Quantitation of Bovine Viral Diarrhea Virus in Embryo Transfer Flush Fluids Collected from a Persistently Infected Heifer
Quantitation of Bovine Viral Diarrhea Virus in Embryo Transfer Flush Fluids Collected from a Persistently Infected Heifer
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从持续感染的小母牛收集的胚胎移植冲洗液中牛病毒性腹泻病毒的定量
DOI：
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发表时间：
1991
影响因子：
1.5
通讯作者：
Nancy E. Irvine
中科院分区：
文献类型：
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作者：
K. Brock;D. Redman;M. Vickers;Nancy E. Irvine
由于持续感染动物的流行病学意义，重要的是要调查可能的传播方法。目前，推荐的BVDV预防和控制措施主要集中在识别和清除持续感染动物以及谨慎使用BVDV疫苗。4，6不幸的是，直到最近才强调持续感染动物的识别，并且仍然不切实际。本报告的目的是强调BVDV持续感染动物的流行病学意义，尤其是与胚胎移植程序相关的意义。通过从鼻拭子和阴道拭子及血清中分离病毒，在有BVDV感染史的奶牛群中鉴定出持续感染BVDV的5月龄荷斯坦小母牛。小母牛未检测到BVDV血清抗体水平（间接荧光试验[IFA]），并将其隔离观察和检测。在14月龄时首次检测到发情。在第三个热循环后，用促卵泡激素（第11-14天）对小母牛进行超数排卵，并在随后的发情期间用BVDV阴性精液（通过病毒分离确认为阴性）授精。在第7天（发情第0天），尝试使用2 L含3% BVDV阴性胎牛血清（通过病毒分离确认为阴性）的Dulbecco磷酸盐缓冲盐水通过标准全身子宫冲洗采集胚胎。在子宫冲洗前，未从冲洗介质中分离出病毒。在子宫冲洗液（2 L）中，通过显微镜检查仅识别出3个未受精卵。通过从10倍稀释的样品中分离病毒，定量测定从持续感染小母牛中采集的各种样品中BVDV的滴度。将1 mL各稀释液接种至在含10%马血清的Dulbecco最低必需培养基中传代5-10次的BVDV阴性二级牛鼻甲骨细胞上，一式3份。1小时后除去接种物，
Due to the epidemiological significance of persistently infected animals, it is important that possible methods of transmission be investigated. Currently, the recommended prevention and control measures for BVDV are centered around the identification and removal of persistently infected animals and the judicious use of BVDV vaccines. 4,6 Unfortunately, the identification of persistently infected animals has not been emphasized until recently and remains impractical. The purpose of this report is to emphasize the epidemiological significance of animals persistently infected with BVDV, especially in relation to embryo transfer procedures. A 5-month-old Holstein heifer, persistently infected with BVDV, was identified in a dairy herd with a history of BVDV infection by virus isolation from nasal and vaginal swabs and serum. The heifer had no detectable levels of BVDV serum antibodies (in indirect fluorescence assay [IFA]) and was kept in isolation for observation and testing. Estrus first was detected at 14 months of age. Following the third heat cycle the heifer was superovulated with follicle-stimulating hormone (days 11-14) and inseminated with BVDV-negative semen (confirmed negative by virus isolation) during the subsequent estrous. Embryo collection was attempted on day 7 (estrus day 0) by standard whole body uterine flush using 2 liters of Dulbecco’s phosphate-buffered saline containing 3% BVDV-negative fetal bovine serum (confirmed negative by virus isolation). Virus was not isolated from the flush medium prior to the uterine flush. Only 3 unfertile eggs were identified by microscopic examination in the uterine flush fluid (2 liters). The titers of BVDV were quantitated in various samples collected from the persistently infected heifer by virus isolation from 10-fold dilutions of the samples. One milliliter of each dilution was inoculated in replicates of 3 onto BVDVnegative secondary bovine turbinate cells passaged 5-10 times in Dulbecco’s minimum essential medium containing 10% horse serum. The inoculum was removed after 1 hour and