Dixit A K, Das G, Dixit Pooja, Singh A P, Kumbhakar N K, Sankar M, Sharma R L
Department of Veterinary Parasitology, College of Veterinary Science & Animal Husbandry, Nanaji Deshmukh Veterinary Science University, Jabalpur, Madhya Pradesh, 482001, India.
Department of Veterinary Medicine, College of Veterinary Science & Animal Husbandry, Nanaji Deshmukh Veterinary Science University, Jabalpur, Madhya Pradesh, 482001, India.
Trop Anim Health Prod. 2017 Oct;49(7):1471-1478. doi: 10.1007/s11250-017-1349-x. Epub 2017 Jul 17.
Current status of resistance to benzimidazole (BZ) group of anthelmintic drugs against caprine nematodes in Central India at Amanala goat farm, Jabalpur, Madhya Pradesh (M. P.), was systematically investigated using faecal egg count reduction (FECR) test and egg hatch test (EHT). Besides, allele-specific PCR (AS-PCR) was deployed to ascertain the susceptible genotype (alleles) especially of the Haemonchus contortus. Randomly selected 30 goats, irrespective of age and sex, were divided into three groups of 10 each, to serve as treated and untreated controls. It was ensured that the animals were not administered with an anthelmintic drug for the past 3 months prior to undertaking the study, and faecal egg counts were estimated. FECR test evidenced fenbendazole resistance by partial elimination (24.90%) copro-egg counts in the treated group of animals vis-à-vis controls with a lower confidence interval of -26%. Further, EHT revealed ED-50 value of 0.335 μg of thiabendazole/ml, confirming benzimidazole resistance in the animals of that farm. AS-PCR showed that 62% of H. contortus larvae were homozygous resistant (rr), 24% heterozygous (rS) and 14% homozygous susceptible (SS). The genotypic frequencies of three genotypes (rr, rS and SS) were significantly (P < 0.01) different. The prevalence of benzimidazole resistance allele (r) was also significantly (P < 0.01) higher (74%) as compared to susceptible allele (S) (26%). The resistance to benzimidazole has been discussed while emphasizing improved managemental practices designed to reduce exposure of the goat population to parasites, minimize frequency of anthelmintic use at optimum dose and rotational use of different chemical groups of medicines with different mode of action, so as to overcome and combat the upcoming problem in the field.
在印度中央邦贾巴尔普尔的阿马纳拉山羊养殖场，运用粪便虫卵计数减少（FECR）试验和虫卵孵化试验（EHT），系统地调查了抗蠕虫药苯并咪唑（BZ）类药物对山羊线虫的耐药现状。此外，采用等位基因特异性PCR（AS-PCR）来确定尤其是捻转血矛线虫的敏感基因型（等位基因）。随机挑选30只山羊，不分年龄和性别，分成三组，每组10只，分别作为治疗组和未治疗对照组。确保在开展研究前的过去3个月内未给这些动物使用抗蠕虫药，并对粪便虫卵计数进行了估算。FECR试验表明，与对照组相比，治疗组动物粪便虫卵计数部分消除（24.90%），置信区间下限为-26%，证明存在芬苯达唑耐药性。此外，EHT显示噻苯达唑的ED-50值为0.335μg/ml，证实该养殖场的动物存在苯并咪唑耐药性。AS-PCR显示，62%的捻转血矛线虫幼虫为纯合抗性（rr），24%为杂合（rS），14%为纯合敏感（SS）。三种基因型（rr、rS和SS）的基因频率存在显著差异（P<0.01）。苯并咪唑抗性等位基因（r）的流行率也显著高于敏感等位基因（S）（26%）（P<0.01）（74%）。讨论了苯并咪唑耐药性问题，同时强调了改进管理措施，旨在减少山羊群体接触寄生虫的机会、以最佳剂量尽量减少抗蠕虫药使用频率以及轮换使用不同化学组且作用方式不同的药物，以便克服和应对该领域即将出现的问题。
