Classification of Cryptococcus neoformans and Yeast-Like Fungus Isolates from Pigeon Droppings by Colony Phenotyping and ITS Genotyping and Their Seasonal Variations in Korea

Diversity and abundance of human‐pathogenic fungi associated with pigeon faeces in urban environments

“…Of these, 42 OTUs representing 35 species were identified as potentially pathogenic (CRF). A comparison of these results with previous, culture‐dependent studies of pigeon faeces fungal diversity in the same location (Chae et al., ; Jang et al., ) showed that 15 species were unique to these previous studies, 28 were unique to our study, and seven were found in both studies.…”

“…Seoul is an ideal place to evaluate the relationship between pigeons and potentially pathogenic fungal diversity because it has a large, dense human population (>24 million in the greater metropolitan area: the fourth largest in the world) and, as is true with most other major cities in the world, pigeon populations have dramatically increased in tandem with the increase in human urbanization (Moller et al., ). In addition, previous culture‐based studies in the Seoul area have identified several potentially pathogenic fungi in pigeon faeces (Chae et al., ; Chee & Lee, ; Jang et al., ).…”

“…To understand the importance of pigeons as potential vectors or facilitators in the spread of pathogenic fungi in human populations, the diversity and abundance of potentially pathogenic fungi in pigeon faeces must be further investigated. To date, approximately 48 species of potentially pathogenic fungi from 28 genera have been isolated from pigeons globally (Chae et al., ; Haag‐Wackernagel & Moch, ; Jang et al., ; Khosravi, ; Ramirez, Robertstad, Hutchinson, & Chavez, ; Soltani, Bayat, Hashemi, Zia, & Pestechian, ; Tokarzewski, ). This is likely a substantial underestimate because most reports were based on culture‐dependent methods, and the majority of fungi are not readily cultured (Pace, ; Rappe & Giovannoni, ).…”

Environmental Factors That Contribute to the Maintenance of Cryptococcus neoformans Pathogenesis

“…These birds re-introduce the cryptococcal cells into the environment by releasing their droppings into the soil [104]. The bird droppings lower the pH of the contaminated soil (due to the presence of uric acid in the excreta), which can favour the replication of the cryptococcal cells [16]. Cryptococcal cells form capsules for protection against harsh conditions through the upregulation of highly conserved pH-response regulatory genes [18].…”

“…When desiccated yeast cells or basidiospores are inhaled, they can lodge in the alveoli of hosts-despite airway turbulence in the respiratory tract [16]-leading to the development of primary lung infection [2]. In immunocompetent individuals, the immune system is usually able to clear the invading fungal cells from the body [17].…”