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The infectious bursal disease virus (IBDV; Birnaviridae family) constitutes one of the main threats to the poultry industry worldwide. Most of the progress in the molecular epidemiology of this virus has been achieved through the study of the coding region of the capsid protein VP2. Little research has been done regarding the molecular evolution and the epidemiological implications of genetic variability of other IBDV genome regions. In this article, the gene that codes the non-structural protein VP5 was analyzed. Although this protein is not essential for the virus replication, recent evidence indicates that it could be related to the virulent phenotype and the adaptive capacity of the virus. The VP5 gene is also of evolutionary interest because it has an open reading frame that terminally overlaps with the pVP2-VP4-VP3 polyprotein coding region. In the first part of this study, the full VP5 gene of a South American strain was characterized. The results revealed that the VP5 gene of Uruguayan hypervirulent IBDV strains (vvIBDV) lacks the alternative AUG start codon characteristic of the vvIBDV strains that have been described to date. Instead, as occurs in classic and variant strains, this VP5 gene has an AUG start site located four codons downstream and, consequently, it codes for a 145 amino acid long protein rather than the putative 149 amino acid long protein of other vvIBDV. In spite of this, these viruses conserved the VP5 and VP2 amino acid signature of the hypervirulent strains and clustered with reference vvIBDV sequences. This finding may represent evidence that the VP5 gene could be evolving by changing the translation initiation site. In the second part of this study, an evolutionary analysis including the sequences reported in this study together with most of VP5 sequences available in the GenBank, showed the existence of a complex system of selective pressures controlling the evolution of the VP5 gene. Using the dN/dS index, we found a strong purifying selection exerted on the 5' terminal overlapping region of VP2 that would be constraining the evolution of VP5. These results reinforce the hypothesis that the VP5 gene was originated late in the IBDV evolution by a mechanism of genetic overprinting. The results described in this study provided new information about the dynamics of the IBDV genome and revealed some of the mechanisms at play in the evolution of this virus. Since VP5 seems to be related to viral pathogenicity, this evolutionary information might be useful to highlight the impact of the genetic variation of this protein on the epidemiology of IBDV.

Background Thoracolumbar fractures are most frequent along the spine, and surgical treatment is indicated for unstable fractures. Percutaneous minimally invasive surgery was introduced to reduce the pain associated with the open posterior approach and reduce the morbidity of the procedure by avoiding damage and dissection of the paravertebral muscles. The goal of this study is to compare the surgical treatment of fractures of the thoracolumbar spine treated by the conventional open approach and the percutaneous minimally invasive approach using similar types of pedicle spine fixation systems. Methods/designs This study is designed as a multi-center, randomized controlled trial of patients aged 18–65 years who are scheduled to undergo surgical posterior fixation. Treatment by the conventional open approach or percutaneous minimally invasive approach will be randomly assigned. The primary outcome measure is postoperative pain, which will be measured using the visual analogue scale (VAS). The secondary outcome parameters are intraoperative bleeding, postoperative drainage, surgery time, length of hospital stay, SF-36, EQ-5D-5 l, HADS, pain medication, deambulation after surgery, intraoperative fluoroscopy time, vertebral segment kyphosis, fracture vertebral body height, compression of the vertebral canal, accuracy of the pedicle screws, and breakage or release of the implants. Patient will be followed up for 1, 2, 3, 6, 12 and 24 months postoperatively and evaluated according to the outcomes using clinical and radiological examinations, plain radiographs and computed tomografy (CT). Discussion Surgical treatment of thoracolumbar fractures by the open or percutaneous minimally invasive approach will be compared in a multicenter randomized study using similar types of fixation systems, and the results will be evaluated according to clinical and radiological parameters at 1, 2, 3, 6, 12 and 24 months of follow-up. Trial registration ClinicalTrial.gov approval number: 1.933.631, code: NCT03316703 in may 2017.

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As evident from the literature, the tretinoin technological delivery systems consist an innovative and potential management for increasing the patient compliance presenting safety and efficacy.