Malasao Rungnapa, Okamoto Michiko, Chaimongkol Natthawan, Imamura Tadatsugu, Tohma Kentaro, Dapat Isolde, Dapat Clyde, Suzuki Akira, Saito Mayuko, Saito Mariko, Tamaki Raita, Pedrera-Rico Gay Anne Granada, Aniceto Rapunzel, Quicho Reynaldo Frederick Negosa, Segubre-Mercado Edelwisa, Lupisan Socorro, Oshitani Hitoshi
Tohoku University Graduate School of Medicine, Sendai, Japan.
Tohoku-RITM Collaborating Research Center on Emerging and Reemerging Diseases, Muntinlupa City, Philippines.
PLoS One. 2015 Nov 5;10(11):e0142192. doi: 10.1371/journal.pone.0142192. eCollection 2015.
Human respiratory syncytial virus (HRSV) is a major cause of acute lower respiratory tract infections in infants and children worldwide. We performed molecular analysis of HRSV among infants and children with clinical diagnosis of severe pneumonia in four study sites in the Philippines, including Biliran, Leyte, Palawan, and Metro Manila from June 2012 to July 2013. Nasopharyngeal swabs were collected and screened for HRSV using real-time polymerase chain reaction (PCR). Positive samples were tested by conventional PCR and sequenced for the second hypervariable region (2nd HVR) of the G gene. Among a total of 1,505 samples, 423 samples were positive for HRSV (28.1%), of which 305 (72.1%) and 118 (27.9%) were identified as HRSV-A and HRSV-B, respectively. Two genotypes of HRSV-A, NA1 and ON1, were identified during the study period. The novel ON1 genotype with a 72-nucleotide duplication in 2nd HVR of the G gene increased rapidly and finally became the predominant genotype in 2013 with an evolutionary rate higher than the NA1 genotype. Moreover, in the ON1 genotype, we found positive selection at amino acid position 274 (p<0.05) and massive O- and N-glycosylation in the 2nd HVR of the G gene. Among HRSV-B, BA9 was the predominant genotype circulating in the Philippines. However, two sporadic cases of GB2 genotype were found, which might share a common ancestor with other Asian strains. These findings suggest that HRSV is an important cause of severe acute respiratory infection among children in the Philippines and revealed the emergence and subsequent predominance of the ON1 genotype and the sporadic detection of the GB2 genotype. Both genotypes were detected for the first time in the Philippines.
人呼吸道合胞病毒（HRSV）是全球婴幼儿急性下呼吸道感染的主要病因。2012年6月至2013年7月，我们在菲律宾的四个研究地点，包括比利兰、莱特、巴拉望和马尼拉大都会，对临床诊断为重症肺炎的婴幼儿进行了HRSV的分子分析。采集鼻咽拭子，采用实时聚合酶链反应（PCR）检测HRSV。阳性样本通过常规PCR检测，并对G基因的第二个高变区（2nd HVR）进行测序。在总共1505份样本中，423份样本HRSV呈阳性（28.1%），其中305份（72.1%）和118份（27.9%）分别被鉴定为HRSV-A和HRSV-B。在研究期间鉴定出两种HRSV-A基因型，即NA1和ON1。G基因2nd HVR中具有72个核苷酸重复的新型ON1基因型迅速增加，最终在2013年成为主要基因型，其进化速率高于NA1基因型。此外，在ON1基因型中，我们发现第274位氨基酸存在正选择（p<0.05），并且在G基因的2nd HVR中存在大量O-和N-糖基化。在HRSV-B中，BA9是在菲律宾流行的主要基因型。然而，发现了两例GB2基因型的散发病例，它们可能与其他亚洲菌株有共同的祖先。这些发现表明，HRSV是菲律宾儿童严重急性呼吸道感染的重要病因，并揭示了ON1基因型的出现及其随后的优势地位以及GB2基因型的散在检测情况。这两种基因型均首次在菲律宾被检测到。
