Frey C F, Eicher R, Raue K, Strube C, Bodmer M, Hentrich B, Gottstein B, Marreros N
Institute of Parasitology, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, 3012 Bern, Switzerland.
Biokema SA, Chemin de la Chatanerie 2, 1023 Crissier, Switzerland.
Vet Parasitol. 2018 Jan 30;250:52-59. doi: 10.1016/j.vetpar.2017.12.004. Epub 2017 Dec 5.
Infections with helminth parasites can negatively affect performance of dairy cows. Knowledge on infection intensity, spatial distributions and risk factors are key to develop targeted treatment strategies. Canada and most EU countries have conducted large investigations, but respective data for Switzerland were missing. We now performed a bulk tank milk serosurvey for Ostertagia ostertagi, Fasciola hepatica, and Dictyocaulus viviparus on a total of 1036 voluntarily participating dairy herds that were sampled at confinement periods, i.e. in winter 2014/15 or 2015/16, respectively. All samples were analyzed with commercial ELISAs for antibodies (AB) against O. ostertagi and F. hepatica, and those of the first sampling period additionally with an in-house ELISA for AB against D. viviparus. Testing for the latter parasite was not done in the second year of the study, as the sampling period might have missed infections due to the short lived nature of specific antibodies. The possible influence of geographic, climatic, and farm management variables on AB levels were assessed for each parasite using scanning cluster and multiple regression analysis. Overall seroprevalence for O. ostertagi was 95.5% (95% C.I.: 94.0-96.6), with a mean optical density ratio (ODR) of 0.83, for F. hepatica 41.3% (95% C.I.: 38.3-44.4), and for D. viviparus 2.9% (95% C.I.: 1.6-4.7). There were no significant differences between the two sampling periods. For all parasites, significant geographic clusters of higher AB levels could be established. Furthermore, AB levels against all three parasites were positively correlated with each other, indicating either cross-reactions or co-infections. For O. ostertagi, herd size and percentage of pasture in the ration were positively correlated with AB levels. For F. hepatica, altitude above sea level (a.s.l.) positively, and milk production per cow and year was negatively correlated with AB levels. This work provides baseline data for further studies performing in-depth risk factor analysis and investigating management as well as targeted treatment options to control the parasites.
感染蠕虫寄生虫会对奶牛的生产性能产生负面影响。了解感染强度、空间分布和风险因素是制定针对性治疗策略的关键。加拿大和大多数欧盟国家都进行了大规模调查，但瑞士缺乏相关数据。我们现在对总共1036个自愿参与的奶牛场进行了奥斯特他线虫、肝片吸虫和胎生网尾线虫的乳罐血清学调查，这些奶牛场分别在2014/15年冬季或2015/16年冬季的圈养期进行采样。所有样本均使用商业化酶联免疫吸附测定法（ELISA）检测针对奥斯特他线虫和肝片吸虫的抗体，并且在第一个采样期的样本还使用了内部ELISA检测针对胎生网尾线虫的抗体。在研究的第二年没有对后一种寄生虫进行检测，因为由于特定抗体寿命较短，采样期可能遗漏了感染情况。使用扫描聚类和多元回归分析评估了地理、气候和农场管理变量对每种寄生虫抗体水平的可能影响。奥斯特他线虫的总体血清阳性率为95.5%（95%置信区间：94.0 - 96.6），平均光密度比（ODR）为0.83，肝片吸虫为41.3%（95%置信区间：38.3 - 44.4），胎生网尾线虫为2.9%（95%置信区间：1.6 - 4.7）。两个采样期之间没有显著差异。对于所有寄生虫，都可以确定抗体水平较高的显著地理聚类。此外，针对所有三种寄生虫的抗体水平彼此呈正相关，表明可能存在交叉反应或共同感染。对于奥斯特他线虫，牛群规模和日粮中牧场比例与抗体水平呈正相关。对于肝片吸虫，海拔高度与抗体水平呈正相关，每头奶牛每年的产奶量与抗体水平呈负相关。这项工作为进一步开展深入的风险因素分析、研究管理措施以及探索针对性治疗方案以控制寄生虫提供了基线数据。
