Bluetongue (BT) is a vector-borne viral disease of ruminant and camelid species which is transmitted by Culicoides spp. The causative agent of BT is bluetongue virus (BTV) that belongs to genus Orbivirus of the family Reoviridae. The clinical disease is seen mainly in sheep but mostly sub-clinical infections of BT are seen in cattle, goats and camelids. The clinical reaction of camels to infection is usually not apparent. The disease is notifiable to the World Organization for Animal Health (OIE), causing great economic losses due to decreased trade and high mortality and morbidity rates associated with bluetongue outbreaks. The objective of this study was to investigate the seroprevalence of BTV in camels in Kassala State, Eastern Sudan and to identify the potential risk factors associated with the infection. A cross sectional study using a structured questionnaire survey was conducted during 2015–2016. A total of 210 serum samples were collected randomly from camels from 8 localities of Kassala State. The serum samples were screened for the presence of BTV specific immunoglobulin (IgG) antibodies using a competitive enzyme-linked immunosorbent assay (cELISA). Seropositivity to BTV IgG was detected in 165 of 210 camels’ sera accounting for a prevalence of 78.6%. Potential risk factors to BTV infection were associated with sex (OR = 0.061, p-value = 0.001) and seasonal river as water source for drinking (OR = 32.257, p-value = 0.0108). Sex and seasonal river as water source for drinking were considered as potential risk factors for seropositivity to BTV in camels. The high prevalence of BTV in camels in Kassala State, Eastern Sudan, necessitates further epidemiological studies of BTV infection in camels and other ruminant species to better be able to control BT disease in this region.

中文翻译：

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苏丹东部喀萨拉州驼峰驼（Camelus dromedarius）蓝舌病的血清流行病学调查

蓝舌病（BT）是反刍动物和骆驼科动物的媒介传播病毒病，由Culicoides spp传播。BT的病原体是蓝舌病毒（BTV），它属于呼肠孤病毒科的Orbivirus属。临床疾病主要见于绵羊，但大多数亚临床的BT感染见于牛，山羊和骆驼科动物。骆驼对感染的临床反应通常不明显。该疾病是世界动物卫生组织（OIE）所报告的，由于贸易减少以及与蓝舌病暴发相关的高死亡率和高发病率，造成了巨大的经济损失。这项研究的目的是调查苏丹东部卡萨拉州骆驼中BTV的血清流行情况，并确定与感染相关的潜在危险因素。在2015-2016年期间，进行了使用结构化问卷调查的横断面研究。从卡萨拉州8个地区的骆驼中随机采集了210份血清样品。使用竞争性酶联免疫吸附测定（cELISA）筛选血清样品中BTV特异性免疫球蛋白（IgG）抗体的存在。在210头骆驼的血清中有165例检测到BTV IgG的血清阳性，占78.6％的患病率。BTV感染的潜在危险因素与性别有关（OR = 0.061，p值= 0.001）和季节性河水作为饮用水来源（OR = 32.257，p值= 0.0108）。性别和季节性河流作为饮用水来源被认为是骆驼对BTV血清反应阳性的潜在危险因素。苏丹东部喀萨拉州，骆驼中BTV的流行率很高，