis. No published reports exist on the seroprevalence of brucellosis in abattoir workers in South Africa. Therefore, this cross-sectional study was conducted to estimate the occurrence and risk factors for Brucella exposure in abattoir workers in Gauteng Province. A total of 103 abattoir workers and managers from 6 abattoirs, where brucellosis-positive slaughtered cattle and sheep were previously detected, were interviewed and tested with serological assays using the Rose Bengal test (RBT), BrucellaCapt, and IgG-ELISA. A pre-tested questionnaire was administered to consenting respondents to obtain information on risk factors for brucellosis. Of the 103 respondents tested, the distribution of female and male workers was 16 (15.5%) and 87 (84.5%), respectively. The seroprevalence for exposure to brucellosis was 21/103 (20.4%, 95%CI: 13.1-29.5) using a combination of RBT, BrucellaCapt, or IgG-ELISA. For test-specific results, seroprevalences by RBT, BrucellaCapt, and IgG-ELISA were 13/103 (12.6%, 95%CI: 6.9-20.6), 9/103 (8.74%, 95%CI: 4.1-15.9), and 18/103 (17.5%, 95%CI: 10.7-26.2), respectively. Low-throughput abattoirs were identified as associated risks, as 29.3% of workers were seropositive compared with 12.7% of workers in high-throughput abattoirs, which highlights that direct contact at abattoirs poses higher risk to workers than indirect and direct contact outside abattoirs. This study confirms the occurrence of Brucella spp. antibodies among abattoir workers in South Africa, possibly due to occupational exposure to Brucella spp., and highlights the occupational hazard to workers. Furthermore, findings underscore that abattoir facilities can serve as points for active and passive surveillance for indicators of diseases of public health importance. We recommend periodic implementation of brucellosis testing of abattoir workers country-wide to establish baseline data for informing appropriate preventive practices and reducing the potential burden of infection rates among these high-risk workers.

Accuracy of serological tests for bovine brucellosis: A systematic review and meta-analysis

The direct methods for diagnosis of bovine brucellosis have several limitations, therefore serological tests are the basis for the diagnosis of the disease. However, a meta-analysis estimating the diagnostic sensitivity (DSe) and diagnostic specificity (DSp) on the main tests used in bovine brucellosis control programs worldwide has not been performed. This systematic review and meta-analysis aimed to estimate the DSe, DSp and thereby accuracy of serological tests individually used in the diagnosis of bovine brucellosis. The databases CABI, Cochrane Library, PubMed/MEDLINE, SciELO, Scopus and Web of Science were used to select articles. The search resulted in 5308 studies, of which 71 were selected for systematic review using quality assessment tools and 65 studies were included in the meta-analysis. For the meta-analysis, 178 assays and 11 different serological tests were considered. To estimate DSe and DSp of the tests, studies were divided according to animal selection for the studies: (1) studies that carried out a random or consecutive selection of participants (noncasecontrol studies) and (2) all studies, including casecontrol studies. Considering only the non-case-control studies to estimate the DSe, the tests that exhibited the best and worst performance were the iELISA test (indirect enzyme immunoassay - bacterial suspension as antigen - BS) (96.5%, 95% CI: 94.1-97.9%) and 2ME (2- mercaptoethanol test) (85.0%, 95% CI: 79.6-89.1%), respectively; while for DSp, the FPA (fluorescence polarization assay) (99, 7%, 95% CI: 99.5-99.8%) and PCFIA tests (protein concentration fluorescence immunoassay) (78.5%, 95% CI: 70.0-85.1%) showed better and worse performance, respectively. Overall, our results showed an overestimation in the DSe and DSp of the eleven serological tests assessed when casecontrol studies were included in the meta-analysis, which is a concern considering its impacts on the time and costs associated with populational diagnosis of the diseases, since several of these tests are routinely used in the control and eradication programs of bovine brucellosis worldwide. Furthermore, the tests that exhibited the best DSe and DSp, iELISA (BS) and FPA, respectively, are relatively easy to perform and interpret and the test which showed the best overall accuracy was FPA.

Brucella spp. are facultative anaerobic bacteria under denitrifying conditions

IMPORTANCE

Respiration is a fundamental and complex process that bacteria use to produce energy. Despite aerobic respiration being the most common, some bacteria make use of a mode of respiration in the absence of oxygen, called anaerobic respiration, which can yield advantages in adaptation to various environmental conditions. Denitrification is part of this respiratory process ensuring higher respiratory flexibility under oxygen depletion. Here, we report for the first time the evidence of anaerobic growth of Brucella spp. under denitrifying conditions, which implies that this genus should be reconsidered as facultative anaerobic. Our study further describes that efficient denitrification is not equally found within the Brucella genus, with atypical species showing a greater ability to denitrify, correlated with higher expression of the genes involved, as compared to classical species.

Epidemiological characteristics and temporal-spatial clustering analysis on human brucellosis in Jiangsu Province, 2006-2021

The marked increase in the incidence rate of brucellosis is a serious public health concern in Jiangsu Province. However, its temporal and spatial distribution has not been studied in depth. The main purpose of this study is to depict the demographic, temporal and spatial distribution patterns and clustering characteristics of brucellosis cases in Jiangsu Province, China, from 2006 to 2021 to develop and implement effective scientific prevention and control strategies. Data for human brucellosis cases in Jiangsu Province from 2006 to 2021 were obtained from the Nationwide Notifiable Infectious Diseases Reporting Information System (NIDRIS). Spatial autocorrelation analysis and temporal-spatial scan statistics were used to identify potential changes in the spatial and temporal distributions of human brucellosis in Jiangsu Province. During the years 2006-2021, 1347 brucellosis cases were reported in Jiangsu Province, with an average annual incidence rate of 0.1036 per 100,000 individuals. Middle-aged and elderly individuals (aged 40-69 years) were the main infected populations, accounting for 69.72% (939/1347) of all reported cases. The incidence of brucellosis in Jiangsu showed a long-term increasing trend and displayed pronounced seasonal variations, with the peak occurring between April and June annually. The incidence gradually expanded from the northern and southern areas to the central areas between 2006 and 2021. Global spatial autocorrelation analysis demonstrated a positive correlation in the incidence of brucellosis between 2008 and 2012-2021. Temporal-spatial clustering analysis showed that the primary cluster was detected in the northern, highly endemic regions of Jiangsu, and the three secondary clusters were in areas where there had been outbreaks of brucellosis. Human brucellosis remains a serious public health issue in Jiangsu Province. Northern and southern Jiangsu regions, with high rates of brucellosis, may require special plans and measures to monitor and control the disease. Additionally, the capacity to respond to outbreaks in high-incidence areas should be improved to prevent further brucellosis outbreaks.

Imipramine Administration in Brucella abortus 2308-Infected Mice Restores Hippocampal Serotonin Levels, Muscle Strength, and Mood, and Decreases Spleen CFU Count

Brucellosis infection causes non-specific symptoms such as fever, chills, sweating, headaches, myalgia, arthralgia, anorexia, fatigue, and mood disorders. In mouse models, it has been associated with increased levels of IL-6, TNF-α, and IFN-γ, a decrease in serotonin and dopamine levels within the hippocampus, induced loss of muscle strength and equilibrium, and increased anxiety and hopelessness. Imipramine (ImiP), a tricyclic antidepressant, is used to alleviate neuropathic pain. This study evaluated the effects of ImiP on Balb/c mice infected with Brucella abortus 2308 (Ba) at 14- and 28-days post-infection. Serum levels of six cytokines (IFN-γ, IL-6, TNF-α, IL-12, MCP-1. and IL-10) were assessed by FACS, while the number of bacteria in the spleen was measured via CFU. Serotonin levels in the hippocampus were analyzed via HPLC, and behavioral tests were conducted to assess strength, equilibrium, and mood. Our results showed that mice infected with Brucella abortus 2308 and treated with ImiP for six days (Im6Ba14) had significantly different outcomes compared to infected mice (Ba14) at day 14 post-infection. The mood was enhanced in the forced swimming test (FST) (p < 0.01), tail suspension test (TST) (p < 0.0001), and open-field test (p < 0.0001). Additionally, there was an increase in serotonin levels in the hippocampus (p < 0.001). Furthermore, there was an improvement in equilibrium (p < 0.0001) and muscle strength (p < 0.01). Lastly, there was a decrease in IL-6 levels (p < 0.05) and CFU count in the spleen (p < 0.0001). At 28 days, infected mice that received ImiP for 20 days (Im20Ba28) showed preservation of positive effects compared to infected mice (Ba28). These effects include the following: (1) improved FST (p < 0.0001) and TST (p < 0.0001); (2) better equilibrium (p < 0.0001) and muscle strength (p < 0.0001); (3) decreased IL-6 levels (p < 0.05); and (4) reduced CFU count in the spleen (p < 0.0001). These findings suggest the potential for ImiP to be used as an adjuvant treatment for the symptoms of brucellosis, which requires future studies.

Immuno-profiling of Brucella proteins for developing improved vaccines and DIVA capable serodiagnostic assays for brucellosis

Brucellosis remains a worldwide zoonotic disease with a serious impact on public health and livestock productivity. Controlling brucellosis in livestock is crucial for limiting human infections in the absence of effective human vaccines. Brucellosis control measures are majorly dependent on rigorous monitoring of disease outbreaks and mass vaccination of livestock. Live attenuated vaccines are available for livestock vaccination that play a vital role in brucellosis control programs in many countries. Even though the existing animal vaccines confer protection against brucellosis, they carry some drawbacks, including their infectivity to humans and interference with sero-monitoring. The available serodiagnostic assays for brucellosis depend on detecting anti-LPS antibodies in the serum. Since diagnosis plays a vital role in controlling brucellosis, developing improved serodiagnostic assays with enhanced specificity, sensitivity and DIVA capability is required. Therefore, it is essential to identify novel antigens for developing improved vaccines and serodiagnostic assays for brucellosis. In the present study, we performed a high throughput immunoprofiling of B. melitensis protein microarray using brucellosis-positive human and animal serum samples. The screening identified several serodominant proteins of Brucella that exhibited common or differential reactivity with sera from animals and humans. Subsequently, we cloned, expressed, and purified ten serodominant proteins, followed by analyzing their potential to develop next-generation vaccines and improved serodiagnostic assays for brucellosis. Further, we demonstrated the protective efficacy of one of the serodominant proteins against the B. melitensis challenge in mice. We found that the seroreactive protein, Dps (BMEI1980), strongly reacted with brucellosis-positive serum samples, but it did not react with sera from B. abortus S19-vaccinated cattle, indicating DIVA capability. A prototype lateral flow assay and indirect ELISA based on Dps protein exhibited high sensitivity, specificity, and DIVA capability. Thus, the present study identified promising candidates for developing improved vaccines and affordable, DIVA-capable serodiagnostic assays for animal and human brucellosis.

Retrospective benefit-cost analysis of bovine brucellosis control in the state of Mato Grosso, Brazil

From 2001, due to the launching of the National Program for the Control and Eradication of Brucellosis and Tuberculosis, Brazil began a series of studies aimed at the epidemiological characterization of bovine brucellosis in its federative units. In the state of Mato Grosso, studies conducted in 2003 and 2014 showed a reduction in the prevalence of infected herds from 41.2 % to 24 % and in the prevalence of seropositive animals from 10.2 % to 5.1 %. These results stemmed from the efficient heifer vaccination program with S19 implemented by the state. From this scenario, the present study quantified and compared the benefits and costs of bovine brucellosis control in the state through a financial analysis. When considering private and public costs, the Net Present Value (NPV) was estimated at US$ 37.5 million, the Internal Rate of Return (IRR) was calculated at 31 %, and the Benefit-Cost Ratio (BCR) was 2.3. When considering only the private costs, the NPV was US$ 51.3 million, the IRR was 46 % and the BCR was 3.43, indicating that the cattle producer in Mato Grosso had a return of US$ 3.43 for each US$ 1.00 invested. Therefore, the bovine brucellosis control actions carried out in the state of Mato Grosso between 2003 and 2014 were highly advantageous from the economic point of view. The most rational way to continue decreasing bovine brucellosis prevalences at low cost in the state is to maintain the heifer vaccination program, using the RB51 vaccine in addition to S19.

Innate Lymphoid Cells and Interferons Limit Neurologic and Articular Complications of Brucellosis

Brucellosis is a globally significant zoonotic disease. Human patients with brucellosis develop recurrent fever and focal complications, including arthritis and neurobrucellosis. The current study investigated the role of innate lymphoid cells (ILCs) in the pathogenesis of focal brucellosis caused by Brucella melitensis. After footpad infection, natural killer cells and ILC1 cells both limited joint colonization by Brucella. Mice lacking natural killer cells, and in particular mice lacking all ILCs, also developed marked arthritis after footpad infection. Following pulmonary infection, mice lacking adaptive immune cells and ILCs developed arthritis, neurologic complications, and meningitis. Adaptive immune cells and ILCs both limited colonization of the brain by Brucella following pulmonary infection. Transcriptional analysis of Brucella-infected brains revealed marked up-regulation of genes associated with inflammation and interferon responses, as well as down-regulation of genes associated with neurologic function. Type II interferon deficiency resulted in colonization of the brain by Brucella, but mice lacking both type I and type II interferon signaling more rapidly developed clinical signs of neurobrucellosis, exhibited hippocampal neuronal loss, and had higher levels of Brucella in their brains than mice lacking type II interferon signaling alone. Collectively, these findings indicate ILCs and interferons play an important role in prevention of focal complications during Brucella infection, and that mice with deficiencies in ILCs or interferons can be used to study pathogenesis of neurobrucellosis.

Global Estimate of Human Brucellosis Incidence

Brucellosis is a major public health concern worldwide, especially for persons living in resource-limited settings. Historically, an evidence-based estimate of the global annual incidence of human cases has been elusive. We used international public health data to fill this information gap through application of risk metrics to worldwide and regional at-risk populations. We performed estimations using 3 statistical models (weighted average interpolation, bootstrap resampling, and Bayesian inference) and considered missing information. An evidence-based conservative estimate of the annual global incidence is 2.1 million, significantly higher than was previously assumed. Our models indicate Africa and Asia sustain most of the global risk and cases, although areas within the Americas and Europe remain of concern. This study reveals that disease risk and incidence are higher than previously suggested and lie mainly within resource-limited settings. Clarification of both misdiagnosis and underdiagnosis is required because those factors will amplify case estimates.

Risk factors associated to bovine brucellosis seroprevalence in the eastern region of Paraguay

In Paraguay, whose main economic activity is cattle raising, bovine brucellosis is an endemic disease. Between May 2019 and October 2020, a national prevalence survey was implemented by the Paraguayan Veterinary Services. In the frame of that survey, a cross-sectional study was conducted in the eastern region of Paraguay to identify the risk factors that could be associated with brucellosis-positive farms and to estimate the bovine brucellosis seroprevalence and farmers' awareness about the disease. A questionnaire was administered to farmers to collect data on potential risk factors for bovine brucellosis as well as awareness on the disease. A logistic regression model was used to identify the risk factors associated with a farm brucellosis positive status. Blood samples were collected from 2551 cattle on 133 farms. The overall apparent seroprevalence was 27.8 % (95 % CI: 20.4-36.3 %) at the farm level, and 5.5 % (95 % CI: 4.7-6.5 %) at the animal level. Among 18 potential risk factors, four were associated with a farm brucellosis positive status. Farm size was associated with a higher risk of positive status in medium (20-80 cows) and large farms (>80 cows), compared with small farms (<20 cows). Barn disinfection had a protective effect on the risk of positive status. Conversely, presence of dogs and not incinerating/burying aborted material increased this risk. Even if 89 % of the farmers acknowledged being aware of the bovine brucellosis transmission to humans, only 46% of these farmers declared using protective gloves during calving or when handling abortions. The findings of this study emphasize the importance of implementing biosecurity measures and proper disposal of aborted material to control the disease. Therefore, to control the disease in Paraguay, vaccination campaigns should be accompanied by awareness campaigns addressing good farm management practices to minimize the risk of introduction and maintenance of brucellosis as well as the risk of human infection.

Evaluation of a Lateral Flow Immunochromatography Assay (LFIA) for Diagnosis and Surveillance of Brucellosis in French Alpine Ibex (Capra ibex)

France has been officially free of bovine brucellosis since 2005. Nevertheless, in 2012, as the source of two human cases, a bovine outbreak due to B. melitensis biovar 3 was confirmed in the French Alpine Bargy massif, due to a spillover from wild, protected Alpine ibex (Capra ibex). In order to reduce high Brucella prevalence in the local ibex population, successive management strategies have been implemented. Lateral flow immunochromatography assay (LFIA) was thus identified as a promising on-site screening test, allowing for a rapid diagnosis far from the laboratory. This study compared a commercial LFIA for brucellosis diagnosis with the WOAH-recommended tests for small ruminants (i.e., Rose Bengal test (RBT), Complement fixation test, (CFT) and Indirect ELISA, (iELISA)). LFIA showed the same analytical sensitivity as iELISA on successive dilutions of the International Standard anti-Brucella melitensis Serum (ISaBmS) and the EU Goat Brucella Standard Serum (EUGBSS). Selectivity was estimated at 100% when vaccinated ibex sera were analyzed. When used on samples from naturally infected ibex, LFIA showed high concordance, as well as relative sensitivity and specificity (>97.25%) in comparison with RBT and CFT. This work shows high reliability and ensures a better standardization of LFIA testing for wild ruminants.

Sero-prevalence and factors associated with anti-Brucella antibodies in slaughter livestock in Uganda

Introduction

Brucellosis is endemic in Uganda and is a major cause of production losses in livestock. Early detection and quantification of the disease is vital for its control and eradication. The aim of this study was to assess the sero-prevalence and factors associated with anti-Brucella antibodies in slaughtered livestock.

Materials and methods

Sera from 886 cattle, 925 small ruminants, and 900 pigs were collected from regional abattoirs in Northern, Eastern and Central Uganda. To estimate sero-prevalence, sera were serially tested using a combination of the Rose Bengal Test (RBT) and Native Hapten (NH) immunoprecipitation test. True sero-prevalence was estimated using the Rogan-Gladden estimator considering the sensitivity and specificity of the NH immunoprecipitation test. Multivariable logistic regression was used to assess factors associated with seropositivity for anti-Brucella antibodies.

Results and discussion

Small ruminants showed the highest seroprevalence (6.7%, 95% CI = 4.2-7.1) followed by cattle (3.8%, 95% CI = 2.4-4.9) and pigs (2.8%, 95% CI = 1.1-2.9). Seropositivity for anti-Brucella antibodies was associated with region of origin (OR = 4.6,95%CI=1.49-17.75, p = 0.013) for cattle; sex (OR = 2.90, 95% C = 1.5-6.34, p = 0.004), age (OR=4.04, 95% CI = 1.07-8.52, p = 0.006) and species (OR = 2.53, 95% CI = 1.08-6.98, p = 0.048) for small ruminants; and finally sex for pigs (OR = 2.88, 95% CI = 1.07-8.52, p = 0.041). Progressive control interventions must include both cattle and small ruminants since they play a bigger role in the maintenance and dissemination of Brucella. The interventions should adopt a risk-based approach with regions at higher risk being given top priority. Bacteriological and molecular studies should be undertaken to clarify the role of pigs and the goat-cattle cross infections in the epidemiological cycle of brucellosis in Uganda.

Current Status of Q Fever and the Challenge of Outbreak Preparedness in Korea: One Health Approach to Zoonoses

Human Q fever, a zoonosis caused by Coxiella burnetii, presents with diverse clinical manifestations ranging from mild self-limited febrile illnesses to life-threatening complications such as endocarditis or vascular infection. Although acute Q fever is a benign illness with a low mortality rate, a large-scale outbreak of Q fever in the Netherlands led to concerns about the possibility of blood transfusion-related transmission or obstetric complications in pregnant women. Furthermore, a small minority (< 5%) of patients with asymptomatic or symptomatic infection progress to chronic Q fever. Chronic Q fever is fatal in 5-50% of patients if left untreated. In South Korea, Q fever in humans was designated as a notifiable infectious disease in 2006, and the number of Q fever cases has increased sharply since 2015. Nonetheless, it is still considered a neglected and under-recognized infectious disease. In this review, recent trends of human and animal Q fever in South Korea, and public health concerns regarding Q fever outbreaks are reviewed, and we consider how a One Health approach could be applied as a preventive measure to prepare for zoonotic Q fever outbreaks.

Prevalence of brucellosis and associated risk factors in dairy cattle in Maekel and Debub Regions, Eritrea

Introduction

Brucellosis is a zoonotic disease with worldwide distribution. It is considered endemic in Eritrea, however, the current prevalence status and related risk factors in animals are unknown. The objective of this study was to determine the prevalence of and risk factors for brucellosis in dairy cattle in Maekel and Debub regions, Eritrea.

Methods

A cross sectional study was conducted between August 2021 and February 2022. A total of 2,740 dairy cattle from 214 herds in 10 sub-regions of Eritrea were selected for blood and data collection. Blood samples were tested using Rose Bengal Plate Test (RBPT) and positive samples were confirmed using competitive (c-ELISA). Data on risk factors was collected using questionnaire and analyzed using logistic regression.

Results

In total, 34/2740 animals tested positive by RBPT. Of these, 29 were confirmed positive by c-ELISA, giving an apparent and estimated true individual-level prevalence of 1.1% (95% CI: 0.7, 1.5%) and 1.3% (95% CI: 0.9, 1.8%), respectively. Sixteen herds (7.5%) tested positive by RBPT and of these 15 herds (7.0%) were confirmed positive by c-ELISA, giving an estimated true herd-level prevalence of 7.0% (95% CI: 4.0, 10.7). Animal and herd-level apparent prevalence was 1.6 and 9.2% in Maekel, while in Debub it was 0.6 and 5.5%, respectively. Multivariable regression analysis indicated that non-pregnant lactating cows (adjusted odds ratio [aOR] = 3.35; p = 0.042) were more likely to be Brucella sero-positive. History of abortion on the farm (aOR = 5.71; p = 0.026) and larger number of cows in the herd (aOR = 1.14; p < 0.001) were associated with brucellosis sero-positivity in herds.

Conclusion

Brucellosis prevalence was low in the study areas. Nonetheless, this low prevalence may increase if the disease is not controlled. Therefore, testing animals before movement, good farming practices, sanitary measures, and an awareness raising program on brucellosis are recommended.

Cell and Tissue Tropism of Brucella spp

Brucella spp. are facultatively intracellular bacteria that can infect, survive, and multiply in various host cell types in vivo and/or in vitro. The genus Brucella has markedly expanded in recent years with the identification of novel species and hosts, which has revealed additional information about the cell and tissue tropism of these pathogens. Classically, Brucella spp. are considered to have tropism for organs that contain large populations of phagocytes such as lymph nodes, spleen, and liver, as well as for organs of the genital system, including the uterus, epididymis, testis, and placenta. However, experimental infections of several different cultured cell types indicate that Brucella may actually have a broader cell tropism than previously thought. Indeed, recent studies indicate that certain Brucella species in particular hosts may display a pantropic distribution in vivo. This review discusses the available knowledge on cell and tissue tropism of Brucella spp. in natural infections of various host species, as well as in experimental animal models and cultured cells.

A Single Nasal Dose Vaccination with a Brucella abortus Mutant Potently Protects against Pulmonary Infection

The Brucella abortus double-mutant (ΔznuA ΔnorD Brucella abortus-lacZ [znBAZ]) was assessed for its protective efficacy after vaccination with a single nasal dose. Superior protection was achieved in znBAZ-vaccinated mice against pulmonary, wild-type B. abortus 2308 challenge when compared with conventional livestock Brucella abortus vaccines, the smooth S19 (smooth B. abortus strain 19 vaccine) and rough RB51 (rough mutant vaccine strain of B. abortus) strains. Nasal znBAZ vaccination reduced splenic and lung colonization by wild-type brucellae by >3-4 logs. In contrast, S19 reduced lung colonization by only 32-fold, and RB51 failed to reduce colonization. One profound attribute of znBAZ vaccination was the >3-fold increase in pulmonary CD8+ T cells when compared with other vaccinated groups. S19 vaccination increased only CD4+ T cells. All vaccines induced IFN-γ and TNF-α production by CD4+ T cells, but only znBAZ vaccination enhanced the recruitment of polyfunctional CD8+ T cells, by >100-fold. IL-17 by both CD4+ and CD8+ T cells was also induced by subsequent znBAZ vaccination. These results demonstrate that, in addition to achieving protective immunity by CD4+ T cells, CD8+ T cells, specifically resident memory T cells, also confer protection against brucellosis. The protection obtained by znBAZ vaccination was attributed to IFN-γ-producing CD8+ T cells, because depletion of CD8+ T cells throughout vaccination and challenge phases abrogated protection. The stimulation of only CD4+ T cells by RB51- and S19-vaccinated mice proved insufficient in protecting against pulmonary B. abortus 2308 challenge. Thus, nasal znBAZ vaccination offers an alternative means to elicit protection against brucellosis.