Neuroaxonal Dystrophy in a Flock of Pied Imperial Pigeons (Ducula bicolor).

Five juvenile pied imperial pigeons (Ducula bicolor) presented with neurological signs including torticollis, ataxia and poor flying ability. All were humanely destroyed and submitted for post-mortem examination. Microscopically, the most significant findings were in the brain and spinal cord. Spheroid formation was evident within the medulla, pons, diencephalon, cortical grey and subcortical white matter, spinal cord white and grey matter and the granular and molecular cell layers of the cerebellum. There was no evidence of associated inflammation. Immunohistochemistry revealed positive labelling within the spheroids for S100 axons and phosphorylated neurofilaments including SMI31, neurofilament cocktail and microtubule-associated protein 2. Transmission electron microscopy confirmed the light microscopical findings of frequent axonal spheroids. These results are consistent with neuroaxonal dystrophy, which has not been described previously in pigeons. This highlights the importance of considering neuroaxonal dystrophy in juvenile birds with neurological signs. A genetic basis is suspected in this group.

Mycobacterial Arthritis and Synovitis in Painted Reed Frogs (Hyperolius marmoratus).

Several species of atypical mycobacteria have been isolated from wild and captive amphibians. In captive anurans, cutaneous and visceral mycobacteriosis are common and can result in significant mortality, particularly when animals are immunocompromised. Mycobacterial arthritis and synovitis are reported rarely in amphibians. We describe 20 cases in painted reed frogs (Hyperolius marmoratus), which presented with cachexia, limb paresis or paralysis or 'spindly leg syndrome'. Histopathology revealed multifocal histiocytic to granulomatous synovitis affecting appendicular, rib or spinal intervertebral joints. Periarticular granulomata, granulomatous cellulitis and skeletal muscle atrophy, necrosis and degeneration were also present. In one case, granulomatous spinal osteomyelitis was recorded. Ziehl-Neelsen stains showed large numbers of acid-fast bacteria in macrophages and histiocytes. The mycobacterial isolates obtained from culture were identified as members of the Mycobacterium chelonae complex (either M. chelonae or Mycobacterium abscessus). This was confirmed by 5'-16S ribosomal ribonucleic acid (rRNA) sequencing. In 17 cases mycobacterial lesions were present only in the joints and skeleton, highlighting the importance of not ruling out mycobacterial infection on the basis of absence of cutaneous or visceral lesions.

Morphology of the pelvis and hind limb of the red panda (Ailurus fulgens) evidenced by gross osteology, radiography and computed tomography.

The red panda (Ailurus fulgens) is a quadrupedal arboreal animal primarily distributed in the Himalayas and southern China. It is a species commonly kept in zoological collections. This study was carried out to describe the morphology of the pelvis and hind limb of the red panda evidenced by gross osteology, radiography and computed tomography as a reference for clinical use and identification of skeletons. Radiography of the pelvis and right hind limb was performed in nine and seven animals, respectively. Radiographic findings were correlated with bone specimens from three adult animals. Computed tomography of the torso and hind limb was performed in one animal. The pelvic bone had a wide ventromedial surface of the ilium. The trochlea of the femur was wide and shallow. The patella was similar to that seen in feline species. The medial fabella was not seen radiographically in any animal. The cochlea grooves of the tibia were shallow with a poorly defined intermediate ridge. The trochlea of the talus was shallow and presented with an almost flattened medial ridge. The tarsal sesamoid bone was always present. The lateral process of the base of the fifth metatarsal (MT) bone was directed laterally. The MT bones were widely spaced. The morphology of the pelvis and hind limb of the red panda indicated flexibility of the pelvis and hind limb joints as an adaptation to an arboreal quadrupedal lifestyle.

Thoracic Limb Morphology of the Ring-tailed Lemur (Lemur catta) Evidenced by Gross Osteology and Radiography.

There is limited information available on the morphology of the thoracic limb of the ring-tailed lemur (Lemur catta). This study describes the morphology of the thoracic limb of captive ring-tailed lemurs evidenced by gross osteology and radiography as a guide for clinical use. Radiographic findings of 12 captive ring-tailed lemurs are correlated with bone specimens of three adult animals. The clavicle is well developed. The scapula has a large area for the origin of the m. teres major. The coracoid and hamate processes are well developed. The lateral supracondylar crest and medial epicondyle are prominent. The metacarpal bones are widely spread, and the radial tuberosity is prominent. These features indicate the presence of strong flexor muscles and flexibility of thoracic limb joints, which are important in arboreal quadrupedal locomotion. Furthermore, an ovoid ossicle is always seen at the inter-phalangeal joint of the first digit. Areas of increased soft tissue opacity are superimposed over the proximal half of the humerus and distal half of the antebrachium in male animals as a result of the scent gland. Knowledge of the morphology of the thoracic limb of individual species is important for accurate interpretation and diagnosis of musculoskeletal diseases.

Osteology and radiographic anatomy of the pelvis and hind limb of healthy ring-tailed lemurs (Lemur catta).

In family Lemuridae, anatomical variations exist. Considering its conservation status (near threatened) and presence of similarities between strepsirrhines and primitive animals, it was thought to be beneficial to describe the gross osteology and radiographic anatomy of the pelvis and hind limb of ring-tailed lemurs (Lemur catta) as a reference for clinical use and species identification. Radiography was performed in 14 captive adult ring-tailed lemurs. The radiographic findings were correlated with bone specimens from two adult animals. Additionally, computed tomography of the hind limbs was performed in one animal. The pelvic bone has a well-developed caudal ventral iliac spine. The patella has a prominent tuberosity on the cranial surface. The first metatarsal bone and digit 1 are markedly stouter than the other metatarsal bones and digits with medial divergence from the rest of the metatarsal bones and digits. Ossicles were seen in the lateral meniscus, inter-phalangeal joint of digit 1 and in the infrapatellar fat pad. Areas of mineral opacity were seen within the external genitalia, which are believed to be the os penis and os clitoris. Variations exist in the normal osteology and radiographic appearance of the pelvis and hind limb of different animal species. The use of only atlases from domestic cats and dogs for interpretative purposes may be misleading.

The first report of otarine herpesvirus-1-associated urogenital carcinoma in a South American fur seal (Arctocephalus australis).

Otarine herpesvirus (OtHV)-1-associated urogenital carcinoma has been well documented in the California sea lion (Zalophus californianus, CSL), but this is the first report of this tumour in a captive South American fur seal (Arctocephalus australis, SAFS). The gross and microscopical morphology of the tumour in the SAFS was identical to that described previously in CSLs and the tumour in the present case had metastasized within the urogenital tract and draining lymph nodes and to the lungs and one kidney. Immunohistochemistry revealed intra- and extracytoplasmic labelling of herpesvirus antigen in the cells of the tumour tissue and transitional epithelium of the urethra. OtHV-1 nucleic acids were detected within tumour tissue and from a urogenital swab by polymerase chain reaction. The ranges of these two species of pinniped do not overlap normally in the wild, suggesting that transmission of OtHV-1 probably occurred in captivity. This confirmed susceptibility of the SAFS to the development of OtHV-1-associated urogenital carcinoma suggests that all species of Otariidae should be screened for OtHV-1 infection prior to movement within and between zoological collections.

Yolk coelomitis in a white-throated monitor lizard (Varanus albigularis).

Yolk coelomitis as a result of pre-ovulatory follicular stasis is a common disorder in captive reptiles, especially in captive lizards of various genera. The clinical signs are generally fairly non-specific and diagnosis is based on clinical signs together with most of the common diagnostic modalities. The condition is most likely a husbandry and environment-related reproductive disorder. It has not been reported in wild free-living specimens. This report describes the clinical presentation and post mortem lesions in a white-throated monitor lizard that died during treatment for non-specific clinical signs related to a severe yolk coelomitis.

Spinal spondylosis and acute intervertebral disc prolapse in a European brown bear (Ursus arctos arctos).

A 22-year-old male European brown bear (Ursus arctos arctos) was presented to the Onderstepoort Veterinary Academic Hospital after an acute onset of hind limb paralysis 4 days earlier. Previous radiographs revealed marked degenerative joint disease of the stifles, tarsi and digits. The clinical findings were consistent with acute disc prolapse. Lateral radiographs of the entire vertebral column were made as well as ventrodorsal pelvic radiographs. The latter were within normal limits. The vertebral column revealed multiple lesions consistent with chronic and acute disc herniations. Lateral compression of the caudal lumbar nerve roots could not be ruled out. Owing to multiple significant findings of the vertebral column and the poor prognosis for full recovery after surgery, the bear was euthanased. The diagnosis of an acute disc prolapse and multiple chronic disc herniations was confirmed on necropsy.

Response during radiotherapy may be associated with outcome in mediastinal Hodgkin's disease.

A relationship between the rate of regression of lymphomas treated with chemotherapy and long-term outcome has been observed. This study was undertaken to determine if the rate of tumor regression during radiotherapy for mediastinal Hodgkin's disease is a predictor of in-field recurrence. Twenty-nine patients with early-stage Hodgkin's disease treated with radiotherapy alone as part of an NCI randomized trial had both a non-massive mediastinal component of disease and all requisite simulation and port films available for analysis. The histology was nodular sclerosis in all patients. Stage distribution was as follows: IA-1; IIA-17; IIB-8; IIIA1-3. The median age was 27 years and the median radiation dose was 4470 cGy. A mediastinal mass ratio was calculated from each patient's simulation and weekly port films by dividing the width of the mediastinal mass by the intrathoracic diameter at the level of the carina. Histopathologic correlation was also done to quantify the degree of tumor vs. sclerosis in the specimens. Univariate analysis and Cox proportional hazards analysis were used to study the association between several covariates (stage, sex, symptoms, extra-lymphatic disease, initial mediastinal mass ratio, age, dose, percent tumor in the specimen, and cumulative percentage of tumor regression) and time to in-field recurrence, as well as probability of any failure. Univariate analysis indicates that lower dose, higher percent tumor in the specimen, and lower cumulative percent regression are statistically significant predictors for in-field recurrence, as well as for any failure. By Cox regression analysis, cumulative percent regression is the sole factor independently associated with in-field recurrence (two-tailed P=0.04). The percent tumor in the specimen is the only factor similarly identified for time to any failure (two-tailed P=0.02). Histopathologic correlation suggests that patients with early stage mediastinal Hodgkin's disease who demonstrate a high percent tumor in the specimen may be at increased risk of failure. Patients with a low cumulative percent regression during radiotherapy appear to be at an increased risk of in-field recurrence.

Microradiographic and electron microscopic observations of the enamel-covered dentine in rat molars.

The enamel-covered primary and secondary coronal dentine in the molars of 90-day-old and 360-day-old rats was examined using microradiography. Some preparations were subsequently examined by transmission and scanning electron microscopy (SEM). Fractured dentine surfaces and methacrylate casts of the tubular system in the primary dentine were also examined with SEM. No microradiographic evidence of a hypermineralized peritubular matrix, such as that seen in man and other species, was seen in either young or old rats. Transmission and SEM confirmed the microradiographic findings. The tubule obliteration and extensive intra-luminal mineral deposits which have been reported in the enamel-free coronal dentine of the rat molar were not seen in the enamel-covered coronal dentine but some evidence of tubule obliteration was seen in the secondary dentine.