Prevalence of COVID-19 at the Wahgnion-Gold mining site in Burkina Faso and use of RT-PCR initial cycle threshold to monitor the dynamics of SARS-CoV-2 load

Background: To control the spread of coronavirus disease-19 (COVID-19) caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), it is necessary to adequately identify and isolate infectious patients particularly at the work place. Real time polymerase chain reaction (RT-PCR) assay is the recommended confirmatory method for the diagnosis of SARS-CoV-2 infection. The aim of this study was to determine the prevalence of SARSCoV-2 infection in Burkina Faso and to use the initial cycle threshold (Ct) values of RT-PCR as a tool to monitor the dynamics of the viral load. Methodology: Between September 2021 and February 2022, oropharyngeal and/or nasopharyngeal swab samples of consecutively selected COVID-19 symptomatic and apparently healthy workers from the Wahgnion mining site in the South-western Burkina Faso who consented to the study were collected according to the two weeks shift program and tested for SARS-CoV-2 using RT-PCR assay. Patients positive for the virus were followed-up weekly until tests were negative. Association of the initial RT-PCR Ct values with disease duration was assessed by adjusted linear regression approach. Two-sided p value < 0.05 was considered statistically significant. Results: A total of 1506 (92.9% males) participants were recruited into the study, with mean age and age range of 37.18.7 and 18-68 years respectively. The overall prevalence of SARS-CoV-2 infection was 14.3% (216/1506). Of the 82 patients included in the follow-up study, the longest duration of positive RT-PCR test, from the first positive to the first of the two negative RT-PCR tests, was 33 days (mean 11.6 days, median 10 days, interquartile range 8- 14 days). The initial Ct values significantly correlated with the duration of RT-PCR positivity (with ß=-0.54, standard error=0.09 for N gene, and ß=-0.44, standard error=0.09 for ORF1ab gene, p<0.001). Participants with higher Ct values corresponding to lower viral loads had shorter viral clearance time than those of lower Ct values or higher viral loads. Conclusion: Approximately 1 out of 7 tested miners had SARS-CoV-2 infection and the duration of their RT-PCR tests positivity independently correlated with the initial viral load measured by initial Ct values. As participants with lower initial Ct values tended to have longer disease duration, initial RT-PCR Ct values could be used to guide COVID-19 patient quarantine duration particularly at the work place.

Contexte: Pour contrôler la propagation de la maladie à coronavirus 19 (COVID-19) causée par le syndrome respiratoire aigu sévère coronavirus-2 (SRAS-CoV-2), il est nécessaire d'identifier et d'isoler de manière adéquate les patients infectieux, en particulier sur le lieu de travail. Le test de réaction en chaîne par polymérase en temps réel (RT-PCR) est la méthode de confirmation recommandée pour le diagnostic de l'infection par le SRAS-CoV-2. Le but de cette étude était de déterminer la prévalence de l'infection par le SRAS-CoV-2 au Burkina Faso et d'utiliser les valeurs du seuil initial du cycle (Ct) de la RT-PCR comme outil de suivi de la dynamique de la charge virale. Méthodologie: Entre septembre 2021 et février 2022, des écouvillonnages oropharyngés et/ou nasopharyngés de travailleurs symptomatiques COVID-19 et apparemment en bonne santé sélectionnés consécutivement du site minier de Wahgnion dans le sud-ouest du Burkina Faso qui ont consenti à l'étude ont été prélevés selon les deux programme de quart de semaines et testé pour le SRAS-CoV-2 à l'aide d'un test RT-PCR. Les patients positifs pour le virus ont été suivis chaque semaine jusqu'à ce que les tests soient négatifs. L'association des valeurs Ct initiales de la RT-PCR avec la durée de la maladie a été évaluée par une approche de régression linéaire ajustée. Une valeur p bilatérale < 0,05 a été considérée comme statistiquement significative. Résultats: Un total de 1506 participants (92,9% d'hommes) ont été recrutés dans l'étude, avec un âge moyen et une tranche d'âge de 37,1 à 8,7 ans et de 18 à 68 ans, respectivement. La prévalence globale de l'infection par le SRAS-CoV-2 était de 14,3% (216/1506). Sur les 82 patients inclus dans l'étude de suivi, la plus longue durée de test RT-PCR positif, du premier test positif au premier des deux tests RT-PCR négatifs, était de 33 jours (moyenne 11,6 jours, médiane 10 jours, intervalle interquartile 8-14 jours). Les valeurs Ct initiales étaient significativement corrélées à la durée de positivité de la RT-PCR (avec ß=-0,54, erreur standard=0,09 pour le gène N et ß=-0,44, erreur standard=0,09 pour le gène ORF1ab, p<0,001). Les participants avec des valeurs de Ct plus élevées correspondant à des charges virales plus faibles avaient un temps de clairance virale plus court que ceux avec des valeurs de Ct plus basses ou des charges virales plus élevées. Conclusion: Environ 1 mineur testé sur 7 était infecté par le SRAS-CoV-2 et la durée de la positivité de ses tests RTPCR était indépendamment corrélée à la charge virale initiale mesurée par les valeurs Ct initiales. Comme les participants avec des valeurs Ct initiales inférieures avaient tendance à avoir une durée de maladie plus longue, les valeurs Ct initiales de la RT-PCR pourraient être utilisées pour guider la durée de la quarantaine des patients COVID19, en particulier sur le lieu de travail.

Musculoskeletal disorders in operator drivers in northwestern Namibia ­ associated factors and awareness

Background: Operator drivers are responsible for driving trackless heavy-duty mining or construction vehicles such as graders, dumpers, loaders, and bulldozers. They have an increased prevalence of musculoskeletal disorders (MSDs) due to the nature of their work. There is a paucity of data on MSDs and associated factors among operator drivers in Namibia. Objective: We assessed awareness of, and factors associated with, MSDs among operator drivers in the construction and mining industries in Namibia. Methods: In this cross-sectional study, questionnaires were administered to operator drivers, and managerial staff were interviewed, using a semi-structured interview guide. Data obtained were analysed using chi-square tests and binary logistic regression modelling. Results: 182 operator drivers completed the questionnaires, and 13 operator drivers' supervisors and managers were interviewed. Factors associated with MSDs were length of service for ≥ 10 years (OR 15.3, 95% CI 6.0­39.0), alcohol consumption (OR 2.8, 95% CI 1.1­6.7), lack of physical fitness activity (OR 8.8, 95% CI 3.8­20.4), and lack of awareness of MSDs (OR 3.1, 95% CI 1.3­7.3). Managerial staff were of the opinion that the operator drivers did not suffer from MSDs. Conclusion: We found health issues that are associated with MSDs among the operator drivers, impacting their general wellness and productivity. Monitoring of health and wellness of these workers by the companies is recommended. There is need to increase MSD awareness, personal protective equipment usage, ergonomics skills training, and physical fitness exercises for operator drivers. Employers are urged to adopt policies, and to design guidelines and interventions aimed at promoting occupational health and safety in this population.

Occupational lung disease among Basotho ex-miners in a large outreach medical assessment programme

Background: Current initiatives in southern Africa to medically assess former migrant miners for silicosis and tuberculosis, including statutory and lawsuit derived compensation programmes, require burden of disease information. nObjective: To use clinical information collected on ex-miners examined at the Occupational Health Service Centre (OHSC) in Lesotho, operated under the Tuberculosis in Mining Sector in Southern Africa (TIMS) project, to measure the burden of lung disease and respiratory impairment. Methods: Demographic, occupational and medical history information, chest radiology, spirometry, GeneXpert testing for tuberculosis, and pulse oximetry outcomes were analysed, and descriptive summary measures calculated, in a group of ex-miners examined in 2017 and 2018. Results: The study sample comprised 2 758 Basotho former underground miners, with median age of 62 years and median length of service of 28 years. Among ex-gold miners (n = 2 678), disease prevalence was high: radiological tuberculosis (consistent with previous or current disease) 60.9%, silicosis 42.5%, HIV 30.7%, silicotuberculosis 25.7%, and current active tuberculosis 6.8%. Of those with tuberculosis diagnosed microbiologically, 6.7% had no radiological evidence of tuberculosis and 54.1% did not report cough. Conclusion: The findings have public health and compensation implications. There are large numbers of ex-miners with potentially compensable disease under both the statutory system and a settlement trust set up following litigation. This overlaps with a tuberculosis-HIV co-epidemic which requires screening and treatment for tuberculosis and HIV, and managing a considerable disability and care burden on families and the Lesotho health system. Coordinated planning and substantial resources are needed for these programmes to do justice to their mandates

Occupational noise-induced hearing loss in platinum miners: what do the data tell us?

Background: Occupational noise-induced hearing loss (ONIHL) is one of the most common occupational health diseases affecting miners in South Africa. Accurate and appropriate medical data are essential for making valid diagnoses. Objectives: The purpose of this study was to describe the electronic records of a South African platinum mine's audiometry medical surveillance system and their role in early diagnosis of ONIHL. Ear-related conditions of affected miners, occupations, and noise levels were concurrently reviewed, and the characteristics of miners with and without ONIHL were described. Methods: This was an analysis of secondary data from the electronic audiometry and employee occupational records of 305 platinum mine workers for the period 2014 to 2017. Data were analysed using descriptive statistics. Results: Although the audiometry records contained appropriate and relevant data, including annual hearing screening percentage loss of hearing (PLH) shifts, there was evidence of inaccurate and insufficient recording of risk factors for hearing loss in the medical surveillance records. The records indicated that the miners in some occupations were exposed to dangerously high noise levels, exceeding 85 dB(A). Miners as young as 21 years of age were diagnosed with ONIHL. Conclusion: The insufficient and inaccurate data captured in the miners' records has important implications for the mine's efficient implementation of hearing conservation programme (HCP) elements aimed at mitigating ONIHL. The hazardous noise levels recorded call for increased attempts to meet noise level regulations, while the presence of conditions such as pseudohypacusis highlights the need for exploration of more reliable assessment measures

Apport du bilan médical chez le travailleur de mines au Burkina Faso

L'inhalation de la poussière de silice issue de l'exploitation minière artisanale au Burkina Faso est associée à bon nombre de cas de pneumoconiose. Un bilan médical avant et après l'embauche du mineur devrait permettre d'en faire le diagnostic. Matériel et méthode : Il s'est agi d'une étude transversale rétrospective à visée descriptive de janvier 2010 à décembre 2012 chez des mineurs reçus dans des structures de soins de la ville de Ouagadougou pour des bilans de santé. Les données ont été collectées à l'aide d'un questionnaire renseigné au cours de l'exploitation de leurs dossiers. Résultats : Les 331 mineurs, tous de sexe masculin avaient un âge moyen de 33, 05 ± 5,9 ans [21- 54]. Parmi eux, 224 (67,7%) étaient venus pour une visite médicale d'embauche (VME). La consommation de tabac et d'alcool étaient retrouvée chez plus de 40% des mineurs à la VME. Aucun signe fonctionnel respiratoire et très peu d'anomalies radiographiques thoraciques (RT) avaient été rapportés chez les mineurs lors VME. A la visite médicale annuelle (VMA) les signes fonctionnels respiratoires étaient retrouvés chez 63,9% des mineurs, et dominés par la dyspnée d'effort (19,6%). La spirométrie révélait des troubles ventilatoires obstructifs (TVO) chez 40,9% des mineurs. La RT montrait des petites opacités arrondies de types « p » et « q » dans 33,3% des cas. Au total 57 mineurs (25,4%) ont été déclarés inaptes lors de cette VME. Conclusion : Le bilan de santé reste un maillon fort pour la prévention de l'apparition des maladies professionnelles dont la pneumoconiose chez tout travailleur de mines. Il devrait être complété aussi bien par des mesures préventives individuelles que collectives