Epidemiologic assessment of trauma-independent skeletal pathology in non-passerine birds from museum collections

A comprehensive diagnostic approach combining phylogenetic disease bracketing and CT imaging reveals osteomyelitis in a Tyrannosaurus rex

Traditional palaeontological techniques of disease characterisation are limited to the analysis of osseous fossils, requiring several lines of evidence to support diagnoses. This study presents a novel stepwise concept for comprehensive diagnosis of pathologies in fossils by computed tomography imaging for morphological assessment combined with likelihood estimation based on systematic phylogenetic disease bracketing. This approach was applied to characterise pathologies of the left fibula and fused caudal vertebrae of the non-avian dinosaur Tyrannosaurus rex. Initial morphological assessment narrowed the differential diagnosis to neoplasia or infection. Subsequent data review from phylogenetically closely related species at the clade level revealed neoplasia rates as low as 3.1% and 1.8%, while infectious-disease rates were 32.0% and 53.9% in extant dinosaurs (birds) and non-avian reptiles, respectively. Furthermore, the survey of literature revealed that within the phylogenetic disease bracket the oldest case of bone infection (osteomyelitis) was identified in the mandible of a 275-million-year-old captorhinid eureptile Labidosaurus. These findings demonstrate low probability of a neoplastic aetiology of the examined pathologies in the Tyrannosaurus rex and in turn, suggest that they correspond to multiple foci of osteomyelitis.

Pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica)

OBJECTIVE

To determine the pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica).

ANIMALS

12 adult orange-winged Amazon parrots (6 males and 6 females).

PROCEDURES

A single dose of amantadine was orally administered to 6 birds at 5 mg/kg (n = 2), 10 mg/kg (2), and 20 mg/kg (2) in a preliminary trial. On the basis of the results, a single dose of amantadine (10 mg/kg, PO) was administered to 6 other birds. Two months later, multiple doses of amantadine (5 mg/kg, PO, q 24 h for 7 days) were administered to 8 birds. Heart rate, respiratory rate, behavior, and urofeces were monitored. Plasma concentrations of amantadine were measured via tandem liquid chromatography-mass spectrometry. Pharmacokinetic parameter estimates were determined via noncompartmental analysis.

RESULTS

Mean ± SD maximum plasma concentration, time to maximum plasma concentration, half-life, and area under the concentration-versus-time curve from the last dose to infinity were 1,174 ± 186 ng/mL, 3.8 ± 1.8 hours, 23.2 ± 2.9 hours, and 38.6 ± 7.4 μg·h/mL, respectively, after a single dose and 1,185 ± 270 ng/mL, 3.0 ± 2.4 hours, 21.5 ± 5.3 hours, and 26.3 ± 5.7 μg·h/mL, respectively, at steady state after multiple doses. No adverse effects were observed.

CONCLUSIONS AND CLINICAL RELEVANCE

Once-daily oral administration of amantadine at 5 mg/kg to orange-winged Amazon parrots maintained plasma concentrations above those considered to be therapeutic in dogs. Further studies evaluating safety and efficacy of amantadine in orange-winged Amazon parrots are warranted.

First diagnosis of septic arthritis in a dinosaur

Identification and interpretation of pathologies in the fossil record allows for unique insights into the life histories of extinct organisms. However, the rarity of such finds limits not only the sample size for palaeopathologic studies, but also the types of analyses that may be performed. In this study, we present the first occurrence of a palaeopathology in a vertebrate from the Mesozoic of the East Coast of North America (Appalachia), a pathologic ulna and radius of an indeterminate hadrosaur from the Navesink Formation (New Jersey). X-ray microtomography allowed for both detailed and more accurate diagnosis of the pathologic condition as well as virtual conservation of the specimen. Based on extant archosaurian comparisons, the hadrosaur was diagnosed with severe septic arthritis affecting the proximal ulna and radius. Diagnosis was based on erosion of the joint and highly reactive periosteal bone growth and fusion of the elements. To the best of our knowledge, this is the first recorded account of septic arthritis in dinosaurs. The severity of the pathology suggests the animal suffered with this condition for some time before death. Unfortunately, only the ulna and radius were found. Thus, the extent to which the condition spread to other parts of the body is unknown.

Interpreting pathologies in extant and extinct archosaurs using micro-CT

Palaeopathology offers unique insight to the healing strategies of extinct organisms, permitting questions concerning bone physiology to be answered in greater depth. Unfortunately, most palaeopathological studies are confined to external morphological interpretations due to the destructive nature of traditional methods of study. This limits the degree of reliable diagnosis and interpretation possible. X-ray MicroTomography (micro-CT, XMT) provides a non-destructive means of analysing the internal three-dimensional structure of pathologies in both extant and extinct individuals, at higher resolutions than possible with medical scanners. In this study, we present external and internal descriptions of pathologies in extant and extinct archosaurs using XMT. This work demonstrates that the combination of external/internal diagnosis that X-ray microtomography facilitates is crucial when differentiating between pathological conditions. Furthermore, we show that the use of comparative species, both through direct analysis and from the literature, provides key information for diagnosing between vertebrate groups in the typical pathological conditions and physiological processes. Micro-CT imaging, combined with comparative observations of extant species, provides more detailed and reliable interpretation of palaeopathologies. Micro-CT is an increasingly accessible tool, which will provide key insights for correctly interpreting vertebrate pathologies in the future.

Arthritis and prolactin: a phylogenetic viewpoint

Arthritic disorders are family of diseases that have existed since vertebrate life began. Their etiology is multifactorial with genetic, environmental, and gender factors driving chronic joint inflammation. Prolactin is a sexually dimorphic hormone in mammals that can act to both promote and ameliorate rheumatic diseases. It is found in all vertebrate groups where it exerts a wide diversity of actions. This review briefly addresses the presence and features of arthritic diseases in vertebrates, the effects of PRL on joint tissues and immune cells, and whether PRL actions could have contributed to the ubiquity of arthritis in nature. This comparative approach highlights the value of PRL as a biologically conserved factor influencing the development and progression of arthritis.

Bilateral coxofemoral degenerative joint disease in a juvenile male yellow-eyed penguin (Megadyptes antipodes)

A juvenile, male, yellow-eyed penguin (Megadyptes antipodes) with abnormal stance and decreased mobility was captured, held in captivity for approximately 6 weeks, and euthanized due to continued clinical signs. Radiographically, there was bilateral degenerative joint disease with coxofemoral periarticular osteophyte formation. Grossly, the bird had bilaterally distended, thickened coxofemoral joints with increased laxity, and small, roughened and angular femoral heads. Histologically, the left femoral articular cartilage and subchondral bone were absent, and the remaining femoral head consisted of trabecular bone overlain by fibrin and granulation tissue. There was no gross or histological evidence of infection. The historic, gross, radiographic, and histopathologic findings were most consistent with bilateral aseptic femoral head degeneration resulting in degenerative joint disease. Although the chronicity of the lesions masked the initiating cause, the probable underlying causes of aseptic bilateral femoral head degeneration in a young animal are osteonecrosis and osteochondrosis of the femoral head. To our knowledge, this is the first reported case of bilateral coxofemoral degenerative joint disease in a penguin.