Temporal variations in air pollution at two roundabouts in the city of Cotonou, Benin

Background: Air pollution has caused health and environmental problems around the world. In this study we analysed the temporal evolution of air pollution in Cotonou regarding the standards of Benin and of World Health Organization (WHO). Methods: Solar-powered electrochemical sensors (CO: carbon monoxide, SO2: sulphur dioxide, and O3/NO2: ozone/nitrogen dioxide) and photoionization detectors (for NMVOC: nonmethane volatile organic compounds) were permanently installed and monitored from June 2019 to March 2020 at Akpakpa PK3 (A) and Vèdokô Cica-Toyota (B) roundabouts. Results: CO and SO2 concentrations at both roundabouts were significantly higher on weekends than on weekdays. The concentrations of NMVOC and O3 / NO2 on Sunday differed considerably from the other days of the week at A and B, respectively. There was a positive linear correlation between the concentrations of CO and SO2, O3 / NO2 and SO2, and CO O3 / NO2 to B, and only between CO and O3 / NO2, in A. At the two sites, the average of SO2 concentrations (in μg/m3) were higher than the WHO standard (500) for an exposure of 10 minutes (2258 A and 2143 B) and the Benin standard (1300) for 1 hour exposure (2181 in A and 2092 in B). Conclusion: Air pollution varies in hours and days in Cotonou. Standards are respected, except for SO2. Particular attention should be paid to the concentrations and the possible sources of gas. More sophisticated monitoring system should be put in place

Clinical Epidemiology of Buruli ulcer from Benin (2005-2013): effect of time-delay to diagnosis on clinical forms and severe phenotypes

Buruli Ulcer (BU) is a neglected infectious disease caused by Mycobacterium ulcerans that is responsible for severe necrotizing cutaneous lesions that may be associated with bone involvement. Clinical presentations of BU lesions are classically classified as papules, nodules, plaques and edematous infiltration, ulcer or osteomyelitis. Within these different clinical forms, lesions can be further classified as severe forms based on focality (multiple lesions), lesions' size (>15 cm diameter) or WHO Category (WHO Category 3 lesions). There are studies reporting an association between delay in seeking medical care and the development of ulcerative forms of BU or osteomyelitis, but the effect of time-delay on the emergence of lesions classified as severe has not been addressed. To address both issues, and in a cohort of laboratory-confirmed BU cases, 476 patients from a medical center in Allada, Benin, were studied. In this laboratory-confirmed cohort, we validated previous observations, demonstrating that time-delay is statistically related to the clinical form of BU. Indeed, for non-ulcerated forms (nodule, edema, and plaque) the median time-delay was 32.5 days (IQR 30.0-67.5), while for ulcerated forms it was 60 days (IQR 20.0-120.0) (p = 0.009), and for bone lesions, 365 days (IQR 228.0-548.0). On the other hand, we show here that time-delay is not associated with the more severe phenotypes of BU, such as multi-focal lesions (median 90 days; IQR 56-217.5; p = 0.09), larger lesions (diameter >15 cm) (median 60 days; IQR 30-120; p = 0.92) or category 3 WHO classification (median 60 days; IQR 30-150; p = 0.20), when compared with unifocal (median 60 days; IQR 30-90), small lesions (diameter =15 cm) (median 60 days; IQR 30-90), or WHO category 1+2 lesions (median 60 days; IQR 30-90), respectively. Our results demonstrate that after an initial period of progression towards ulceration or bone involvement, BU lesions become stable regarding size and focal/multi-focal progression. Therefore, in future studies on BU epidemiology, severe clinical forms should be systematically considered as distinct phenotypes of the same disease and thus subjected to specific risk factor investigation.The research leading to these results received funding from the Health Services of the Fundacao Calouste Gulbenkian under the grant Proc. No94776 LJ; from the Fundacao para a Ciecia e Tecnologia (FCT), cofunded by Programa Operacional Regional do Norte (ON.2-O Novo Norte); from the Quadro de Referencia Estrategico Nacional (QREN) through the Fundo Europeu de Desenvolvimento Regional (FEDER) and from the Projeto Estrategico - LA 26 - 2013-2014 (PEst-C/SAU/LA0026/2013). A. G. Fraga received an individual FCT fellowship (SFRH/BPD/68547/2010) and J. Menino received an individual QREN fellowship (UMINHO/BPD/14/2014). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Genetic variation in autophagy-related genes influences the risk and phenotype of Buruli ulcer

Introduction Buruli ulcer (BU) is a severe necrotizing human skin disease caused by Mycobacterium ulcerans. Clinically, presentation is a sum of these diverse pathogenic hits subjected to critical immune-regulatory mechanisms. Among them, autophagy has been demonstrated as a cellular process of critical importance. Since microtubules and dynein are affected by mycolactone, the critical pathogenic exotoxin produced by M. ulcerans, cytoskeleton-related changes might potentially impair the autophagic process and impact the risk and progression of infection. Objective Genetic variants in the autophagy-related genes NOD2, PARK2 and ATG16L1 has been associated with susceptibility to mycobacterial diseases. Here, we investigated their association with BU risk, its severe phenotypes and its progression to an ulcerative form. Methods Genetic variants were genotyped using KASPar chemistry in 208 BU patients (70.2% with an ulcerative form and 28% in severe WHO category 3 phenotype) and 300 healthy endemic controls. Results The rs1333955 SNP in PARK2 was significantly associated with increased susceptibility to BU [odds ratio (OR), 1.43; P = 0.05]. In addition, both the rs9302752 and rs2066842 SNPs in NOD2 gee significantly increased the predisposition of patients to develop category 3 (OR, 2.23; P = 0.02; and OR 12.7; P = 0.03, respectively, whereas the rs2241880 SNP in ATG16L1 was found to significantly protect patients from presenting the ulcer phenotype (OR, 0.35; P = 0.02). Conclusion Our findings indicate that specific genetic variants in autophagy-related genes influence susceptibility to the development of BU and its progression to severe phenotypes.The research leading to these results received funding from the Health Services of the Fundação Calouste Gulbenkian under the grant Proc.N°94776 LJ; from the Fundação para a Ciência e Tecnologia (FCT), cofunded by Programa Operacional Regional do Norte (ON.2—O Novo 267 Norte); from the Quadro de Referência Estratégico Nacional (QREN) through the Fundo Europeu de Desenvolvimento Regional (FEDER) and from the Projeto Estratégico – LA 26 – 2013–2014 (PEst-C/SAU/LA0026/2013). JFM received an individual QREN fellowship (UMINHO/BPD/14/2014); CCu and AGF received an individual FCT fellowship (SFRH/BPD/96176/2013 and SFRH/BPD/68547/2010, respectively); and AC received an FCT contract (IF/00735/2014). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript

Buruli ulcer treatment:Rate of surgical intervention differs highly between treatment centers in West Africa

BACKGROUND: Antibiotic treatment proved itself as the mainstay of treatment for Buruli ulcer disease. This neglected tropical disease is caused by Mycobacterium ulcerans. Surgery persists as an adjunct therapy intended to reduce the mycobacterial load. In an earlier clinical trial, patients benefited from delaying the decision to operate. Nevertheless, the rate of surgical interventions differs highly per clinic. METHODS: A retrospective study was conducted in six different Buruli ulcer (BU) treatment centers in Benin and Ghana. BU patients clinically diagnosed between January 2012 and December 2016 were included and surgical interventions during the follow-up period, at least one year after diagnosis, were recorded. Logistic regression analysis was carried out to estimate the effect of the treatment center on the decision to perform surgery, while controlling for interaction and confounders. RESULTS: A total of 1193 patients, 612 from Benin and 581 from Ghana, were included. In Benin, lesions were most frequently (42%) categorized as the most severe lesions (WHO criteria, category III), whereas in Ghana lesions were most frequently (44%) categorized as small lesions (WHO criteria, category I). In total 344 (29%) patients received surgical intervention. The percentage of patients receiving surgical intervention varied between hospitals from 1.5% to 72%. Patients treated in one of the centers in Benin were much more likely to have surgery compared to the clinic in Ghana with the lowest rate of surgical intervention (RR = 46.7 CI 95% [17.5-124.8]). Even after adjusting for confounders (severity of disease, age, sex, limitation of movement at joint at time of diagnosis, ulcer and critical sites), rates of surgical interventions varied highly. CONCLUSION: The decision to perform surgery to reduce the mycobacterial load in BU varies highly per clinic. Evidence based guidelines are needed to guide the role of surgery in the treatment of BU

Psychometric Properties of the Participation Scale among Former Buruli Ulcer Patients in Ghana and Benin

Background: Buruli ulcer is a stigmatising disease treated with antibiotics and wound care, and sometimes surgical intervention is necessary. Permanent limitations in daily activities are a common long term consequence. It is unknown to what extent patients perceive problems in participation in social activities. The psychometric properties of the Participation Scale used in other disabling diseases, such as leprosy, was assessed for use in former Buruli ulcer patients. Methods: Former Buruli ulcer patients in Ghana and Benin, their relatives, and healthy community controls were interviewed using the Participation Scale, Buruli Ulcer Functional Limitation Score, and the Explanatory Model Interview Catalogue to measure stigma. The Participation Scale was tested for the following psychometric properties: discrimination, floor and ceiling effects, internal consistency, inter-item correlation, item-total correlation and construct validity. Results: In total 386 participants (143 former Buruli ulcer patients with their relatives (137) and 106 community controls) were included in the study. The Participation Scale displayed good discrimination between former Buruli ulcer patients and healthy community controls. No floor and ceiling effects were found. Internal consistency (Cronbach's alpha) was 0.88. In Ghana, mean inter-item correlation of 0.29 and item-total correlations ranging from 0.10 to 0.69 were found while in Benin, a mean inter-item correlation of 0.28 was reported with item-total correlations ranging from 20.08 to 0.79. With respect to construct validity, 4 out of 6 hypotheses were not rejected, though correlations between various constructs differed between countries. Conclusion: The results indicate the Participation Scale has acceptable psychometric properties and can be used for Buruli ulcer patients in Ghana and Benin. Future studies can use this Participation Scale to evaluate the long term restrictions in participation in daily social activities of former BU patients

Family Relationship, Water Contact and Occurrence of Buruli Ulcer in Benin

Mycobacterium ulcerans disease (Buruli ulcer) is the most widespread mycobacterial disease in the world after leprosy and tuberculosis. How M. ulcerans is introduced into the skin of humans remains unclear, but it appears that individuals living in the same environment may have different susceptibilities. This case control study aims to determine whether frequent contacts with natural water sources, family relationship or the practice of consanguineous marriages are associated with the occurrence of Buruli ulcer (BU). The study involved 416 participants, of which 104 BU-confirmed cases and 312 age, gender and village of residence matched controls (persons who had no signs or symptoms of active or inactive BU). The results confirmed that contact with natural water sources is a risk factor. Furthermore, it suggests that a combination of genetic factors may constitute risk factors for the development of BU, possibly by influencing the type of immune response in the individual, and, consequently, the development of BU infection per se and its different clinical forms. These findings may be of major therapeutic interest

Implementation of a Decentralized Community-based Treatment Program to Improve the Management of Buruli Ulcer in the Ouinhi District of Benin, West Africa

Background: Mycobacterium ulcerans infection, commonly known as Buruli ulcer (BU), is a debilitating neglected tropical disease. Its management remains complex and has three main components: antibiotic treatment combining rifampicin and streptomycin for 56 days, wound dressings and skin grafts for large ulcerations, and physical therapy to prevent functional limitations after care. In Benin, BU patient care is being integrated into the government health system. In this paper, we report on an innovative pilot program designed to introduce BU decentralization in Ouinhi district, one of Benin’s most endemic districts previously served by centralized hospital-based care. Methodology/Principal Findings: We conducted intervention-oriented research implemented in four steps: baseline study, training of health district clinical staff, outreach education, outcome and impact assessments. Study results demonstrated that early BU lesions (71% of all detected cases) could be treated in the community following outreach education, and that most of the afflicted were willing to accept decentralized treatment. Ninety-three percent were successfully treated with antibiotics alone. The impact evaluation found that community confidence in decentralized BU care was greatly enhanced by clinic staff who came to be seen as having expertise in the care of most chronic wounds. Conclusions/Significance: This study documents a successful BU outreach and decentralized care program reaching early BU cases not previously treated by a proactive centralized BU program. The pilot program further demonstrates the added value of integrated wound management for NTD control

Detection of Mycobacterium ulcerans in the Environment Predicts Prevalence of Buruli Ulcer in Benin

Background: Mycobacterium ulcerans is the causative agent of Buruli ulcer (BU). In West Africa there is an association between BU and residence in low-lying rural villages where aquatic sources are plentiful. Infection occurs through unknown environmental exposure; human-to-human infection is rare. Molecular evidence for M. ulcerans in environmental samples is well documented, but the association of M. ulcerans in the environment with Buruli ulcer has not been studied in West Africa in an area with accurate case data. Methodology/Principal Finding: Environmental samples were collected from twenty-five villages in three communes of Benin. Sites sampled included 12 BU endemic villages within the Ouheme and Couffo River drainages and 13 villages near the Mono River and along the coast or ridge where BU has never been identified. Triplicate water filtrand samples from major water sources and samples from three dominant aquatic plant species were collected. Detection of M. ulcerans was based on quantitative polymerase chain reaction. Results show a significant association between M. ulcerans in environmental samples and Buruli ulcer cases in a village (p = 0.0001). A ‘‘dose response’ ’ was observed in that increasing numbers of M. ulceran- positive environmental samples were associated with increasing prevalence of BU cases (R 2 = 0.586). Conclusions/Significance: This study provides the first spatial data on the overlap of M. ulcerans in the environment and BU cases in Benin where case data are based on active surveillance. The study also provides the first evidence on M. ulcerans i

Data from: Spatial analysis of anthropogenic landscape disturbance and Buruli ulcer disease in Benin

Background: Land use and land cover (LULC) change is one anthropogenic disturbance linked to infectious disease emergence. Current research has focused largely on wildlife and vector-borne zoonotic diseases, neglecting to investigate landscape disturbance and environmental bacterial infections. One example is Buruli ulcer (BU) disease, a necrotizing skin disease caused by the environmental pathogen Mycobacterium ulcerans (MU). Empirical and anecdotal observations have linked BU incidence to landscape disturbance, but potential relationships have not been quantified as they relate to land cover configurations. Methodology/Principal Findings: A landscape ecological approach utilizing Bayesian hierarchical models with spatial random effects was used to test study hypotheses that land cover configurations indicative of anthropogenic disturbance were related to Buruli ulcer (BU) disease in southern Benin, and that a spatial structure existed for drivers of BU case distribution in the region. A final objective was to generate a continuous, risk map across the study region. Results suggested that villages surrounded by naturally shaped, or undisturbed rather than disturbed, wetland patches at a distance within 1200m were at a higher risk for BU, and study outcomes supported the hypothesis that a spatial structure exists for the drivers behind BU risk in the region. The risk surface corresponded to known BU endemicity in Benin and identified moderate risk areas within the boundary of Togo. Conclusions/Significance: This study was a first attempt to link land cover configurations representative of anthropogenic disturbances to BU prevalence. Study results identified several significant variables, including the presence of natural wetland areas, warranting future investigations into these factors at additional spatial and temporal scales. A major contribution of this study included the incorporation of a spatial modeling component that predicted BU rates to new locations without strong knowledge of environmental factors contributing to disease distribution