Shedding of ovine herpesvirus 2 in sheep nasal secretions: the predominant mode for transmission
Shedding of ovine herpesvirus 2 in sheep nasal secretions: the predominant mode for transmission
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DOI：
10.1128/jcm.42.12.5558-5564.2004
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发表时间：
2004-12-01
影响因子：
9.4
通讯作者：
Traul, DL
中科院分区：
文献类型：
--
作者：
Li, H;Taus, NS;Traul, DL
绵羊疱疹病毒2型(OvHV-2)是世界各地反刍动物恶性卡他热的主要病原体，但从未在体外繁殖过。用实时荧光定量聚合酶链式反应检测到6~9月龄青春羊(n=56)鼻腔分泌物中病毒DNA含量在10(5)至10(8)拷贝/2以上。相比之下，只有大约18%的成年绵羊(n=33)在研究期间经历了脱落事件。鼻腔分泌物中病毒DNA出现的一般模式是在24至36小时内急剧上升和随后下降，这意味着病毒复制的单个周期。这些发作是零星和罕见的，但在3个月的时间里，56只羔羊中的大多数(33只，或60.7%)至少经历了一次发作。在外周血白细胞和血浆中都没有发现相应的DNA水平波动。在DNA酶保护试验中，所有绵羊在经历强烈脱毛期间的鼻分泌物中都显示出完整的OvHV-2病毒粒子。OvHV-2阴性绵羊鼻腔分泌物的雾化试验也证明了OvHV-2在鼻腔分泌物中的传染性。本研究资料表明，家羊OvHV-2主要传播方式为鼻脱落，青少年是传播的高危人群。
Ovine herpesvirus 2 (OvHV-2), the major causative agent of malignant catarrhal fever in ruminant species worldwide, has never been propagated in vitro. Using real-time PCR, a striking, short-lived, peak of viral DNA, ranging from 10(5) to over 10(8) copies/2 mug of DNA, was detected in nasal secretions from over 60.7% of adolescent sheep (n = 56) at some point during the period from 6 to 9 months of age. In contrast, only about 18% of adult sheep (n = 33) experienced a shedding episode during the study period. The general pattern of the appearance of viral DNA in nasal secretions was a dramatic rise and subsequent fall within 24 to 36 h, implying a single cycle of viral replication. These episodes occurred sporadically and infrequently, but over the 3-month period most of the 56 lambs (33, or 60.7%) experienced at least one episode. No corresponding fluctuations in DNA levels were found in either peripheral blood leukocytes or plasma. In a DNase protection assay, complete, enveloped OvHV-2 virions were demonstrated in the nasal secretions of all sheep examined during the time when they were experiencing an intense shedding episode. OvHV-2 infectivity in nasal secretions was also demonstrated by aerosolization of the secretions into OvHV-2-negative sheep. The data herein show that nasal shedding is the major mode of OvHV-2 transmission among domestic sheep and that adolescents represent the highest risk group for transmission.