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.

If You're Not Confused, You're Not Paying Attention: Ochrobactrum Is Not Brucella.

Bacteria of the genus Brucella are facultative intracellular parasites that cause brucellosis, a severe animal and human disease. Recently, a group of taxonomists merged the brucellae with the primarily free-living, phylogenetically related Ochrobactrum spp. in the genus Brucella. This change, founded only on global genomic analysis and the fortuitous isolation of some opportunistic Ochrobactrum spp. from medically compromised patients, has been automatically included in culture collections and databases. We argue that clinical and environmental microbiologists should not accept this nomenclature, and we advise against its use because (i) it was presented without in-depth phylogenetic analyses and did not consider alternative taxonomic solutions; (ii) it was launched without the input of experts in brucellosis or Ochrobactrum; (iii) it applies a non-consensus genus concept that disregards taxonomically relevant differences in structure, physiology, population structure, core-pangenome assemblies, genome structure, genomic traits, clinical features, treatment, prevention, diagnosis, genus description rules, and, above all, pathogenicity; and (iv) placing these two bacterial groups in the same genus creates risks for veterinarians, medical doctors, clinical laboratories, health authorities, and legislators who deal with brucellosis, a disease that is particularly relevant in low- and middle-income countries. Based on all this information, we urge microbiologists, bacterial collections, genomic databases, journals, and public health boards to keep the Brucella and Ochrobactrum genera separate to avoid further bewilderment and harm.

A comprehensive meta-analysis of Brucella infections in aquatic mammals.

The presence of Brucella infections was documented in a large number of aquatic mammals, affecting wild animals living in oceans, seas, lakes and rivers within both northern and southern hemispheres. Through meta­regression analysis, this study provides acom prehensive view of the prevalence of Brucella spp. in aquatic mammals, identifying risksu bgroups as well as most common sampling and testing methods. Brucella ceti and Brucella pinnipedialis represent the main marine Brucella spp., with documented enzootic potential, for which information on standardized diagnostic methods for the implementation of efficient screening and monitoring programs is needed. A total of 71 articles investigating the occurrence of brucellosis in aquatic mammals have been reported since 1987. The prevalence of brucellosis in males (30.42%) was significantly higher than females (18.59%). The family of Delphinidae was the most studied among aquatic mammals with a total prevalence of 39.66%. Our meta­regression analysis showed a strong and significant association between the prevalence of Brucella spp. in mammals and water temperature (C = 0.02, p value = 0.003), while no significant correlation was found with water salinity (C = ­ 0.09; p value = 0.10). At least 130 species of aquatic mammals have been identified as potential hosts for Brucella spp. There is no systematic veterinary inspection and global or local requirements for the monitoring of brucellosis in aquatic mammals. The association of brucellosis prevalence and water temperature warrants further studies to assess the potential direct and indirect impacts of climate change on brucellosis in aquatic mammals. This study would help to determine the basis of adaptive management strategies in order to control enzootic brucellosis in wild aquatic mammals.

Identification and molecular characterization of Brucella abortus and Brucella melitensis isolated from milk in cattle in Azerbaijan.

BACKGROUND: Azerbaijan currently ranks thirteenth in global incidence of human brucellosis, with an estimated annual incidence through 2000 at over 50 cases per million. Brucella melitensis has been isolated from patients and is thought to have been acquired through contact with small ruminants or as a foodborne infection. To reduce the burden of human brucellosis, the Azerbaijani government began in 2002, a nationwide vaccination control campaign in small ruminants. There is serological evidence of bovine brucellosis (presumably due to Brucella abortus) in Azerbaijan, but no prevalence estimates were available when this study started in March 2017. The aim of this study was to isolate and identify Brucella spp. from cow milk in the Ganja region, where brucellosis takes a heavy toll on humans and livestock. RESULTS: Blood and milk samples were collected from cows (n = 1075) in early lactation (up to 90-days) in farms that had a history of previous positive serological results and abortions. Twenty-two out of 57 milk samples collected from seropositive cows, showed growth on Farrell's media, when incubated with 5% CO2. Eight additional milk samples showed growth in the absence of CO2. The classical biotyping classified them as Brucella abortus (22) and Brucella melitensis (8). RT-PCR confirmed that strains belonged to the genus Brucella. MLVA profiles were obtained for DNA extracted from two B. abortus and six B. melitensis strains. While the B. abortus genetic profile was described in the MLVA database, matching the profile of B. abortus strains isolated in East Europe, Central Asia and China, we found a new genotype for the B. melitensis strains isolated in Azerbaijan, clustering with strains belonging to the American clade, rarely identified in the region. CONCLUSION: Despite the implementation of the vaccination program in small ruminants, our results suggest that spill-over events of B. melitensis from small ruminants to cattle have occurred. However, cattle are likely to be primarily infected with B. abortus, which warranted the implementation of a bovine brucellosis program. Such a program started in fall 2017. In the Ganja region, cattle should be considered as a potential source of B. abortus and B. melitensis for humans.

Brucella melitensis biovar 1 isolation in a captive wildlife population in the United Arab Emirates. First isolation in the scimitar-horned Oryx (Oryx dammah).

In 2013, Brucella melitensis biovar 1 was recovered from the stomach contents of a scimitar-horned Oryx - SHO (Oryx dammah) aborted foetus, and from the articular fluid of a sand gazelle (Gazella marica) in a captive wildlife collection near Abu Dhabi, United Arab Emirates. Other evidence of exposure to the pathogen was collected through serological testing (Rose Bengal test) and B. melitensis-specific PCR of samples from captive wildlife kept in six different enclosures. A Multiple Locus Variable Number of Tandem Repeats (VNTR) Analysis (MLVA) using 15 markers showed that the two strains isolated in animals kept in enclosures, located 1300 m apart from each other, shared an identical genotype. The phylogenetic analysis of MLVA-15 profiles retrieved from the public database suggested that these strains belong to the African clade, clustering regionally in the UAE, Oman and Qatar. This is the first confirmed case of B. melitensis in a SHO, an African antelope extinct in the wild and warrants further investigation.

Efficacy of Brucella abortus S19 and RB51 vaccine strains: A systematic review and meta-analysis.

This systematic review and meta-analysis aimed to recalculate the efficacy of Brucella abortus S19 and RB51 vaccine strains and discuss the main variables associated with controlled trials to evaluate bovine brucellosis vaccine efficacy (VE). The most commonly used vaccine strain was S19, at a dose of 1010 colony forming units (CFU), followed by RB51 at 1010 CFU. The most commonly used challenge strain was B. abortus 2308, at a dose of 107 CFU, by the intraconjunctival route. Regarding the meta-analysis, trials were grouped according to the vaccine strain and dose to recalculate protection against abortion (four groups) or infection (five groups) using pooled risk ratio (RR) and VE. Regarding protection against abortion (n = 15 trials), the S19 vaccine at 109 CFU exhibited the highest protection rate (RR = 0.25, 95% confidence interval (CI) : 0.12-0.52; VE = 75.09%, 95% CI: 48.08-88.05), followed by RB51 at 1010 CFU (RR = 0.31, 95% CI: 0.16-0.61; VE = 69.25%, 95% CI: 39.48-84.38). Regarding protection against infection (n = 23 trials), only two subgroups exhibited significant protection: S19 at 109 CFU (RR = 0.28, 95% CI: 0.14-0.55; VE = 72.03%, 95% CI: 57.70- 81.50) and RB51 at 1010 CFU (RR = 0.43, 95% CI: 0.22-0.84; VE = 57.05%, 95% CI: 30.90-73.30). In conclusion, our results suggest that a dose of 109 CFU for S19 and 1010 CFU for RB51 are the most suitable for the prevention of abortion and infection caused by B. abortus.

Brucella Seroprevalence and Associated Risk Factors in Occupationally Exposed Humans in Selected Districts of Southern Province, Zambia.

Background: Brucellosis is a neglected debilitating zoonosis widely recognized as an occupational health hazard. The seroprevalence of human anti-Brucella antibodies in high-risk populations, as well as their risk factors, have not been well-documented in Zambia. This study aimed at estimating the Brucella seroprevalence in herdsmen and abattoir workers and assess the associated risk factors. Methods: A cross-sectional seroepidemiological study was carried out between May and December 2020 among abattoir workers and herdsmen in Namwala, Monze and Choma districts of Southern Province in Zambia. Seroprevalence was assessed by indirect enzyme-linked immunosorbent assay (i-ELISA) or competitive enzyme-linked immunosorbent assay (c-ELISA) while a questionnaire was administered to obtain epidemiological data. Results: A total of 153 individuals were recruited in the study. The overall Brucella seroprevalence was 20.3% (95% CI: 14.6-27.5). Seropositivity among herdsmen and abattoir workers was 14.4% (95% CI: 9.2-21.8) and 46.4%, (95% CI: 28.8-65.0), respectively. Comparable seropositive results among districts showed Namwala with 26.9%, which was the highest, seconded by Monze 19.0%, and the least was Choma with 11.36%, seropositivity. The multivariate logistic regression model showed that occupation, age category, and district of residence were predictors of being seropositive to Brucella spp. antibodies. The odds of abattoir workers being seropositive to Brucella antibodies were 8.6 (95% CI: 2.6-28.2) higher than that of herdsmen being the reference group. The odds of age category 17-50 years being seropositive to Brucella antibodies were 7.0 (95% CI: 0.7-72.2) higher than being <16 years as the reference group. The odds of one having attained primary level of education being seropositive to Brucella were 1.3 (95% CI: 0.1-14.7) or secondary level of education were 6.2 (95% CI: 0.5-72.6) or tertiary level of education were 5.1 (95% CI: 0.2, 113.3) higher than that of no level of education as the reference group. Furthermore, the odds of a respondent being seropositive to Brucella antibodies were 4.5 (95% CI: 1.3-15.7) for Namwala and 4.9 (95% CI: 1.1-21.7) for Monze higher than that of Choma as the reference group. Conclusion: Anti-Brucella antibodies are prevalent among herdsmen and abattoir workers in the study areas of Zambia (20.26%), a sign of exposure to Brucella pathogens. Type of profession, age and level of education seem to influence the exposure to Brucella pathogens. This zoonosis should be considered as one of the differential diagnosis in humans presenting intermittent fever, malaria-like signs and general pain in humans.

Immunostimulant Bathing Influences the Expression of Immune- and Metabolic-Related Genes in Atlantic Salmon Alevins.

Disease resistance of fish larvae may be improved by bath treatment in water containing immunostimulants. Pattern recognition receptors, such as TLR3, TLR7, and MDA5, work as an "early warning" to induce intracellular signaling and facilitate an antiviral response. A single bath of newly hatched larvae, with Astragalus, upregulated the expression of IFNα, IFNc, ISG15, MDA5, PKR, STAT1, TLR3, and TLR7 immune genes, on day 4 post treatment. Similar patterns were observed for Hyaluronic acid and Poly I:C. Increased expression was observed for ISG15, MDA5, MX, STAT1, TLR3, TLR7, and RSAD2, on day 9 for Imiquimod. Metabolic gene expression was stimulated on day 1 after immunostimulant bath in ULK1, MYC, SLC2A1, HIF1A, MTOR, and SIX1, in Astragalus, Hyaluronic acid, and Imiquimod. Expression of NOS2 in Poly I:C was an average fourfold above that of control at the same timepoint. Throughout the remaining sampling days (2, 4, 9, 16, 32, and 45 days post immunostimulant bath), NOS2 and IL1B were consistently overexpressed. In conclusion, the immunostimulants induced antiviral gene responses, indicating that a single bath at an early life stage could enable a more robust antiviral defense in fish. Additionally, it was demonstrated, based on gene expression data, that cell metabolism was perturbed, where several metabolic genes were co-regulated with innate antiviral genes.

Documenting the absence of bovine brucellosis in dairy cattle herds in the southern region of Malawi and the associated knowledge, attitudes and practices of farmers.

There is paucity of Brucella prevalence data in Malawi. For this reason, a cross-sectional study was conducted, from 06 January 2020 to 27 February 2020, to estimate the seroprevalence of brucellosis in dairy cattle herds amongst smallholder farmers, government and private dairy farms in the southern region. A total of 529 serum samples were screened for anti-Brucella antibodies using the Rose Bengal test (RBT) and a competitive enzyme-linked immunosorbent assay (cELISA). A pre-tested electronic (Epicollect tool, Wellcome Sanger Institute, United Kingdom) questionnaire was administered to 378 smallholder farmers to assess their knowledge, attitudes and practices towards brucellosis. Descriptive statistics were used to analyse the data in Microsoft Excel® and Statistical Package for Social Sciences (SPSS®) version 21. No animal tested positive for presence of anti-Brucella antibodies, indicating 0% prevalence (individual and herd levels). The majority (94.2%; 95% confidence interval [CI]: 91.8-96.5) of smallholder farmers had never heard about brucellosis. Furthermore, assisting during parturition without protective equipment (41.3%; 95% CI: 36.3-46.2) and using bulls for breeding (75%; 95% CI: 70.2-78.9) were amongst the common risk practices that were identified. We could not detect brucellosis in this study that indicates the disease could be very rare or even absent in the dairy cattle herds of the southern region of Malawi. However, further Brucella studies need to be conducted in cattle, small livestock, wildlife and humans to document the true status of brucellosis in the country. Brucellosis surveillance, monitoring, awareness and preventive measures are required to maintain this favourable situation.

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.

Brucellosis in wildlife in Africa: a systematic review and meta-analysis.

This study aimed to consolidate current knowledge of wildlife brucellosis in Africa and to analyse available predictors of infection. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Information on species, test used, test results, area, rainfall, livestock and wildlife contact and year of study were extracted. This systematic review revealed 42 prevalence studies, nine disease control articles and six articles on epidemiology. Brucella abortus, Brucella melitensis, Brucella inopinata and Brucella suis were reported in wildlife. The prevalence studies revealed serological evidence of brucellosis in buffalo, antelope (positive in 14/28 species), carnivores (4/12) and other species (7/20) over the last five decades. Buffalo populations were more likely to be infected and had a higher seroprevalence than other species; the pooled seroprevalence was 13.7% (95% CI 10.3-17.3%) in buffalo, 7.1% (95% CI 1.1-15.5%) in carnivores and 2.1% (95% CI 0.1-4.9%) in antelope. Wildlife in high rainfall areas (≥ 800 mm) were more likely to be infected, and infected populations showed higher seroprevalence in high rainfall areas and in studies published after 2000. Domestic animal contact was associated with increased seroprevalence in antelope and carnivore species, but not in buffalo, supporting the hypothesis that buffalo may be a reservoir species.

Seroprevalence of Bovine Brucellosis in Selected Districts of Zambia.

Brucellosis is an infectious zoonosis that has huge economic and public health implications globally. The disease is prevalent in humans, livestock and wildlife in Sub-Saharan Africa. A cross-sectional study was conducted between 6 May 2017 and 31 July 2020 during which 1712 sera from 175 cattle herds in five districts from Southern, Western and Eastern Provinces of Zambia were collected and screened against brucellosis. The Rose Bengal Test (RBT) and competitive Enzyme-linked Immuno Assay (c-ELISA) were used in serial testing for the detection of antibodies against Brucella species. A total of 127 animals from 37 herds tested positive, giving overall individual animal and herd-level seroprevalences of 7.53% (95% CI: 6.28-8.78%) and 21.14% (95% CI: 15.0-27.2%), respectively. Namwala district had the highest herd seroprevalence (33.9%, 95% CI: 21.6-46.1%), while Lundazi did not record any seropositivity. Comparably, Southern Province had the highest individual animal (8.97%, 95% CI: 7-11%) and herd-level (28.5%, 95% CI: 20.3-36.7%) seroprevalences, although this was not statistically significant. Within Southern Province, higher seropositivity was observed in Namwala district (OR: 8.55; CI: 2.66-27.44), among female animals (OR: 2.48; CI: 1.38-4.46) and in those aged 11 years and above (OR: 2.67; CI: 1.34-5.34) as well as in gravid cows (OR: 4.34; CI: 2.08-8.92). Seropositivity was also observed among some animals with hygromas (OR: 6.5; CI: 0.45-94.08) and those with a history of abortion (OR: 1.13; CI: 0.18-7.28) although the findings were not statistically significant. Brucella seroprevalence among traditional cattle in Zambia remains high. Control programs against bovine brucellosis must be introduced to reduce its impact on human health and animal production.

The global epidemiology of Brucella infections in terrestrial wildlife: A meta-analysis.

Brucellosis is a widespread zoonotic disease with serious consequences on human and animal health. Brucella infections were reported in many terrestrial wild animals, from subtropical and temperate regions to arctic regions. In many areas, the epidemiology of brucellosis in wildlife is closely associated with the occurrence of the disease in livestock. Some wild species may contribute to the re-introduction of Brucella infections in livestock (spillback), even in officially brucellosis-free (OBF) regions. Through meta-regression analysis, this study draws a global picture of the prevalence of Brucella spp. in terrestrial wild animals, trying to determine most affected subgroups as well as preferential sampling and screening methods. For this purpose, a literature search was carried out among publications published from 1983 to 2019. Different subgroups were compared according to animal species, feeding, gender, age as well as the method used for sampling and for brucellosis diagnostic. To determine heterogeneity of studies, chi-squared test was used and a random-effects model (REM) estimated the pooled prevalence among subgroups. A total of 68 publications, comprising 229 data reports/studies, were selected. The most-reported Brucella species in wildlife was Brucella abortus, and the highest prevalence rate was found in American bison, Bison bison (39.9%) followed by Alpine ibex, Capra ibex (33%). Serology was the most widely applied diagnostic approach (66%), while PCR appeared to be highly sensitive (36.62% of positive results). The gender of animals showed no significant association with the prevalence of brucellosis (p > .05). Blood samples and visceral organs constituted the great majority of specimen used for the detection of Brucella spp., while lymph nodes showed a high prevalence of positive samples (94.6%). The present study provides insight into the global epidemiology and enzootic potential of brucellosis in wild terrestrial animals worldwide, aiming at helping the appropriate authorities to strengthen prevention, surveillance and control strategies.

Shedding of Brucella melitensis happens through milk macrophages in the murine model of infection.

Although shedding of zoonotic brucellae in milk has been demonstrated in natural hosts, these data are still missing for the standard murine infection model. We therefore analysed shedding kinetics and the niche of B. melitensis in murine milk. Pregnant Balb/cByJ mice were intraperitoneally infected with 105 CFU of the 16 M reference strain, a 16 M mCherry mutant or a human isolate. Milk was collected over the course of lactation, and subjected to culture and immunofluorescence assays. Bacteria were also quantified in spleen and mammary glands of maternal mice and in spleen of the litter. The shedding of the three strains did not differ significantly (p = 0.301), ranging from log10 1.5 to 4.04 CFU/ml. A total of 73% of the mice excreted B. melitensis into the milk with peak values at mid-lactation; up to 30 bacteria/cell were found in macrophages and neutrophils. While the bacterial counts in the spleen of lactating females confirmed a well-established infection, only 50% of the pups harboured brucellae in their spleen, including the spleen of an uninfected pup fed by an infected foster mother. In conclusion, the murine model of infection may contribute to a better understanding of the zoonotic transmission of brucellosis.

Hair Cortisol Concentration and Body Mass in Moose (Alces alces) Infested with Deer Keds (Lipoptena cervi).

The deer ked (Lipoptena cervi), a hematophagous ectoparasite of cervids, is currently spreading in Scandinavia, and the moose (Alces alces) is its main host. However, little is known about the impact of deer keds on moose. We analyzed the hair cortisol concentration (HCC) from 262 moose harvested in the fall in relation to age class, sex, body mass (BM), and deer ked infestation intensity, and BM in relation to age class, sex, and infestation intensity. We found that HCC decreased with increasing deer ked intensity at low ked intensities, but for the higher levels of ked intensities, there was a positive relationship between HCC and ked intensity. The HCC was higher in males than in females and lower in yearlings than in calves and adults. Our failure to find any association between BM and deer ked intensity suggested a negligible impact of deer ked infestation on moose foraging and metabolism at the level of infestation observed early in the infestation, but did not exclude an effect later in winter. Our findings suggested that moose generally tolerated moderate parasitism by keds. However, the increase in HCC at higher ked intensities suggested that the tolerance strategy could be disrupted with further increases in intensities and consequently may negatively affect animal health and welfare.

The Epidemiology of Zoonotic Brucellosis in Bahr el Ghazal Region of South Sudan.

Background: In this study, we focused on three zoonotic brucellosis risk groups; abattoir workers, febrile cases at Wau hospital and cattle herders, in Bahr el Ghazal region, South Sudan. Competitive c-ELISA was used to detect anti-Brucella antibodies in 725 individuals between December 2015 and May 2016. In addition, questionnaire metadata, focus group discussions and key informant interviews were used to characterize the epidemiology of zoonotic brucellosis in this region. Results: Overall, we estimate 27.2 % (95% CI = 23.9-30.6) brucellosis sero-prevalence; 32.1% (95% CI = 26.2-38.4), 23.0% (95% CI = 19.1-27.4) and 34.6% (95% CI = 24.4-46.3) among abattoir workers, febrile cases, and herders, respectively. Marital status (Single, OR = 0.58, 95%CI: 0.36-0.91, P = 0.02) and ethnicity (Kerash OR = 6.01, 95%CI: 1.97-21.10, P = 0.003 and Balanda, OR = 3.78, 95%CI: 1.42-12.02, P = 0.01) were associated with brucellosis. While gender and ethnicity were important factors for general awareness of zoonotic diseases. Highly ranked occupations at risk included veterinarian, butchers and milk handlers. We also identified covariate patterns for clinical diagnostics and public health interventions. Conclusion: We report the highest sero-prevalence of zoonotic brucellosis in three risk groups in the East African region. All this is not only occurring in a population with limited awareness that brucellosis is a zoonotic disease but also where one in nine health workers tested was sero-positive. We identified social demographic associations with brucellosis, however, the qualitative analysis suggests these are more complex and nuanced. Therefore, future studies could benefit from the use of the mixed methods approach to add extensiveness and depth to our understanding of zoonotic disease drivers, in order to implement mitigating measures such as cattle vaccination.

Correction to: Seroprevalence of bovine brucellosis and associated risk factors in Nakasongola district, Uganda.

In the originally published article, the name of the fifth author was incorrectly presented as Godfroid Jacques. The correct name is Jacques Godfroid.

Sero-prevalence of brucellosis among slaughterhouse workers in Bahr el Ghazal region, South Sudan.

BACKGROUND: Brucellosis is an infectious zoonotic disease and is common especially among pastoral communities in most low and middle-income countries. The aim of this study was to determine sero-prevalence, and risk factors of Brucella infection among Slaughterhouse workers, in Bahr el Ghazal region, South Sudan. METHODS: A cross sectional study was conducted among Slaughterhouse workers in Bahr el Ghazal region, South Sudan from December 2015 to May 2016. A pre-tested questionnaire was used in data collection. Each randomly selected participant was interviewed and a venous blood sample collected. The blood samples were screened for Brucellosis infection using Rose Bengal Plate Test (RBPT) and confirmed using Competitive Enzyme link Immuno Sorbet Assay (c-ELISA). Data was analyzed using Stata version 13 at 95% level of confidence. RESULTS: A total of 234 Slaughterhouse workers were screen for Brucella infection. Overall, a third, 32.1% (75/234) of the participants were sero-positive for brucellosis. The prevalence of brucellosis was higher, 17.1% (40/234) in Wau state compared to other states. There was high prevalence among males, 28.6% (67/234) compared to females 3.4% (8/234). The mean age of study participants was 34.4 ± 9.6 years. A high proportion, 12.8% (30/234) of participants with confirmed brucellosis infection were 31-40 years of age. Brucellosis prevalence was high among butchers, 14.5% (34/234), and meat handlers, 9.0% (21/234). CONCLUSIONS: Brucellosis is common among animal slaughterhouse workers in Bahr el Ghazal region, South Sudan. There is need for public awareness campaigns and educational programs to help sensitize communities on Brucella infection.

Seroprevalence of bovine brucellosis and associated risk factors in Nakasongola district, Uganda.

A cross-sectional study was carried out between November 2015 and January 2016 to determine the seroprevalence of Brucella antibodies in cattle raised under communal, fenced farms and tethering systems and the associated factors. Seven hundred twenty-eight bovine sera were collected and tested with rose Bengal test as a screening test and the indirect enzyme-linked immunosorbent assay as a confirmatory test. Animal- and herd-level data were collected and binary logistic regression was used to assess the potential risk factors. True animal- and herd-level prevalence was highest in the fenced farms (4.5% (95%CI, 2.3-6.9) and 19.5% (95%CI, 8.2-32.7) respectively). The risks for natural brucellosis infection were sharing water with wild animals (OR = 0.21, 95%CI, 0.104-0.83), herd size (medium: OR = 0.089, 95%CI 0.017-0.449; large: OR = 0.024, 95%CI 0.003-0.203), fenced farms (OR = 3.7, 95% CI, 1.7-7.9), sex (OR = 0.03, 95%CI, 0.01-0.079), and lactation (OR = 0.013, 95%CI, 0.004-0.049). Changes in rangeland tenure and the shift towards intensive cattle production have influenced brucellosis epidemiology. Future studies should aim at identifying the infecting Brucellae and examining the role of wildlife in brucellosis epidemiology.