Uveal Malignant Melanoma in a Hybrid Macaw Parrot (Ara chloropterus × Ara militaris).

An adult male green-winged (Ara chloropterus) × military (Ara militaris) hybrid macaw of unknown age was presented to the Texas A&M Veterinary Medical Teaching Hospital for evaluation of left periocular swelling, blepharospasm, and ocular discharge. Complete ophthalmic examination and B mode ocular ultrasonography were performed to evaluate the affected eye. Ocular examination revealed a blind left globe with exophthalmos, periocular swelling, diffuse corneal edema, and severe anterior fibrinous uveitis obscuring visualization of the intraocular structures. An ultrasound examination revealed a hyperechoic mass that filled the posterior segment of the globe. Focal discontinuity of the posterior sclera suggested scleral rupture. Enucleation with histopathology was recommended and performed 1.5 months later. Intraoperatively, a heavily pigmented and friable soft tissue mass extruded through the posterior sclera and extended into the orbit. Histologically, the mass was consistent with a malignant melanoma. The patient died 18 hours after the surgical procedure because of unknown complications. Postmortem examination did not identify evidence of metastasis. This study described the clinical appearance and histopathologic findings of a rare ocular neoplasm with extrascleral extension in a hybrid macaw. Although uncommon in psittacine birds, primary ocular melanocytic neoplasms may display features of malignancy with scleral or orbital invasion, or both.

Comparison of Serum Thyroid Hormone Levels in Green-winged Macaws (Ara chloropterus) Using Radio and Chemiluminescent Immunoassays.

This study compared the use of radioimmunoassay (RIA) and chemiluminescent immunoassay (CLIA) to measure serum thyroid hormone levels in green-winged macaws (Ara chloropterus). The sample group comprised 20 male and 13 female (n = 33) healthy, captive green-winged macaws of reproductive age but outside of breeding season. Mean free triiodothyronine (T3), total T3, and free thyroxine (T4) measured by CLIA and RIA corresponded to 5.11 and 5.08 pmol/L (3.33 and 3.31 pg/mL), 1.59 and 1.56 nmol/L (103.5 and 101.5 ng/dL), and 8.25 and 8.82 pmol/L (0.64 and 0.69 ng/dL), respectively. Mean total T4 by RIA corresponded to 6.29 nmol/L (0.49 µg/dL). Mean free T4 and thyroid-stimulating hormone (TSH) levels differed according to immunoassay method, with higher values measured by RIA compared with CLIA. Sex influence was statistically significant in immunoassay results only on free T3 levels. Free T3 levels measured by RIA were higher than levels measured by CLIA in male birds, but this difference was not found with the female bird samples. Conversely, free T3 levels measured by CLIA were higher in the female macaws compared with male birds. Comparative analysis of thyroid hormone measurements in this study revealed that RIA and CLIA are equivalent methods to measure free T4 and total T3 levels but not TSH levels. These findings support the use of CLIA for free T4 and total T3 level determinations in green-winged macaws. However, the CLIA kit used in this study provided invalid total T4 level results for the macaws sampled. Radioimmunoassay and CLIA were equally ineffective for determining TSH levels in this species.

Impact of Dietary Fructose on the Lipid Profile in Six Macaws.

Atherosclerosis is frequently diagnosed in captive parrots. Recent studies have highlighted the potential role of high fructose intake in the development of human cardiovascular disease. The objective of this study was to investigate the effects of dietary fructose on the lipid profile in psittacine birds. Six macaws, composed of 3 green-winged macaws (Ara chloropterus, 2 females, 1 male), and 3 blue-and-gold macaws (Ara ararauna, 1 female, 2 males), ranging from 15 to 26 years of age, were used as subject animals for this dietary investigation. Initially, fruits were removed from the diet and replaced with vegetables lower in fructose for a month. Then, with a crossover study design, each bird was randomly selected to receive either 34 kcal of a fructose solution daily for 5 days then an equivalent volume of water for 5 days, or water in the first 5 days followed by the 34 kcal fructose solution. Lipid profiles were repeatedly performed over the course of the study at specific intervals. Serum cholesterol (3.01-5.55 mmol/L), triglycerides (0.27-2.70 mmol/L), high-density lipoprotein-cholesterol (1.43-4.79 mmol/L), low-density lipoprotein-cholesterol (0.02-0.85 mmol/L), and very low density lipoprotein-cholesterol (0.12-1.22 mmol/L) levels were not statistically significantly different over time and treatment. Although no significant effect could be demonstrated in this study, further studies are needed to investigate the effect of a high fructose intake in psittacine birds, because it could have a deleterious influence on their cardiovascular health if proven to be linked with dyslipidemia as reported in humans. Higher amounts of fructose and longer periods of administration should be considered for future studies.

Characterization and phylogenetic analysis of the complete Green-winged macaw (Ara chloropterus) mitogenome.

In this study, we sequenced and characterized the complete mitochondrial genome of Green-winged macaw (Ara chloropterus) listed on CITES Appendix II. The circular double-stranded genome was 16,991 bp in size and included 22 transfer RNA (tRNA) genes, 13 protein-coding genes (PCGs), two ribosomal RNA genes (rrnL and rrnS), and one non-coding control region (D-loop). Both order and arrangement of genes were identical to those of other animal mitogenomes. The base content was 30.00% A, 14.38% G, 23.27% T, and 32.35% C, with an A + T content of 53.37%. Furthermore, phylogenetic analysis indicated that A. chloropterus is closely related to the Blue and yellow macaw (A. ararauna).

Genomic characterization of enteropathogenic Escherichia coli (EPEC) of avian origin and rabbit ileal loop response; a pet macaw (Ara chloropterus) as a possible zoonotic reservoir.

Enteropathogenic Escherichia coli (EPEC) constitutes one of the main causes of mortality in children in low- to medium-income countries. Diverse animal species have been linked as reservoirs, including birds. The aim of this study was to describe the genomic and phylogenetic features of an EPEC recovered from a pet macaw and further characterizing the macro and microscopic lesion in a rabbit ileal loop experimental model. The isolate was whole-genome sequenced (WGS) obtaining its genotypic and phenotypic in silico characteristics and inoculated in a rabbit experimental model with subsequently evaluating the strain's pathogenicity by scanning electron microscopy (SEM) and histopathology. The isolate was characterized as O109:H21-B1-ST40 typical EPEC, harboring several virulence factors of diarrheagenic E. coli. The macaw EPEC genome was located in a monophyletic clade of human and animal ST40 EPEC sequences. In vivo inoculation demonstrated severe hemorrhage with SEM and histopathological analysis confirming these lesions to be associated with intra-epithelial lymphocytes. Therefore, the isolate not only shared several genotypic and phylogenetic similarities with EPEC that affects humans and animals, but was able to induce severe tissue injury in a mammal model. These findings highlight the underrated role of pet birds as zoonotic reservoirs and the diversity in virulence factors being unraveled by new WGS studies.

New Haemoproteus parasite of parrots, with remarks on the virulence of haemoproteids in naive avian hosts.

Haemoproteus infections can cause fatal disease in parrots (Psittaciformes), one of the most endangered groups of birds. The great diversity of parrots in tropical and subtropical ecosystems has been markedly understudied in terms of their parasite diversity. Only two psittacine Haemoproteus species have been described. Here we report a new Haemoproteus parasite, H. (Parahaemoproteus) homohandai n. sp. (lineage hARCHL01) found in erythrocytes of a Red-and-green macaw Ara chloropterus. We morphologically and genetically characterize the parasite based on a segment of the mitochondrial cytochrome b gene, which can be used for identification and diagnosis of infection. This is the first Haemoproteus species described from South American parrots and the first genetically characterized psittacine Haemoproteus sp. Haemoproteus homohandai n. sp. can be readily distinguished from other haemoproteids by its growing circumnuclear and close to circumnuclear macrogametocytes, which are strictly associated with erythrocyte nuclei, but do not touch the erythrocyte envelope along their entire margin and do not fill erythrocytes up to their poles. Illustrations of growing and mature gametocytes of the new species are given, and a phylogenetic analysis identifies the position of this parasite lineage in relation to other Haemoproteus parasites. Importantly, H. homohandai n. sp. and all other Haemoproteus lineages reported from parrots cluster with species of the subgenus Parahaemoproteus, indicating the transmission by Culicoides biting midges.