The hostile conditions at informal and illegal mining sites in the Amazonian forest erode the miner’s health, exposing workers to a broad range of diseases because most of the gold is extracted using mercury (Hg). The Hg vapor used daily at gold panning sites presents an environmental threat to the ecosystems and human health. We report the case of a 58-year-old man who has worked in gold panning for over 30 years, presented with diffuse interstitial pneumonia characterized by bilateral images of ground glass and mosaic opacities on the chest CT scan. Based on the negative differential diagnosis (cardiovascular, infectious, autoimmune or cancer), the context of chronic exposure to Hg in a patient who has been working for decades on illegal gold panning sites, we concluded to a chronic form of heavy metal hypersensitivity pneumonia. This hypothesis was supported by high levels of mercury in blood and urine. Mercury hypersensitivity pneumonia might be more frequent than presently thought with thousands of workers chronically exposed to high mercury concentrations among others pollutants. Medical practitioners should systematically seek for chronic respiratory illnesses associated with pollutants exposure in these vulnerable workers with poor health.
Introduction
Unlike diseases caused by Mycobacterium tuberculosis, M. leprae and M. ulcerans, the epidemiology of pulmonary non-tuberculous mycobacteria (PNTM) has not received due attention in French Guiana. The main objective of the current study was to define the incidence of these PNTM infections: NTM pulmonary diseases (NTM-PD) and casual PNTM isolation (responsible of latent infection or simple colonization). The secondary objectives were to determine species diversity and geographic distribution of these atypical mycobacteria.
Methods
A retrospective observational study (2008–2018) of French Guiana patients with at least one PNTM positive respiratory sample in culture was conducted. Patients were then classified into two groups: casual PNTM isolation or pulmonary disease (NTM-PD), according to clinical, radiological and microbiological criteria defined by the American Thoracic Society / Infectious Disease Society of America (ATS / IDSA) in 2007.
Results
178 patients were included, out of which 147 had casual PNTM isolation and 31 had NTM-PD. Estimated annual incidence rate of respiratory isolates was 6.17 / 100,000 inhabitants per year while that of NTM-PD was 1.07 / 100,000 inhabitants per year. Among the 178 patients, M. avium complex (MAC) was the most frequently isolated pathogen (38%), followed by M. fortuitum then M. abscessus (19% and 6% of cases respectively), the latter two mycobacteria being mainly found in the coastal center region. Concerning NTM-PD, two species were mainly involved: MAC (81%) and M. abscessus (16%).
Discussion/Conclusion
This is the first study on the epidemiology of PNTM infections in French Guiana. PNTM’s incidence looks similar to other contries and metropolitan France and NTM-PD is mostly due to MAC and M.abscessus. Although French Guiana is the French territory with the highest tuberculosis incidence, NTM should not be overlooked.
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