Mycobacterium genavense is a common cause of mycobacteriosis in birds, and an occasional cause of atypical mycobacteriosis in immunosuppressed humans.3-7 Within zoological institutions housing a variety of birds, diagnosis of avian mycobacteriosis can be challenging due to the lack of reliable ante-mortem tests.8 In 2009, a Lady Gouldian finch (Chloebia gouldiae) was diagnosed on postmortem examination with Mycobacterium genavense. It had been housed in a free-flight, walk-through, single-species aviary that was contained within a larger free-flight, walk-through, multi-species aviary. In the State of Iowa, M. genavense, as part of the Avian Mycobacteria-Complex (MAC), is reportable to the Iowa State Department of Agriculture.2 The Blank Park Zoo developed a protocol to identify infected and shedding finches which included necropsy of all deceased birds and annual group fecal M. genavense direct PCR screening using primers MG22 and MG23.1 In 2011, the flock of finches was subdivided into groups and pooled feces from each group submitted for M. genavense direct PCR which was detected in one pooled sample from a group of 11 finches. These 11 birds were euthanatized and submitted for necropsy. Hepatic granulomas were evident in 7/11 finches and acid-fast organisms were identified in granulomas in 5 of these 7 birds. In 2012, 82 finches were again divided into six groups, and feces pooled for direct PCR testing; these tests were negative. From 2009 to the present, necropsy of deceased finches and birds in the surrounding aviary did not reveal any evidence of mycobacterial disease.
The authors appreciate the avian caretakers and veterinary support team at the Blank Park Zoo for their assistance in obtaining samples and caring for these animals. Special thanks also to Dr. David Schmitt, State Veterinarian for the State of Iowa, for assistance with the interpretation of the Iowa Codes and Rules.
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2. Code of Iowa, chapter 163 (Infectious and Contagious Diseases Among Animals): 163.1, 163.2, 163.10, and the Iowa Administrative Code of Rules, chapter 21–64.1(163). 2012. https://www.legis.iowa.gov/IowaLaw/statutory Law.aspx (VIN editor: Link was not accessible 12-16-20.)
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