The Use of Doramectin Reduces Respiratory Mite Associated Mortality in a Population of Gouldian Finches (Chloebia gouldiae).

Respiratory acariasis caused by the mite Sternostoma tracheacolum can result in significant disease in the Gouldian finch (Chloebia gouldiae), an endangered Australian passerine. A previous study published at the authors' institution reviewed morbidity and mortality of S. tracheacolum in Gouldian finches from May 2013 to March 2021 as well as a prophylactic ivermectin treatment protocol. The mite-associated mortality rate was 39%, with no reduction in mortality observed after ivermectin treatment. In response to this finding, the institution trialed an alternative prophylactic treatment protocol using doramectin in November 2021. Doramectin, an antiparasitic drug in the avermectin family, was administered to 68 Gouldian finches at a dosage of 1 mg/kg SC for 2 doses. The average time between doses was 15.8 days. Concurrently, meloxicam was also administered at 1 mg/kg SC. Treatment was well tolerated, with 2.8% (2/72) of the finches showing tachypnea immediately after the first treatment; this resolved within 10 days. A review of Gouldian finch mortality from January 2022 to December 2024 was performed. Mild mite infection was identified postmortem in 3.4% (2/58) of the mortalities but was not considered a significant contributor to death. Five (8.6%, 5/58) other birds had significant respiratory inflammation of undetermined origin, where mites were a possible etiology but could not be confirmed. This study describes a prophylactic doramectin protocol for Gouldian finches that effectively reduced mortality associated with S. tracheacolum.