Hecker Anna Sophie, Raulf Marie-Kristin, König Sven, Knubben-Schweizer Gabriela, Wenzel Christoph, May Katharina, Strube Christina
Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hanover, Germany.
Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, Ludwigstraße 21b, 35390 Gießen, Germany.
Vet Parasitol. 2024 Apr;327:110142. doi: 10.1016/j.vetpar.2024.110142. Epub 2024 Feb 1.
Infections with liver and rumen flukes are among the most frequent parasitic diseases in cattle worldwide. In Europe, the predominant liver fluke species is Fasciola hepatica, and the recently rapidly spreading rumen flukes are mostly Calicophoron daubneyi and occasionally Paramphistomum leydeni. In this study, 1638 faecal samples from individual dairy cows from 24 northern and 18 southern German farms as well as one central German farm, all preselected for potential F. hepatica infection, were examined to determine in-herd prevalences of liver and rumen fluke infections. Furthermore, individual faecal egg counts (FECs) were determined in the northern and central German cows. On farms with patent F. hepatica infections, the mean in-herd prevalence was 15.8% in northern Germany, 41.6% in southern Germany and 14.0% in the central German farm. Rumen fluke infections resulted in high in-herd prevalences in all regions with a mean prevalence of 46.0% in northern, 48.4% in southern and 40.0% in central Germany. Individual FECs varied between 0.1 and 4.1 (mean 0.4) eggs per gram faeces (EPG) for F. hepatica and between 0.1 and 292.4 (mean 16.9) EPG for rumen flukes. Mean in-herd prevalence and mean FECs did not differ significantly between mono- and coinfected farms for either fluke species. Comparison of the classical sedimentation technique and the Flukefinder® method on a subset of 500 faecal samples revealed a similar number of positive samples, however, Flukefinder® mean FECs were three to four times higher for liver and rumen fluke eggs, respectively, with an increasing gap between EPG levels with rising egg counts. Fluke egg size measurement confirmed P. leydeni eggs on average to be larger in length and width (161.0 µm x 87.1 µm) than those of C. daubneyi (141.8 µm x 72.9 µm). However, due to overlap of measurements, morphological species identification based on egg size proved unreliable. For accurate identification, a real-time pyrosequencing approach was established, offering the advantage over classical Sanger sequencing of unambiguously identifying rumen fluke mixed species infections. Real-time pyrosequencing confirmed C. daubneyi (78.1% [50/64]) as the predominant rumen fluke species in Germany, while P. leydeni was detected in 12.5% (8/64) of sampled cows. A total of 9.4% (6/64) cows were infected with both C. daubneyi and P. leydeni, representing the first finding of a mixed infection in domestic ruminants in Europe to date.
肝吸虫和瘤胃吸虫感染是全球牛群中最常见的寄生虫病之一。在欧洲，主要的肝吸虫种类是肝片吸虫（Fasciola hepatica），而最近迅速传播的瘤胃吸虫大多是道氏杯殖吸虫（Calicophoron daubneyi），偶尔也有莱登双口吸虫（Paramphistomum leydeni）。在本研究中，对来自德国北部24个、南部18个以及中部1个奶牛场的1638份个体奶牛粪便样本进行了检测，所有样本均因潜在的肝片吸虫感染而预先选定，以确定牛群中肝吸虫和瘤胃吸虫感染的患病率。此外，还测定了德国北部和中部奶牛的个体粪便虫卵计数（FEC）。在有明显肝片吸虫感染的农场中，德国北部牛群的平均患病率为15.8%，南部为41.6%，中部农场为14.0%。瘤胃吸虫感染在所有地区导致的牛群患病率都很高，德国北部的平均患病率为46.0%，南部为48.4%，中部为40.0%。肝片吸虫的个体FEC在每克粪便0.1至4.1（平均0.4）个虫卵（EPG）之间，瘤胃吸虫的个体FEC在每克粪便0.1至292.4（平均16.9）个EPG之间。对于这两种吸虫，单一感染和混合感染的农场之间，平均牛群患病率和平均FEC没有显著差异。在500份粪便样本的子集中对经典沉淀技术和Flukefinder®方法进行比较，结果显示阳性样本数量相似，然而，Flukefinder®方法测得的肝吸虫和瘤胃吸虫虫卵的平均FEC分别高出三到四倍，随着虫卵计数的增加，EPG水平之间的差距也在增大。吸虫虫卵大小测量证实，莱登双口吸虫虫卵的长度和宽度平均（161.0 µm×87.1 µm）比道氏杯殖吸虫（141.8 µm×72.9 µm）的大。然而，由于测量值有重叠，基于虫卵大小的形态学物种鉴定被证明不可靠。为了进行准确鉴定，建立了一种实时焦磷酸测序方法，与经典的桑格测序相比，它具有能够明确鉴定瘤胃吸虫混合物种感染的优势。实时焦磷酸测序证实，道氏杯殖吸虫（78.1% [50/64]）是德国瘤胃吸虫的主要种类，而在12.5%（8/64）的采样奶牛中检测到了莱登双口吸虫。共有9.4%（6/64）的奶牛同时感染了道氏杯殖吸虫和莱登双口吸虫，这是欧洲迄今为止首次在家养反刍动物中发现混合感染。
