Abstract

We aimed to assess the occurrence of bovine viruses (bovine leukemia virus–BLV and bovine adenovirus–BAdV) at workplaces in traditional dairies and to evaluate the potential role of airborne and surface contamination in spreading of these viruses derived from raw milk. The total amount of 122 samples—including 37 air (bioaerosol), 40 surface, and 45 milk samples—were checked for the presence of BLV and BAdV genomes using RT-qPCR/qPCR method. The study showed that the viruses were present in 7 air (among them 71.4% were BLV-positive and 28.6% were BAdV-positive), 14 surface (among them 85.7% were BLV-positive and 14.3% were BAdV-positive), and 34 milk (all were BLV-positive only) samples. Statistical analysis revealed that both the air and surfaces in studied occupational environment were more frequently contaminated with BLV than with BAdV (Chi-square test: p = 0.002, Fisher’s Exact test: p = 0.002). Kruskal-Wallis tests showed significant differences in BLV genome concentrations in the air (p = 0.045) as well as in BLV and BAdV genome concentrations on surfaces (p = 0.005 and p = 0.040, respectively) between studied processing areas. In units of genome copies (gc) per area, the highest concentrations of BLV and BAdV genomes in the air (9.8 × 10¹ ± 1.14 × 10² gc/m³ and 5.4 × 10¹ ± 9.1 × 10¹ gc/m³, respectively) and on surfaces (9.83 × 10² ± 7.41 × 10² gc/100cm² and 2.30 × 10² ± 3.8 × 10² gc/100cm², respectively) were observed in milk reception area. The air and surfaces of pre-production zones were also significantly more contaminated with BAdV genomes compared to production areas (Mann-Whitney test: p = 0.039 and p = 0.029, respectively). This study showed that dairy workers may be exposed to bovine viruses through the inhalation of bioaerosols and contact with contaminated surfaces. To reduce the probability of virus transmission from the raw milk to humans, efficient surface cleaning procedures degrading viral particles should be introduced and the use of personal protection equipment, especially within pre-production zones, should be required. As the raw milk may be a source of bovine viruses, the development of strategies for both the control and eradication of BLV and BAdV among cattle seems to be also urgently needed.

摘要

我们旨在评估传统乳制品厂在工作场所牛病毒（牛白血病病毒– BLV和牛腺病毒– BAdV）的发生情况，并评估空气传播和表面污染在传播这些源自生乳的病毒中的潜在作用。使用RT-qPCR / qPCR方法检查了122个样品的总数，包括37个空气（生物气溶胶），40个表面和45个牛奶样品，以检查是否存在BLV和BAdV基因组。研究表明，这些病毒存在于7种空气中（其中BLV阳性占71.4％，BAdV阳性占28.6％），表面14种表面（其中BLV阳性占85.7％，BAdV阳性占14.3％），以及34份牛奶（均为BLV阳性）。统计分析表明，在研究的职业环境中，空气和地面受到BLV的污染比受到BAdV的污染更频繁（卡方检验：p = 0.002，费舍尔精确检验：p = 0.002）。Kruskal-Wallis试验显示，研究区域之间空气中BLV基因组浓度（p = 0.045）以及表面的BLV和BAdV基因组浓度（分别为p = 0.005和p = 0.040）存在显着差异。以单位面积的基因组拷贝数（gc）为单位，空气中BLV和BAdV基因组的最高浓度（9.8×10 ¹ ±1.14×10 ² gc / m ³和5.4×10 ¹ ±9.1×10 ¹ gc / m ³分别在表面上（9.83×10 ² ±7.41×10 ² gc / 100cm ²和2.30×10 ² ±3.8×10 ²gc / 100cm ²，分别）在牛奶接收区。与生产区域相比，生产前区域的空气和表面受到BAdV基因组的污染也明显更多（Mann-Whitney测试：分别为p = 0.039和p = 0.029）。这项研究表明，乳制品工人可能通过吸入生物气溶胶和接触被污染的表面而暴露于牛病毒。为了减少病毒从生乳传播到人类的可能性，应采用有效的表面清洁程序降解病毒颗粒，并应使用个人防护设备，尤其是在预生产区内。由于原料乳可能是牛病毒的来源，因此迫切需要制定控制和消除牛中BLV和BAdV的策略。