Identification of Aspergillus terreus and Aspergillus pseudonomiae as causative agents of aspergillosis in endangered Okinawa Rails

Sofia Rivelli Zea¹Yumiko Nakaya²Hiroki Takahashi³Takashi Nagamine²Takashi Yaguchi³Takahito Toyotome^3,4,5*

• ¹National Service for Quality and Animal Health (SENACSA), San Lorenzo, Paraguay
• ²Okinawa Wildlife Federation, Uruma, Japan
• ³Chiba Daigaku Shinkin Igaku Kenkyu Center, Chiba, Japan
• ⁴International University of Health and Welfare, Narita, Narita, Japan
• ⁵Obihiro Chikusan Daigaku, Obihiro, Japan

Aspergillosis is a serious infectious disease in avian species, including endangered birds. However, reports in such species remain scarce. This study focused on the Okinawa Rail (Hypotaenidia okinawae), an endangered flightless bird restricted to the northern forests of Okinawa, Japan. Using culture-based isolation, antifungal susceptibility testing, aflatoxin assays, and whole-genome sequencing, we identified and characterized Aspergillus terreus and Aspergillus pseudonomiae as causative agents of aspergillosis in two captive Okinawa Rails. In Case 1, an A. terreus isolate showed low susceptibility to voriconazole. Whether this low susceptibility was intrinsic or acquired during antifungal treatment remains unclear. Two phenotypically distinct isolates of A. pseudonomiae were obtained from the second case. One of them lacked sclerotia and aflatoxin production, suggesting a possible adaptation during infection. This is the first report of A. pseudonomiae isolation from animal hosts in Japan. Accurate identification and genomic analysis of Aspergillus isolates provide insights into antifungal resistance and the ecological dynamics of aspergillosis in Okinawa's forest environment, highlighting implications for wildlife conservation.