Sibhat Berhanu, Ayelet Gelagay, Gebremedhin Endrias Zewdu, Skjerve Eystein, Asmare Kassahun
College of Veterinary Medicine, Haramaya University, P.O. Box 138, Dire Dawa, Ethiopia.
National Veterinary Institute, P.O. Box 19, Debre Zeit, Ethiopia.
Acta Trop. 2018 Feb;178:61-67. doi: 10.1016/j.actatropica.2017.10.024. Epub 2017 Oct 27.
Schmallenberg virus (SBV) is a recently identified member of the genus Orthobunyavirus of the family Bunyaviridae. It is an arbovirus transmitted by different members of Culicoides spp of biting midges. The virus is more recognized for its effect on reproductive disorders in ruminants characterised by abortion, stillbirth and birth of congenitally defective newborns with hydranencephaly-arthrogryposis syndrome. The current study was undertaken with the objectives of exploring the presence of SBV exposure and identification of factors affecting its distribution among dairy cattle in Ethiopia. A cross-sectional study was conducted on 1379 dairy cattle sampled from 149 dairy herds in central, southern and western Ethiopia during September 2011 to May 2012. Serum samples were examined using competitive enzyme linked immunosorbent assay (cELISA). Data on hypothesised risk factors were collected from farm records where available and semi-structured questionnaire-based interview. The apparent seroprevalence of exposure to SBV was 56.6% (95% confidence interval (CI): 53.9-59.3). True prevalence adjusted for sensitivity and specificity of the cELISA kit used was 58.3% (95% CI 55.7-60.9). Among the sampled herds, 82.6% (95% CI: 75.5-88.3) had at least one seropositive animal. Seropositive cattle were found in all of the 15 conurbations studied. Adult dairy cows [odds ratio (OR)=1.6] were more commonly affected than young heifers. Dairy cattle kept in commercial (OR=1.6) and breeding farms (OR=3.5) and Midland agroecology (OR=2.5) showed statistically significant seroconversion than cattle kept under small-holder dairy farms and Highland agroecology respectively (p<0.05). Reproductive disorders including abortion, retention of the fetal membranes, and metritis were associated with serostatus of SBV. In conclusion, the seroprevalence of SBV is high and widely distributed in the studied parts of Ethiopia. This being the first study of its kind on SBV in Ethiopia, further longitudinal studies on isolation of the virus and its impact on reproductive disorders are recommended.
施马伦贝格病毒（SBV）是布尼亚病毒科正布尼亚病毒属中最近发现的一个成员。它是一种虫媒病毒，由蠓科库蠓属的不同成员传播。该病毒因其对反刍动物生殖系统紊乱的影响而更为人所知，其特征为流产、死产以及生出患有积水性无脑-关节弯曲综合征的先天性缺陷新生儿。本研究旨在探索埃塞俄比亚奶牛中SBV暴露情况的存在，并确定影响其分布的因素。2011年9月至2012年5月期间，对从埃塞俄比亚中部、南部和西部149个奶牛场采集的1379头奶牛进行了一项横断面研究。血清样本采用竞争酶联免疫吸附测定（cELISA）进行检测。关于假设风险因素的数据从可获得的农场记录以及基于半结构化问卷的访谈中收集。SBV暴露的表观血清阳性率为56.6%（95%置信区间（CI）：53.9 - 59.3）。根据所使用的cELISA试剂盒的敏感性和特异性调整后的真实阳性率为58.3%（95% CI 55.7 - 60.9）。在抽样的牛群中，82.6%（95% CI：75.5 - 88.3）至少有一头血清阳性动物。在所研究的所有15个聚居区都发现了血清阳性的奶牛。成年奶牛[优势比（OR）=1.6]比年轻小母牛更易受影响。与小农户奶牛场和高地农业生态区饲养的奶牛相比，商业奶牛场（OR = 1.6）和繁殖场（OR = 3.5）以及中部农业生态区（OR = 2.5）饲养的奶牛血清转化具有统计学显著差异（p<0.05）。包括流产、胎膜滞留和子宫炎在内的生殖系统紊乱与SBV血清状态相关。总之，SBV的血清阳性率在埃塞俄比亚研究地区很高且分布广泛。作为埃塞俄比亚首次此类关于SBV的研究，建议进一步开展关于病毒分离及其对生殖系统紊乱影响的纵向研究。
