Gastrointestinal nematode populations with multiple anthelmintic resistance in sheep farms from the hot humid tropics of Mexico.
Gastrointestinal nematode populations with multiple anthelmintic resistance in sheep farms from the hot humid tropics of Mexico.
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DOI：
10.1016/j.vprsr.2017.04.007
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发表时间：
2017-08-01
期刊：
影响因子：
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通讯作者：
Torres-Acosta, J F J
中科院分区：
文献类型：
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作者：
Herrera-Manzanilla, F A;Ojeda-Robertos, N F;Torres-Acosta, J F J
本研究评估了墨西哥湿热热带地区7个绵羊养殖场的驱虫药对三种市售药物的耐药性。药物类别包括苯并咪唑（BZ）、伊维菌素（IVM）和左旋咪唑（LV）。在每个农场进行了相应的粪便虫卵计数减少试验（FECRT）。从每个农场>100只绵羊的直肠中获得粪便样品。包括每克粪便排出>150个卵（EPG）的成年绵羊。在每个农场中，动物被分配到具有相似平均EPG的四个组之一：对照组（未处理）、BZ组（阿苯达唑亚砜5 mg/kg LW）、IVM组（伊维菌素，0.2mg/kg LW）和LEV组（左旋咪唑7.5mg/kg LW）。皮下给药。给药后14天，对每个农场的相同动物进行第二次粪便采样。在不同的农场中，对每组从粪便培养物中获得的GIN属进行了鉴定。使用RESO ®软件估计粪便虫卵计数减少百分比（%R）和95%置信区间。一份调查问卷适用于农场主描述驱虫管理的做法。所有羊场都有GIN人群，对测试的三种驱虫药具有多重耐药性。BZ的%R范围为0 - 48%，IVM为29 - 82%，LEV为1 - 88%。血矛线虫属和毛虫属（Trichostongylus spp.）在研究农场的所有给药组中均发现。耐药食管口线虫属在各鸡场发现幼虫（BZ或IVM）。研究农场的处理实践包括每两个月进行一次频繁的大规模处理，并在出现临床体征时单独进行额外处理。药物剂量采用目测估计体重，而不是每只动物的确切体重。使用检疫驱虫剂处理进货，但疗效未得到证实。
This study evaluated the status of anthelmintic resistance against the three available classes of commercial drugs in seven sheep farms in the hot humid tropics of Mexico. Drug classes included benzimidazole (BZ), ivermectin (IVM) and levamisole (LV). Respective faecal egg count reduction tests (FECRT) were performed in each farm. Faecal samples were obtained from the rectum of >100 sheep in each farm. Adult sheep shedding >150 eggs per gram of faeces (EPG) were included. In each farm, animals were allotted to one of four groups with similar mean EPG: Control Group (untreated), BZ group (albendazole sulfoxide 5mg/kg LW), IVM group (ivermectin, 0.2mg/kg LW) and LEV group (levamisole 7.5mg/kg LW). Drugs were administered subcutaneously. A second faecal sampling was performed on the same animals of each farm 14days post-treatment. The GIN genera obtained from faecal cultures were identified for each group in different farms. Percentage faecal egg count reduction (%R) and 95% confidence intervals were estimated using the RESO© software. A questionnaire was applied to farm owners to describe anthelmintic management practices. All sheep farms had GIN populations with multiple resistance to the three anthelmintic classes tested. The %R ranged from 0 to 48% for BZ, 29 to 82% for IVM and 1 to 88% for LEV. Haemonchus spp. and Trichostongylus spp. were found in all treated groups of the study farms. Resistant Oesophagostomum spp. larvae (BZ or IVM) were found in respective farms. Treatment practices in study farms included frequent mass treatment every two months with extra treatments applied individually in the presence of clinical signs. Drug dosage used visual estimation of body weight rather than the exact weight of each animal. Quarantine anthelmintic treatment of incoming stock was used but efficacy was not confirmed.