Mitigating Clandestine Gold-Mining Risks to Human and Animal Health by Conserving the Ecological Integrity of Their Shared Environment: An Example of Joint Investigation into Heavy Metal Intoxication Using a One-Health Approach in Kedougou, Senegal

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Résumé

Alerted to an unusual event (a cluster of 10 acute flaccid paralyses (AFP), including two deaths) in Kedougou, it was urgent to initiate a joint, multisectoral and transdisciplinary mission to investigate this event. Thus, 12 animal cases and 19 additional human cases were found, totaling 29 human cases, 61% of which were found in the community and the remainder in health facilities around gold-mining sites. The human median age was 27 years, with a predominance of women (62%). The epidemic curve showed a regular appearance of neurological disorders with no increase, suggesting a persistent source of contamination. Simultaneously, toxicological analyses confirmed excessive concentrations of mercury, lead and cadmium in the Bantaco well water, which were, respectively, 571.66, 4397 and 740 times higher than the standards. In the village of Pondala, these concentrations were 911.66 (mercury), 9741 (lead) and 1063.33 (cadmium) times higher. Elsewhere, these significant environmental concentrations of heavy metals were also found in human blood, urine and hair, at levels more than 50 times the standards set by the WHO. In addition, virological tests confirmed non-polio enterovirus in 85% of children (0–15 years) with AFP, whereas this percentage was 0% for the over-15s. Finally, animal health was mainly concerned with lameness in the sheep found in the villages of Bantaco and Pondala. They were also predominantly female (91.66%), with 66.66% of the animals in the 0–2-year age group. Farming was extensive in 50% of cases, although there was some evidence of foaming sputum (25%) and notion of abortion (16.66%). Finally, this joint investigation enabled corrective measures to be implemented, including raising awareness among stakeholders of the dangers of the misuse and unregulated use of heavy metals, pending the implementation of a plan to resolve the problems encountered on site.

Mots-clés

Acute flaccid paralysis, Heavy metal poisoning, Artisanal gold mining, Environmental contamination, One Health investigation