Genomic and phylogenetic analysis of avian polyomaviruses isolated from parrots in Taiwan.

Avian polyomavirus (APV) is a non-enveloped virus with a circular double-stranded DNA genome approximately 5000 bp in length. APV was first reported in fledgling budgerigars (Melopsittacus undulatus) as the causative agent of budgerigar fledgling disease, resulting in high parrot mortality rates in the 1980s. This disease has been observed worldwide, and APV has a wide host range including budgerigars, cockatoos, lorikeets, lovebirds, and macaws. Twenty APV isolates have been collected from healthy and symptomatic parrots in Taiwan from 2015 to 2019. These isolates were then amplified via polymerase chain reaction, after which the whole genomes of these isolates were sequenced. The overall APV-positive rate was 14.2%, and the full lengths of the APV Taiwan isolates varied from 4971 to 4982 bps. The APV genome contains an early region that encodes two regulatory proteins (the large tumor antigen (Large T-Ag) and the small tumor antigen (Small t-Ag)) and a late region which encodes the capsid proteins VP1, VP2, VP3, and VP4. The nucleotide identities of the VP1 and VP4 genes ranged from 98.7 to 100%, whereas the nucleotide sequence of the Large T-Ag gene had the highest identity (99.2-100%) relative to other APV isolates from the GenBank database. A phylogenetic tree based on the whole genome demonstrated that the APV Taiwan isolates were closely related to Japanese and Portuguese isolates. Recombination events were analyzed using the Recombination Detection Program version 4 and APV Taiwan isolate TW-3 was identified as a minor parent of the APV recombinants. In this study, we first reported the characterization of the whole genome sequences of APV Taiwan isolates and their phylogenetic relationships with all APV isolates available in the GenBank database.

Surgical outcomes of centripetal non-fovea-sparing internal limiting membrane peeling for myopic foveoschisis with and without foveal detachment: a follow-up of at least 3 years.

BACKGROUND: We evaluated the surgical outcomes of vitrectomy with non-fovea-sparing internal limiting membrane (ILM) peeling for myopic foveoschisis with a follow-up of at least 3 years. METHODS: In this retrospective study, 32 consecutive eyes with high myopia with or without foveal detachment underwent vitrectomy and centripetal, non-fovea-sparing ILM peeling with gas tamponade for myopic foveoschisis. Outcome measures were visual acuity (VA) and optical coherence tomography findings. RESULTS: Mean axial length was 29.39±1.92 mm; mean follow-up was 42.66 (±8.29) months. Foveoschisis and foveal detachment completely resolved in all eyes postoperatively. Mean central foveal thickness (CFT) improved significantly from 631.88±191.72 to 232.65±69.67 µm, and mean best-corrected visual acuity improved significantly from 0.90 (Snellen equivalent (SE), 20/160)±0.43 logarithm of minimum angle of resolution (logMAR) to 0.43 (SE, 20/54)±0.29 logMAR (both p<0.001; two-tailed, paired t-test). Eyes with foveal detachment (n=10) at baseline had thicker preoperative CFT (737.8±239.83 vs 583.73±147.78 µm; p=0.033) but thinner postoperative CFT (188.20±31.52 vs 252.86±73.29 µm; p=0.012). Eyes without foveal detachment at baseline had significantly better postoperative VA (0.33 (SE, 20/43)±0.18 vs 0.65 (SE, 20/86)±0.37 logMAR; p=0.002). No macular hole or other complications occurred during follow-up. CONCLUSION: Centripetal, non-fovea-sparing ILM peeling with gas tamponade may achieve myopic foveoschisis resolution and vision improvement without macular hole formation during at least 3-year follow-up.

SURGICAL OUTCOMES IN EYES WITH EXTREMELY HIGH MYOPIA FOR MACULAR HOLE WITHOUT RETINAL DETACHMENT.

PURPOSE: The authors evaluated surgical outcomes in eyes with extremely high myopia for macular hole (MH) without retinal detachment. METHODS: In this retrospective study, 14 eyes with axial lengths of ≥30.0 mm underwent vitrectomy and internal limiting membrane (ILM) peeling with or without inverted ILM flap insertion for MH without retinal detachment (October 2009-June 2016). Outcome measures were MH closure confirmed by optical coherence tomography, best-corrected visual acuity, and complications. RESULTS: The mean axial length was 30.69 ± 0.76 mm. The overall final closure rate was 85.7% (12/14 eyes); the mean follow-up was 17.29 (±20.20) months. Primary anatomical MH closure after 1 operation was achieved in three of eight eyes (37.5%) without an inverted ILM flap and was achieved in six of six eyes (100%) with inverted ILM flap insertion (P = 0.031). There was no reopening of MH during follow-up. Mean visual acuity improved significantly from 1.10 ± 0.43 logarithm of the minimum angle of resolution (Snellen equivalent, 20/254) to 0.84 ± 0.50 logarithm of the minimum angle of resolution (Snellen equivalent, 20/138) (P = 0.046; 2-tailed, paired t-test). Only 1 eye developed an MH-associated retinal detachment 4.5 years after previously failed MH surgery; reattachment was achieved after a second operation. CONCLUSION: Patients with extremely high myopia obtained anatomical and functional improvements from MH surgery; inverted ILM flap insertion achieved significantly higher primary success rates in MH closure.

Development of an antigen-capture ELISA for beak and feather disease virus.

Psittacine beak and feather disease (PBFD) is characterised by degenerative feather, feather dystrophy, and beak deformity. Sometimes acute forms can lead to fatal cases in nestlings. The worldwide distribution of this disease affects numerous species of parrots with an average prevalence of 40%, including in Taiwan. The pathogen of PBFD is beak and feather disease virus (BFDV), which is a single-stranded circular DNA virus, circovirus. To date, hemagglutination and PCR assays have been routinely used to detect this virus. In this study, both the replication-associated protein (Rep) and the structural capsid protein (Cap) were expressed and then used as antigens for the production of monoclonal antibodies. Conserved epitopes recognised by the anti-Cap and anti-Rep monoclonal antibodies were determined to be NFEDYRI and LSALKKM, respectively. Clinical samples collected from different species of parrots were tested by hemagglutination, PCR, and anti-Cap antigen-capture ELISA assays and the positive rates were the same at 49%. Thus, this anti-Cap antigen-capture ELISA is able to be used for the rapid identification of BFDV-infected birds in a non-invasive manner.