Division of Animal Resources, Animal Technology Laboratories, Agricultural Technology Research Institute, Hsinchu City, Taiwan.
Zoonosis Research Center, School of Veterinary Medicine, National Taiwan University, Taipei City, Taiwan.
Influenza Other Respir Viruses. 2019 Jan;13(1):91-105. doi: 10.1111/irv.12588. Epub 2018 Oct 27.
Influenza B viruses (IBVs) have never been isolated from natural-infected pigs in clinical cases, although the susceptibility of domestic pigs to experimental IBV infections had been confirmed as well as IBV-specific antibodies were detected from pigs under natural and experimental conditions.
We aimed to assess and investigate the activities for infection and circulation of IBVs in pigs.
Annual active surveys for influenza have been implemented on swine populations in Taiwan since July 1998. Nasal swabs, trachea, lungs, and blood from pigs were tested using virological and serological assays for influenza. Gene sequences of influenza viral isolates were determined and characterized. Preliminary sero-epidemiological data for influenza virus were investigated.
Three strains of IBV were isolated and identified from natural-infected pigs in 2014. Genetic characterization revealed the highest identities (>99%) of molecular sequence with the contemporary IBVs belonged to the B/Brisbane/60/2008 genetic clade of Victoria lineage in the phylogenetic trees for all 8 genes. IBV-specific antibodies were detected in 31 (0.2%; 95%CI: 0.1%-0.2%) of 15 983 swine serum samples from 29 (2.8%; 95%CI: 1.9%-3.9%) of 1039 farm visits under annual active surveys from 2007 through 2017. Seropositive cases have been found sparsely in 1-5 of test prefectures every year except 2015 and 2017 as well as scattered loosely over 26 townships/districts of 11 prefectures in Taiwan cumulatively in 11 years.
Influenza B viruse infections from humans to pigs remained sporadic and accidental currently in Taiwan but might have paved potential avenues for newly emerging zoonotic influenza in the future.
流感 B 型病毒（IBV）从未在临床病例中从自然感染的猪中分离出来，尽管已证实家猪对实验性 IBV 感染的易感性，并且在自然和实验条件下从猪中检测到了 IBV 特异性抗体。
评估和调查 IBV 在猪中的感染和传播活动。
自 1998 年 7 月以来，台湾一直在对猪群进行年度流感主动监测。使用病毒学和血清学检测方法对猪的鼻拭子、气管、肺和血液进行检测。确定和表征流感病毒分离株的基因序列。调查了流感病毒的初步血清流行病学数据。
2014 年从自然感染的猪中分离和鉴定了 3 株 IBV。遗传特征表明，在所有 8 个基因的系统发育树中，与当代 IBV 的分子序列相似度最高（>99%），与维多利亚谱系的 B/Brisbane/60/2008 遗传分支最为接近。在 2007 年至 2017 年的年度主动监测中，从 1039 个农场的 29 次访问（95%CI：1.9%-3.9%）中，从 15983 份猪血清样本中检测到 31 份（0.2%；95%CI：0.1%-0.2%）的 IBV 特异性抗体。除 2015 年和 2017 年外，每年在 1-5 个测试县中发现了血清阳性病例，在 11 年中，在台湾的 11 个县的 26 个乡镇/区中零散地发现了这些病例。
目前流感 B 型病毒从人类传播到猪仍然是零星和偶然的，但可能为未来新出现的人畜共患流感病毒铺平了道路。
