Renal disease in captive swift parrots (Lathamus discolor): Clinical findings and disease management

This report details the investigation of renal disease associated with neurologic signs and deaths in a captive research colony of the endangered swift parrot (Lathamus discolor). The syndrome affected birds irregularly during 11 months from October 1999 to September 2000. Ten birds from 4 aviaries were clinically affected, and 9 birds died. The most common clinical signs were weight loss, neurologic dysfunction (ataxia and generalized tremors), and articular gout. At necropsy, common findings included gross nephropathy, visceral gout, and gonadal regression or inflammation. Histopathologic changes included renal tubular degeneration and accumulations of black crystals, assumed to be urates, in renal tubules and collecting ducts. These histopathologic changes are nonspecific and could be associated with a wide variety of nephrotoxins including, but not limited to, heavy metals, organic solvents, phenol, antibacterial agents, pesticides, and ethylene glycol. The syndrome was associated with the feeding of a high-protein diet and the presence of nesting boxes and other environmental factors. A number of potentially toxic substances were found in the swift parrots' environment, including nitrate fertilizer, zinc from galvanized wire, and potentially toxic wood fragments (Tasmanian sassafras [Atherosperma moschatum]). However, not all affected birds were exposed to these toxins, or diagnostic testing ruled them out of consideration. Regardless of the initial cause of renal damage, the overall renal pathologic changes were consistent with a urate nephropathy. There is still uncertainty as to the initial cause of the neurologic disease and renal damage despite the intensive investigation described here. The immediate deterioration of 2 swift parrots after the reintroduction of the high-protein diet led us to suspect that dietary levels of protein might be a contributing factor to the renal disease

Ventral dermatitis in rowi (Apteryx rowi) due to cutaneous larval migrans

The rowi is a critically endangered species of kiwi. Young birds on a crèche island showed loss of feathers from the ventral abdomen and a scurfy dermatitis of the abdominal skin and vent margin. Histology of skin biopsies identified cutaneous larval migrans, which was shown by molecular sequencing to be possibly from a species of Trichostrongylus as a cause of ventral dermatitis and occasional ulcerative vent dermatitis. The predisposing factors that led to this disease are suspected to be the novel exposure of the rowi to parasites from seabirds or marine mammals due to the island crèche and the limited management of roost boxes. This is the first instance of cutaneous larval migrans to be recorded in birds. Severe and fatal complications of the investigation resulted in the death of eight birds of aspergillosis and pulmonary complications associated with the use of bark as a substrate in hospital. Another bird died of renal failure during the period of hospitalisation despite oral and intravenous fluid therapy. The initiating cause of the renal failure was not determined. These complications have the potential to undermine the working relationship between wildlife veterinarians and conservation managers. This case highlights that intensive conservation management can result in increased opportunities for novel routes of cross-species pathogen transmission