Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
Transbound Emerg Dis. 2019 Jul;66(4):1539-1547. doi: 10.1111/tbed.13179. Epub 2019 Apr 7.
Lumpy skin disease (LSD) is an important transboundary animal disease of cattle with significant economic impact because of the implications for international trade in live animals and animal products. LSD is caused by a Capripoxvirus, LSD virus (LSDV), and results in extensive hide and udder damage, fever and pneumonia. LSDV can be shed in semen of infected bulls for prolonged periods and transmitted venereally to cows at high doses. This study examined the effects of LSDV in frozen-thawed semen on in vitro embryo production parameters, including viral status of media and resulting embryos. Bovine oocytes were harvested from abattoir-collected ovaries and split into three experimental groups. After maturation, the oocytes were fertilized in vitro with frozen-thawed semen spiked with a high (HD) or a lower (LD) dose of LSDV, or with LSDV-free semen (control). Following day 7 and day 8 blastocyst evaluation, PCR and virus isolation were performed on all embryonic structures. After completing sufficient replicates to reach 1,000 inseminated oocytes, further in vitro fertilization (IVF) runs were performed to provide material for electron microscopy (EM) and embryo washing procedures. Overall, in vitro embryo yield was significantly reduced by the presence of LSDV in frozen-thawed semen, irrespective of viral dose. When semen with a lower viral dose was used, significantly lower oocyte cleavage rates were observed. LSDV could be detected in fertilization media and all embryo structures, when higher doses of LSDV were present in the frozen-thawed semen used for IVF. Electron microscopy demonstrated LSDV virions inside blastocysts. Following the International Embryo Transfer Society washing procedure resulted in embryos free of viral DNA; however, this may be attributable to a sampling dilution effect and should be interpreted with caution. Further research is required to better quantify the risk of LSDV transmission via assisted reproductive procedures.
牛结节疹病（Lumpy skin disease，LSD）是一种重要的动物传染病，对国际活畜和动物产品贸易有重大影响。该病由山羊痘病毒引起，可导致牛皮和乳房广泛损伤、发热和肺炎。感染牛的精液中可长期排出 LSD 病毒（LSDV），并以高剂量经交配传染给母牛。本研究检测了冻融精液中 LSDV 对体外胚胎生产参数的影响，包括媒介物的病毒状态和由此产生的胚胎。从屠宰场采集的卵巢中采集牛卵母细胞，并将其分为三个实验组。成熟后，将卵母细胞与高剂量（HD）或低剂量（LD）LSDV 冻融精液或无 LSDV 精液（对照）体外受精。在第 7 天和第 8 天进行囊胚评估后，对所有胚胎结构进行 PCR 和病毒分离。完成足够的重复以达到 1000 个授精卵后，进行进一步的体外受精（IVF）运行，以提供电子显微镜（EM）和胚胎洗涤程序所需的材料。总的来说，无论病毒剂量如何，冻融精液中存在 LSDV 都会显著降低体外胚胎的产量。当使用低病毒剂量的精液时，观察到卵母细胞的分裂率显著降低。当使用用于 IVF 的冻融精液中存在较高剂量的 LSDV 时，可在受精介质和所有胚胎结构中检测到 LSDV。电子显微镜显示 LSDV 病毒粒子存在于囊胚中。根据国际胚胎移植协会的洗涤程序，胚胎中没有病毒 DNA，但这可能归因于采样稀释效应，应谨慎解释。需要进一步研究以更好地量化通过辅助生殖程序传播 LSDV 的风险。
