Characteristics of fungal flora in onion farmlands with potential link to human mycotic keratitis |
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| Authors: | Ching-Wen Chang Yaw-Huei Hwang Zuei-Ching Chen Chi-Kung Ho Mao-Yen Chen |
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| Institution: | 1. Institute of Environmental Health, College of Public Health, National Taiwan University , Taipei, Taiwan, Republic of China;2. Department of Public Health , College of Public Health, National Taiwan University , Taipei, Taiwan, Republic of China cchang@ha.mc.ntu.edu.tw;4. Department of Public Health , College of Public Health, National Taiwan University , Taipei, Taiwan, Republic of China;5. Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University , Taipei, Taiwan, Republic of China;6. Department of Botany , National Taiwan University , Taipei, Taiwan, Republic of China;7. Graduate Institute of Occupational Safety and Health, Kaohsiung Medical University , Kaohsiung, Taiwan, Republic of China;8. Department of Occupational Medicine , Kaohsiung Medical University Hospital , Kaohsiung, Taiwan, Republic of China |
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| Abstract: | Acquisition of mycotic keratitis has been linked to agricultural activities. Although fungi were identified in injured eyes, data derived directly from farmlands are limited. Following five cases of fungal corneal ulcers in onion harvesters in the monsoon area of Taiwan, the present study further determined fungi genera and their concentrations in onion crops and surface soils of onion farmlands. In total, 52, 100 and 100 samples of soils, onion leaves and bulb scales, respectively, were collected from three monsoon and one non-monsoon farmlands. Fungal colonies were counted and microscopically examined after incubation at 25°C for 4–7 days on malt extract agar with 40?g?mL?1 chloramphenicol. Results showed the peak fungi levels were mostly observed at harvest time. Among keratitis-related fungi, Aspergillus predominated in soils as well as in onion bulb scales, while Alternaria in onion leaves. Cladosporium was also prevalent in soils, onion leaves and scales. Other keratitis-related fungi included Acremonium, Curvalaria, Fusarium, Mycelia, Penicillium, Rhizoctonia and Rhizopus. The present study provides an exposure link between onion harvesters and presence of keratitis-related fungi from onion crops and soils, which may account for mycotic ocular infection via hand-to-eye contact and airborne transmission during the monsoon season. |
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