Tyzzer's disease in a neonatal rainbow lorikeet (Trichoglossus haematodus)

A captive-born 8-day-old male rainbow lorikeet (Trichoglossus haematodus) was found dead. Histologically, there were necrotizing hepatitis, myocarditis, and ventriculitis. Silver stain revealed argyrophilic filamentous bacilli within hepatocytes, smooth myofibers of the gizzard, and cardiac myofibers surrounding foci of necrosis. Immunohistochemistry using anti-Clostridium piliforme RT and MSK strain antisera reacted positively against bacilli within hepatocytes, cardiac myofibers, smooth myofibers of the gizzard, and splenic and intestinal macrophages. Polymerase chain reaction (PCR) assay of paraffin-embedded liver, heart, gizzard, spleen, and small intestine amplified the 196-bp DNA fragment specific to 16S ribosomal RNA of C. piliforme. The results of histopathology, immunohistochemistry, and PCR are consistent with C. piliforme infection in this lorikeet.