La brucellose à l’aube du 21e siècle

Impact of herd mobility on brucellosis seroprevalence and spread risk resulting from cross-border transhumance

BACKGROUND

Cross-border livestock mobility through transhumance is mainly practiced in West African countries for seasonal access to resources and market. Cross-border herds are involved in the dynamic of transboundary animal diseases among them brucellosis taken as model. Brucellosis is a zoonotic disease causing abortion.

OBJECTIVES

This study explores the seroprevalence of brucellosis according to mobility and infection spread between Mali and Côte d'Ivoire in the context of seasonal cross-border transhumance.

METHODS

From February to April 2021, a transversal serological survey of brucellosis was conducted on 521 cattle from 111 transhumant herds and 283 cattle from 59 sedentary herds, all from Mali.

RESULTS

The global individual seroprevalence for Brucella spp. in transhumant and sedentary cattle from Mali was 8.2% (95% CI = 6.0-10.5). At herd level, seroprevalence was 21.2% with a significant variation between transhumant (11.7%) and sedentary (39.0%) herds. For herds in transhumance, cattle seropositivity was associated with a previous infection suspected by herdsmen odds ratio (OR = 4.4; 95% CI = 1.1-18.1) and unknown abortion aetiology (OR = 4.3; 95% CI = 1.0-17.3). The departure region (coming from Sikasso) and previous brucellosis infection or unexplained abortion could be used to predict Brucella infection in transhumant herds with a probability of around 60%. The risk of brucellosis introduction in host regions was high despite the individual animal seroprevalence of 3.6% and a low sale rate in transhumant cattle.

CONCLUSIONS

The findings suggest that testing transhumant during border control and survey of cattle markets and sales could improve risk control of the spread of disease at regional scale.

Original and introduced lineages co-driving the persistence of Brucella abortus circulating in West Africa

Introduction

Brucellosis, a serious public health issue affecting animals and humans, is neglected in West Africa (WA).

Methods

In the present study, bio-typing, multi-locus sequence typing (MLST), multiple-locus variable-number tandem repeat analysis (MLVA), and whole genome sequencing single-nucleotide polymorphism (WGS-SNP) analysis were used to characterize the Brucella abortus (B. abortus) strains from WA.

Results

All of the 309 strains analyzed in this study were extracted and downloaded from the international MLVA bank and were from 10 hosts (cattle, humans, ovine, buffalo, dromedaries, horse, sheep, zebu, dog, and cat) distributed in 17 countries in WA. Based on the bio-typing, three biovars, dominated by B. abortus bv.3, were observed and reported across seven decades (1958–2019). With MLST, 129 B. abortus strains from the present study were sorted into 14 STs, with ST34 as the predicted founder. These 14 STs clustered into the global MLST data into three clone complexes (C I–C III) with the majority of strains clustering in C I, while C II forms an independent branch, and C III harbors three STs shared by different continents. These data revealed that most cases were caused by strains from native lineages. According to the MLVA-11 comparison, 309 strains were divided into 22 MLVA-11 genotypes, 15 of which were unique to WA and the remaining seven had a global distribution. MLVA-16 analysis showed that there were no epidemiological links among these strains. Based on the MLVA data, B. abortus strains from WA have high genetic diversity, and predominated genotypes were descended from a native lineage. While the MLVA-16 globally highlights that the dominant native and few introduced lineages (from Brazil, the USA, South Korea, Argentina, India, Italy, Portugal, the UK, Costa Rica, and China) co-driving the B. abortus ongoing prevalence in WA. The high-resolution SNP analysis implied the existence of introduced B. abortus lineages, which may be reasonably explained by the movement and trade of dominant hosts (cattle) and/or their products.

Discussion

Our results indicated that B. abortus strains in WA consist of native and introduced strains that necessitate control such as vaccination, testing, slaughtering, and movement control by the relevant country authorities to reduce brucellosis in livestock.

Establishment of brucellosis relapse and complications registry: a study protocol

Brucellosis is an endemic bacterial zoonotic disease in developing countries; that is a serious public health problem in Iran. Brucellosis is a life-threatening multi-system disease in human with different clinical manifestations, complications and relapse. The incidence of brucellosis in Hamadan province, west of Iran is high. In addition, there is few reliable and population-based studies regarding relapse and complications of brucellosis in developing countries, therefore establishment of the registry system in areas with adequate occurrence of cases is needed to better understand the predictors of brucellosis relapse and complications and management of the disease. Detecting occurrence of relapse and complications over time and by geographical area provide information for further investigations and identification of health system deficiencies in the management of patients.

Clinical Presentations of Brucellosis Over a Four-Year Period at Sultan Qaboos University Hospital and Armed Forces Hospital, Muscat, Oman

Objectives

Brucellosis is a highly contagious zoonotic disease which can have serious health implications for affected humans and livestock. This study aimed to evaluate the clinical presentation, geographical distribution and risk factors of brucellosis cases admitted over a four-year period to two hospitals in Muscat, Oman.

Methods

This observational study was conducted from January 2015 to December 2018 at the Sultan Qaboos University Hospital and Armed Forces Hospital in Muscat. All patients with probable or definitive diagnoses of brucellosis according to the diagnostic criteria of the World Health Organization were included. Relevant data were gathered from the patients’ medical records, including results from standard agglutination tests, Brucella enzyme-linked immunosorbent assays, bacterial blood or tissue/aspirate cultures and Brucella polymerase chain reaction tests.

Results

A total of 64 patients were diagnosed with brucellosis over the study period. The median age was 31.5 years and 73.4% were male. The majority (95.2%) presented with fever, followed by weight loss (51%), transaminitis (48.4%), peripheral arthritis/arthralgia (15.9%) and back pain (spondylodiscitis/sacroiliitis; 23.4%). Overall, 75.5% reported having consumed raw dairy products, while only 25.9% gave a positive history of animal contact.

Conclusion

Patients with brucellosis presented with a wide range of clinical features, the most predominant of which was fever. The majority of patients were residents of or had recently visited Salalah and had consumed raw dairy products. These findings highlight the need for healthcare practitioners to maintain a high index of suspicion for this diagnosis. Moreover, further regulatory measures are necessary to oversee the sale of raw/unpasteurised dairy products.

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

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

Pancytopenia revealing acute brucellosis

Brucellosis is the most prevalent bacterial zoonosis worldwide. The WHO estimates that the infection is responsible for more than 500 000 cases per year across the world [1].

Hematological complications like mild anemia and leukopenia have been frequently associated with acute brucellosis, but pancytopenia and thrombocytopenia are less frequently encountered [2]. We are reporting the case of a 73 year old male patient, with pancytopenia that revealed acute brucellosis. Following 6 weeks of antibiotic therapy, our patient showed favorable clinical outcome, and the complete blood count returned to normal. Acute brucellosis should be highly suspected in patients with pancytopenia.

Risk factors for human brucellosis among a pastoralist community in South-West Kenya, 2015

Objective

Brucellosis is one of the top five priority zoonosis in Kenya because of the socio-economic burden of the disease, especially among traditional, livestock keeping communities. We conducted a 1 year, hospital based, unmatched case–control study to determine risk factors for brucellosis among Maasai pastoralists of Kajiado County in 2016. A case was defined by a clinical criteria; fever or history of fever and two clinical signs suggestive of brucellosis and a positive competitive enzyme-linked immunosorbent assay test (c-ELISA). A control was defined as patients visiting the study facility with negative c-ELISA. Unconditional logistic regression was used to study association between exposure variables and brucellosis using odds ratios (OR) and 95% confidence intervals (CI).

Results

Forty-three cases and 86 controls were recruited from a population of 4792 individuals in 801 households. The mean age for the cases was 48.7 years while that of the controls was 37.6 years. The dominant gender for both cases (62.7%) and controls (58.1%) groups was female. Regular consumption of un-boiled raw milk and assisting animals in delivery were significantly associated with brucellosis by OR 7.7 (95% CI 1.5–40.1) and OR 3.7 (95% CI 1.1–13.5), respectively.

Complete Genome Sequencing of 10 Brucella abortus Biovar 3 Strains Isolated from Water Buffalo

Brucellosis is a zoonotic disease that affects both humans and animals. Its distribution is global, concentrated in the Mediterranean area, India, Central Asia, and Latin America. Here, we present a complete genome assembly of 10 Brucella abortus strains isolated from water buffaloes farmed in the Campania region of Italy.

Sero-prevalence of Bovine Brucellosis and associated risk factors in mbeya region, Southern highlands of Tanzania

A cross-sectional study was conducted to establish the seroprevalence of brucellosis and associated risk factors in indigenous and exotic breeds of cattle from 178 farms in Mbeya region. A total of 1211 cattle (929exotic cattle from 108 commercial farms and 282 indigenous cattle from 70 traditional farms) were tested for Brucella antibodies using the Rose Bengal Plate Test (RBPT) and competitive Enzyme Linked Immunosorbent Assay (c-ELISA) as screening and confirmatory tests, respectively. The overall animal-level seroprevalence was 9.3%; 11.3% (95% CI: 9.4-13.5) in indigenous cattle and 2.8% (95% CI:1.4-5.6) in exotic cattle. Further, the overall herd level seroprevalence was 32.0%; 50.5% (95% CI: 40.9-59.9) in indigenous cattle and 4.2% (95% CI: 1.3-12.4) in exotic cattle. Infections were higher in cattle aged 6-10 years old, (39.8%; 95% CI: 31.2-49.1) followed by those aged 1-5 years (5.8%; 95% CI: 4.8-6.6) and 11-15years old (2.7%; 95% CI: 0.8-8). When compared to cattle sampled from herds size of 1-50, those sampled from the herd sizes of 51-100 and 101-150 had higher odds of brucellosis seropositivity [(OR=3.6, CI: 1.76-7.16, p<0.001) and (OR=3.0, CI: 1.09-8.04, p=0.033). The odds of seropositivity in animals which calved on pasture was 3.0 (CI: 1.1-7.8, p=0.028) compared to those that calved at home. Brucella seroprevalence was also observed to vary according to districts, with Mbarari district recording the highest (45.4%). It is evident from the study that Brucellosis is present in Mbarari, Mbeya and Momba districts of Mbeya Region. The findings of this study provide some baseline data that could contribute to the design and implementation of brucellosis control measures in the study areas.

First case-control study of zoonotic brucellosis in Gafsa district, Southwest Tunisia

A case-control study was conducted, aimed to describe the clinical human brucellosis (CHB) pattern during 2015 in the Gafsa region (Southwest Tunisia) and to investigate the main risk factors involved in the disease occurrence. One hundred and four CHB cases were notified in 2015 in Gafsa district. All CHB cases that own ruminants were contacted, but only 32 accepted to participate in a matched case-control study. Thirty-two and thirty-one CHB cases and controls, respectively, were included in the study. The subjects were interviewed using a structured questionnaire. A total of 662 domestic ruminants (cattle, sheep and goats) belonging to cases and controls, were screened using the Rose Bengal Test, as recommended by the World Organisation of Animal Health. During 2015, the incidence of CHB was estimated to 30.8 per 100,000 inhabitants affecting mainly males aged between 30 and 39 years. The overall animal seropositivity to Brucella, was 21 and 1.9% in case and control farms, respectively (p < 0.0001). Only five risk factors were found to be significant: overall animal seropositivity (OR = 65.2; 95%CI: 13.3–318.7); handling aborted females (OR = 43.1; 95%CI: 8.3–222.7); presence of male ruminants in the herds (OR = 18.5; 95%CI: 5.18–66); owning seropositive goats (OR = 18.3; 95%CI: 2.4–137.6), owning seropositive sheep (OR = 9.66; 95%CI: 2.9–31.5) and history of abortion during the previous year in the herd (OR = 4.6; 95%CI: 1.3–12.6). Vaccination of animals against brucellosis was associated with lower odds of human brucellosis (OR = 0.03; 95%CI: 0.004–0.2). Raw milk and derivatives consumption was not a risk factor of human brucellosis. Based on this study, ruminants' vaccination coverage should be increased by enhancing the number of vaccinated animals and systematically including male ruminants in Tunisia. Comprehensive education programmes targeting both farmers and general population should be implemented.

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The human brucellosis in Gafsa district (Southwest Tunisia) was estimated to 30.8 per 100,000 inhabitants.

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Handling aborted females increase significantly the risk of human brucellosis.

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Comprehensive education programmes targeting both farmers and general population should be implemented.

Exploring the Diversity of Field Strains of Brucella abortus Biovar 3 Isolated in West Africa

Brucellosis is one of the most widespread bacterial zoonotic diseases in the world, affecting both humans and domestic and wild animals. Identification and biotyping of field strains of Brucella are of key importance for a better knowledge of the epidemiology of brucellosis, for identifying appropriate antigens, for managing disease outbreaks and for setting up efficient preventive and control programmes. Such data are required both at national and regional level to assess potential threats for public health. Highly discriminative genotyping methods such as the multiple locus variable number of tandem repeats analysis (MLVA) allow the comparison and assessment of genetic relatedness between field strains of Brucella within the same geographical area. In this study, MLVA biotyping data retrieved from the literature using a systematic review were compared using a clustering analysis and the Hunter-Gaston diversity index (HGDI). Thus, the analysis of the 42 MLVA genotyping results found in the literature on West Africa [i.e., from Ivory Coast (1), Niger (1), Nigeria (34), The Gambia (3), and Togo (3)] did not allow a complete assessment of the actual diversity among field strains of Brucella. However, it provided some preliminary indications on the co-existence of 25 distinct genotypes of Brucella abortus biovar 3 in this region with 19 genotypes from Nigeria, three from Togo and one from Ivory Coast, The Gambia, and Niger. The strong and urgent need for more sustainable molecular data on prevailing strains of Brucella in this sub-region of Africa and also on all susceptible species including humans is therefore highlighted. This remains a necessary stage to allow a comprehensive understanding of the relatedness between field strains of Brucella and the epidemiology of brucellosis within West Africa countries.

Epidemiological and clinical characteristics of neurobrucellosis case patients in Tunisia

OBJECTIVE

We aimed to identify epidemiological, clinical, therapeutic, diagnostic, and outcome characteristics of neurobrucellosis case patients in Tunisia.

PATIENTS AND METHODS

We conducted a retrospective and descriptive study over a 17-year period (January 1997-December 2013). We included all neurobrucellosis patients hospitalized in the infectious disease department of La Rabta Hospital of Tunis during the study period.

RESULTS

A total of 13 patients were included in the study: 9 men and 4 women. Mean age was 31.6 years. Six patients presented with meningitis, three with encephalitis, two with meningoencephalitis, and two with meningo-myeloradiculitis. All patients had a lumbar puncture performed. Eleven patients had an abnormal cerebrospinal fluid (CSF) (84.6%): lymphocytic pleocytosis in seven patients, high level of CSF proteins in 11, and low level of CSF glucose in seven. All patients had a positive Brucella serological test in blood. A Brucella serological test was also performed in CSF and was positive for 10 patients (77%). A total of nine patients had a cerebral CT scan and/or MRI performed and abnormalities were observed in six patients. Antibiotic therapy was prescribed to all patients: a combination of rifampicin and co-trimoxazole (n=9) or doxycycline (n=4) for an average duration of eight months. Two patients also received steroids. A positive outcome was observed in 10 patients. Three patients were lost to follow up.

CONCLUSION

Brucellosis may be severe when neurological involvement occurs. Brucellosis should be considered in the event of any neurological involvement associated with suggestive epidemiological features.

The Brucella pathogens are polarized bacteria

Brucella pathogens are responsible for brucellosis, a worldwide zoonosis. They are facultative intracellular pathogens characterized by their asymmetric division and their unipolar growth. This growth modality generates poles with specialized functions (through polar recruitment of polar adhesins or of cell cycle regulators) and progeny cells with potentially different fates.

The status of bovine brucellosis in Ethiopia with special emphasis on exotic and cross bred cattle in dairy and breeding farms

A cross-sectional study was conducted to investigate the seroprevalence of brucellosis and identify risk factors in exotic and cross bred cattle in Ethiopia. A total of 2334 cattle from 273 farms were tested serially for Brucella antibodies using the Rose Bengal Plate Test (RBPT) and the Compliment Fixation Test (CFT). The overall animal level seroprevalence was 1.9% (95% CI: 1.2, 2.6), with urban and peri-urban dairy 2.4% (95% CI: 1.4, 3.4), commercial 1.5% (95% CI: 0.5, 2.5) and breeding farms 1.5% (95% CI: 0.2, 3.2). The overall farm level prevalence was 10.6% (95% CI: 6.9, 14.3), with 8.6% (95% CI: 4.8, 12.4) in urban and peri-urban dairy followed by 16.9% (95% CI: 7.3, 26.6) in commercial and 20.0% (95% CI: 0.0, 59.4) in breeding farms. At individual animal level, purchased cows and adult age groups were observed to associate with Brucella seropositivity while presence of small ruminants on the farm was the only factor associated with increased risk of herd level Brucella infection. The lack of association between reproductive disorders and Brucella seroprevalence suggest that other causes largely outweigh as causes of the aforesaid disorder in studied production systems and demands an investigation. Finally, the need for isolation and characterization of circulating Brucella spp. and institution of regulatory measures to reinforce farm biosecurity was suggested.

Acute postinfectious glomerulonephritis with native aorta valve endocarditis and myopericarditis due to brucellosis

Human brucellosis is a systemic disease that involves multiple organs and tissues concomitantly. In this case, we describe a patient with pancarditis and nephrotic syndrome requiring hemodialyses, which is an unusually fatal condition resulting from brucellosis. He was successfully treated with early aortic valve replacement and intensive medical therapy.

Brucellosis seroprevalence in livestock in Uganda from 1998 to 2008: a retrospective study

A total of 17,359 samples were analysed serologically, of which 1,061, 15,758 and 585 samples were from Makerere, Entebbe and Tororo laboratories, respectively, were used to determine the seroprevalence of brucellosis. The overall seroprevalence of brucellosis was 10% while from individual laboratories was 38%, 32% and 7% for Makerere, Entebbe and Tororo laboratories, respectively. Majority of these positive brucellosis test results were in the cattle corridor with P value = 0.399. There were significant differences in brucellosis seroprevalence among species (P value = 0.014). The trends of brucellosis seroprevalence among the different species were decreasing with time but were highest in bovine species (P value = 0.043). Brucellosis seroprevalence had a bimodal monthly pattern corresponding with rainfall. The study showed that brucellosis was prevalent, though the trend of the disease has declined over years. It was recommended that regular disease surveillance, control programmes and further studies be carried out in the country.

PESQUISA DE FATORES DE RISCO PARA A BRUCELOSE HUMANA ASSOCIADOS À PRESENÇA DE BRUCELOSE BOVINA NO MUNICÍPIO DE CORRENTES, ESTADO DE PERNAMBUCO, BRASIL

RESUMO Objetivou-se com este estudo investigar a presença de anticorpos anti-Brucella abortus em grupos ocupacionais envolvidos com a criação de bovinos no Município de Correntes, Estado de Pernambuco, avaliando-se os fatores de risco associados à infecção em humanos, e estimar a prevalência em rebanhos bovinos leiteiros. Para tanto, foram colhidas 1.089 amostras de bovinos adultos e de 56 pessoas e examinadas pelo teste do antígeno acidificado tamponado (AAT). As amostras humanas foram submetidas à soroaglutinação lenta em tubos (SAL) e ao 2-mercaptoetanol (2-ME) e, quando reagentes a uma ou ambas as técnicas, para qualquer título, foram examinadas pela técnica de fixação do complemento (FC). Adicionalmente, pessoas submetidas à colheita de sangue foram solicitadas a responder um questionário investigativo. A prevalência para bovinos foi de 6,8% (74/1.089) obtidas através da SAL e 2-ME, e em humanos de 1,8% (1/56) ao AAT. Na SAL foi observada positividade em 21,4% (12/56) das amostras humanas, não havendo, entretanto, amostras reagentes ao 2-ME (0% 0/12) e ao FC (0% 0/12). Os fatores de risco estudados: consumo de leite cru e seus derivados, contato com secreções, manipulação de carnes, uso de luvas e transmissão iatrogênica na manipulação de vacina B19 não foram analisados estatisticamente, pois não se detectou nenhum indivíduo positivo ao teste de fixação do complemento. Os resultados deste estudo sugerem que a população da zona rural do Município de Correntes, PE, encontra-se exposta à infecção por B. abortus, embora não se possa inferir a existência de intercorrência entre a infecção bovina e a humana. De qualquer forma uma vigilância maior por parte das autoridades sanitárias deve ser implementada.

[Clinical manifestations, complications and treatment of brucellosis: 45-patient study]

The aim of this study was to evaluate the clinical, laboratory findings and therapeutic features of patients with brucellosis. The diagnosis was made by clinical findings, automated blood culture, serology (Rose Bengal plate agglutination test, standard tube agglutination (Wright) and immunofluorerescence). The susceptibility of 13 strains was tested in vitro. The base sequence was determined for four strains. Forty-five cases were collected (31 acute and 14 sub-acute). Contamination was digestive in 62%. Symptoms of patients were fever (93%), sweating (82%), arthralgia (78%) and splenomegaly (51%). Elevated erythrocyte sedimentation rate was determined in 80%, leukopenia in 49% and anaemia in 37% of cases. Blood cultures were positives in 39% of cases. The four sequenced strains were identified as Brucella melitensis biovar abortus. Six strains were resistant to sufomethoxazol-trimetoprim (54%). In 93% of cases, the treatment was associated rifampicin and doxycyclin. One patient died. No relapse was reported.

Chronic Brucella infection of the humerus diagnosed after a spontaneous fracture

Brucellosis is uncommon in humans and only rarely manifests as osteomyelitis. We report the case of a 57-year-old patient with chronic Brucella osteomyelitis of both humeri. The diagnosis was established upon evaluation of a spontaneous fracture of the right humerus. The organism was recovered in fluid draining to the skin from an abscess located in the bone and soft tissues.