Hatay Mustafa Kemal University, Faculty of Veterinary Medicine, Department of Virology, Hatay, Turkey.
Ankara University, Faculty of Veterinary Medicine, Department of Virology, Ankara, Turkey.
Infect Genet Evol. 2020 Nov;85:104469. doi: 10.1016/j.meegid.2020.104469. Epub 2020 Jul 22.
Bovine leukemia virus (BLV) is known as the etiological agent of Enzootic bovine leukosis (EBL), which is the most common neoplastic disease of cattle. While the major route of virus transmission is believed to be iatrogenic, BLV proviral DNA has been identified in biological materials, including nasal secretions, saliva, milk, colostrum, and semen, and in several insect species, including horses flies. However, insects' role in the natural transmission of BLV has not been clearly demonstrated. This study assessed the possible role of midges - Culicoides spp. - in BLV transmission. BLVs were genetically characterized and BLV infection seroprevelance was determined in 224 cattle sampled from 27 different small family herds in five different districts in Hatay province, southern Turkey. Out of the 25 Culicoides spp. pools, one (4.0%; 1/25) was a C.schultzei pool while 2.67% (6/224) of the sampled cattle were positive for BLV nucleic acid. The seroprevalance rates for the sampled herds and all sampled cattle were 7.40% (2/27) and 1.33% (3/224), respectively. According to the phylogenetic analysis, the sequences of the BLVs from the cattle (n = 6) and the one BLV-positive C.schultzei pool clustered on genotype 1 (G1) BLVs. Although these results do not reveal the exact role of Culicoides spp. or other midges flies in BLV transmission, the simultaneous presence of same substitions in BLVs from both cattle and a C.schultzei pool is noteworthy. Further studies on the env gene and other BLV gene regions detected from cattle and C.schultzei pools are ongoing to understand the possible epidemiological relationship between cattle and flies.
牛白血病病毒（BLV）是一种已知的传染病原，可导致地方性牛白血病（EBL），这是牛最常见的肿瘤疾病。虽然病毒传播的主要途径被认为是医源性的，但 BLV 前病毒 DNA 已在包括鼻分泌物、唾液、牛奶、初乳和精液在内的生物材料，以及包括马蝇在内的几种昆虫物种中被鉴定出来。然而，昆虫在 BLV 的自然传播中的作用尚未得到明确证实。本研究评估了中气门蠓（Culicoides spp.）在 BLV 传播中的可能作用。BLV 进行了基因特征分析，并在土耳其南部哈塔伊省五个不同地区的 27 个不同小家庭畜群中采集的 224 头牛中确定了 BLV 感染血清阳性率。在 25 个 Culicoides spp. 池中，有 1 个（4.0%；1/25）是 C.schultzei 池，而 2.67%（6/224）的采样牛对 BLV 核酸呈阳性。采样畜群和所有采样牛的血清阳性率分别为 7.40%（2/27）和 1.33%（3/224）。根据系统进化分析，来自牛（n = 6）和一个 BLV 阳性 C.schultzei 池的 BLV 序列聚集在基因型 1（G1）BLV 上。尽管这些结果并未揭示出 Culicoides spp. 或其他蠓蝇在 BLV 传播中的确切作用，但在牛和 C.schultzei 池的 BLV 中同时存在相同的替代物是值得注意的。正在对从牛和 C.schultzei 池中检测到的 env 基因和其他 BLV 基因区域进行进一步研究，以了解牛和苍蝇之间可能的流行病学关系。
