Aspergillus section Nigri in indoor environments: a silent sentinel for occupational and public health

Aspergillus section Nigri, a filamentous fungus within the Aspergillus genus, proliferates in organic matter-rich environments and produces dark-pigmented spores. While recognized for its metabolic versatility and industrial applications, Aspergillus section Nigri also presents significant public health concerns, particularly in environmental and occupational settings. The fungus is known to produce mycotoxins (Ochratoxin A (OTA); Fumonisins), which pose risks to human health, including respiratory disorders and allergic reactions. Its prevalence is notably elevated in occupational environments such as industrial facilities and laboratories, where favorable conditions (e.g., elevated humidity and temperature) facilitate its growth. This study aimed to assess the distribution of Aspergillus section Nigri across various indoor environments and evaluate its implications for public and occupational health. The research was conducted in eight different indoor settings, including nursing homes (n = 15), archives (n = 25), municipal waste collection vehicles (n = 168), grocery stores (n = 101), gyms (n = 67), cemeteries (n = 72), fire stations (n = 360), and coffee industry facilities (n = 58). A total of 866 samples were collected using active (Coriolis µ air sampler, Millipore) and passive (electrostatic dust collectors, surface swabs, and settled dust) methods. Fungal growth was promoted through incubation at 25 ± 2°C, and identification was performed using lactophenol cotton blue staining and microscopic analysis. The distribution of Aspergillus section Nigri will be analyzed across all sampled environments to determine prevalence and potential exposure risks. This study highlights the need for enhanced surveillance of Aspergillus section Nigri in indoor environments to mitigate occupational and public health risks. Prolonged exposure may contribute to respiratory and allergic conditions, particularly in vulnerable populations. Preventive measures should be prioritized to reduce exposure in high-risk settings.