Han Tianlong, Wang Min, Zhang Guanghe, Han Dongsheng, Li Xinwei, Liu Guowen, Li Xiaobing, Wang Zhe
.
Acta Parasitol. 2017 Dec 20;62(4):815-822. doi: 10.1515/ap-2017-0098.
Gastrointestinal nematodes (GIN) are a crucial restraint to grazing sheep production worldwide. This study was conducted to determine the infections and anthelmintic resistance (AR) of GIN in pasture-based sheep in the Eastern Inner Mongolia, China. GIN eggs were tested from 600 grazing sheep feces of 10 farms using saturated saline flotation method and McMaster's method. The egg hatch test (EHT) and the faecal egg count reduction test (FECRT) were used to evaluate resistance of GIN to anthelmintics. We found that the average infection rate was 79.2% (range: 45%-100%). The grand mean faecal egg count (FEC) was 1813.2 eggs per gram (EPG) (range: 0-32400 EPG). There were significant differences in GIN infection among different breeds of sheep. The sequence of infection intensity and infection rate were Small fat tail > Ujimqin > Ju Ud (p<0.05). The 50% effective doses (ED50) of albendazole(ABZ) and levamisole (LMS) for expelling were 5.670 µg/mL and 0.302 µg/mL, respectively. The percentage reductions of avermectin (AVM), ivermectin (IVM), ABZ and LMS were 81.28%, 86.49%, 76.21% and 96.59%, respectively. The most predominant parasite genus in all four anthelmintics was Haemonchus. In these tested areas, mixed infections of GIN in grazing sheep were very common. AR, especially in Haemonchus, was a serious problem in these sheep flocks. Thus, actions are urgently required to taken to mitigate the worsening situation.
胃肠道线虫（GIN）是全球范围内限制放牧绵羊生产的关键因素。本研究旨在确定中国内蒙古东部以放牧为主的绵羊中GIN的感染情况及抗蠕虫药耐药性（AR）。采用饱和盐水漂浮法和麦克马斯特法对10个养殖场的600份放牧绵羊粪便中的GIN虫卵进行检测。采用虫卵孵化试验（EHT）和粪便虫卵计数减少试验（FECRT）评估GIN对驱虫药的耐药性。我们发现平均感染率为79.2%（范围：45%-100%）。粪便虫卵计数（FEC）的总体平均值为每克1813.2个虫卵（EPG）（范围：0-32400 EPG）。不同品种绵羊的GIN感染存在显著差异。感染强度和感染率的顺序为小尾寒羊>乌珠穆沁羊>杜泊羊（p<0.05）。阿苯达唑（ABZ）和左旋咪唑（LMS）驱虫的半数有效剂量（ED50）分别为5.670 µg/mL和0.302 µg/mL。阿维菌素（AVM）、伊维菌素（IVM）、ABZ和LMS的减少百分比分别为81.28%、86.49%、76.21%和96.59%。在所有四种驱虫药中最主要的寄生虫属是血矛线虫属。在这些检测区域，放牧绵羊中GIN混合感染非常普遍。AR，尤其是血矛线虫属的AR，在这些羊群中是一个严重问题。因此，迫切需要采取行动来缓解这种恶化的情况。
