Laboratory of Animal Health, Cooperative Division of Veterinary Sciences, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan.
Laboratory of Animal Health, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan.
J Vet Med Sci. 2022 Jul 1;84(7):929-937. doi: 10.1292/jvms.22-0026. Epub 2022 May 4.
After improvement of hygiene protocols on boots in a bovine operation (farm A) in Ibaraki, Japan in September 2017, mortality of calves and the detection of 4 viral pathogen indicators, including bovine rotavirus A (RVA), became significantly low for one year. Subsequently, in the present study, these indicators and mortality were monitored and confirmed all were still low, except for the detection rate of bovine RVA in calves less than 3 weeks old. The present study aimed to investigate G and P genotypic profiles of RVAs in farm A from 2018 to 2020. Molecular analysis using semi-nested multiplex RT-PCR of positive RVAs (n=122) and sequencing of selected samples revealed the presence of G6, G8, G10, P[1], P[5] and P[11] genotypes and the prevalence of G and/or P combination and mixed infections. The most common combination of G and P types was G10P[11] (41.8%), followed by mixed infection with G6+G10P[5] (11.5%). Phylogenetic analysis of RVAs showed clustering with bovine and other animal-derived RVA strains, suggesting the possibility of multiple reassortant events with strains of bovine and others animal origins. Noteworthy as well is that vaccinated cattle might fail to provide their offspring with maternal immunity against RVA infections, due to insufficient colostrum feeding. Our findings further highlight the importance of RVA surveillance in bovine populations, which may be useful to improving effective routine vaccination and hygiene practices on bovine farms.
2017 年 9 月，日本茨城县的一家奶牛场（农场 A）改进了靴子的卫生方案，此后一年内，犊牛死亡率和包括牛轮状病毒 A（RVA）在内的 4 种病毒病原体指标的检测结果显著降低。随后，在本研究中，这些指标和死亡率仍持续较低，除了 3 周龄以下犊牛中牛轮状病毒 A 的检出率。本研究旨在调查 2018 年至 2020 年农场 A 的 RVAs 的 G 和 P 基因型谱。对 122 份阳性 RVAs 进行半嵌套多重 RT-PCR 分子分析和选择样本的测序显示存在 G6、G8、G10、P[1]、P[5]和 P[11]基因型，以及 G 和/或 P 组合和混合感染的流行。G 和 P 型最常见的组合是 G10P[11]（41.8%），其次是 G6+G10P[5]混合感染（11.5%）。RVAs 的系统进化分析显示与牛和其他动物来源的 RVA 株聚类，表明与牛和其他动物来源的株发生了多次重配事件的可能性。同样值得注意的是，由于初乳摄入不足，接种疫苗的牛可能无法为其后代提供针对 RVA 感染的母源免疫力。我们的研究结果进一步强调了对牛群中 RVA 监测的重要性，这可能有助于改善牛场的常规疫苗接种和卫生实践。
