Sero-prevalence and community awareness on the risks associated with Livestock and Human brucellosis in selected districts of Fafan Zone of Ethiopian-Somali National Regional State

Prevalence of human brucellosis in Ethiopia: systematic review and meta-analysis

Brucellosis is a significant public health challenge in Ethiopia, which is characterized by a high prevalence among humans. The disease is primarily transmitted through the consumption of unpasteurized dairy products, direct contact with infected animals, or inhalation of contaminated aerosols. In addition to its impact on human health, brucellosis imposes substantial economic burdens. However, existing epidemiological studies provide inconsistent prevalence estimates, underscoring the need for a more comprehensive and systematic analysis of the disease's burden and associated risk factors in Ethiopia. This systematic review and meta-analysis aimed to generate representative data on the prevalence of human brucellosis in Ethiopia. We searched databases like PubMed and Science Direct for articles published between 2007 and 2022. The analysis included 26 studies covering 5,718 human serum samples. The Complement Fixation Test served as the confirmatory diagnostic test. The results suggest a relatively high seroprevalence of human brucellosis in Ethiopia, with an overall pooled prevalence of 14.0% (95% CI: 10.23, 18.12). Prevalence varied significantly across regions, with the highest observed in Afar (24.21%) and the lowest in Oromia (7.75%). Substantial heterogeneity was observed (I² = 97.64%), suggesting significant variations in prevalence across regions and over time. Additionally, the analysis suggests a possible increasing trend in prevalence over the years. Human brucellosis is a significant health concern in Ethiopia, and further research is crucial for effective prevention and control. The higher prevalence than previously reported in meta-analyses underscores the urgent need for intervention strategies from policymakers, such as the Ministry of Health. Identifying risk factors associated with human brucellosis is essential for implementing effective control measures. Prioritizing brucellosis prevention and control is vital for ensuring public health and well-being. Prospero registration number: CRD42022350237.

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.

Detection and Molecular Diversity of Brucella melitensis in Pastoral Livestock in North-Eastern Ethiopia

Brucellosis is a neglected zoonotic disease affecting livestock and humans that remains endemic in Ethiopia. Despite its prevalence, only a few studies have identified Brucella species circulating in livestock in the country. This study aimed to determine the Brucella species responsible for infections in livestock in the Afar region of Ethiopia and characterize the isolates using whole-genome single nucleotide polymorphism (wgSNP) analysis and in silico multi-locus sequence typing (MLST). Comparisons were made between Ethiopian Brucella and regional and global isolates to determine their phylogenetic relationships. Surveys conducted in May and October-November 2022 in six villages of the Amibara district involved the collection of vaginal swabs (n = 231) and milk samples (n = 17) from 32 sheep and 199 goats kept by 143 pastoral households reporting recent abortions in the animals. Brucella melitensis was detected in three sheep and 32 goats, i.e., 15% (35/231) of animals across 20% (29/143) of households using bacterial culture and PCR-based methods (bcsp31, AMOS, and Bruce-ladder multiplex PCR). Of the 35 positive animals, B. melitensis was isolated from 24 swabs, while the remaining 11 were culture-negative and detected only by PCR. The genomic DNA of the 24 isolates was sequenced using Illumina Novaseq 6000 and assembled using the SPAdes pipeline. Nine- and 21-locus MLST identified 23 isolates as genotype ST12, while one isolate could not be typed. The wgSNP-based phylogenetic analysis revealed that the Ethiopian isolates clustered within the African clade and were closely related to isolates from Somalia. Several virulence factors responsible for adhesion, intracellular survival, and regulatory functions were detected in all isolates. No antimicrobial resistance genes associated with resistance to drugs commonly used for treating brucellosis were detected. Since B. melitensis is prevalent in sheep and goats, vaccination with the B. melitensis Rev-1 vaccine is the recommended strategy in these pastoral systems to protect animal and human health.

Sero-epidemiological study of brucellosis in cattle under pastoral/agro-pastoral and mixed crop-livestock systems in South Omo, southern Ethiopia

Background

In the pastoral/agro-pastoral communities in Ethiopia, like in South Omo, brucellosis constitutes a serious health threat for livestock and the public. The public health risk is especially high in these communities, as their way of life is highly linked with their herds.

Objective

The study was conducted to estimate the seroprevalence and identify potential risk factors of cattle brucellosis in South Omo zone in southern Ethiopia.

Methods

A total of 614 traditionally managed local zebu female cattle, above six months old, were bled and data on hypothesized risk factors were collected using a semi-structured questionnaire. The preliminary screening of the sera for Brucella antibodies was done using Rose Bengal Plate Test (RBPT) and positive sera were further subjected to complement fixation test (CFT).

Results

The overall animal level seroprevalence of brucellosis was 2.8 % (95 % CI: 1.72-4.41) while herd level prevalence was 11.3 % (95 % CI: 6.5-19.0). Among the risk factors considered, seroprevalence was associated with herd size, new animal introduction, district, history of occurrence of abortion, and retained fetal membranes (RFM), at both individual- and herd-level (p < 0.05). Higher seroprevalence of brucellosis was observed in cows than heifers and in animals older than 4 years (p < 0.05). Brucella seroprevalence was higher in herds in lowland areas than those in mid-altitude and highlands (p < 0.05).

Conclusion

The individual and herd level prevalence observed in our study indicates endemicity of brucellosis and the potential public health threat it poses in pastoral and agro-pastoral areas of southern Ethiopia. The results of the study also suggest that the disease might be responsible for significant losses in cattle productivity due to impaired reproductive performance.

Molecular Detection and Associated Risk Factors of Brucella melitensis in Aborted Sheep and Goats in Duhok Province, Iraq

Brucellosis in sheep and goats has a significant economic and zoonotic impact on the livestock population of Duhok province, Iraq. A total of 681 blood samples from aborted sheep and goats were collected from different flocks in seven districts of Duhok and tested using real-time polymerase chain reaction (RT-PCR). Logistic regression was used for the analysis of the potential risk factors associated with RT-PCR positivity. Results revealed an overall prevalence of 35.45% (CI = 2.57) and 23.8% 18 (CI = 0.44) in sheep and goats, respectively. A statistically significant (p = 0.004) difference in prevalence was found between the two species. RT-PCR detected more positive cases in older-aged animals (OR = 0.7164; p = 0.073). A significant difference was found in RT-PCR positivity in relation to different risk factors, including body condition, treatment taken, and abortion frequency (<0.001). The phylogenetic tree based on the 16S rRNA gene indicated that the isolates belonged to B. melitensis and shared a common ancestor and were genetically related to the United States of America (USA), Greece, China, and Nigeria. This study demonstrates that brucellosis is widely prevalent in the study regions. Therefore, the study suggests the implementation of preventive control measures for brucellosis.

Seroprevalence of human brucellosis in selected sites of Central Oromia, Ethiopia

Brucellosis is one of the most neglected zoonotic diseases in the world. It affects all age groups and both sexes. A cross-sectional study was conducted from December 2019 to May 2020 to estimate the seroprevalence and assess the potential risk factors of brucellosis among dairy cow owners and dairy farmworkers, and assess their knowledge, attitudes, and practices in selected sites in the central highlands of Oromia, Ethiopia. A structured interview question was administered to 284 respondents, and only 166 of them volunteered to give a blood sample. Most respondents had limited knowledge of brucellosis (93.3%), zoonotic diseases transmitted by handling animal delivery (88%), and consuming raw milk and other animal products (90.0%). Accordingly, 149 blood samples from animal owners and 17 farmworkers were collected for serological testing. The serum samples collected were initially screened using the Rose Bengal Plate test, and the Complement Fixation test was used as a confirmatory test. The overall seroprevalence of zoonotic brucellosis was 1.2% (95%CI: 0.32-4.27). There was a statistically significant association of human brucellosis with human housing (OR = 1.8, p = 0.002), contact with aborted fetus (OR = 21.19, p = 0.017), drinking raw milk from non-aborted (OR = 24.99, p = 0.012), aborted (OR = 5.72, 0.019), and retained fetal membrane (OR = 4.22, p = 0.029) cows. In conclusion, the present study revealed that the seroprevalence of brucellosis in the study area was low. Public awareness among animal owners, farm and animal health workers on the transmission and health hazards of brucellosis needs to be addressed through community training. Implementing one health approach between veterinary and medical health professionals must be strengthened.

Bovine Brucellosis: Epidemiology, Public Health Implications, and Status of Brucellosis in Ethiopia

Brucellosis is a globally distributed zoonotic disease that causes serious problems in developing countries such as Ethiopia. Brucella abortus is the primary cause of brucellosis in cattle, and Brucella melitensis and Brucella suis also occasionally cause Brucella infection in cattle. Abortion and the retained fetal membrane are typical signs in females, whereas orchitis and bursitis are the known signs in male cattle. Brucellosis is typically transmitted to healthy cattle by direct or indirect contact with diseased cattle or their discharges. Humans can acquire brucellosis through the consumption of unpasteurized milk or milk products, and through contact with diseased cattle or their discharges. The occurrence of bovine brucellosis is affected by different factors related to the management system, host, and environmental factors. In Ethiopia, the occurrence of brucellosis is high in pastoral and mixed cattle management systems, wherever humans live closely with cattle and so have a higher probability of picking up the Brucella organism. The most suitable technique in the management of Brucella infection is the vaccination of young female cattle. Brucella abortus can also be eradicated by the isolation of diseased cattle, administration of immunizing agents, and test-and-slaughter methods. Therefore, it is important to implement applicable management techniques and to increase public awareness about the transmission of brucellosis, and further research should be conducted on brucellosis in high-risk groups.

Seroprevalence of Bovine Brucellosis and Associated Risk Factors in Western Ethiopia

Background

Brucellosis is a contagious bacterial disease, which affects domestic animals, humans, and wildlife in Ethiopia and other countries.

Methods

A cross-sectional study design using a simple random sampling technique was conducted in Diga, Guto, Gida, and Sibu Sire districts of East Wollega Zone, Western Oromia, from November 2019 to July 2020 to determine the prevalence of bovine brucellosis and identify associated risk factors. A lottery method was used during serum collection and risk factors identified during interview.

Results

A total of 1152 serum samples were collected from cattle of 6 months age and above. Serum samples were tested by enzyme linked immunosorbent assay (I-ELISA). An overall seroprevalence of brucellosis was 1.82% (21/1152). Statically significant variation (P<0.05) in seroprevalence of bovine brucellosis was recorded among potential risk factors such as breed [P≤0.05; OR:8.905; CI:1.568–50.573], parity [P≤0.05; OR:0.017; CI:0.042–5.195], retained fetal membrane [P≤0.001; OR:0.018; CI:0.00–2.169], and abortion history [P≤0.001; OR:0.030; CI:0.004–0.212]. Conversely, seroprevalence variations in sex, district, villages, body condition score, and age were statistically insignificant (P>0.05).

Conclusion

The current study revealed bovine brucellosis is posing a threat to livestock with no strict control and prevention scheme in place. Therefore, public awareness creation about the zoonotic importance of the disease is crucial and the Government should establish legislation, support, control, and prevention of the disease recommended.

Knowledge, Attitudes, and Practices Regarding Brucellosis among Parents in Aseer Region, Southwestern Saudi Arabia

This study aimed to investigate the knowledge, attitudes, and practices regarding brucellosis among parents in the Aseer region of southwestern Saudi Arabia in order to estimate the population sectors that are at high risk for accidental exposure to brucellosis. This was a cross-sectional survey conducted in 2018, including 311 participants representing various genders, ages, and levels of education. Bivariate analysis showed a significant association of good awareness of the disease with the male gender and higher education levels. Of the 311 participants, 90.0% had good knowledge, whereas 10.0% showed inadequate knowledge about brucellosis. Practices and attitudes regarding brucellosis were satisfactory as participants did not eat meat from their own animals (52.7%), did not practice slaughtering (71.4%), did not participate in the birth of animals (91.3%), were not exposed to abortion in animals (93.2%), and practiced burial of aborted animal fetuses (59.2%). The practice regarding brucellosis was unsatisfactory as 66.6% never wore gloves when dealing with animals. The study concluded that the majority of parents showed fair and positive knowledge, attitudes, and practices regarding brucellosis and found that gender and education were determinants of satisfactory awareness.

Epidemiology of bovine brucellosis in Hisar, India: identification of risk factors and assessment of knowledge, attitudes, and practices among livestock owners

Brucellosis caused by facultative intracellular bacteria, Brucella, remains a global threat to both animal and human health. In this study we aimed to identify potential risk factors of bovine brucellosis and to assess the knowledge, attitudes, and practices (KAPs) of livestock keepers in Hisar, India. A standardized questionnaire was used to collate information regarding potential risk factors of bovine brucellosis and livestock owners' KAPs. A total of 127 livestock keepers were involved. Serum samples from their animals (n = 635) were tested for the presence of antibodies against Brucella by Rose Bengal Plate Test (RBPT) and indirect enzyme-linked immunosorbent assay (iELISA). Out of these, 78 (61.4%) of the herds had at least one seropositive animal, and 302 (47.6%) of the cattle were seropositive. Univariate and multivariate analysis revealed significant associations between intensive farm type (OR = 4.6; 95% CI, 1.6-16.7; P = 0.009), hygienic disposal of aborted fetuses (OR = 0.3; 95% CI, 0.08-0.9; P = 0.04) and herd seropositivity for brucellosis. The majority, 96 (75.6%) of the respondents, were males aged 18-50, and 82 (64.6%) owned a small-backyard farm. Only 51 (40.2%) of the participants knew about brucellosis; out of them, 54.9% (28/51) could not identify clinical signs of brucellosis. Six (11.8%) participants indicated abortion as the most noticeable clinical sign, and 45.1% indicated that consumption of raw milk is associated with high risk of contracting brucellosis. A large proportion of respondents confirmed that milk from their animals was regularly consumed (86.6%) and sold (59.8%) to other people. These results suggest that bovine brucellosis is endemic in Haryana, where Brucella-contaminated milk is likely being regularly sold. Brucellosis control efforts in Haryana should include education programs to raise awareness of the disease and means to control it in cattle and to prevent zoonotic transmission.

Seroprevalence and Risk Factors Associated with Brucella Infection in Camels in the Puntland State of Somalia

Brucellosis is an important zoonotic disease caused by members of the genus Brucella. Camel brucellosis has been reported in almost all camel-rearing countries in Africa and Asia. A cross-sectional study was conducted between February 2020 and February 2021 in Galkayo, Garowe, and Bosaso districts in the Puntland State of Somalia to investigate the seroprevalence and risk factors of brucellosis in camels. A competitive enzyme-linked immunosorbent assay (c-ELISA) was used to detect anti-Brucella antibodies, while a structured questionnaire was used to collect epidemiological data. A total of 441 camel sera were screened against Brucella antibodies. Thirty-one (7%; 95% CI: 4.8–9.8%) samples were positive, and thirteen (54.2%; 95% CI: 32.8–74.4%) out of the twenty-four farms sampled had at least one seropositive animal. Galkayo district had the highest number of Brucella-seropositive camels (10.3%), followed by Bosaso district (8.6%), while Garowe district had the lowest number of seropositive camels (1.4%). The binary logistic regression model revealed that camels in Galkayo district (p = 0.015; OR: 9.428; 95% CI: 1.539–57.755), camels from large herd sizes of >50 animals (p = 0.019; OR: 5.822; 95% CI: 1.336–25.371), and those in contact with small ruminants (p = 0.011; OR: 10.941; 95% CI: 1.728–69.285) were significantly associated with seropositive cases of camel brucellosis in the Puntland State of Somalia. The present study shows that Brucella infections in camels are prevalent in the three districts covered by the study. This poses a public health risk, because milk from these camels is used for human consumption. Studies focusing on the isolation of Brucella strains in camels and investigating brucellosis in ruminants and humans are recommended in the study area. Validation of serological tests—including c-ELISA—for Brucella antibody detection in camels is also needed.

Epidemiological investigation of brucellosis in breeding female cattle under the traditional production system of Jimma zone in Ethiopia

Bovine brucellosis is a serious zoonotic infectious disease with widespread occurrence in developing countries like Ethiopia. A cross-sectional study was conducted from November 2017 to November 2018 to investigate the prevalence and associated risk factors of brucellosis in breeding female cattle under the traditional production system of the Jimma zone in Ethiopia. Blood samples were collected from a total of 423 breeding female cattle to test the presence of Brucella antibody. The presence of antibody against Brucella spp. was serially tested first by the Rose Bengal Plate test, then positive sera were confirmed using the complement fixation test. Potential risk factors for Brucella seropositivity were analyzed using multivariable logistic regression analysis. An overall 11.6% (95%CI: 6.25-16.94) and 4.3% (95%CI: 2.15-5.89) seroprevalence of brucellosis was recorded at herd and animal level, respectively in study areas. We identified age (OR=9.6, 95% CI: 2.08-44.07), breed (OR=4.5, 95%CI: 1.54-12.99), herd size (OR=10.4, 95%CI: 1.27-85.04) and species composition (OR=4.4, 95%CI: 1.31-14.89) as risk factors for Brucella infection. Herd level analysis of risk factor shows that herds kept with sheep and/goats was at higher risk (OR=3.7, 95% CI: 1.25-11.17) of acquired Brucella infection. This result showed that brucellosis was a widely spread disease in the study areas. Thus, important to carry out appropriate control methods and creating awareness on public zoonotic transmissions of brucellosis are recommended. Moreover, further investigation should be carried out to isolate and characterized brucellosis as a cause of reproduction problems in the study areas.