Department of Agroecology, Aarhus University, Forsøgsvej 1, DK-4200, Slagelse, Denmark.
Parasit Vectors. 2012 Jul 23;5:143. doi: 10.1186/1756-3305-5-143.
Host preference studies in haematophagous insects e.g. Culicoides biting midges are pivotal to assess transmission routes of vector-borne diseases and critical for the development of veterinary contingency plans to identify which species should be included due to their risk potential. Species of Culicoides have been found in almost all parts of the world and known to live in a variety of habitats. Several parasites and viruses are transmitted by Culicoides biting midges including Bluetongue virus and Schmallenberg virus. The aim of the present study was to determine the identity and diversity of blood meals taken from vertebrate hosts in wild-caught Culicoides biting midges near livestock farms.
Biting midges were collected at weekly intervals for 20 weeks from May to October 2009 using light traps at four collection sites on the island Sealand, Denmark. Blood-fed female biting midges were sorted and head and wings were removed for morphological species identification. The thoraxes and abdomens including the blood meals of the individual females were subsequently subjected to DNA isolation. The molecular marker cytochrome oxidase I (COI barcode) was applied to identify the species of the collected biting midges (GenBank accessions JQ683259-JQ683374). The blood meals were first screened with a species-specific cytochrome b primer pair for cow and if negative with a universal cytochrome b primer pair followed by sequencing to identify mammal or avian blood meal hosts.
Twenty-four species of biting midges were identified from the four study sites. A total of 111,356 Culicoides biting midges were collected, of which 2,164 were blood-fed. Specimens of twenty species were identified with blood in their abdomens. Blood meal sources were successfully identified by DNA sequencing from 242 (76%) out of 320 Culicoides specimens. Eight species of mammals and seven species of birds were identified as blood meal hosts. The most common host species was the cow, which constituted 77% of the identified blood meals. The second most numerous host species was the common wood pigeon, which constituted 6% of the identified blood meals.
Our results suggest that some Culicoides species are opportunistic and readily feed on a variety of mammals and birds, while others seems to be strictly mammalophilic or ornithophilic. Based on their number, dispersal potential and blood feeding behaviour, we conclude that Culicoides biting midges are potential vectors for many pathogens not yet introduced to Denmark.
在吸血昆虫（如致倦库蚊）中进行宿主偏好研究对于评估媒介传播疾病的传播途径至关重要，对于制定兽医应急计划也至关重要，这可以确定哪些物种由于其潜在风险而应被纳入计划。库蠓种类几乎存在于世界的各个角落，已知生活在各种栖息地中。几种寄生虫和病毒通过致倦库蚊传播，包括蓝舌病病毒和沙氏门菌病毒。本研究的目的是确定在丹麦西兰岛的四个采集点，使用诱虫灯每周采集一次，从 2009 年 5 月到 10 月采集的野生捕获的致倦库蚊的脊椎动物宿主的血液摄入量。采集的吸血雌蚊进行分类，去除头部和翅膀进行形态物种鉴定。随后，对个体雌蚊的胸部和腹部以及血液进行 DNA 分离。应用细胞色素氧化酶 I（COI 条码）分子标记识别采集的致倦库蚊的物种（GenBank 登录号 JQ683259-JQ683374）。首先用牛种特异性细胞色素 b 引物对检测血液中的物质，如果为阴性，则用通用细胞色素 b 引物对进行检测，随后进行测序，以确定哺乳动物或鸟类的血液摄入宿主。
从四个研究地点鉴定出 24 种致倦库蚊。共采集到 111356 只致倦库蚊，其中 2164 只为吸血蚊。在 20 种标本的腹部发现了血液。通过 DNA 测序成功鉴定了 320 只致倦库蚊中的 242 只（76%）的血液摄入源。鉴定出 8 种哺乳动物和 7 种鸟类作为血液摄入宿主。最常见的宿主物种是奶牛，占鉴定血液摄入的 77%。第二多的宿主物种是普通斑鸠，占鉴定血液摄入的 6%。
我们的研究结果表明，一些库蠓物种是机会主义的，很容易以多种哺乳动物和鸟类为食，而另一些则似乎严格地以哺乳动物或鸟类为食。根据它们的数量、扩散潜力和吸血行为，我们得出结论，致倦库蚊可能是许多尚未引入丹麦的病原体的潜在传播媒介。
