Background. Acute respiratory tract infections (ARTIs) are the leading cause of illnesses in children. Human respiratory syncytial virus (HRSV) and human parainfluenza viruses (HPIVs) are among the most common etiologic agents associated with viral respiratory tract infections in children worldwide. Nevertheless, limited information is available on the spread of infections of these two viruses in northwest Iran. Objective. The purpose of the current study is to evaluate the frequency of RSV and HPIV-3 and clinical features among Iranian children with confirmed respiratory infections between April 2019 and March 2020. Methods. 100 nasopharyngeal swabs were collected from hospitalized patients (under 5 years old) with ARTI from Tabriz Children’s Hospital. Detection of respiratory viruses was performed using the nested RT-PCR method. Results. Respiratory syncytial virus and HPIV-3 were recognized in 18% (18/100) and 2% (2/100) of children, respectively. Ten (55.6%) of the RSV-positive samples were male, while 8 (44.4%) were female. HPIV‐3 was found only among 2 male patients (100%). Most patients (61.1%) with RSV infection were less than 12 months old. Additionally, samples that were positive for HPIV-3 were less than 12 months old. RSV infections had occurred mainly during the winter season. Conclusions. This study confirms that RSV can be one of the important respiratory pathogens in children in northwestern Iran. However, according to this study, HPIV-3 has a lower prevalence among children in this area than RSV. Therefore, implementing a routine diagnosis for respiratory pathogens can improve the management of respiratory infections in children.

中文翻译：

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伊朗西北部住院儿童的人类呼吸道合胞病毒和人类副流感病毒 3 型评估

背景。急性呼吸道感染 (ARTIs) 是儿童患病的主要原因。人类呼吸道合胞病毒 (HRSV) 和人类副流感病毒 (HPIV) 是与全球儿童病毒性呼吸道感染相关的最常见病原体。然而，关于这两种病毒在伊朗西北部传播的信息有限。客观。本研究的目的是评估 2019 年 4 月至 2020 年 3 月期间确诊呼吸道感染的伊朗儿童的 RSV 和 HPIV-3 频率和临床特征。方法. 从大不里士儿童医院的 ARTI 住院患者（5 岁以下）收集 100 份鼻咽拭子。使用嵌套式 RT-PCR 方法检测呼吸道病毒。结果。呼吸道合胞病毒和 HPIV-3 分别在 18% (18/100) 和 2% (2/100) 的儿童中被识别。RSV 阳性样本中有 10 个（55.6%）为男性，而 8 个（44.4%）为女性。仅在 2 名男性患者 (100%) 中发现了 HPIV-3。大多数 RSV 感染患者 (61.1%) 小于 12 个月大。此外，HPIV-3 呈阳性的样本不到 12 个月大。RSV 感染主要发生在冬季。结论. 这项研究证实RSV可能是伊朗西北部儿童的重要呼吸道病原体之一。然而，根据这项研究，HPIV-3 在该地区儿童中的流行率低于 RSV。因此，实施呼吸道病原体的常规诊断可以改善儿童呼吸道感染的管理。