Investigating an Outbreak of Aspergillus fumigatus Infection in a Racing Pigeon (Columba livia domestica) Flock

In this study, the clinical course, pathological findings, and potential risk factors of a systemic aspergillosis outbreak caused by Aspergillus fumigatus in racing pigeons (Columba livia domestica) were investigated. The disease was reported during the period of intense exercise in a 120 head racing pigeon flock. The exercise period coincided with the high environmental temperatures. Affected birds displayed symptoms, such as weakness, fatigue, depression, inability to stand, rapidly developing weakness, incoordination, convulsions, and death. Necropsy revealed varying sized, prominent nodular or plaque-like lesions on the lungs, air sacs, and visceral peritoneum. Single or multiple case- onecrotic fungal granulomas invading the existing and/or adjacent tissues were seen histopathologically. Malacic le- sions associated with fungal elements were observed in the central nervous system. Histopathologic and cytological findings revealed the presence of characteristic A. fumigatus elements and lesions. Considering the fact that the envi- ronmental temperatures were above the seasonal norms during the emergence of the disease as well as subjugation of pigeons to intense exercise for race preparations, A. fumigatus colonization and its spread in racing pigeons was seen likely due to the combined effects of these risk factors.