Department of Laboratory Medicine & Pathology, University of Washington, Seattle, Washington, USA.
Department of Medicine, University of Washington, Seattle, Washington, USA.
J Pediatric Infect Dis Soc. 2021 Apr 30;10(4):408-416. doi: 10.1093/jpids/piaa118.
Acute respiratory tract infections are a serious clinical burden in infants; human metapneumovirus (HMPV) is an important etiological agent. We investigated genotypic variation and molecular epidemiological patterns among infants infected with HMPV in Sarlahi, Nepal, to better characterize infection in a rural, low-resource setting.
Between May 2011 and April 2014, mid-nasal swabs were collected from 3528 infants who developed respiratory symptoms during a longitudinal maternal influenza vaccine study. Sequencing glycoprotein genes permitted genotyping and analyses among subtypes.
HMPV was detected by reverse-transcriptase polymerase chain reaction (RT-PCR) in 187 (5%) infants, with seasonality observed during fall and winter months. Phylogenetic investigation of complete and partial coding sequences for the F and G genes, respectively, revealed that 3 genotypes were circulating: A2, B1, and B2. HMPV-B was most frequently detected with a single type predominating each season. Both HMPV genotypes exhibited comparable median viral loads. Clinically significant differences between genotypes were limited to increased cough duration and general respiratory symptoms for type B.
In rural Nepal, multiple HMPV genotypes circulate simultaneously with an alternating predominance of a single genotype and definitive seasonality. No difference in viral load was detected by genotype and symptom severity was not correlated with RT-PCR cycle threshold or genotype.
急性呼吸道感染是婴儿的严重临床负担；人偏肺病毒（HMPV）是一个重要的病因。我们研究了在尼泊尔萨拉希感染 HMPV 的婴儿的基因型变异和分子流行病学模式，以便更好地描述农村低资源环境中的感染情况。
在 2011 年 5 月至 2014 年 4 月期间，对 3528 名在纵向母亲流感疫苗研究中出现呼吸道症状的婴儿进行了中鼻拭子采集。测序糖蛋白基因允许进行亚型基因分型和分析。
通过逆转录聚合酶链反应（RT-PCR）检测到 187 名（5%）婴儿存在 HMPV，秋冬季有季节性。对 F 和 G 基因的全长和部分编码序列进行系统发育分析，发现有 3 种基因型在循环：A2、B1 和 B2。HMPV-B 是最常检测到的，每种亚型在每个季节都有单一类型占主导地位。两种 HMPV 基因型的病毒载量中位数相当。基因型之间的临床显著差异仅限于 B 型咳嗽持续时间和一般呼吸道症状的增加。
在尼泊尔农村，多种 HMPV 基因型同时循环，单一基因型交替占主导地位，且具有明确的季节性。基因型之间未检测到病毒载量的差异，症状严重程度与 RT-PCR 循环阈值或基因型无关。
