Höglund Johan, Elmahalawy Safaa T, Halvarsson Peter, Gustafsson Katarina
Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Uppsala, Sweden.
Farm and Animal Health, Rådde gård, SE-51405, Länghem, Sweden.
Vet Parasitol X. 2019 Oct 15;2:100018. doi: 10.1016/j.vpoa.2019.100018. eCollection 2019 Nov.
An enhanced sampling strategy for detection of gastrointestinal parasites of sheep based on faecal sampling covering approximately 10% of the animals in the flock was evaluated with focus on the major sheep pathogen We also compared traditional diagnostics based on faecal eggs counts (FEC) by microscopy with DNA detection on frozen faeces samples using a droplet digital (dd)PCR assay. The investigation was carried out in 2018 in 20 conventional and 19 organic sheep flocks in Sweden with between 70 and 250 production ewes. On 76 different sampling occasions a total of 810 individual faecal samples were collected. Samples were pooled in the laboratory into 270 triplets which were examined both by microscopy and a ddPCR assay. On most farms (95%) a minimum of three triplets were investigated, first from the ewes prior to turn-out and later from the lambs after they had been grazing for at least six weeks. Extra information about the status was provided on 48% of the 76 sampling occasions by including more triplets compared with the old sampling strategy applied in Sweden before 2015 based on two triplets per sampling occasion irrespective of flock size. At a farm level was identified by microscopy in 22 (56%) of the 39 flocks and by ddPCR it was found in 28 (72%) flocks with the enhanced protocol. There was a substantial agreement between the two diagnostic tests (Cohens kappa = 0.70 ± 0.087). No significant differences in infection levels were observed between the two production systems (conventional and organic) irrespective of the diagnostic method used. However, samples from the ewes were more often positive than those from the lambs indicating that the level of parasite control was in general acceptable. Combined, our results show that infection is widespread throughout Sweden. In conclusion, we have validated a practical tool for sheep producers to assess infection with high precision.
基于粪便采样（覆盖羊群中约10%的动物）的一种用于检测绵羊胃肠道寄生虫的强化采样策略进行了评估，重点关注主要的绵羊病原体。我们还将基于粪便虫卵计数（FEC）的传统显微镜诊断与使用液滴数字（dd）PCR检测法对冷冻粪便样本进行DNA检测进行了比较。该调查于2018年在瑞典的20个传统绵羊群和19个有机绵羊群中进行，每个羊群中有70至250只生产母羊。在76个不同的采样场合共收集了810份个体粪便样本。样本在实验室中合并为270个三联样本，分别通过显微镜检查和ddPCR检测法进行检测。在大多数农场（95%），至少对三个三联样本进行了调查，首先是在母羊出圈前采集样本，随后在羔羊放牧至少六周后采集样本。与2015年之前瑞典应用的旧采样策略（每个采样场合基于两个三联样本，无论羊群大小）相比，在76个采样场合中的48%通过纳入更多三联样本提供了关于感染状况的额外信息。在农场层面，通过显微镜检查在39个羊群中的22个（56%）检测到感染，而采用强化方案通过ddPCR检测在28个（72%）羊群中发现感染。两种诊断测试之间存在高度一致性（科恩斯kappa系数=0.70±0.087）。无论使用哪种诊断方法，在两种生产系统（传统和有机）之间均未观察到感染水平的显著差异。然而，母羊的样本比羔羊的样本更常呈阳性，这表明寄生虫控制水平总体上是可接受的。综合来看，我们的结果表明感染在瑞典广泛存在。总之，我们已经验证了一种实用工具，可供绵羊生产者高精度地评估感染情况。
