Fungal Assemblages on Indoor Surfaces with Visible Mold Growth in Homes after the 2016 Flood Disaster in Thailand

Abstract

Southern Thailand suffers from floods due to heavy rainfalls every year. Post-flood increases in indoor fungi are a public health concern. Here, we investigated fungal assemblages on indoor surfaces with visible mold growth in homes after the 2016 flood disaster in Trang Province in Southern Thailand, using swab sampling followed by high-throughput DNA sequencing of the fungal internal transcribed spacer 1 region. The most abundant phyla detected were Ascomycota and Basidiomycota, with respective mean relative abundances of 87% and 13%. The dominant genera and their mean relative abundances were Leptospora (12.0%), Cystobasidium (7.7%), and Pyrenochaetopsis (6.5%). P-tests showed that indoor visible fungal assemblages in flooded homes in Thailand were significantly different from those in the non-flooded mold-laden homes observed in our previous study in South Korea. We detected 20 genera that contain species that can induce type I allergies, including Alternaria (3.8%) and Trichoderma (4.0%). Genera related to infectious, melanized, and toxigenic fungi were also detected. Indoor fungal measurements gathered using a DNA-based approach revealed fungal communities in homes in Thailand and provide important information about the potential health risks. Future research should examine the fungal infections and allergies that might be caused by flood disasters in less well studied tropical countries.