Macrorhabdus ornithogaster Infection and Spontaneous Proventricular Adenocarcinoma in Budgerigars ( Melopsittacus undulatus).

Proventricular infection with the anamorphic, ascomycetous yeast Macrorhabdus ornithogaster and disease associated with infection (macrorhabdiosis) have been widely reported in budgerigars ( Melopsittacus undulatus). Proventricular adenocarcinoma has also been previously reported in this species. In a retrospective archival search of clinical cases submitted to a zoo animal and exotic pet pathology service between 1998 and 2013, a total of 28 128 avian submissions were identified, which included 1006 budgerigars kept in zoos or aviaries or as pets. Of these budgerigars, 177 were identified histologically as infected with M. orthithogaster at the time of necropsy. Histologic examination of tissues from budgerigars infected with M. orthithogaster identified an apparent continuum in the development of proventricular isthmus lesions associated with M. ornithogaster that included inflammation, mucosal hyperplasia, glandular dysplasia, and adenocarcinoma. Proventricular adenocarcinoma was identified histologically in 21 budgerigars. Budgerigars with proventricular adenocarcinoma were significantly more likely to have macrorhabdiosis than budgerigars without proventricular adenocarcinoma. Based on odds ratios for archival data, budgerigars were 41 times (95% confidence interval [CI], 33-52) more likely to have macrorhabdiosis than other avian species and 19 times (95% CI, 11-33) more likely to have proventricular adenocarcinoma than other birds. Budgerigars were 323 times (95% CI, 42-2490) more likely to be affected by both diseases simultaneously compared with other avian species. These findings suggest that macrorhabdiosis may be an associated factor for proventricular adenocarcinoma, although the explanation for this statistically significant correlation remains unknown and further investigation is warranted.

Outcome for client-owned domestic rabbits undergoing limb amputation: 34 cases (2000-2009).

OBJECTIVE: To describe morbidity, function, outcome, and owner satisfaction associated with limb amputation in domestic rabbits. DESIGN: Retrospective case series. ANIMALS: 34 client-owned domestic rabbits. PROCEDURES: Medical records of domestic rabbits undergoing limb amputation for any cause between 2000 and 2009 were reviewed. The Kaplan-Meier method was used to estimate survival rate and median survival time, and variables were analyzed for relationship to risk of morbidity resulting in euthanasia and to outcome (survival vs nonsurvival [death or euthanasia]). Owners were interviewed to determine satisfaction with outcome of the procedure. RESULTS: 28 rabbits underwent pelvic limb amputation, and 6 underwent thoracic limb amputation. At the last follow-up, 18 rabbits were dead, 9 were alive, and 7 were lost to follow-up. Median overall survival time was 720 days (range, 4 to 3,250 days). Acute and delayed or chronic complications were observed in 22 of 34 and 19 of 32 rabbits, respectively, most commonly difficulty ambulating, hygiene issues, and pododermatitis (cutaneous ulcers at the hock). Six rabbits were euthanized because of complications at a median of 104 days (range, 4 to 399 days) after surgery. Risk of morbidity resulting in euthanasia increased with heavier body weight and concurrent disease affecting ambulation at the time of amputation. Weight, age, and pododermatitis at the time of amputation were significantly negatively associated with survival time. Thirty-one (91%) owners were satisfied with the outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Although limb amputation was tolerated by most rabbits and most owners were satisfied, complications resulted in death in 6 of 34 (18%) rabbits, and 19 of 32 (59%) developed chronic complications. Amputation in heavy rabbits or those with concurrent pododermatitis, musculoskeletal disease, or neurologic disease should be considered carefully. Because of the small sample size and retrospective nature of this study, results should be interpreted as exploratory and hypothesis generating.