Clinical and Pathological Aspects of SystemicInfection in Blue-crowned Laughing Thrushes () at Jersey Zoo.

Abstract

Based on a review of species mortalities, systemicspecies was identified as the primary cause of death in 22% (19 of 87) of blue-crowned laughing thrushes (BCLTs;) at the Jersey Zoo between 1997 and 2016. Fifty-eight percent of the affected birds were between 1 and 2 years old, and in 89% of cases, death occurred between August and December. Abnormal clinical findings in BCLTs withspecies infections included hepatomegaly and pectoral muscle myositis in 79% of the cases. The results of diagnostic blood testing in 90% of infected BCLTs 30 days before death were consistent with a severe leukocytosis with greater than 20% of mononuclear cells infected by merozoites. The most common lesions identified during gross necropsy examination were splenomegaly (100%), hepatomegaly (95%), and multifocal, raised, white foci in pectoral (84%) and heart (79%) muscle. Lymphohistiocytic inflammation was identified in the liver, heart, spleen, lung, striated muscle, and kidney tissue of birds with positive results forspecies. Merozoites were often observed in spleen, liver, pectoral muscle, and hearts of infected BCLTs. Polymerase chain reaction diagnostic testing that targeted the cytochromeoxidase subunit, followed by Sanger sequencing, was used to confirmspecies in all 14 birds tested. Of samples tested, the highest genetic correlation was with GenBank accession number KT203397 (species JRB-2016 mitochondrion).