a Department of Virology , National Centre of Infectious and Parasitic Diseases , Sofia , Bulgaria.
b Paediatric clinic , University Hospital Alexandrovska, Medical University , Sofia , Bulgaria.
Pathog Glob Health. 2017 Oct;111(7):351-361. doi: 10.1080/20477724.2017.1375708. Epub 2017 Sep 26.
The respiratory syncytial virus (RSV) is a leading cause of acute respiratory illnesses (ARI) in infants and young children. The objectives of this study were to investigate the RSV circulation among children aged <5 years in Bulgaria, to identify the RSV-A and RSV-B genotypes and to perform an amino acid sequence analysis of second hypervariable region (HVR2) of the G gene. During the 2014/15 and 2015/16 winter seasons, nasopharyngeal specimens of 610 children aged <5 years with ARI were tested using Real Time RT-PCR for influenza viruses, RSV, metapneumovirus, parainfluenza viruses, rhinoviruses and adenoviruses. Viral respiratory pathogens were detected in 429 (70%) out of 610 patients examined and RSV was the most frequently identified virus (26%) followed by influenza A(H1N1)pdm09 virus (14%) (p < .05). RSV was the most prevalent pathogen in patients with bronchiolitis (48%) and pneumonia (38%). In the 2014/15 season, RSV-A dominated slightly (53%), while in the next season RSV-B viruses prevailed more strongly (66%). The phylogenetic analysis based on the G gene indicated that all 21 studied RSV-A strains belonged to the ON1 genotype; the vast majority (96%) of the RSV-B strains were classified into BA9 genotype and only one - into BA10 genotype. All Bulgarian RSV-A and RSV-B sequences contained a 72-nt and a 60-nt duplication in the HVR2, respectively. The study showed the leading role of this pathogen as a causative agent of serious respiratory illnesses in early childhood, year-on-year fluctuations in RSV incidence, a shift from RSV-A to RSV-B subgroup dominance and relatively low genetic divergence in the circulating strains.
呼吸道合胞病毒（RSV）是导致婴儿和幼儿急性呼吸道疾病（ARI）的主要原因。本研究的目的是调查保加利亚<5 岁儿童中 RSV 的流行情况，鉴定 RSV-A 和 RSV-B 基因型，并对 G 基因第二高变区（HVR2）进行氨基酸序列分析。在 2014/15 年和 2015/16 年冬季，使用实时 RT-PCR 对 610 名<5 岁患有 ARI 的儿童的鼻咽标本进行了流感病毒、RSV、副流感病毒、呼吸道合胞病毒和腺病毒的检测。在 610 名接受检查的患者中，有 429 名（70%）检测到了病毒呼吸道病原体，RSV 是最常被识别的病毒（26%），其次是甲型流感病毒（H1N1）pdm09（14%）（p<0.05）。RSV 是毛细支气管炎（48%）和肺炎（38%）患者中最常见的病原体。在 2014/15 年，RSV-A 略占优势（53%），而在接下来的季节，RSV-B 病毒则更为流行（66%）。基于 G 基因的系统发育分析表明，所有 21 株研究的 RSV-A 株均属于 ON1 基因型；绝大多数（96%）RSV-B 株分为 BA9 基因型，只有一株分为 BA10 基因型。保加利亚所有的 RSV-A 和 RSV-B 序列在 HVR2 中分别含有 72-nt 和 60-nt 的重复。该研究表明，这种病原体作为幼儿严重呼吸道疾病的致病原，其作用显著，RSV 发病率逐年波动，从 RSV-A 到 RSV-B 亚组优势的转变，以及循环株的遗传差异相对较低。
