## 4 Discussion  
Indoor dampness and visible mold growth are known to be linked to allergies and respiratory illnesses [17]. However, knowledge is limited regarding these molds' compositions and diversities, especially in tropical countries such as Thailand. In this study, we aimed to characterize fungal assemblages on indoor surfaces with visible mold growths in homes in Thailand. We compared the results of this Thai study with those of our previous study in South Korea [18]. It is important to understand the possible geographical differences, since dampness problems differ between countries with different climate characteristics and building structures [32]. There are four categories of sources of dampness in buildings: outdoor, indoor, building sources, and accidents [32]. The sources might be different in each country. For instance, indoor dew condensation due to cold outdoor temperatures might be a major source of dampness in winter heating seasons in South Korea (indoor source) [18], whereas floods might be an important source of dampness in monsoon seasons in southern Thailand (outdoor source). To date, several studies have reported airborne fungi in flood-damaged homes [4; 12; 13; 14]. In Thailand, previous studies reported post-flood measurements of concentrations of airborne fungi in a hospital after the 2011 flood disaster [13; 14]. It is similarly important to conduct post-flood measurements of fungal communities on surfaces, since airborne fungi originate from indoor surfaces laden with mold growths [33]. In this study, we analyzed fungal assemblages on indoor surfaces laden with visible mold growths in homes after the 2016 flood disaster in the historically neglected  
Figure 6: Relative abundances of the nine most abundant genera detected against both the UNITE and RefSeq databases. (**a**) _Leptospora_, (**b**) _Cystobasidium_, (**c**) _Pyrenochaetopsis_, (**d**) _Trichoderma_, (**e**) _Alternaria_, (**f**) _Nederviesia_, (**g**) _Wickerhamomyces_, (**h**) _Arthrinium_, and (**i**) _Cyhellophora_. Dashed lines indicate 1:1 ratios. southern part of Thailand. The sampling site is situated in a tropical zone that experiences heavy rainfalls every year. Flood disasters are known to be followed by human health problems [34]. In this study, we analyzed fungal communities, including the genera related to human allergens and infectious pathogens, using high-throughput DNA sequencing. The Institute of Medicine indicated the association of indoor dampness and molds with upper respiratory tract symptoms such as coughing, wheezing, asthma, and hypersensitivity pneumonitis in susceptible individuals [35]. Thus, the indoor molds observed in this study might present a risk for such symptoms in residents in flood-damaged homes in the southern rural parts of Thailand. Our previous study conducted in South Korea showed that _Cladosporium_ was the most abundant genus, with a mean relative abundance of 41%, on indoor surfaces with visible molds [18]. Our present study in Thailand showed that _Cladosporium_ was not abundant, with a mean relative abundance of 0.055%, on surfaces with visible molds in flood-damaged homes (Figure 5). P-tests showed significant differences in the fungal assemblage memberships (\(p<0.001\)) and structures (\(p=0.0005\)) between the two countries (Figure 2). These results suggest that indoor visible fungal communities are different between the two countries. Various factors can affect indoor visible fungal communities, which might include building structure as well as regional climate and mycoforlad characteristics. Additionally, the communities might be affected by the different sources of dampness (i.e., flood vs. dew condensation). We do not know the causes of the difference in fungal assemblages on indoor visible molds observed between our two different studies. Nonetheless, our observations indicate possible geographical differences in the taxonomic structures of indoor visible molds. We also observed commonalities between the two countries.