Systematic review of brucellosis in Kenya: disease frequency in humans and animals and risk factors for human infection

Long ignored but making a comeback: a worldwide epidemiological evolution of human brucellosis

Brucellosis is a commonly neglected zoonosis that remains a serious global public health concern. The epidemiological evolution of human brucellosis has considerably changed over the past few decades, and epidemic geography is continuously expanding. Human brucellosis is emerging and re-emerging, and is imported from areas where it is endemic due to travel, immigration, and international trade. The disease continues to be prevalent in Asia and Africa, including West Asia, Central Asia, North Africa, and East Africa, with the highest incidence in Syria, Kyrgyzstan, Mongolia, Iran, Algeria, and Kenya. Re-emerging cases are frequently recorded in places where brucellosis has been controlled, such as Bosnia, Herzegovina, Azerbaijan, and the USA. In countries with a high disease burden, disease control and eradication have been extremely difficult because of livestock farming being the only source of livelihood, unique religious beliefs regarding animals, nomadic lifestyle, and low socioeconomic levels. Interventions focused on protecting livestock keepers are needed, particularly for those assisting with goat and sheep births and the consumption of raw dairy products. Notably, in most countries with a high disease burden, each period of several years with a low incidence rate was followed by a subsequent increase in cases, highlighting the necessity of continuous investment and surveillance. In addition, advocacy for the inclusion of brucellosis as a globally mandated reported disease, strict restrictions on animal movement, mandated consumption of pasteurized milk, and health education are needed. This study will help form an evidence-based strategy for international organizations to curb the future spread of brucellosis.

The Goat Cytotoxic T Lymphocyte-Associated Antigen-4 Gene: mRNA Expression and Association Analysis of Insertion/Deletion Variants with the Risk of Brucellosis

The cytotoxic T lymphocyte-associated antigen-4 (CTLA4) gene, a member of the immunoglobulin superfamily, is crucial for maintaining immune homeostasis and preventing autoimmune diseases. Studies have shown that polymorphisms in the CTLA4 gene are linked to an increased risk of brucellosis in humans, but its association with brucellosis in goats remains unexplored. In this study, the tissue expression profile of CTLA4 in goats was investigated, and the correlation between InDel polymorphisms in the CTLA4 gene and susceptibility to brucellosis in goats was examined. The findings reveal the widespread expression of CTLA4 in goat tissues, particularly in the spleen and testes. The tested goat populations presented genotypes insertion/insertion (II), insertion/deletion (ID), and deletion/deletion (DD) at both the P1 and P2 loci, and an association analysis revealed significant differences in the distribution of genotypes and allele frequencies at the P1 and P2 loci of the CTLA4 gene between the Brucella goat case and the control groups (p < 0.05). Specifically, compared with the II genotype, the P1 and P2 loci were significantly associated with an elevated risk of brucellosis development in goats under both the codominant (ID/II) and dominant (ID + DD/II) models (P1, p = 0.042, p = 0.016; P2, p = 0.011, p = 0.014). Additionally, haplotype analysis indicated that haplotypes IP1DP2, DP1IP2, and DP1DP2 were significantly associated with an increased risk of brucellosis in goats compared to the reference haplotype IP1IP2 (p = 0.029, p = 0.012, p = 0.034). Importantly, the Lipopolysaccharide (LPS) stimulation of peripheral blood monocytes and/or macrophages from goats with the II, ID, and DD genotypes resulted in increased CTLA4 expression levels in the II genotype, leading to a robust LPS-induced inflammatory response. Through bioinformatic analysis, the observed effect of the InDel locus on Brucella pathogenesis risk in goats could be attributed to the differential binding of the transcription factors nuclear factor kappaB (NF-κB) and CCAAT/enhancer-binding protein α (C/EBPα). These findings offer potential insights for breeding strategies against brucellosis.

Enhanced diagnostic accuracy of combined serological and bacteriological tests for brucella infection

OBJECTIVE

To analyze the effects and value of combining serological and bacteriological tests in diagnosing Brucella infection.

METHODS

In this retrospective study, patients suspected of having Brucella infection admitted to Lishui Second People's Hospital from January 2019 to December 2022 were assessed using serological, bacteriological, and combined (serological + bacteriological) tests. The diagnostic performance of each test was compared using previous clinical results as the gold standard. We also compared the acceptance rate and satisfaction with clinical diagnostic results for the different testing modalities.

RESULTS

The combined examination (serological + bacteriological test) showed higher diagnostic efficiency for Brucella infection compared to single serological and single bacteriological tests (P < 0.05). Similarly, the satisfaction rate for the clinical diagnostic effects of the combined examination was higher than for the serological and bacteriological tests alone (P < 0.05).

CONCLUSION

The combination of serological and bacteriological tests provides superior diagnostic value for Brucella infection, with high diagnostic accuracy, sensitivity, and specificity. It is recommended as the preferred method for clinical diagnosis.

Molecular and serological diagnosis of multiple bacterial zoonoses in febrile outpatients in Garissa County, north-eastern Kenya

Bacterial zoonoses are diseases caused by bacterial pathogens that can be naturally transmitted between humans and vertebrate animals. They are important causes of non-malarial fevers in Kenya, yet their epidemiology remains unclear. We investigated brucellosis, Q-fever and leptospirosis in the venous blood of 216 malaria-negative febrile patients recruited in two health centres (98 from Ijara and 118 from Sangailu health centres) in Garissa County in north-eastern Kenya. We determined exposure to the three zoonoses using serological (Rose Bengal test for Brucella spp., ELISA for C. burnetti and microscopic agglutination test for Leptospira spp.) and real-time PCR testing and identified risk factors for exposure. We also used non-targeted metagenomic sequencing on nine selected patients to assess the presence of other possible bacterial causes of non-malarial fevers. Considerable PCR positivity was found for Brucella (19.4%, 95% confidence intervals [CI] 14.2-25.5) and Leptospira spp. (1.7%, 95% CI 0.4-4.9), and high endpoint titres were observed against leptospiral serovar Grippotyphosa from the serological testing. Patients aged 5-17 years old had 4.02 (95% CI 1.18-13.70, p-value = 0.03) and 2.42 (95% CI 1.09-5.34, p-value = 0.03) times higher odds of infection with Brucella spp. and Coxiella burnetii than those of ages 35-80. Additionally, patients who sourced water from dams/springs, and other sources (protected wells, boreholes, bottled water, and water pans) had 2.39 (95% CI 1.22-4.68, p-value = 0.01) and 2.24 (1.15-4.35, p-value = 0.02) times higher odds of exposure to C. burnetii than those who used unprotected wells. Streptococcus and Moraxella spp. were determined using metagenomic sequencing. Brucellosis, leptospirosis, Streptococcus and Moraxella infections are potentially important causes of non-malarial fevers in Garissa. This knowledge can guide routine diagnosis, thus helping lower the disease burden and ensure better health outcomes, especially in younger populations.

Global and regional seroprevalence of coxiellosis in small ruminants: A systematic review and meta-analysis

BACKGROUND

Coxiellosis is a neglected zoonosis for occupationally exposed people in many parts of the world. Sheep and goats are two important small ruminants that act as reservoirs for human contamination; however, there is a lack of comprehensive data on the epidemiological aspects of coxiellosis in sheep and goats at regional and global levels. The aim of this study was to systematically review the available articles on seroprevalence of coxiellosis in sheep and goats and estimate the overall seroprevalence in different regions.

METHODS

A systematic search strategy was performed in five electronic repositories for articles published until December 2021. Relevant data were extracted from the selected articles based on the inclusion criteria. A random effect meta-analysis model was used to analyse the data. Results are presented as the prevalence of seropositivity as a percentage and 95% confidence intervals.

RESULTS

The global pooled seroprevalence of coxiellosis in sheep was 17.38% (95% confidence interval [CI]: 15.59%-19.17%). Overall, the regional level pooled prevalence estimates in sheep ranged from 15.04% (95% CI: 7.68%-22.40%) to 19.14% (95% CI: 15.51%-22.77%), depending on region. The global pooled seroprevalence of coxiellosis in goats was 22.60% (95% CI: 19.54%-25.66%). Overall, the regional level pooled prevalence estimates in goats ranged from 6.33% (95% CI: 2.96%-9.71%) to 55.13% (95% CI: 49.61%-60.65%), depending on the region. The prevalence estimates also varied significantly in both sheep and goats depending on age, sex, and rearing systems of the animals (p < 0.001).

CONCLUSION

Seroprevalence of coxiellosis in both sheep and goats is considerable. Routine monitoring of the sheep and goat populations is needed to prevent spillover infection in other livestock and humans.

Biodegradation of selected aminophosphonates by the bacterial isolate Ochrobactrum sp. BTU1

Aminophosphonates, like glyphosate (GS) or metal chelators such as ethylenediaminetetra(methylenephosphonic acid) (EDTMP), are released on a large scale worldwide. Here, we have characterized a bacterial strain capable of degrading synthetic aminophosphonates. The strain was isolated from LC/MS standard solution. Genome sequencing indicated that the strain belongs to the genus Ochrobactrum. Whole-genome classification using pyANI software to compute a pairwise ANI and other metrics between Brucella assemblies and Ochrobactrum contigs revealed that the bacterial strain is designated as Ochrobactrum sp. BTU1. Degradation batch tests with Ochrobactrum sp. BTU1 and the selected aminophosphonates GS, EDTMP, aminomethylphosphonic acid (AMPA), iminodi(methylene-phosphonic) (IDMP) and ethylaminobis(methylenephosphonic) acid (EABMP) showed that the strain can use all phosphonates as sole phosphorus source during phosphorus starvation. The highest growth rate was achieved with AMPA, while EDTMP and GS were least supportive for growth. Proteome analysis revealed that GS degradation is promoted by C-P lyase via the sarcosine pathway, i.e., initial cleavage at the C-P bond. We also identified C-P lyase to be responsible for degradation of EDTMP, EABMP, IDMP and AMPA. However, the identification of the metabolite ethylenediaminetri(methylenephosphonic acid) via LC/MS analysis in the test medium during EDTMP degradation indicates a different initial cleavage step as compared to GS. For EDTMP, it is evident that the initial cleavage occurs at the C-N bond. The detection of different key enzymes at regulated levels, form the bacterial proteoms during EDTMP exposure, further supports this finding. This study illustrates that widely used and structurally more complex aminophosphonates can be degraded by Ochrobactrum sp. BTU1 via the well-known degradation pathways but with different initial cleavage strategy compared to GS.

The Reasons Behind Long-Term Endemicity of Brucellosis in Low and Middle-Income Countries: Challenges and Future Perspectives

Brucellosis is a neglected worldwide zoonotic disease with more than 500,000 new human cases each year. Direct contact with infected animals and consumption of undercooked animal origin foods are the main routes of brucellosis transmission to humans. Although long endeavor has been applied to control and eliminate brucellosis from animal and human populations in developing countries especially in low- and middle-income countries (LMICs), the disease is still endemic in these regions. Many common or unique factors including raw milk consumption, unhygienic slaughter of livestock, extensive husbandry, budgetary limitations, misdiagnosis, and other conditions play a role in long-term endemicity of brucellosis in these locations. It has been shown that One Health is the only practical approach to control brucellosis; however, applying such methods is challenging in low-resource areas. In such conditions, brucellosis is continuously maintained in animals and repeatedly spread to human populations. In this article, factors playing a critical role in brucellosis endemicity, and the real conditions challenging the application of One Health approach in control of brucellosis are highlighted.

Seroprevalence and related risk factors of Brucella spp. in livestock and humans in Garbatula subcounty, Isiolo county, Kenya

BACKGROUND

Brucellosis is a neglected zoonotic disease that affects both animals and humans, causing debilitating illness in humans and socio-economic losses in livestock-keeping households globally. The disease is endemic in many developing countries, including Kenya, but measures to prevent and control the disease are often inadequate among high-risk populations. This study aimed to investigate the human and livestock seroprevalence of brucellosis and associated risk factors of Brucella spp. in a pastoralist region of northern Kenya.

METHODS

A cross-sectional survey was conducted using a two-stage cluster sampling method to select households, livestock, and humans for sampling. Blood samples were collected from 683 humans and 2157 animals, and Brucella immunoglobulin G (IgG) antibodies were detected using enzyme-linked immunosorbent assays. A structured questionnaire was used to collect data on potential risk factors associated with human and animal exposures. Risk factors associated with Brucella spp. exposures in humans and livestock were identified using Multivariate logistic regression.

RESULTS

The results indicated an overall livestock Brucella spp. seroprevalence of 10.4% (95% Confidence Interval (CI): 9.2-11.7). Camels had the highest exposure rates at 19.6% (95% CI: 12.4-27.3), followed by goats at 13.2% (95% CI: 9.3-17.1), cattle at 13.1% (95% CI: 11.1-15.3) and sheep at 5.4% (95% CI: 4.0-6.9). The herd-level seroprevalence was 51.7% (95% CI: 47.9-55.7). Adult animals (Adjusted Odds Ratio (aOR) = 2.3, CI: 1.3-4.0), female animals (aOR = 1.7, CI: 1.1-2.6), and large herd sizes (aOR = 2.3, CI: 1.3-4.0) were significantly associated with anti-brucella antibody detection while sheep had significantly lower odds of Brucella spp. exposure compared to cattle (aOR = 1.3, CI: 0.8-2.1) and camels (aOR = 2.4, CI: 1.2-4.8). Human individual and household seroprevalences were 54.0% (95% CI: 50.2-58.0) and 86.4% (95% CI: 84.0-89.0), respectively. Significant risk factors associated with human seropositivity included being male (aOR = 2.1, CI:1.3-3.2), residing in Sericho ward (aOR = 1.6, CI:1.1-2.5) and having no formal education (aOR = 3.0, CI:1.5-5.9). There was a strong correlation between human seropositivity and herd exposure (aOR = 1.6, CI:1.2-2.3).

CONCLUSIONS

The study provides evidence of high human and livestock exposures to Brucella spp. and identifies important risk factors associated with disease spread. These findings emphasize the need for targeted prevention and control measures to curb the spread of brucellosis and implement a One Health surveillance to ensure early detection of the disease in Isiolo County, Northern Kenya.

Global Estimate of Human Brucellosis Incidence

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

Design of multi-epitope vaccine candidate against Brucella type IV secretion system (T4SS)

Brucellosis is a common zoonosis, which is caused by Brucella infection, and Brucella often infects livestock, leading to abortion and infertility. At present, human brucellosis remains one of the major public health problems in China. According to previous research, most areas in northwest China, including Xinjiang, Tibet, and other regions, are severely affected by Brucella. Although there are vaccines against animal Brucellosis, the effect is often poor. In addition, there is no corresponding vaccine for human Brucellosis infection. Therefore, a new strategy for early prevention and treatment of Brucella is needed. A multi-epitope vaccine should be developed. In this study, we identified the antigenic epitopes of the Brucella type IV secretion system VirB8 and Virb10 using an immunoinformatics approach, and screened out 2 cytotoxic T lymphocyte (CTL) epitopes, 9 helper T lymphocyte (HTL) epitopes, 6 linear B cell epitopes, and 6 conformational B cell epitopes. These advantageous epitopes are spliced together through different linkers to construct a multi-epitope vaccine. The silico tests showed that the multi-epitope vaccine was non-allergenic and had a strong interaction with TLR4 molecular docking. In immune simulation results, the vaccine construct may be useful in helping brucellosis patients to initiate cellular and humoral immunity. Overall, our findings indicated that the multi-epitope vaccine construct has a high-quality structure and suitable characteristics, which may provide a theoretical basis for the development of a Brucella vaccine.

Seroprevalence of Brucellosis in Patients Having Complained of Joint Pain: A Case Control

BACKGROUND

Brucellosis is a neglected zoonotic disease affecting humans and animals.

OBJECTIVES

This study aimed to estimate the seroprevalence of brucellosis in patients with joint pain.

METHODS

A total of 200 participants aged from 7 to 86 years were involved in this study. Blood samples were collected from all the participants for two years, from September 2019 to September 2021, and screened for Brucella using anti-brucella IgM ELISA and anti-brucella IgG ELISA antibodies. A questionnaire was used to collect data on socio-demographic characteristics and human brucellosis-related risk factors.

RESULTS

Human Brucella seroprevalence was 19 (9.5%) for Brucella IgM ELISA and 23 (11.5%) for Brucella IgG ELISA. The sensitivity for Brucella IgM ELISA and Brucella IgG ELISA was 65.2% and 31.6%, respectively, while the specificity was 44.1% for Brucella IgM ELISA and 77.9% for Brucella IgG ELISA. All blood culture reports of all patients were negative. The principal presentation was the observable symptoms of human brucellosis: fever, headache, chills, myalgia, and Joint pain.

CONCLUSION

Risk factors like consumption of raw milk or their products were found to be the most important for Brucella infection, so the awareness or information of risk factors and the modes of transmission is much more important in control and prevention programs. General awareness about clinical symptoms should be increased, which will improve proper diagnosis and will be helpful in early treatment. An ELISA test should be considered for diagnosing brucellosis in both acute and chronic phases.

Knowledge, Attitudes, and Practices Regarding Brucellosis Among the General Population in Qassim Region, Saudi Arabia: A Cross-Sectional Study

Background Brucellosis is an endemic infection in the Middle East. The World Health Organization has identified the illness as one of the most prevalent "neglected zoonotic diseases." Public perceptions regarding brucellosis infection vary across different regions. Thus, this study aimed to assess the knowledge, attitudes, and practices concerning brucellosis among the general population in the Qassim region of Saudi Arabia. Methods A descriptive, cross-sectional study was conducted in the Qassim region of Saudi Arabia between March 2023 and May 2023. We distributed an online questionnaire through social media platforms and received a total of 1,244 responses from different governorates in the Qassim region. Results The level of awareness of brucellosis was moderate. Out of the 1,244 participants, 706 (56.8%) were aware of the disease. Among the participants who were aware of the disease, their knowledge of brucellosis was assessed. The majority of these respondents demonstrated a good level of knowledge (70.5%). Regarding attitudes and practices toward brucellosis, no significant association was found between the participants' level of knowledge and their attitudes. Conclusion Awareness levels about brucellosis in the Qassim region vary depending on age group, area of residency, and other factors. The younger age group and certain governorates in the Qassim region showed low levels of awareness. Moreover, participants with good knowledge about the disease obtained their information from healthcare practitioners. The significant difference in our findings between Qassim's governorates demonstrates the need for more targeted awareness campaigns in areas with lower levels of awareness.

Human brucellosis in Baringo County, Kenya: Evaluating the diagnostic kits used and identifying infecting Brucella species

Human brucellosis diagnosis has been a challenge in Brucella-endemic areas. In Kenya, diagnosis is usually carried out using Febrile Brucella Antigen agglutination test (FBAT) whose performance is not well documented. This paper reports on the sensitivity and specificity of the FBAT used for brucellosis diagnosis on blood samples/serum collected in three healthcare facilities in Baringo County, Kenya, and on Brucella species present in the study area. The FBAT test results at the hospitals were used to guide patient management. Patients who visited the hospital's laboratory with a clinician's request for brucellosis testing also filled a questionnaire to assess knowledge and attitudes associated with transmission of the disease in the study area. The remaining serum samples were tested again using FBAT and Rose Bengal Plate Test (RBPT) within a month of blood collection at the University Nairobi Laboratory. The two rapid tests were then compared, with respect to brucellosis diagnostic sensitivity and specificity. To identify infecting Brucella species, a proportion 43% (71/166) of the blood clots were analyzed by multiplex polymerase chain reaction (PCR) using specific primers for B. abortus, B. melitensis, B. ovis and B. suis. Out of 166 serum samples tested, 26.5% (44/166) were positive using FBAT and 10.2% (17/166) positive using RBPT. The sensitivity and specificity of FBAT compared to RBPT was 76.47% and 71.19%, respectively while the positive and negative predictive values were 29.55% and 96.72%, respectively. The FBAT showed higher positivity then RBPT. The difference in sensitivity and specificity of FBAT and RBPTs was relatively low. The high FBAT positivity rate would be indication of misdiagnosis; this would lead to incorrect treatment. Brucella abortus was detected from 9.9% (7/71) of the blood clots tested; no other Brucella species were detected. Thus human brucellosis, in Baringo was mainly caused by B. abortus.

Brucellosis in the Brazilian Pantanal wetland: threat to animal production and wildlife conservation

This review was performed to gather knowledge about brucellosis in livestock and wildlife in the Brazilian Pantanal, a biome with a huge biodiversity and extensive livestock production. Following the preferred reporting items for narrative review guidelines and using the terms "Brucella" and "Pantanal," we explored the PubMed, SciELO, Jstor, Science Direct, and Scholar Google databases. Information on host species, diagnostic test, number of positive animals, and positivity rates were acquired. Articles dating from 1998 to 2022 registered 14 studies including cattle, dogs, and the following wildlife species: Ozotoceros bezoarticus, Sus scrofa, Tayassu peccari, Nasua nasua, Cerdocyon thous, Panthera onca, Dasypus novemcintus, Cabassous unicinctus, Euphractus sexcinctus, Priodontes maximus, Myrmecophaga tridactyla and Hydrochoerus hydrochaeris. Brucella occurrence in cattle was demonstrated through the serological confirmatory test 2-mercaptoetanol. Molecular diagnosis detected Brucella abortus in dogs, smooth Brucella in O. beoarticus, and Brucella spp. in T. peccari. Cattle may have a pivotal importance in maintenance and spreading of Brucella spp. due to their high population density, environmental contamination from abortion of infected cows, and eventual excretion of B. abortus S19 strain from vaccinated heifers. The occurrence of Brucella spp. in O. bezoarticus and T. peccari represent a risk for wildlife conservation. These data indicate that Brucella spp. are enzootic in the Pantanal wetland, sustained by a reservoir system including domestic and wild mammals. Due to marked seasonality and large populations of wildlife species sharing same environments with livestock, brucellosis acquires great complexity in Pantanal and, therefore, must be analyzed considering both animal production and conservation.

Sero - epidemiology of brucellosis in people and their livestock: A linked human - animal cross-sectional study in a pastoralist community in Kenya

BACKGROUND

Brucellosis is associated with massive livestock production losses and human morbidity worldwide. Efforts to control brucellosis among pastoralist communities are limited by scarce data on the prevalence and risk factors for exposure despite the high human-animal interactions in these communities. This study simultaneously assessed the seroprevalence of brucellosis and associated factors of exposure among pastoralists and their livestock in same households.

METHODS

We conducted a cross-sectional study in pastoralist communities in Marsabit County - Kenya. A total of 1,074 women and 225 children participated and provided blood samples. Blood was also drawn from 1,876 goats, 322 sheep and 189 camels. Blood samples were collected to be screened for the presence of anti-Brucella IgG antibodies using indirect IgG Enzyme-Linked Immunosorbent Assay (ELISA) kits. Further, Individual, household and herd-level epidemiological information were captured using a structured questionnaire. Group differences were compared using the Pearson's Chi-square test, and p-values < 0.05 considered statistically significant. Generalized mixed-effects multivariable logistic human and animal models using administrative ward as the random effect was used to determine variables correlated to the outcome.

RESULTS

Household-level seropositivity was 12.7% (95% CI: 10.7-14.8). The individual human seroprevalence was 10.8% (9.1-12.6) with higher seroprevalence among women than children (12.4 vs. 3.1%, p < 0.001). Herd-level seroprevalence was 26.1% (23.7-28.7) and 19.2% (17.6-20.8) among individual animals. Goats had the highest seroprevalence 23.1% (21.2 - 25.1), followed by sheep 6.8% (4.3-10.2) and camels 1.1% (0.1-3.8). Goats and sheep had a higher risk of exposure OR = 3.8 (95% CI 2.4-6.7, p < 0.001) and 2.8 (1.2-5.6, p < 0.007), respectively relative to camels. Human and animal seroprevalence were significantly associated (OR = 1.8, [95%CI: 1.23-2.58], p = 0.002). Herd seroprevalence varied by household head education (OR = 2.45, [1.67-3.61, p < 0.001]) and herd size (1.01, [1.00-1.01], p < 0.001).

CONCLUSIONS

The current study showed evidence that brucellosis is endemic in this pastoralist setting and there is a significant association between animal and human brucellosis seropositivity at household level representing a potential occupational risk. Public health sensitization and sustained human and animal brucellosis screening are required.

Seroprevalence and Risk Factors for Brucella Infections in Jordan

Brucellosis is a significant zoonotic disease and is endemic in several regions of the world. This study is aimed to determine the nationwide spatial distribution, seroprevalence, and risk factors for Brucella infections in Jordan. Serum samples of 938 individuals from 11 governorates were tested for Brucella spp. antibodies using Rose Bengal and Brucellacapt® tests. A validated questionnaire was used to collect demographic, animal ownership, and food consumption data. The seroprevalence of Brucella infection in Jordan’s population was 6.7% (95% CI, 5.2–8.5%). The multivariate model showed that location of residence, consuming raw milk/milk products, and owning small ruminants (goat and/or sheep) were significantly associated with seropositivity after controlling for age and gender. Individuals living in the northern Badia region had 8.82 greater odds (95% CI, 4.56–17.03) of seropositivity than individuals living in the Middle region of the country. Individuals who reported consumption of raw milk/milk products had 3.7 higher odds (95% CI, 2.01–6. 81) of seropositivity compared with individuals not consuming raw milk/milk products. In addition, individuals who own small ruminants (goat and/or sheep) had 2.14 higher odds (95% CI, 1.11–4.12) of seropositivity compared with individuals who do not own small ruminants. The identified geographic hotspots and small ruminants’ ownership, risk of raw milk products highlight the need for tailored training, education campaigns, and resources for controlling brucellosis in Jordan.

Longitudinal Study of Selected Bacterial Zoonoses in Small Ruminants in Tana River County, Kenya

Brucellosis, Q fever, and leptospirosis are priority zoonoses worldwide, yet their epidemiology is understudied, and studies investigating multiple pathogens are scarce. Therefore, we selected 316 small ruminants in irrigated, pastoral, and riverine settings in Tana River County and conducted repeated sampling for animals that were initially seronegative between September 2014 and June 2015. We carried out serological and polymerase chain reaction tests and determined risk factors for exposure. The survey-weighted serological incidence rates were 1.8 (95% confidence intervals [CI]: 1.3–2.5) and 1.3 (95% CI: 0.7–2.3) cases per 100 animal-months at risk for Leptospira spp. and C. burnetii, respectively. We observed no seroconversions for Brucella spp. Animals from the irrigated setting had 6.83 (95% CI: 2.58–18.06, p-value = 0.01) higher odds of seropositivity to C. burnetii than those from riverine settings. Considerable co-exposure of animals to more than one zoonosis was also observed, with animals exposed to one zoonosis generally having 2.5 times higher odds of exposure to a second zoonosis. The higher incidence of C. burnetii and Leptospira spp. infections, which are understudied zoonoses in Kenya compared to Brucella spp., demonstrate the need for systematic prioritization of animal diseases to enable the appropriate allocation of resources.

Human and Animal Brucellosis in Nigeria: A Systemic Review and Meta-Analysis in the Last Twenty-One Years (2001–2021)

Simple Summary

Brucellosis caused by Brucella spp. is transmitted by direct or indirect contact with infected animals or their secretions and through the consumption of infected animal meat and unpasteurized milk/milk products. Brucellosis is classified as one of the top neglected zoonosis by the World Health Organization (WHO), and despite this, it does not attract the appropriate attention it requires from both the Federal and State ministries of health in Nigeria. Currently, there is a lack of coordinated national data on the prevalence and distribution of human and animal brucellosis. Thus, published research works between 2001 and 2021 were studied based on set criteria to estimate the burden and distribution of brucellosis in Nigeria. The results of the national seroprevalence of human and animal brucellosis were 17.6% (554/3144) and 13.3% (8547/64,435), respectively. Specifically, 15.8% (7178/45,363) seroprevalence of brucellosis was recorded in northern Nigeria as against 8.7% (1902/21,740) in the southern part. Brucella abortus, B. melitensis, B. suis, and B. canis were reported in 27 of the 36 states. Improved sanitation at the abattoirs, use of personal protective equipment by animal handlers, vaccination of animals against brucellosis, and ranching of animals to curb the spread of the disease should be paramount to all stakeholders.

Abstract

The global burden of human and animal brucellosis remains enormous. The disease, which is endemic in Nigeria, lacks appropriate attention and national data. This review estimated the burden and distribution of human and animal brucellosis in Nigeria in the last twenty-one years (2001–2021). Publications reporting the detection of brucellosis in Nigeria were sorted from different search engines, including PubMed, ResearchGate, Scopus, and Google Scholar, to generate data on its prevalence, spatial distribution, and predisposing factors. The results of the national seroprevalence of human and animal brucellosis as revealed in this study were 17.6% (554/3144) and 13.3% (8547/64,435), respectively. Specifically, 15.8% (7178/45,363) seroprevalence of brucellosis was recorded in northern Nigeria as against 8.7% (1902/21,740) seroprevalence in the southern part. It also indicated that 78.7% of the detected brucellae were un-typed. The Brucella species detected were B. abortus (15.2%), B. melitensis (4%), B. suis (1.8%), and B. canis (0.4%). This study revealed that brucellosis is endemic in Nigeria. Culture and molecular methods for detecting brucellosis and reports on antimicrobial susceptibility testing remain a conjecture. This review will help researchers redirect their research focus and serve as a guide for policymakers on measures for managing brucellosis in Nigeria.

Human brucellosis: Widespread information deficiency hinders an understanding of global disease frequency

Background

For decades, human brucellosis has been recognized worldwide as a significant cause of morbidity, yet the annual incidence of this disease remains unknown. We analyzed this frequency, using international reports (2005–2019), identifying information gaps, and distinguishing a possible path forward.

Methodology/Principal findings

A novel approach to estimating the incidence of this disease was explored. We utilized annual health data extracted from the World Organization for Animal Health (OIE)–World Animal Health Information System (WAHIS) database, assessing the dataset completeness and representativeness of the data for the world population. Additionally, we assessed the reported country level human brucellosis case counts and the factors that influenced the observed changes over time. Our analysis revealed incomplete and unrepresentative information, preventing the estimation of annual human brucellosis case incidence at the global level. In the OIE-WAHIS database, only 48.4% of the required reports have been submitted as of 2019, with approximately 47.3% of the world population represented. Additionally, geographic regions were disproportionate in completeness, representativeness, and actual reported case counts. Africa and Asia constituted the majority of reported cases, while simultaneously submitting the lowest percentage of reports as well as covering the lowest percentage of their populations within those reports, when compared to the rest of the world.

Conclusions/Significance

The global annual frequency of human brucellosis cases remains elusive. Furthermore, there exists great heterogeneity in diagnostic, surveillance, and reporting systems worldwide, calling into question the validity of available information. This study reveals that the Neglected Zoonotic Disease priority status for brucellosis should be restored.

Despite brucellosis being a major concern worldwide, particularly for populations residing within resource-limited settings, a suitable estimate of annual incidence is currently nonexistent for human disease. To our knowledge, this is the first study to characterize global human brucellosis frequency by utilizing nationally reported case data supplied to the global intergovernmental public health authorities. The combined records demonstrate that within currently available and established international reporting systems, there are insufficient data to calculate the annual global frequency of human brucellosis. Furthermore, the regional differences in populations represented within reports, as well as actual reported case counts, bias the correct interpretation of the overall human brucellosis disease frequency. This suggests that broadcasting a specific global quantity of new cases each year is misleading and, accordingly, there is presently no way to assess the global public health impact of this disease. In past years, disease prioritization by individual countries, including the reallocation of funds to national surveillance, have been demonstrated to positively impact the completeness and representativeness of the data. In the future, the international community must similarly reallocate resources to understand and fill gaps within the available information. Application of this information can be directed towards effectively pinpointing disease burden and efficient control strategies. The reinstatement of human brucellosis as a priority Neglected Zoonotic Disease by the WHO would substantially facilitate this process.

From policy to practice: An assessment of biosecurity practices in cattle, sheep and goats production, marketing and slaughter in Baringo County, Kenya

Globally, biosecurity is instrumental in prevention, control and management of livestock diseases and protection of human health. It is defined, prescribed, adopted and enforced through global, regional and national frameworks, laws, policies and strategies. There is more biosecurity practice research conducted in developed countries than developing ones. Consequently, the gap between the ideals recommended in biosecurity frameworks and what is practical in under-resourced rural settings is poorly understood. This anthropological study sought to assess adoption of biosecurity practices across a cattle, sheep and goat value chains continuum to demonstrate where risks lie. The cross-sectional mixed-methods study took place in Baringo County, Kenya. Qualitatively, it utilized 26 focus group discussions with community members and 10 observational interviews with slaughter facility workers. Quantitatively, it included a household survey with 560 community members and a separate survey with 231 livestock traders. Results show that producers, traders and slaughter facility workers did observe some biosecurity practices but not others due but not limited to personal preference, limitations in veterinary service delivery and enforcement of some biosecurity measures, and lack of requisite infrastructure. The study concludes that the implementation of biosecurity measures in rural settings is more complex than envisioned in biosecurity policies and frameworks. It can be hampered by resource limitations, poor enforcement, and contestations with cultural practices. The study recommends that further studies on willingness to adopt biosecurity measures targeting community members in under-resourced settings be conducted to identify possible critical points of intervention at county and national levels.

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.

Identification and distribution of pathogens coinfecting with Brucella spp., Coxiella burnetii and Rift Valley fever virus in humans, livestock and wildlife

Zoonotic diseases, such as brucellosis, Q fever and Rift Valley fever (RVF) caused by Brucella spp., Coxiella burnetii and RVF virus, respectively, can have devastating effects on human, livestock, and wildlife health and cause economic hardship due to morbidity and mortality in livestock. Coinfection with multiple pathogens can lead to more severe disease outcomes and altered transmission dynamics. These three pathogens can alter host immune responses likely leading to increased morbidity, mortality and pathogen transmission during coinfection. Developing countries, such as those commonly afflicted by outbreaks of brucellosis, Q fever and RVF, have high disease burden and thus common coinfections. A literature survey provided information on case reports and studies investigating coinfections involving the three focal diseases. Fifty five studies were collected demonstrating coinfections of Brucella spp., C. burnetii or RVFV with 50 different pathogens, of which 64% were zoonotic. While the literature search criteria involved ‘coinfection’, only 24/55 studies showed coinfections with direct pathogen detection methods (microbiology, PCR and antigen test), while the rest only reported detection of antibodies against multiple pathogens, which only indicate a history of co‐exposure, not concurrent infection. These studies lack the ability to test whether coinfection leads to changes in morbidity, mortality or transmission dynamics. We describe considerations and methods for identifying ongoing coinfections to address this critical blind spot in disease risk management.

Prevalence of brucellosis in livestock keepers and domestic ruminants in Baringo County, Kenya

Brucellosis is widely distributed in more than 170 countries around the world, where it poses a huge threat to animal husbandry and human health. Brucellosis is a worldwide re-emerging zoonotic disease that poses serious public health problems in many developing countries including Kenya. However, prevalence of brucellosis has not been determined in Baringo County, Kenya, yet there is a continuous movement of cattle resulting from trade and grazing, thus predisposing many herds to brucellosis infection. We investigated the sero-prevalence of brucellosis in humans and domestic ruminants: sheep, goats, cattle and camels among livestock keeping communities in Baringo County, Kenya. In addition, we analyzed the seropositive samples for molecular detection of Brucella species. The study adopted a cross-sectional survey using quantitative data collection methods. The diagnosis was carried out using a competitive enzyme-linked immunosorbent assay (c-ELISA) and the real-time PCR assays. The sero-prevalence of brucellosis among human blood samples was 0.6% (n = 4/640) in Baringo County. About 22.30% (n = 143/640) of animal blood samples examined tested positive for Brucella genus-specific ELISA test. Cattle had a high prevalence of 22.88% (n = 93/322) followed by camels 20.00% (n = 21/105), goats 15.48% (n = 24/155) and subsequently sheep at 8.62% (n = 5/58). Overall, 7.5% (n = 6/80) of the seropositive samples amplified with the genus-specific primers. Brucella melitensis was detected in one out of the six genus positive samples, while none amplified with the B. abortus target. Even though there was high prevalence of brucellosis among livestock in Baringo County, the highest prevalence was invariably noted in cattle, followed by camels, goats and sheep, respectively. Livestock keepers had low prevalence of brucellosis. This implies that there was low risk of transmission of brucellosis between livestock keepers and their livestock.

The VirB System Plays a Crucial Role in Brucella Intracellular Infection

Brucellosis is a highly prevalent zoonotic disease caused by Brucella. Brucella spp. are gram-negative facultative intracellular parasitic bacteria. Its intracellular survival and replication depend on a functional virB system, an operon encoded by VirB1–VirB12. Type IV secretion system (T4SS) encoded by the virB operon is an important virulence factor of Brucella. It can subvert cellular pathway and induce host immune response by secreting effectors, which promotes Brucella replication in host cells and induce persistent infection. Therefore, this paper summarizes the function and significance of the VirB system, focusing on the structure of the VirB system where VirB T4SS mediates biogenesis of the endoplasmic reticulum (ER)-derived replicative Brucella-containing vacuole (rBCV), the effectors of T4SS and the cellular pathways it subverts, which will help better understand the pathogenic mechanism of Brucella and provide new ideas for clinical vaccine research and development.

Brucellosis in Camels and Humans: Seroprevalence and Associated Risk Factors in Amibara District of Afar Region, Ethiopia

Brucellosis is an important neglected zoonotic disease caused by infection with bacteria of the genus Brucella affecting different mammalian species including humans. A cross-sectional study was conducted to estimate the seroprevalence of brucellosis in camels and humans and its associated risk factors in Amibara District of Afar Region in Northeast Ethiopia, from October 2019 to May 2020. A total of 250 camel and 120 human sera were serially tested using the Rose Bengal plate test (RBPT) and complement fixation test (CFT). The overall seroprevalence of camel brucellosis in this study was 7.6% (95% CI: 4.9-11.56) by RBPT and 3.2% (95% CI: 1.63-6.2) by combined RBPT and CFT. In humans, twelve (10%) of the collected sera were positive by RBPT among which only four of them (3.33%) were positive by CFT. The risk factor analysis indicated that age, body condition, number of parity, and abortion history were significantly associated with Brucella seropositivity in camel (P ≤ 0.05). In humans, occupation and nonprotective handling of dystocia cases showed an apparent association with Brucella seropositivity. The results of this study indicated that brucellosis is a common health problem in camels and humans in Amibara District of Afar Region. The public health importance of this disease is associated with raw milk consumption and close contact with the animals having history of recent abortion. Therefore, controlling the risk factors, establishing Brucella diagnostic service in human clinics and hospitals, continuous social training with feedback assessments, and overall implementing of One Health approach framework to attain optimal health for people and domestic animals in area are recommended to safeguard the health of society.

Incidence of Brucella infection in various livestock species raised under the pastoral production system in Isiolo County, Kenya

Background

We implemented a longitudinal study to determine the incidence of Brucella infection in cattle, camels, sheep and goats that were being raised in a pastoral area in Isiolo County, Kenya. An initial cross-sectional survey was implemented to identify unexposed animals for follow up; that survey used 141 camels, 216 cattle, 208 sheep and 161 goats. Sera from these animals were screened for Brucella spp. using the Rose Bengal Plate test (RBPT), a modified RBPT, and an indirect multispecies Enzyme Linked Immunosorbent Assay (iELISA). Results of RBPT and iELISA were interpreted in parallel to determine seroprevalence. A total of 30 camels, 31 cattle, 22 sheep and 32 goats that were seronegative by all the above tests were recruited in a subsequent longitudinal study for follow up. These animals were followed for 12 months and tested for anti-Brucella antibodies using iELISA. Seroconversion among these animals was defined by a positive iELISA test following a negative iELISA result in the previous sampling period. All seropositive samples were further tested using real-time PCR-based assays to identify Brucella species. These analyses targeted the alkB and BMEI1162 genes for B. abortus, and B. melitensis, respectively. Data from the longitudinal study were analysed using Cox proportional hazards model that accounted for within-herds clustering of Brucella infections.

Results

The overall incidence rate of Brucella infection was 0.024 (95% confidence interval [CI]: 0.014–0.037) cases per animal-months at risk. Brucella infection incidence in camels, cattle, goats and sheep were 0.053 (0.022–0.104), 0.028 (0.010–0.061), 0.013 (0.003–0.036) and 0.006 (0.0002–0.034) cases per animal-month at risk, respectively. The incidence rate of Brucella infection among females and males were 0.020 (0.009–0.036) and 0.016 (0.004–0.091), respectively. Real-time PCR analyses showed that B. abortus was more prevalent than B. melitensis in the area. Results of multivariable Cox regression analysis identified species (camels and cattle) as an important predictor of Brucella spp. exposure in animals.

Conclusions

This study estimated an overall brucellosis incidence of 0.024 cases per animal-months at risk with camels and cattle having higher incidence than sheep and goats. These results will inform surveillance studies in the area.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03036-z.

Case Report: Metagenomic Next-Generation Sequencing Confirmed a Case of Central Nervous System Infection With Brucella melitensis in Non-endemic Areas

Brucellosis is a highly contagious zoonotic disease caused by bacteria that belong to the genus Brucella. It is a major endemic disease in northern China. We reported a rare case of central nervous system (CNS) infection caused by Brucella melitensis in a patient living in non-endemic areas. The medical history of the patient included chronic headache and trunk numbness. Based on the presented clinical symptoms and medical examinations, a clinical diagnosis of binocular uveo-encephalitis was made in the local hospital. The patient's symptoms were unrelieved after being treated with empiric therapy. Soon after, the patient was admitted to our hospital because of the obnubilation and coma in the trip. We ran a few examinations and sent the cerebrospinal fluid (CSF) for metagenomic next-generation sequencing (mNGS) immediately. The Magnetic resonance imaging (MRI) examination was unremarkable, and bilateral mastoid inflammation was attached. Metagenomic next-generation sequencing suggested a CNS infection caused by Brucella melitensis. Then, the results of the serum agglutination test and quantitative polymerase chain reaction assay also confirmed that. After being treated with doxycycline, rifampin, and cefatriaxone, consciousness of the patient was restored and headache diminished. Two months later, a lumbar puncture was used to check the pressure of the CSF, and the total course of treatment was more than 6 months. This case highlighted the potential value of mNGS in early clinal diagnosis. We believe that mNGS may be a complementary method for rapid identification of infection of CNS caused by the pathogen.

Prevalence and risk factors of human brucellosis and malaria among patients with fever in malaria-endemic areas, attending health institutes in Awra and Gulina district, Afar Region, Ethiopia

Background

Brucellosis is an important neglected bacterial zoonotic disease that has been affecting animals and humans for decades. Malaria has been considered major cause of illness in tropical areas, including Ethiopia. This study aimed to identify prevalence and risk factors of human brucellosis and malaria among patients with fever in malaria-endemic areas attending health institutes in Awra and Gulina district, Afar Region, Ethiopia.

Methods

A purposive cross-sectional study was conducted among febrile patients who attended health institutes in Awra and Gulina district of Afar region from February to May 2019. 3–5 ml blood samples were collected, thick and thin blood films were prepared and examined for malaria; serum was separated and tested for anti-Brucella using Rose Bengal Plate Test, and the seropositives were subjected to ELISA. Data were entered using EpiData3.1 and analyses were performed using Stata SE 14.

Results

A total of 444 febrile individuals (59.5% female) of age ranging from 2 to 83 years (mean = 26.1, SD =  ± 11.8) were participated in this study. The overall seroprevalence of brucellosis was 31.5% (95% CI; 27.4–36.0%) by RBPT and 15.8% (95% CI; 12.7–19.7%) by ELISA, as well as the prevalence of malaria (P. falciparum) was 4.3% (95% CI; 2.7–6.6%) among febrile patients. Malaria was more common in males (7.2% 95% CI; 4.2–12.1%) than in female (2.3% 95% CI; 1.0–5.0%, p = 0.01) and in non-married than in married (7.6% 95% CI; 4.1–13.6% vs. 2.9% 95% CI; 1.5–5.4%, p = 0.02). Being male (AOR = 2.41, 95%CI: 1.36–4.26, p < 0.002), drinking raw milk (AOR = 26.68, 95%CI: 3.22- 221.13, p = 0.002) and boiled milk (AOR = 17.52, 95%CI: 2.06—149.04, p = 0.009) and touching aborted fetus/discharges without protective (AOR = 2.56, 95%CI: 1.01–6.528.50, p = 0.048) were independently associated with brucellosis among febrile patients.

Conclusion

The prevalence of brucellosis in fever patients in this study area is higher than malaria. Consumption of raw milk and contact with animal discharge can cause significant risk of Brucella infection. So, brucellosis disease must be sought in the differential diagnosis, like ELISA test that can be used to differentiate from other febrile diseases like malaria.

Rift Valley fever and Brucella spp. in ruminants, Somalia

Background

Fourteen-years after the last Rift Valley fever (RVF) virus (RVFV) outbreak, Somalia still suffers from preventable transboundary diseases. The tradition of unheated milk consumption and handling of aborted materials poses a public health risk for zoonotic diseases. Limited data are available on RVF and Brucella spp. in Somali people and their animals. Hence, this study has evaluated the occurrence of RVFV and Brucella spp. antibodies in cattle, goats and sheep sera from Afgoye and Jowhar districts of Somalia.

Methods

Serum samples from 609 ruminants (201 cattle, 203 goats and 205 sheep), were serologically screened for RVF by a commercial cELISA, and Brucella species by modified Rose Bengal Plate Test (mRBPT) and a commercial iELISA.

Results

Two out of 609 (0.3 %; 95 %CI: 0.04–1.2 %) ruminants were RVF seropositive, both were female cattle from both districts. Anti-Brucella spp. antibodies were detected in 64/609 (10.5 %; 95 %CI: 8.2–13.2 %) ruminants by mRBPT, which were 39/201 (19.4 %) cattle, 16/203 (7.9 %) goats and 9/205 (4.4 %) sheep. Cattle were 5.2 and 2.8 times more likely to be Brucella-seropositive than sheep (p = 0.000003) and goats (p = 0.001), respectively. When mRBPT-positive samples were tested by iELISA, 29/64 (45.3 %; 95 %CI: 32.8–58.3 %) ruminant sera were positive for Brucella spp. Only 23/39 (58.9 %) cattle sera and 6/16 (37.5 %) goat sera were positive to Brucella spp. by iELISA.

Conclusions

The present study showed the serological evidence of RVF and brucellosis in ruminants from Afgoye and Jowhar districts of Somalia. Considering the negligence of the zoonotic diseases at the human-animal interface in Somali communities, a One Health approach is needed to protect public health.

Transcriptome Landscape of Intracellular Brucella ovis Surviving in RAW264.7 Macrophage Immune System

Brucella ovis infection results in genital damage and epididymitis in rams, placental inflammation and rare abortion in ewes, and neonatal mortality in lambs. However, the mechanism underlying B. ovis infection remains unclear. In the present study, we used prokaryotic transcriptome sequencing to identify the differentially expressed genes (DEGs) between wild-type B. ovis and intracellular B. ovis in RAW264.7 macrophages. Gene ontology (GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed, and quantitative reverse transcriptase PCR (qRT-PCR) was used to validate the top 10 upregulated and downregulated DEGs. The results showed that 212 genes were differentially expressed, including 68 upregulated and 144 downregulated genes, which were mainly enriched in 30 GO terms linked to biological process, cellular component, and molecular function. KEGG analysis showed that the DEGs were enriched in the hypoxia-inducible factor 1 (HIF-1) signaling pathway, mitogen-activated protein kinase (MAPK) signaling pathway, beta-alanine metabolism, and quorum sensing pathway. BME_RS01160, BME_RS04270, BME_RS08185, BME_RS12880, BME_RS25875, predicted_RNA865, and predicted_RNA953 were confirmed with the transcriptome sequencing data. Hence, our findings not only reveal the intracellular parasitism of B. ovis in the macrophage immune system, but also help to understand the mechanism of chronic B. ovis infection.

Tokpa K, Fokou G, Shilabukha K, Ezekiel M, Bonfoh B, Kazwala R, Kreppel K. Lay attitudes and misconceptions and their implications for the control of brucellosis in an agro-pastoral community in Kilombero district, Tanzania

Brucellosis is a priority zoonotic disease in Tanzania that causes ill-health in people and affects livestock productivity. Inadequate awareness and behavior risking transmission can impede control efforts. We conducted a cross-sectional survey of 333 livestock owners in three villages in the Kilombero district, Tanzania, to understand their awareness, knowledge and behavior associated with brucellosis. Six Focus Group Discussions (FGDs), two in each village, were conducted, as well as an additional FGD with male herders from one of the villages. Factors associated with knowledge on brucellosis, food consumption and animal husbandry behavior risking transmission of this disease, were identified using generalized linear models. Predictors for knowledge of brucellosis were being male and having a higher educational level, while age was positively associated with a higher level of knowledge. Faith and ethnicity were associated with the performance of practices risking transmission. Following traditional religion and belonging to the Wamaasai ethnicity significantly increased the odds of carrying out these practices. Qualitative analysis gave insight into risk practices and reasoning. Of the 333 respondents, 29% reported that they had experienced abortions in their herds, 14% witnessed retained placentas, and 8% had seen still-births in their cattle within the previous year. However, survey results also showed that only 7.2% of participants had heard about brucellosis as a disease in livestock. Of those who had heard about brucellosis in livestock, 91% associated abortions with it and 71% knew that humans can get infected through raw milk consumption. People overwhelmingly attributed symptoms and transmission of brucellosis in livestock to infection with trypanosomiasis and to supernatural reasons instead. In the community, consumption of raw milk was valued and handling of aborted material was not considered a risk for infection. This agro-pastoralist community holds on to long-held beliefs and practices and lacks understanding of the biomedical concept of brucellosis. Transmission routes and symptoms of brucellosis in humans and livestock are completely unknown. The disparity between risk perception and actual transmission risk related to animal handling and consumption of animal products presents a challenge for disease awareness communication. This study recommends focused community engagement and sensitization to address the limited awareness and misconceptions among agro-pastoralists.

Brucellosis: Prevalence with reference to East African community countries - A rapid review

Brucellosis is a zoonotic disease which is endemic to certain regions of the world including Sub-Saharan Africa. The aim of this article is to provide a recent and rapid review on brucellosis prevalence in East African Community (EAC) countries. Literature was obtained using Google Scholar search engine and screened for relevancy and fulfilment of criteria to 1, 17, 4, 4, 30 and 29 articles retained for brucellosis prevalence in Burundi, Kenya, Rwanda, South Sudan, Tanzania and Uganda. Recent literature (published in the last decade 2010 to 2019) was considered for prevalence results in this review. In EAC, livestock had an animal-level prevalence of 0.2% to 43.8%, 0.0% to 20.0% and 0.0% to 13.8% for cattle, goats and sheep respectively. In humans, the prevalence varied mostly between 0.0% and 35.8%. In conclusion, brucellosis is quite prevalent in the region. The reported prevalence calls for plans or more efforts from individual member countries and from EAC, as a region, to control brucellosis.

Molecular epidemiology of Brucella species in mixed livestock-human ecosystems in Kenya

Brucellosis, caused by several species of the genus Brucella, is a zoonotic disease that affects humans and animal species worldwide. Information on the Brucella species circulating in different hosts in Kenya is largely unknown, thus limiting the adoption of targeted control strategies. This study was conducted in multi-host livestock populations in Kenya to detect the circulating Brucella species and assess evidence of host-pathogen associations. Serum samples were collected from 228 cattle, 162 goats, 158 sheep, 49 camels, and 257 humans from Narok and Marsabit counties in Kenya. Information on age, location and history of abortion or retained placenta were obtained for sampled livestock. Data on age, gender and location of residence were also collected for human participants. All samples were tested using genus level real-time PCR assays with primers specific for IS711 and bcsp31 targets for the detection of Brucella. All genus positive samples (positive for both targets) were further tested with a speciation assay for AlkB and BMEI1162 targets, specific for B. abortus and B. melitensis, respectively. Samples with adequate quantities aggregating to 577 were also tested with the Rose Bengal Test (RBT). A total of 199 (33.3%) livestock and 99 (38.5%) human samples tested positive for genus Brucella. Animal Brucella PCR positive status was positively predicted by RBT positive results (OR = 8.3, 95% CI 4.0-17.1). Humans aged 21-40 years had higher odds (OR = 2.8, 95% CI 1.2-6.6) of being Brucella PCR positive compared to the other age categories. The data on detection of different Brucella species indicates that B. abortus was detected more often in cattle (OR = 2.3, 95% CI 1.1-4.6) and camels (OR = 2.9, 95% CI 1.3-6.3), while B. melitensis was detected more in sheep (OR = 3.6, 95% CI 2.0-6.7) and goats (OR = 1.7, 95% CI 1.0-3.1). Both B. abortus and B. melitensis DNA were detected in humans and in multiple livestock host species, suggesting cross-transmission of these species among the different hosts. The detection of these two zoonotic Brucella species in humans further underpins the importance of One Health prevention strategies that target multiple host species, especially in the multi-host livestock populations.

Prioritizing smallholder animal health needs in East Africa, West Africa, and South Asia using three approaches: Literature review, expert workshops, and practitioner surveys

Managing the health needs of livestock contributes to reducing poverty and improving the livelihoods of smallholder and pastoralist livestock keepers globally. Animal health practitioners, producers, policymakers, and researchers all must prioritize how to mobilize limited resources. This study employed three approaches to prioritize animal health needs in East and West Africa and South Asia to identify diseases and syndromes that impact livestock keepers. The approaches were a) systematic literature review, b) a series of expert workshops, and c) a practitioner survey of veterinarians and para-veterinary professionals. The top constraints that emerged from all three approaches include endo/ ectoparasites, foot and mouth disease, brucellosis, peste des petits ruminants, Newcastle disease, and avian influenza. Expert workshops additionally identified contagious caprine pleuropneumonia, contagious bovine pleuropneumonia, mastitis, and reproductive disorders as constraints not emphasized in the literature review. Practitioner survey results additionally identified nutrition as a constraint for smallholder dairy and pastoralist small ruminant production. Experts attending the workshops agreed most constraints can be managed using existing veterinary technologies and best husbandry practices, which supports a shift away from focusing on individual diseases and new technologies towards addressing systemic challenges that limit access to veterinary services and inputs. Few research studies focused on incidence/ prevalence of disease and impact, suggesting better incorporation of socio-economic impact measures in future research would better represent the interests of livestock keepers.

Serological evidence of single and mixed infections of Rift Valley fever virus, Brucella spp. and Coxiella burnetii in dromedary camels in Kenya

Camels are increasingly becoming the livestock of choice for pastoralists reeling from effects of climate change in semi-arid and arid parts of Kenya. As the population of camels rises, better understanding of their role in the epidemiology of zoonotic diseases in Kenya is a public health priority. Rift Valley fever (RVF), brucellosis and Q fever are three of the top priority diseases in the country but the involvement of camels in the transmission dynamics of these diseases is poorly understood. We analyzed 120 camel serum samples from northern Kenya to establish seropositivity rates of the three pathogens and to characterize the infecting Brucella species using molecular assays. We found seropositivity of 24.2% (95% confidence interval [CI]: 16.5–31.8%) for Brucella, 20.8% (95% CI: 13.6–28.1%) and 14.2% (95% CI: 7.9–20.4%) for Coxiella burnetii and Rift valley fever virus respectively. We found 27.5% (95% CI: 19.5–35.5%) of the animals were seropositive for at least one pathogen and 13.3% (95% CI: 7.2–19.4%) were seropositive for at least two pathogens. B. melitensis was the only Brucella spp. detected. The high sero-positivity rates are indicative of the endemicity of these pathogens among camel populations and the possible role the species has in the epidemiology of zoonotic diseases. Considering the strong association between human infection and contact with livestock for most zoonotic infections in Kenya, there is immediate need to conduct further research to determine the role of camels in transmission of these zoonoses to other livestock species and humans. This information will be useful for designing more effective surveillance systems and intervention measures.

Dromedary camels are well adapted to the arid and semi-arid environment that makes up about 80% of Kenya’s landmass. As such, camels play an important role in the socio-economic wellbeing and food security of pastoralists in the country. However, the species remains relatively neglected in scientific research, one of the main reasons being camels are mostly found in remote, low-income, arid regions of Africa and Asia. We carried out a study to determine the levels of exposure of camels in northern Kenya to Brucella spp., Coxiella burnetii and Rift Valley fever virus, three priority zoonotic pathogens in the country. We found high levels of exposure to the three pathogens, indicating the important role camels might play in the epidemiology of the zoonotic diseases in humans and other livestock. Based on the study findings, we argue for the immediate need for investments in disease surveillance and control strategies for priority zoonotic disease in camels in Kenya.

Brucellosis risk factors and milk hygiene handling practices in pastoral communities in Isiolo county, Kenya

The study was conducted from June to August 2014 in Isiolo Central division of Isiolo Sub‐County and Sericho division of Garbatulla Sub‐County and comprised two components: (i) a cross‐sectional study on the milk‐handling hygiene practices, where milk traders’ households were the study units and (ii) a case‐control study on the risk factors for Brucella spp. infection in humans. Results of the cross‐sectional study showed that 26.74% of the respondents never washed their hands before milking, 60.47% never washed the udder before milking and 54.65% never withhold consumption of milk from animals under treatment with antibiotics. The case–control study included household units with previous cases of brucellosis (53.33%) and those without (46.67%) over the previous 5 years and identified drinking of raw milk as the main risk factor for infection (OR = 26.44; 95% CI: 8.04–86.99). Pastoralists’ unhygienic handling of milk from production to market is suboptimal and this is due to poor knowledge on hygienic practices, poor knowledge on the risks associated with poor milk hygiene and lack of sufficient and potable water for cleaning of milk containers. Many pastoralists still consume milk raw and this is a major public health risk for milk‐borne diseases.

The intersection of land use and human behavior as risk factors for zoonotic pathogen exposure in Laikipia County, Kenya

A majority of emerging infectious diseases (EIDs) are zoonotic, mainly caused through spillover events linked to human-animal interactions. We conducted a survey-based human behavioral study in Laikipia County, Kenya, which is characterized by a dynamic human-wildlife-livestock interface. Questionnaires that assessed human-animal interactions, sanitation, and illnesses experienced within the past year were distributed to 327 participants among five communities in Laikipia. This study aimed to 1) describe variation in reported high-risk behaviors by community type and 2) assess the relationship between specific behaviors and self-reported illnesses. Behavioral trends were assessed in R via Fisher’s exact tests. A generalized linear mixed model with Lasso penalization (GLMMLasso) was used to assess correlations between behaviors and participants’ self-reported illness within the past year, with reported behaviors as independent variables and reported priority symptoms as the outcome. Reported behaviors varied significantly among the study communities. Participants from one community (Pastoralist-1) were significantly more likely to report eating a sick animal in the past year (p< 0.001), collecting an animal found dead to sell in the past year (p<0.0001), and not having a designated location for human waste (p<0.0001) when compared to participants from other communities. The GLMMLasso revealed that reports of an ill person in the household in the past year was significantly associated with self-reported illness. Sixty-eight percent of participants reported that bushmeat is available within the communities. Our study demonstrates community-level variation in behaviors that may influence zoonotic pathogen exposure. We further recommend development of targeted studies that explore behavioral variations among land use systems in animal production contexts.

Many infectious diseases, such as H1N1, Ebola, and COVID-19, can be spread to humas from animals. In order to reduce the risk of disease “spillover” (disease transmission from an animal to a person), it is important to understand how interactions between humans and animals can influence spread. Certain behaviors, such as eating raw meat, hunting, or sharing drinking water with animals can put people at greater risk of contacting bacteria and viruses that can cause these diseases. Globally, communities that depend on animal production are at heightened risk due to increased contact with animals. In this study, the authors conducted human behavioral surveys among different communities in Kenya that raise livestock. Results show that reported behaviors varied greatly by community. One of the communities reported a significantly higher proportion of behaviors, such as eating raw meat or eating animals found dead. Communities that show high prevalence of these behaviors may be at greater risk for contracting diseases from animals. Understanding this variation is important for developing plans for community outreach and addressing behaviors that can influence risk of disease spread.

High incidence of human brucellosis in a rural Pastoralist community in Kenya, 2015

Background

Brucellosis occurs globally with highly variable incidence in humans from very low in North America and Western Europe to high in the Middle East and Asia. There are few data in Sub-Saharan Africa. This study estimated the incidence of human brucellosis in a pastoralist community in Kenya.

Methods

Between February 2015 and January 2016, we enrolled persons living in randomly selected households in Kajiado County. Free health care was offered at three facilities in the study area. Those who met the study clinical case definition completed a standardized questionnaire on demographics, clinical history and presentation. A blood sample was collected and tested by Rose Bengal test (RBT), then later tested at the Kenya Medical Research Institute laboratory for Brucella IgG and IgM by ELISA. Those who tested positive by both RBT and ELISA (IgG or IgM antibodies) were classified as confirmed while those that only tested positive for IgG or IgM antibodies were classified as probable. Further, sera were tested by polymerase chain reaction using a TaqMan Array Card (TAC) for a panel of pathogens causing AFI including Brucella spp. Annual incidence of brucellosis was calculated as the number of confirmed cases in one year/total number in the study population.

Results

We enrolled a cohort of 4746 persons in 804 households. Over half (52.3%) were males and the median age was 18 years (Interquartile range (IQR) 9 months– 32 years). A total of 236 patients were enrolled at three health facilities; 64% were females and the median age was 40.5 years (IQR 28–53 years). Thirty-nine (16.5%) were positive for Brucella antibodies by IgG ELISA, 5/236 (2.1%) by IgM ELISA and 4/236 (1.7%) by RBT. Ten percent (22/217) were positive by TAC. We confirmed four (1.7%) brucellosis cases giving an annual incidence of 84/100,000 persons/year (95% CI 82, 87). The incidence did not significantly vary by gender, age and location of residence.

Conclusion

We report a high incidence of brucellosis in humans among members of this pastoralist community. Brucellosis was the most common cause of febrile illness in this community.

Brucellosis is a bacterial disease that affects both humans and animals. Humans get infected via ingestion of unpasteurized animal products from infected animals and direct contact during animal abortions and deliveries. Infected animals shed bacteria for life through milk and during deliveries posing a risk to those with occupational exposure to infected animals. As such, human disease is disproportionately high in regions with high prevalence of animal brucellosis. While human brucellosis is distributed globally, incidence is low in North America and Western Europe and high in Asia and the Middle East where the disease is endemic. Data from Africa are scarce. We set out to estimate the incidence of brucellosis in a pastoralist community with documented high Brucella sero-prevalence in humans and livestock. We followed up a cohort of 804 households for one year and tested household members who became ill in three designated health facilities. We estimated an incidence of 84 cases per 100,000 persons per year in this community. We also found that Brucella was the most common pathogen among persons who had febrile illness highlighting the importance of this pathogen in this rural pastoralist community. No brucellosis intervention measures were being implemented.

Hospital-based evidence on cost-effectiveness of brucellosis diagnostic tests and treatment in Kenyan hospitals

Hospitals in Kenya continue to use the Febrile Antigen Brucella Agglutination Test (FBAT) to diagnose brucellosis, despite reports showing its inadequacy. This study generated hospital-based evidence on the performance and cost-effectiveness of the FBAT, compared to the Rose Bengal Test (RBT).Twelve hospitals in western Kenya stored patient serum samples that were tested for brucellosis using the FBAT, and these were later re-tested using the RBT. Data on the running time and cost of the FBAT, and the treatment prescribed for brucellosis, were collected. The cost-effectiveness of the two tests, defined as the cost in US Dollars ($) per Disability Adjusted Life Year (DALY) averted, was determined, and a basic sensitivity analysis was run to identify the most influential parameters. Over a 6-month period, 180 patient serum samples that were tested with FBAT at the hospitals were later re-tested with RBT at the field laboratory. Of these 24 (13.3%) and 3 (1.7%) tested positive with FBAT and RBT, respectively. The agreement between the FBAT and RBT was slight (Kappa = 0.12). Treatment prescribed following FBAT positivity varied between hospitals, and only one hospital prescribed a standardized therapy regimen. The mean $/DALY averted when using the FBAT and RBT were $2,065 (95% CI $481-$6,736) and $304 (95% CI $126-$604), respectively. Brucellosis prevalence was the most influential parameter in the cost-effectiveness of both tests. Extrapolation to the national level suggested that an estimated $338,891 (95% CI $47,000-$1,149,000) per year is currently spent unnecessarily treating those falsely testing positive by FBAT. These findings highlight the potential for misdiagnosis using the FBAT. Furthermore, the RBT is cost-effective, and could be considered as the mainstay screening test for human brucellosis in this setting. Lastly, the treatment regimens must be harmonized to ensure the appropriate use of antibiotics for treatment.

Brucellosis is the most common bacterial zoonosis globally, with a higher burden in low-resource settings. In humans, the disease manifests itself with non-specific clinical signs, and current international guidelines recommend the use of two serological diagnostic tests to make a confirmatory diagnosis. Many hospitals in Kenya and some neighbouring countries have been using the Febrile Antigen Brucella Agglutination Test (FBAT) for diagnosis, despite reports showing its poor performance. In this study we compared the diagnostic performance and cost-effectiveness of the FBAT with that of the Rose Bengal Test (RBT), a serological assay recommended by international guidelines. Our results showed that, compared to the RBT, the FBAT incorrectly diagnosed a number of patients. This is of concern as it leads to unnecessary antibiotic treatments, increasing the economic burden of the disease and exacerbating the risk of antibiotic resistance. We also highlight the discrepancies in brucellosis treatment regimens currently being prescribed by various hospitals. Finally, we showed that the RBT is a more cost-effective diagnostic test. Our recommendation, therefore, is for the RBT to be considered as the mainstay diagnostic test for human brucellosis in all Kenyan hospitals, and for the harmonization of treatment guidelines.

Arranging The Questionnaire To Identify Brucellosis Risk Factors In Western Kazakhstan

Background ― In some Kazakhstan regions, the epidemic situation on brucellosis remains tense, despite the observed trend to decrease in the incidence: 5.5 per 100,000 population by 2018 vs. 6.2 in 2017. The article aims at presenting the steps of preparing the brucellosis questionnaire to identify infection risk factors. Methods ― A questionnaire is developed based on the Health Belief Model to arrange interviews among the adult population of the Aktobe region. Stages of the drafting process included: 1) review of relevant literature sources; 2) assessment of the target audience to calculate N (number of interviewees); 3) development of the questionnaire itself; 4) testing the tool in focus-groups; 5) validation through Cronbach’s alpha (α) calculation to reach the internal consistency of the questionnaire; 6) final editing of the survey tool. The Cronbach’s alpha was calculated using the item-analysis in the SPSS Modeler.v.25. Results ― The designed questionnaire consisted of the three domains with twenty-two questions of the semi-closed type and underwent testing in the focus-group of ninety-eight livestock owners. A preliminary analysis revealed five items with unsatisfactory mean values, which were either modified or deleted so that the α resulted in 0.71 (moderately reliable). The adjusted tool eventually contained seventeen items (questions). Conclusion ― A simple design and adequate validation of the survey tool should facilitate information on population awareness of the clinical symptoms and paths of brucellosis infection transmission. Data on accepted practice on caring for livestock in private households across the region also become available for analysis owing to the presented questionnaire.

Serum changes in pyridinoline, type II collagen cleavage neoepitope and osteocalcin in early stage male brucellosis patients

Musculoskeletal changes are the most common clinical manifestation of brucellosis. The main objective of this study was to provide a better understanding of this disease, while also attempting to identify potential markers that can identify the early stage musculoskeletal changes associated with human brucellosis. In this case–control study, 41 male early-stage brucellosis patients (within 6 months of diagnosis) who had not received drug therapy and 44 matched controls were examined. Venous blood samples were collected and serum pyridinoline (PYD), type II collagen cleavage neoepitope (C2C) and osteocalcin (OC) levels were quantified using an enzyme-linked immunosorbent assay (ELISA). In the brucellosis group, the median serum levels of PYD (278.53 µg/L), C2C (82.23 µg/L) and OC (8.41 µg/L) were significantly elevated relative to the control group (Z = 5.686, 3.997, 3.579; P = 0.000). Serum PYD, C2C, and OC levels were increased in early-stage male brucellosis patients, and these factors appear to have promise as potential indicator biomarkers that can reflect the osteoarticular changes that occur in the early stage of human brucellosis.

Serological detection of brucellosis among febrile, malaria-negative children and domesticated dogs in an urban African setting

Background

Childhood brucellosis and malaria are co-endemic febrile illnesses in some sub-Saharan African countries. Malaria and brucellosis co-infection or brucellosis sole infections are often missed due to an over emphasis on malaria and the lack of appropriate diagnostic infrastructure. Brucellosis in dogs is usually overlooked and yet there is extensive contact between humans and their pets.

Objective

This study investigated brucellosis in children and dogs using a confirmatory serological testing series that screens for three Brucella sp.

Methods

Residual blood samples from malaria smear-negative febrile children were collected and tested for Brucella sp and malaria parasite. During the same period, residual blood samples presented to a veterinary microbiology laboratory in the same area were tested for brucellosis using the same approach.

Results

A total of 105 human and 80 canine blood samples were tested for brucellosis antibodies. The seroprevalence of brucellosis was 22.86% (25/105) in children and 1.3% (1/80) in dogs using the Card, buffered acidified plate antigen, and standard plate agglutination tests but was 0% using the rivanol precipitation plate agglutination test.

Conclusion

Given that brucellosis can be caused by both smooth and rough colony strains, there is a need to modify the current serological surveillance strategy (targeted at only Brucella abortus and other smooth colony Brucella strains) to figure out the relative contribution of rough colony Brucella strains (B. ovis and B. canis). Since Uganda is endemic for brucellosis there is a need to modify the brucellosis surveillance strategy.

Detection of Brucella spp. in raw milk from various livestock species raised under pastoral production systems in Isiolo and Marsabit Counties, northern Kenya

Introduction

Brucellosis is an important zoonotic disease in Kenya, and identifying the bacteria in milk is important in assessing the risk of exposure in people.

Methods

A cross-sectional study that involved 175 households was implemented in the pastoral counties of Marsabit and Isiolo in Kenya. Pooled milk samples (n = 164) were collected at the household level, and another 372 were collected from domesticated lactating animals (312 goats, 7 sheep, 50 cattle and 3 camels). Real-time polymerase chain reaction (qPCR) testing of the milk samples was performed to identify Brucella species. Brucella anti-LPS IgG antibodies were also detected in bovine milk samples using an indirect enzyme-linked immunosorbent assay (ELISA).

Results

Based on the qPCR, the prevalence of the pathogen at the animal level (considering samples from individual animals) was 2.4% (95% confidence interval (CI) 1.1–4.5) and 3.0% (CI: 1.0–7.0) in pooled samples. All 14 samples found positive by qPCR were from goats, with 10 contaminated with B. abortus and 4 with B. melitensis. The Brucella spp. antibody prevalence in bovine milk using the milk ELISA was 26.0% (95% CI: 14.6–40.3) in individual animal samples and 46.3% (95% CI: 30.7–62.6) in pooled samples.

Conclusion

The study is the first in Kenya to test for Brucella spp. directly from milk using qPCR without culturing for the bacteria. It also detected B. abortus in goats, suggesting transmission of brucellosis between cattle and goats. The high prevalence of Brucella spp. is a significant public health risk, and there is a need for intervention strategies necessary in the study area.

Electronic supplementary material

The online version of this article (10.1007/s11250-020-02389-1) contains supplementary material, which is available to authorized users.

Zoonotic Pathogens of Dromedary Camels in Kenya: A Systematised Review

Kenya is home to Africa’s third largest population of dromedary camels, and production at commercial and local levels are increasingly important. In pastoral and nomadic communities in the arid and semi-arid lands (ASALs), camels play a vital role in food security, while commercial milk production and formalized export markets are rapidly emerging as camel populations expand into non-traditional areas. Until recently, little focus was placed on camels as hosts of zoonotic disease, but the emergence of Middle Eastern respiratory coronavirus (MERS-CoV) in 2012, and the discovery of exposure to the virus in Kenyan camels, highlighted the need for further understanding of this area. This systematised review utilised a robust search strategy to assess the occurrence of camel-associated zoonoses in Kenya and to evaluate the quality of the published literature. Seventy-four studies were identified, covering sixteen pathogens, with an increasing number of good quality studies in recent years. Despite this, the area remains under-researched and there is a lack of robust, high-quality research. Trypanosome spp., Echinococcus granulosus and Brucella spp. appeared most frequently in the literature. Pathogens with the highest reported prevalence were MERS-CoV (0–100%), Echinococcus granulosa (7–60%) and Rift Valley fever virus (7–57%). Exposure to Brucella spp., Coxiella burnetii and Crimean-Congo haemorrhagic fever virus showed higher levels in camel or camel-associated vectors than other livestock species, although brucellosis was the only disease for which there was robust evidence linking camel and human exposure. Zoonotic agents with less severe human health outcomes, such as Dermatophilosus congolensis and contagious ecthyma, were also represented in the literature. This review provides an important summary of the scope and quality of current knowledge. It demonstrates that further research, and improved adherence to robust study design and reporting are essential if the zoonotic risk from camels in Kenya, and elsewhere, is to be better understood.

Molecular characterization of Brucella species detected in humans and domestic ruminants of pastoral areas in Kagera ecosystem, Tanzania

Brucellosis is a zoonotic disease of importance to both public health and the livestock industry. The disease is likely to be endemic in Tanzania and little is reported on molecular characterization of Brucella species in pastoral settings. This study aimed at characterizing Brucella species (targeting genus Brucella) infecting humans, cattle and goat in Kagera region (Ngara and Karagwe districts) using real-time PCR, PCR amplification of 16S rRNA genes and Sanger sequencing. Brucella spp. were detected in 47 samples (19 sera and 28 milk) out of 125 samples (77 sera, 35 milk and 13 aborted materials) using real-time PCR. All aborted materials (13 samples) were negative to real-time PCR. Out of the 47 real-time PCR positive samples (28 milk and 19 sera), 20 samples (10 milk and 10 sera) showed an expected 16S rRNA gene PCR product. Sequence analysis and blasting confirmed the presence of Brucella spp. in pastoral areas of Kagera region. The Brucella spp. from Kagera were phylogenetically grouped in two clades and three branches all closer to B. melitensis, B. abortus and B. suis from USA, Sudan and Iran. However, they were distinct from other species isolated also in USA, New Zealand, Germany and Egypt. This was expected based on the distance between the geographical regions from which the data (nucleotides sequences from 16S gene sequencing) for the phylogeny reconstruction were obtained. This is the first study to report Brucella species identified using 16S rRNA gene sequencing in East and Central Africa. A livestock vaccination program re-inforced with a high index of Brucella diagnosis is needed to eradicate brucellosis in animals and minimize suffering from Brucella infections in humans in Tanzania.

Serological and molecular evidence of Brucella species in the rapidly growing pig sector in Kenya

BACKGROUND

Brucellosis is an emerging yet neglected zoonosis that has been reported in Kenya. Epidemiological data on brucellosis in ruminants is readily accessible; however, reports on brucellosis in pigs remain limited. This study sought to detect Brucella infection in pig serum by both serological and molecular techniques. Serum from 700 pigs randomly collected at a centralized abattoir in Nairobi region, Kenya were screened in parallel, using both Rose Bengal Test (RBT) and competitive Enzyme-Linked Immuno-sorbent Assay (cELISA) for antibodies against Brucella spp. All sera positive by RBT and 16 randomly selected negative samples were further tested using conventional PCR targeting bcsp31 gene and real-time PCR (RT-PCR) assays targeting IS711 and bcsp31 genes.

RESULTS

A prevalence of 0.57% (n = 4/700) was estimated using RBT; none of these samples was positive on cELISA. All RBT positive sera were also positive by both PCRs, while two sero-negative samples also tested positive on RT-PCR (n = 6/20). Brucella abortus was detected in four out of the six PCR positive samples through a real-time multiplex PCR.

CONCLUSION

The detection of antibodies against Brucella spp. and DNA in serum from slaughterhouse pigs confirm the presence of Brucella in pigs. Therefore, investigation of the epidemiology and role of pigs in the transmission of brucellosis in Kenya is needed. Further targeted studies would be useful to systematically quantify and identify the spp. of Brucella in pigs.

Prevalence and speciation of brucellosis in febrile patients from a pastoralist community of Tanzania

Brucellosis is an endemic zoonosis in sub-Saharan Africa. Pastoralists are at high risk of infection but data on brucellosis from these communities are scarce. The study objectives were to: estimate the prevalence of human brucellosis, identify the Brucella spp. causing illness, describe non-Brucella bloodstream infections, and identify risk factors for brucellosis in febrile patients from a pastoralist community of Tanzania. Fourteen (6.1%) of 230 participants enrolled between August 2016 and October 2017 met study criteria for confirmed (febrile illness and culture positivity or ≥four-fold rise in SAT titre) or probable (febrile illness and single SAT titre ≥160) brucellosis. Brucella spp. was the most common bloodstream infection, with B. melitensis isolated from seven participants and B. abortus from one. Enterococcus spp., Escherichia coli, Salmonella enterica, Staphylococcus aureus and Streptococcus pneumoniae were also isolated. Risk factors identified for brucellosis included age and herding, with a greater probability of brucellosis in individuals with lower age and who herded cattle, sheep or goats in the previous 12 months. Disease prevention activities targeting young herders have potential to reduce the impacts of human brucellosis in Tanzania. Livestock vaccination strategies for the region should include both B. melitensis and B. abortus.

Risk factors for acute human brucellosis in Ijara, north-eastern Kenya

Brucellosis is an important zoonotic disease globally, with particularly high burdens in pastoral settings. While the zoonotic transmission routes for Brucella spp. are well known, the relative importance of animal contact, food-handling and consumption practices can vary. Understanding the local epidemiology of human brucellosis is important for directing veterinary and public health interventions, as well as for informing clinical diagnostic decision making. We conducted a cross-sectional study in Ijara District Hospital, north-eastern Kenya. A total of 386 individuals seeking care and reporting symptoms of febrile illness were recruited in 2011. Samples were tested for the presence of Brucella spp. using a real-time PCR (RT-PCR) and results compared to those from the test for brucellosis used at Ijara District Hospital, the febrile Brucella plate agglutination test (FBAT). A questionnaire was administered to all participants and risk factors for brucellosis identified using logistic regression with an information theoretic (IT) approach and least absolute shrinkage and selection (LASSO). Sixty individuals were RT-PCR positive, resulting in a prevalence of probable brucellosis of 15.4% (95% CI 12.0-19.5). The IT and LASSO approaches both identified consuming purchased milk as strongly associated with elevated risk and boiling milk before consumption strongly associated with reduced risk. There was no evidence that livestock keepers were at different risk of brucellosis than non-livestock keepers. The FBAT had poor diagnostic performance when compared to RT-PCR, with an estimated sensitivity of 36.6% (95% CI 24.6-50.1) and specificity of 69.3% (95% CI 64.0-74.3). Brucellosis is an important cause of febrile illness in north-eastern Kenya. Promotion of pasteurisation of milk in the marketing chain and health messages encouraging the boiling of raw milk before consumption could be expected to lead to large reductions in the incidence of brucellosis in Ijara. This study supports the growing evidence that the FBAT performs very poorly in the diagnosis of brucellosis.

Relationship of meteorological factors and human brucellosis in Hebei province, China

BACKGROUND

Brucellosis has always been one of the major public health problems in China. Investigating the influencing factors of brucellosis is conducive to its prevention and control. The incidence trend of brucellosis shows an obvious seasonality, suggesting that there may be a correlation between brucellosis and meteorological factors, but related studies were few. We aimed to use the autoregressive integrated moving average (ARIMA) model to analyze the relationship between meteorological factors and brucellosis.

METHODS

The data of monthly incidence of brucellosis and meteorological factors in Hebei province from January 2004 to December 2015 were collected from the Chinese Public Health Science Data Center and Chinese meteorological data website. An ARIMA model incorporated with covariables was conducted to estimate the effects of meteorological variables on brucellosis.

RESULTS

There was a highest peak from May to July every year and an upward trend during the study period. Atmospheric pressure, wind speed, mean temperature, and relative humidity had significant effects on brucellosis. The ARIMA(1,0,0)(1,1,0)₁₂ model with the covariates of atmospheric pressure, wind speed and mean temperature was the optimal model. The results showed that the atmospheric pressure with a 2-month lag (β = -0.004, p = 0.037), the wind speed with a 1-month lag (β = 0.030, p = 0.035), and the mean temperature with a 2-month lag (β = -0.003, p = 0.034) were significant predictors.

CONCLUSION

Our study suggests that atmospheric pressure, wind speed, mean temperature, and relative humidity have a significant impact on brucellosis. Further understanding of its mechanism would help facilitate the monitoring and early warning of brucellosis.