Brucellosis in ruminants and pastoralists in Borena, Southern Ethiopia

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.

Brucella Seropositivity and Associated Risk Factors in Pastoral Livestock System in Northeastern Ethiopia

Brucellosis is a common zoonotic disease affecting livestock and humans globally. The disease is endemic in Ethiopian livestock. This study was conducted to estimate Brucella seropositivity and identify its risk factors in livestock, and practices that may expose pastoralists to the disease. Data were collected from 2133 animals across 149 households (HHs) in Dubti and Amibara districts, Afar region, Ethiopia. Blood samples from livestock and household data were collected, and interviews were conducted on husbandry and dairy consumption practices. Sera were serially tested using the Rose Bengal test and indirect enzyme-linked immunosorbent assay. The overall seropositivity to anti-Brucella antibodies was 8% (95% CI, 6.6-9.2). The antibodies were found in 12.4%, 6.5%, 6%, and 3% of the goats, cattle, camels, and sheep, respectively. Among the HHs, 59.7% had at least one seropositive animal. A mixed-effects logistic regression analysis revealed species and the acquisition of new animals (in cattle and camels), and age and district (in sheep, goats, and cattle) as significant risk factors. Goats, cattle, and camels had significantly higher odds of Brucella seropositivity than sheep (p < 0.05). Seropositivity was significantly higher (p < 0.05) in adults than in young animals, in acquired than in homebred (cattle and camels), and in those with reproductive disorders than those without. Pastoralists lacked knowledge of brucellosis and its modes of transmission, while practices exposing humans and livestock to brucellosis were common. The findings underscore the need for public awareness campaigns and implementation of brucellosis control measures in pastoral systems.

Serological and Molecular Prevalence and Associated Risk Factors in Caprine Brucellosis, Northeastern Thailand

Brucellosis is a significant zoonotic disease with global implications for animal and human public health. This study investigated the prevalence of caprine brucellosis in 39 meat goat herds in northeastern Thailand using serological and molecular methods. Seroprevalence, determined by the modified Rose Bengal test (mRBT), was negative, indicating no detectable antibodies against Brucella. However, real-time PCR identified Brucella spp. DNA in 11 samples from 8 herds. Intraherd prevalence varied from 0.0% to 9.09%, averaging 6.73% (95% CI, 4.74-8.72). Univariate analysis revealed significant risk factors associated with brucellosis at the herd level. Larger herd size correlated with increased brucellosis odds ratio (OR: 6.30; 95% CI: 1.07-36.93; p=0.041). Herds with multiple reproductive failures, including abortion, repeat breeding, and sterile, together with weak offspring, showed higher prevalence (OR: 9.37; 95% CI: 1.17-74.84; p=0.034). Multivariable analysis identified herd sizes over thirteen as a significant risk factor (OR: 10.20; 95% CI: 1.06-97.40; p=0.044). Notably, herds where owners were aware of direct transmission risks exhibited lower infection rates (OR: 0.05; 95% CI: 0.006-0.54; p=0.012). This study underscores the complementary role of molecular techniques alongside serological tests in detecting Brucella infection accurately. The findings highlight the importance of effective herd management, reproductive health monitoring, and owner education in mitigating brucellosis transmission. Implementing robust control measures, including stringent biosecurity protocols and enhanced stakeholder awareness, is crucial for controlling brucellosis in meat goat populations.

Seroprevalence of small ruminant brucellosis and owners knowledge, attitude and practices in Chiro and Burka Dhintu Districts, West Hararghe, Ethiopia

Brucellosis is one of zoonotic bacterial diseases with significant veterinary and public health consequences in sub-Saharan African countries, including Ethiopia. A cross-sectional study design was conducted with the objective of estimating the seroprevalence of small ruminant brucellosis and assessing owners' knowledge, attitude and practices (KAP) on brucellosis in Chiro and Burka Dhintu Districts in Eastern Ethiopia. A total sample of 444 animals were taken using a cluster based multistage sampling technique. Screening for Brucella antibodies and confirmation of positive test results were conducted using Modified Rose Bengal Plate Test (MRBPT) and indirect enzyme-linked immunosorbent assay (I-ELISA) respectively. For the questionnaire survey, 444 randomly selected sheep and goat owners were interviewed using a pretested structured questionnaire. The overall seroprevalence of small ruminant brucellosis was found to be 6.5 % (95 % CI: 4.6-9.3). The multivariable logistic regression analysis identified sex and age as potential risk factors (P < 0.05). More specifically, females were 3.4 times (AOR = 3.4, 95 % CI: 1.2-9.2) more likely to become seropositive than their counterparts, and the odds of seropositivity in adult sheep and goats was 5.6 times (AOR = 5.6, 95 % CI: 1.3-24.7) higher than that of young animals. The knowledge, attitude and practices of animal owners with regard to brucellosis were low, and the level of education was independently associated with the owners' knowledge and attitude. Moderate seroprevalence, combined with inadequate knowledge, attitudes, and practices of animal owners, makes small ruminant brucellosis a threat to animals and the entire community. Hence, strengthening veterinary services and raising community awareness about the disease is essential to reduce the impact on small ruminant productivity and minimize the risks to public health.

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.

One health: a structured review and commentary on trends and themes

BACKGROUND

One Health (OH) is defined as a unifying approach aiming to sustainably balance and optimise the health of people, animals and the ecosystem. It recognises that the health of humans, animals (both domestic and wild), plants and the wider ecosystem are both interdependent and linked. As a concept, it aims to address complex problems requiring input from multiple disciplines. Suitable issues for OH approaches typically include global issues which can widely impact not only the health of humans and animals, but also have a significant environmental impact. Examples include emerging zoonotic diseases and antimicrobial resistance (AMR). Interpretations and use of the term OH differ in the literature and have the potential to dilute its impact. The meaning of OH among the research community has evolved over time. Here, we collate the OH relevant literature from the last two decades, identifying major themes and trends and considering how OH has been embraced differently across various geographical regions.

METHODS AND RESULTS

Bibliographic databases were searched using the term "One Health" AND ("Veterinary" OR "Animal") AND ("Medicine" OR "Human") AND ("Environment" OR "Ecosystem") during the period between 1980 and 2022. Data analysis and narrative synthesis identified themes, similarities, and differences within literature. Web of Science and PubMed returned 948 and 1250 results for the period mentioned above. The predominant literature focused on human health, with veterinary health second, although often to benefit human health. It was found that OH is often utilised as a public health approach, generally towards the end of disease surveillance and control. Interestingly, while authors from low- and middle-income countries were well-represented within studies using the term OH, they were less well-represented as corresponding authors.

CONCLUSIONS

The predominant focus of the literature was on human and veterinary health, implying OH approach is human-orientated, despite its suggestion that all domains share a common 'health'. Potential improvement to OH could be achieved through greater incorporation of the environmental and social sciences for a more encompassing approach.

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.

Brucellosis in camel, small ruminants, and Somali pastoralists in Eastern Ethiopia: a One Health approach

Brucellosis is a neglected bacterial zoonotic disease with economic and public health importance in pastoral communities of sub-Saharan Africa. A cross-sectional study was conducted from December 2021 to April 2022, to estimate the prevalence and identify the associated risk factors causing brucellosis in animals and associated with occupational diseases in humans from three selected districts of "the Somali Pastoral region," Eastern Ethiopia. In this study, 1,000 serum samples were screened for anti-Brucella spp. antibodies using Rose Bengal Plate Test (RBPT) and further confirmed using a competitive enzyme-linked immunosorbent assay (cELISA). A structured questionnaire was used to collect the biodata of tested animals and animal attendants to test the association between explanatory and outcome variables. The overall animal level prevalence was 5% (95% CI, 6.1-7.2.0) in small ruminants, 2.9% (95% CI, 1.5-4.9) in camels, and 2.0% (95% CI, 0.2-3.7) in occupationally linked humans. Herd size and herd history of retained fetal membranes were risk factors associated with Brucella spp. seropositivity in animals (p < 0.05). Disposing of retained fetal membranes was significantly associated (p < 0.05) with Brucella spp. seropositivity in humans. Evidence of brucellosis in various livestock species and associated seropositivity in humans indicates the need for a coordinated One Health approach, considering sociocultural dynamics of pastoral communities in controlling brucellosis to safe guard public health and increase livestock productivity.

Seroepidemiology and associated risk factors of brucellosis in small ruminants of district Khanewal, Pakistan

Objectives

Keeping in view the economic and veterinary public health importance of brucellosis, this research was conducted to determine its seroprevalence and associated risk determinants in small ruminants in district Khanewal, Southern Punjab, Pakistan.

Materials and Methods

Two-stage cluster sampling technique was used for sampling, and the sample size was calculated using C-survey 2.0. Accordingly, sera samples (n = 392) were collected from small ruminants in the study area from October 2022 to July 2023. All the samples were tested for the presence of anti-Brucella antibodies by Rose Bengal Plate Test (RBPT), followed by confirmation of all the samples using an enzyme linked immunosorbent assay (ELISA) kit (ID.vet®, France; sensitivity and specificity=100%, each).

Results

The seropositivity rate of brucellosis was 7.14% [n = 28/392; 95% confidence interval (CI) = 4.87%-10.12%] by RBPT, whereas the results of ELISA showed an overall seroprevalence rate of 7.40% (n = 29/392; 95% CI = 5.11%-10.37%) in the study population. Univariate analysis of risk factors revealed that abortion history (AH), retained fetal membranes (RFMs), repeat breeding, flock size (FS), educational status of farmers (ESFs), awareness about brucellosis (AB), and farm hygiene had a significant association with the seroprevalence of brucellosis (p < 0.05). The multivariate analysis using a binary logistic regression model revealed that variables including tehsil, FS, AH, RFM, ESF, AB, and farming system were significant factors (p < 0.05) associated with brucellosis in the target population.

Conclusion

Brucellosis is prevalent in small ruminants in Khanewal, Pakistan. The disease burden can be reduced by improving the reproductive health of animals, farm hygiene, and farmers' awareness about the diseases. Further studies are needed on a larger scale to devise stringent disease control strategies to avoid losses associated with brucellosis at regional, national, and global levels.

Farmers' perceptions of bovine brucellosis in Benin

Background and Aim

Cattle are the main source of meat in Benin. To improve the attitudes and practices of cattle breeders in relation to bovine brucellosis, a study has been carried out in Benin according to different agroecological zones. This study aimed to assess farmers' knowledge and practices concerning bovine brucellosis to generate essential information for control programs and public health interventions.

Materials and Methods

The study was conducted from February to May 2022, during which 608 farmers were interviewed using a structured questionnaire that provided information on socioeconomic characteristics, knowledge, and practices related to bovine brucellosis. Analysis of variance, Poisson regression, and the proportion comparison test were used to compare these characteristics in the different agroecological zones. At the end of the surveys, three distinct and homogeneous groups of perceptions (hierarchical classification of Multiple Correspondence Analysis components of R software) of bovine brucellosis were identified (these groups only consider farmers who declared knowledge of the disease). Groups were formed by applying the multiple correspondence analysis function of the FactoMineR library in R software, followed by a hierarchical ascending classification using the hierarchical clustering on principal component function of the same software (Agrocampus Rennes, France).

Results

Only 38% of respondents were aware of brucellosis. Knowledge of brucellosis was not related to sex or education level but was higher among farmers in agroecological Zones 1 and 4. Ethnic Dendi herders (62.16%) had better knowledge of the disease than those from other sociolinguistic groups (Somba: 50%, Fulani: 40.91%, Baribas: 26.97%, and others: 8.82%). Reduced milk production (98.29%), presence of hygroma (87.18%), and abortion (56.84%) are the main signs reported by herders familiar with the disease. All three groups had good knowledge of the disease and its zoonotic nature. Groups 1 (96% of breeders) and 2 (2.14%) were aware of the risk factors (contact with affected animals, the consumption of raw milk, the handling of runts, and reproductive rejection). In the case of Brucella, they prefer to treat animals rather than sell them and use both traditional and modern medicines. Group 3 (1.71%) did not know the risk factors and preferred to sell animals in the event of illness.

Conclusion

Pastoralists need to be made aware of the mode of transmission of bovine brucellosis, its clinical manifestations, its impact on animal health, and the zoonotic nature of the disease (impact on public health) so that bovine brucellosis can be rapidly detected in herds.

A study on the epidemiology of brucellosis in bovine population of peri-urban and rural areas of district Multan, southern Punjab, Pakistan

BACKGROUND

Brucellosis is a zoonotic disease caused by a bacterial pathogen belonging to the genus Brucella. It is one of the most frequent bacterial zoonoses globally but unfortunately, it is still considered as a neglected disease in the developing world. Keeping in view, this study was conducted to determine the prevalence and risk determinants of brucellosis in large ruminants of peri-urban and rural areas of district Multan-Pakistan. For this purpose, blood samples (n = 490) were collected from the cattle (n = 245) and buffalo (n = 245) population of the study area and subjected to preliminary screening of brucellosis using local and imported RBPT reagents. All the samples were further analyzed using commercially available multi-specie indirect ELISA kit followed by their confirmation by PCR using genus and species-specific primers. Data obtained from lab analysis and questionnaires were subjected to statistical analysis for Pearson Chi-square, Odds Ratio and Confidence intervals (95%).

RESULTS

The results showed that the maximum seropositivity was recorded with local RBPT reagent (VRI, Pakistan; 12.45%; 95%CI = 9.72-15.65%) followed by RBPT-IDEXX (12.24%; 95%CI = 9.52-15.45%) and RBPT-ID.vet (11.84%; 95%CI = 9.18-14.95%) however statistical difference was non-significant (P = 0.956). The ELISA results showed an overall seroprevalence rate of 11.22% (95%CI = 8.59-14.33%) with comparatively higher rate in cattle (12.65%; 95%CI = 8.82-17.44%) as compared to buffaloes (9.80%; 95%CI = 6.49-14.15%). The PCR analysis confirmed the presence of genus Brucella in all seropositive samples whereas frequency of B. abortus and B. melitensis in seropositive samples was 80% and 20%, respectively. The co-existence of both species was also observed in 5.45% samples. The statistical analysis showed a significant association of bovine brucellosis with herd size, breed, reproductive disorders, mode of insemination, educational status and farmers' awareness about brucellosis (P < 0.05). Conversely, locality, age, weight, gender, pregnancy status, parity and puberty status had no associations with brucellosis (P > 0.05).

CONCLUSION

In conclusion, brucellosis is prevalent in large ruminants of district Multan, Pakistan. It is suggested to devise and implement stringent policies for the effective control and prevention of brucellosis in the region. Further, the current situation also warrants the need to strengthen interdisciplinary coordination among veterinarians and physicians in one health perspective to ensure and strengthen the human and animal health care systems in the region.

Seroprevalence and spatial distribution of livestock brucellosis using three serological tests in Kajiado County, Kenya

Background

Brucellosis is a serious zoonotic infection with a global socioeconomic impact on both the livestock industry and human health. In Kenya, brucellosis is endemic but there is limited information on the true burden of the disease due to weak or peace-meal surveillance. The true burden and spread of animal brucellosis in Kajiado County is not known.

Aim

The aim of the study was to determine the current seroprevalence and spatial distribution of livestock brucellosis in Kajiado County and also to compare the three serological tests, namely; Rose Bengal plate test (RBPT), indirect enzyme-linked immunosorbent assay (i-ELISA), and competitive ELISA (c-ELISA) in the detection of seropositive animals.

Methods

A cross-sectional study was undertaken in 5 sub-counties and 13 wards, where a total of 782 serum samples from unvaccinated bovine (n = 278; 34 herds), ovine (n = 256; 25 flocks), and caprine (n = 248; 28 flocks), were screened for anti-Brucella antibodies using RBPT, i-ELISA, and c-ELISA tests, in parallel.

Results

Overall animal seroprevalence was 6.91% (54/782); while that for bovine, ovine, and caprine was 18.35% (51/278), 0.78% (2/256), and 0.4% (1/248), respectively. Bovine seroprevalence was 2.2% (6/278), 14.4% (40/278), and 4.7% (13/278) in RBPT, i-ELISA, and c-ELISA tests, respectively; while ovine 0.78% (2/256) and caprine 0.4% (1/248) were positive only in c-ELISA. Bovine herd seropositivity was 67.65% (23/34), whereas ovine and caprine flock seropositivities were 8% (2/25) and 3.6% (1/28), respectively.

Conclusion

The findings indicate a moderate seroprevalence of brucellosis in bovine, while that of ovine and caprine was low in Kajiado County. Indirect ELISA was found superior to both c-ELISA and RBPT in detecting bovine seropositive animals, while c-ELISA was superior to both RBPT and i-ELISA in detecting seropositive ovines and caprines. These results will contribute to baseline data for further study of Brucella infection and a starting point for the formulation of a strategy for the control of brucellosis in Kajiado County.

Seroprevalence and potential risk factors of brucellosis in sheep from America, Africa and Asia regions: A systematic review and meta-analysis

BACKGROUND

Brucellosis, a neglected and global zoonotic disease, infect a variety of mammals, among which sheep are one of the main hosts. This disease results in huge economic losses and is a widespread concern around the world.

RESULT

Based on the selection criteria, 40 articles from 2010 to 2021 of five databases (CNKI, Wanfang, VIP, PubMed and Science Direct) reported in America, Africa and Asia were included. The data showed that during this period, the overall seroprevalence of sheep brucellosis on these three continents was 6.2%. At the regional level, sheep brucellosis had the highest seroprevalence (8.5%) in Africa and the lowest seroprevalence (1.9%) in the Americas. With regard to the age of the sheep, the seroprevalence was significantly higher in adult sheep (15.5%) than in lambs (8.6%). Further, the seroprevalence was significantly higher in sheep that had abortion (44.3%) than in pregnant (13.0%) and non-pregnant sheep (9.5%). With regard to herd size, herds with >20 sheep (35.4%) had a significantly higher seroprevalence than herds with <20 sheep (16.8%). In terms of farming and grazing mode, free-range rearing (8.4%) was associated with a significantly higher seroprevalence than intensive farming (2.8%), and mixed grazing (37.0%) was associated with a significantly higher seroprevalence than single grazing (5.7%).

CONCLUSION

Sheep brucellosis is widely distributed in sheep-rearing regions of America, Africa and Asia, and sheep are susceptible to brucellosis by themselves or from other infectious sources. Therefore, timely monitoring of ovine brucellosis and improving farming and grazing patterns are critical to reducing the prevalence of brucellosis.

Seroprevalence and assessment of public awareness of Brucella spp., Toxoplasma gondii and Chlamydia abortus in small ruminants from selected smallholder commercial farms of Zimbabwe

Brucella spp., Toxoplasma gondii, and Chlamydia abortus have long been recognized as zoonoses and significant causes of reproductive failure in small ruminants globally. A cross-sectional study was conducted in August 2020 to determine the seroprevalences of Brucella spp., Toxoplasma gondii and Chlamydia abortus in 398 small ruminants from four districts of Zimbabwe (Chivi, Makoni, Zvimba, and Goromonzi) using Indirect-ELISAs. A structured questionnaire was used to assess the knowledge, attitudes, and practices of 103 smallholder farmers towards small ruminant abortions, Brucella spp., T. gondii and C. abortus, and to obtain a general overview of the significance of small ruminant reproductive failure(s) on their livelihoods. The overall seroprevalences were: 9.1% (95% CI: 6.4-12.3) for Brucella spp., 6.8% (95% CI: 4.5-9.7) for T. gondii and 2.0% (95% CI: 0.9-3.9) for C. abortus. Location, age, parity, and abortion history were associated with Brucella spp. seropositivity. Location was also associated with both T. gondii and C. abortus seropositivity. The questionnaire survey established that 44% of respondents had recently faced reproductive disease challenges within their flocks, with 34% correctly identifying abortion causes and only 10%, 6% and 4% having specific knowledge of Brucella spp., C. abortus and T. gondii, respectively. This study provides the first serological evidence of Brucella spp. in small ruminants since 1996 and builds the evidence on small ruminant toxoplasmosis and chlamydiosis in Zimbabwe. Evidence of these zoonoses in small ruminants and the paucity of knowledge shows the need for a coordinated One Health approach to increase public awareness of these diseases, and to establish effective surveillance and control measures. Further studies are required to establish the role these diseases play in small ruminant reproductive failure(s), to identify the Brucella spp. detected here to species/subspecies level, and to assess the socio-economic impact of reproductive failure in livestock among marginalised rural communities.

Shedding rate of Brucella spp. in the milk of seropositive and seronegative dairy cattle

Brucellosis in cattle herds has caused severe economic losses in many regions worldwide. A cross-sectional study was performed to investigate the presence of Brucella spp. in industrial dairy cattle farms in Iran. For this purpose, 935 blood and 935 milk samples were randomly collected from industrial dairy cattle farms in Iran's Alborz and Tehran provinces. Blood and milk samples were collected on the same day from each cow. Serological, bacteriological, and molecular characterization of Brucella isolates were performed using standard methods. Our results revealed the seroprevalence of brucellosis in dairy cattle farms in the Alborz and Tehran provinces, reaching 19.8%, 6.7%, 5.1%, 14.1%, and 13.1% using the Rose Bengal plate test (RBPT), serum agglutination test (SAT), 2-mercaptoethanol test (2-ME), indirect enzyme-linked immunosorbent assay (i-ELISA) and milk ring test (MRT), respectively. Furthermore, the results of bacterial culture and PCR analyses showed the presence of Brucella abortus among dairy cattle in the Alborz province and Brucella melitensis and B. abortus among dairy cattle in the Tehran province. Moreover, statistical analysis with Cohen's Kappa has highlighted the near-perfect agreement between RBPT and i-ELISA (k = 0.86). In contrast, substantial agreement was shown between RBPT and SAT performance (k = 0.70) and moderate agreement between RBPT and 2-ME (k = 0.67). The findings of this investigation showed shedding of Brucella in the milk of seropositive cows, which is a serious problem involving the maintenance and further spread of Brucella infection on the farm. Therefore, for brucellosis detection or eradication in dairy cattle farms, bacteriological and serological tests of milk samples should be performed along with blood analysis to inhibit the uncontrolled spread of the disease in animals and humans.

MicroRNAs in Ruminants and Their Potential Role in Nutrition and Physiology

The knowledge of how diet choices, dietary supplements, and feed intake influence molecular mechanisms in ruminant nutrition and physiology to maintain ruminant health, is essential to attain. In the present review, we focus on the role of microRNAs in ruminant health and disease; additionally, we discuss the potential of circulating microRNAs as biomarkers of disease in ruminants and the state of technology for their detection, also considering the major difficulties in the transition of biomarker development from bench to clinical practice. MicroRNAs are an inexhaustible class of endogenous non-protein coding small RNAs of 18 to 25 nucleotides that target either the 3' untranslated (UTR) or coding region of genes, ensuring a tight post-transcriptionally controlled regulation of gene expression. The development of new "omics" technologies facilitated a fresh perspective on the nutrition-to-gene relationship, incorporating more extensive data from molecular genetics, animal nutrition, and veterinary sciences. MicroRNAs might serve as important regulators of metabolic processes and may present the inter-phase between nutrition and gene regulation, controlled by the diet. The development of biomarkers holds the potential to revolutionize veterinary practice through faster disease detection, more accurate ruminant health monitoring, enhanced welfare, and increased productivity. Finally, we summarize the latest findings on how microRNAs function as biomarkers, how technological paradigms are reshaping this field of research, and how platforms are being used to identify novel biomarkers. Numerous studies have demonstrated a connection between circulating microRNAs and ruminant diseases such as mastitis, tuberculosis, foot-and-mouth disease, fasciolosis, and metabolic disorders. Therefore, the identification and analysis of a small number of microRNAs can provide crucial information about the stage of a disease, etiology, and prognosis.

Whole genome sequencing of Ethiopian Brucella abortus isolates expands the known diversity of an early branching sub-Saharan African lineage

Brucellosis remains one of the most significant zoonotic diseases globally, responsible for both considerable human morbidity and economic losses due to its impacts on livestock productivity. Despite this, there remain significant evidence gaps in many low- and middle-income countries, including those of sub-Saharan Africa. Here we report the first molecular characterisation of Brucella sp. from Ethiopia. Fifteen Brucella sp. isolates from an outbreak in cattle from a herd in central Ethiopia were identified as Brucella abortus, using bacterial culture and molecular methods. Sequencing of the Ethiopian B. abortus isolates allowed their phylogenetic comparison with 411 B. abortus strains of diverse geographical origins, using whole genome single nucleotide polymorphisms (wgSNP). The Ethiopian isolates belonged to an early-branching lineage (Lineage A) previously only represented by data from two strains, both of sub-Saharan African origin (Kenya and Mozambique). A second B. abortus lineage (Lineage B), also comprised solely of strains originating from sub-Saharan Africa, was identified. The majority of strains belonged to one of two lineages of strains originating from a much broader geographical range. Further analyses based on multi-locus sequence typing (MLST) and multi-locus variable-number tandem repeat analysis (MLVA) expanded the number of B. abortus strains available for comparison with the Ethiopian isolates and were consistent with the findings from wgSNP analysis. MLST profiles of the Ethiopian isolates expanded the sequence type (ST) diversity of the early branching lineage of B. abortus, equivalent to wgSNP Lineage A. A more diverse cluster of STs, equivalent to wgSNP Lineage B, was comprised solely of strains originating from sub-Saharan Africa. Similarly, analysis of B. abortus MLVA profiles (n = 1891) confirmed that the Ethiopian isolates formed a unique cluster, similar to only two existing strains, and distinct from the majority of other strains of sub-Saharan African origin. These findings expand the known diversity of an under-represented lineage of B. abortus and suggest a potential evolutionary origin for the species in East Africa. In addition to providing information concerning Brucella species extant within Ethiopia this work serves as the basis for further studies on the global population structure and evolutionary history of a major zoonotic pathogen.

Brucellosis in small ruminant: seroprevalence, risk factors, and distribution in the southeast of Algeria

The impact of brucellosis on public health and economy is unquestionable in developing countries such as the case of Algeria. This study aimed to provide further understanding of epidemiological status of brucellosis in small ruminant flocks in the southeast of Algeria. Therefore, a cross-sectional study was conducted among small ruminant flocks (n = 51) in El Oued district using simple random sampling strategy. The serum samples collected from 612 sheep and goats (sheep = 280, goats = 332) were screened for Brucella antibodies using the Rose Bengal test (RBT) and the indirect enzyme-linked immunosorbent assay (iELISA) in parallel on all the serum samples. The seropositive serum samples of both tests were confirmed with the complement fixation test (CFT). A structured questionnaire regarding animal, herd, and farm management was prepared and completed in parallel to sampling. Association between variables and Brucella spp. seropositivity status of herds was assessed by univariate and multivariate analysis using simple and binary logistic regression. Estimated true herd prevalence was 27.95% (95% CI, 17.18-42.01), and true individual prevalence was 3.98% (95% CI, 2.51-6.03). Seropositive herds were detected in bordering areas and regions with the highest livestock density. Occurrence of abortions in herds (p = 0.03) increased at least five times (5) the odds of being seropositive (OR, 6.25; 95% CI, 1.20-32.46). Poultry presence in farms revealed to be a protective factor (p = 0.01) (OR, 0.11; 95% CI, 0.02-0.61). The high-level seroprevalence quantified in this study in small ruminant flocks reflects the persistent animal infection endemicity and the high risk of human exposure.

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

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

Brucellosis in Ethiopia: A comprehensive review of literature from the year 2000-2020 and the way forward

Brucellosis is a zoonotic disease of considerable economic and public health significance globally. Despite the limited bacteriological evidence, a large number of serological works revealed that it is prevalent both in livestock and humans in Ethiopia. The current comprehensive review was carried out to provide apparent pooled seroprevalence (APS) estimates at individual animal and herd levels in livestock, and identify factors causing variability between studies conducted over the last two decades, show the spatial distribution, as well as summarizes Brucella species reported from livestock. It also provides APS of brucellosis in humans and evaluates the public health awareness of zoonotic brucellosis. In this review, systematic and synthetic review approaches were followed to summarize the available information. For the systematic review and meta-analysis, articles were selected based on predefined criteria. Data extracted from these articles were analyzed using meta-analytical approaches to provide APS estimates and in-between study variations for humans and all livestock species considered. Sensitivity analyses and bias assessments were conducted using influence plot analysis and, Egger's and Begg's statistics along with funnel plots, respectively. Synthetic review approaches were used to summarize data on isolates and public health awareness. Pooled seroprevalence estimate of brucellosis at national level was 2.6% (95% CI, 2.2-3.0) in cattle, 4% (95% CI, 3.1-5.1) in goats, 3% (95% CI, 2.3-3.9) in sheep and 3% (95% CI, 2.4-3.7) in camels. At a herd level, 16.3% (95% CI, 12.9, 20.5) of cattle, 12.1% (7.1, 19.9) of goat, 13.3% (7.6, 22.1) of sheep and 19.7% (13.8, 27.4) of camel herds in the country had at least one seropositive animal. Cattle in the pastoral/agropastoral production systems had significantly higher (p < 0.05) APS compared to mixed crop-livestock and urban/peri-urban dairy production systems. Pooled seroprevalence of brucellosis in small ruminants (8.3%, 95% CI, 6.3, 10.8) and camels (4.4%, 95% CI, 3.5, 5.6) in Afar were significantly higher (p<0.05) than in other regions. Reports conducted using ELISA and serial Rose Bengal plate test (RBPT)-ELISA had higher (p<0.05) APS estimates than serial RBPT and complement fixation test. Brucella melitensis and B. abortus were reported from goats and cattle, respectively, from three available reports. The APS of brucellosis in humans was 5% (95% CI: 3.3, 7.3). Public awareness of brucellosis was low (18.4%), while, practices that expose humans to Brucella infection were high. Scenario-based control interventions on regions and production systems using one health approach are suggested. This article is protected by copyright. All rights reserved.

The first study on seroprevalence and risk factors for zoonotic transmission of ovine and caprine brucellosis in the Province of Bam, Burkina Faso

Background and Aim:

Brucellosis is a bacterial disease notorious for its ability to infect a wide range of domestic and wildlife animals, as well as humans. This study aimed to determine the seroprevalence of ovine and caprine brucellosis and the associated risk factors in the Province of Bam in Burkina Faso.

Materials and Methods:

The individual serological status of 300 unvaccinated sheep and 300 unvaccinated goats was determined by Rose Bengal and indirect enzyme-linked immunosorbent assay (iELISA) serological tests used in parallel. The frequency of behaviors conferring risk of developing this zoonotic disease was determined through two epidemiological questionnaires, which identified known risk factors for the transmission of brucellosis between animals and humans.

Results:

Individual seroprevalence was estimated at 6.0% (18/300) in sheep and 4.3% (13/300) in goats. The “herd” prevalence of brucellosis was estimated at 60% in sheep while 40% in goats. Positivity in the iELISA serological test was significantly associated with age, sex, and husbandry system in sheep and goats.

Conclusion:

These results indicate that Brucella melitensis circulates in sheep and goat farms in the Province of Bam in Burkina Faso. As B. melitensis is highly pathogenic to humans, adequate measures must be taken to protect the population against this zoonotic disease.

Risk factors for Brucellosis and knowledge-attitude practice among pastoralists in Afar and Somali regions of Ethiopia

BACKGROUND

Brucellosis is a neglected bacterial zoonotic disease with substantial economic impact on households. Pastoral communities are a potential risk group due to their way of life being closely interlinked with their large livestock herds.

METHODOLOGY

A semi-structured questionnaire survey was conducted in households in the pastoral Afar and Somali (SRS) regions. All households had people and animals serologically tested for brucellosis. Questions were related to husbandry, consumption habits, and knowledge-attitude-practice towards the disease and zoonoses. Descriptive statistics and logistic analysis were performed to assess potential risk factors for having households with positive humans and/or animals.

RESULT

647 households were included in the survey. Herd brucellosis prevalence was 40.3 % (15.9-86.3 % in Afar; 4-72.2 % in SRS). Over half (56.3 %) of the households in Afar and 41.8 % in SRS had at least one human reactor. Nearly a quarter of the households (22.8 %), recalled abortions in goats in the last 12 months, whereas 52.5 % and 50.3 % recalled stillborn in all species and membrane retentions respectively. All respondents drank raw milk and discarded animal afterbirths in the direct surroundings with minimal protection. Risk factors for animal reactors were goat herd size, and goat abortion. There was no identified risk factor for having human reactors in households. None of the households knew about brucellosis.

CONCLUSION

Although being endemic in Afar and SRS, Brucellosis is not known by the pastoralists. Brucellosis control programs will have to be tailored to the pastoral context, accounting for their mobility, large, multi-species herds and habits.

Integrated human-animal sero-surveillance of Brucellosis in the pastoral Afar and Somali regions of Ethiopia

Background

Brucellosis is widespread in Ethiopia with variable reported prevalence depending on the geographical area, husbandry practices and animal species. However, there is limited information on the disease prevalence amongst pastoral communities, whose life is intricately linked with their livestock.

Methodology

We conducted an integrated human-animal brucellosis sero-surveillance study in two adjacent pastoral regions, Afar and Somali region (SRS). This cross-sectional study included 13 woredas (districts) and 650 households. Blood samples were collected from people and livestock species (cattle, camel, goats and sheep). Sera were analyzed with C-ELISA for camels and shoats (sheep and goats), with I-ELISA for cattle and IgG ELISA for humans. Descriptive and inferential statistics analyses were performed.

Results

A total of 5469 sera were tested by ELISA. Prevalence of livestock was 9.0% in Afar and 8.6% in SRS (ranging from 0.6 to 20.2% at woreda level). In humans, prevalence was 48.3% in Afar and 34.9% in SRS (ranging from 0.0 to 74.5% at woreda level). 68.4% of all households in Afar and 57.5% of households in SRS had at least one animal reactor. Overall, 4.1% of animals had a history of abortion. The proportion of animals with abortion history was higher in seropositive animals than in seronegative animals. Risk factor analysis showed that female animals were significantly at higher risk of being reactors (p = 0.013). Among the species, cattle had the least risk of being reactors (p = 0.014). In humans, there was a clear regional association of disease prevalence (p = 0.002). The older the people, the highest the odds of being seropositive.

Conclusion

Brucellosis is widespread in humans and animals in pastoral communities of Afar and SRS with the existence of geographical hotspots. No clear association was seen between human and particular livestock species prevalence, hence there was no indication as whether B. abortus or B. melitensis are circulating in these areas, which warrants further molecular research prior to embarking on a national control programs. Such programs will need to be tailored to the pastoral context.

Brucellosis is a neglected disease of livestock that can be transmitted to people through consumption of raw animal products and direct contact with animal birth material. Although prevalent in Ethiopia, there is limited information on the disease prevalence amongst pastoral communities, whose life is intricately linked with their livestock. We therefore, conducted a disease surveillance in people and their livestock in Afar and Somali region (SRS), two pastoral regions of Ethiopia. The study included 13 districts and 650 households. A total of 5469 blood samples were collected from people and livestock species (cattle, camel, sheep and goats) and analyzed using commercial brucellosis ELISA assays. Livestock brucellosis prevalence was 9% in Afar and 8.6% in SRS (ranging from 0.6 to 20.2% at woreda level). In humans, prevalence was 48.3% in Afar and 34.9% in SRS (ranging from 0 to 74.5% at woreda level). 68.4% of all households in Afar and 57.5% of households in SRS had at least one positive animal. This study showed that the disease is widespread in human and their livestock in pastoral communities of Afar and SRS with the existence of geographical hotspots. Results will advise on tailored surveillance programs in pastoral communities.

Seroprevalence and Associated Risk Factors of Canine Leptospira and Brucella Species Infection in West Shewa Zone, Central Ethiopia

Purpose

Canine leptospirosis and brucellosis are significant zoonotic gram-negative bacterial diseases that affect humans and animal species. This study was aimed to estimate the seroprevalence and assess associated risk factors of canine Leptospira and Brucella species infections in Ambo, Bako, and Gojo Towns, West Shewa Zone, Ethiopia.

Methods

A total of 385 serum samples were collected from randomly selected dogs. Antibodies against Brucella and Leptospira species infection were tested using the Enzyme-Linked immunosorbent Assay technique (ELISA). A structured questionnaire survey was administered to each dog-owning household to gather information on potential risk factors. The association between independent and outcome variables was analyzed using the Chi-square test followed by univariable, and multivariable logistic regression analyses.

Results

The overall seroprevalence of Brucella and Leptospira species infections were found to be 15.06% (95% confidence interval (ci): 11.64–19.04%) and 4.16% (95% ci: 2.39–6.67%), respectively. Multivariable logistic regression analysis showed that the town was the significant risk factor of Brucella species infection seropositivity. Accordingly, dogs found in Gojo ((odds ratio (OR)): 17.72 CI: 1.17–117.54, p=0.036) and Bako (OR: 7.99, 95% CI: 0.96–66.37), p=0.054 towns were more at risk to be infected with Brucella species than dogs living in Ambo.

Conclusion

The seroprevalence of Leptospira and Brucella species infections in dogs of the West Shewa Zone was high and moderate, respectively, suggesting the possible transmission of the disease between dogs and other animals. These infections might be an under-recognized threat to public health and animal welfare. Further research on the identification of the serovars of Leptospira and biotypes of Brucella circulating in dogs is encouraged. Finally, knowledge of the comprehensive epidemiology of these diseases is an invaluable input for veterinarians, healthcare professionals, and policy-makers to avoid or manage canine leptospirosis and brucellosis.