Chagas Ana Carolina S, Katiki Luciana M, Silva Ives C, Giglioti Rodrigo, Esteves Sérgio N, Oliveira Márcia Cristina S, Barioni Júnior Waldomiro
Embrapa Pecuária Sudeste, São Carlos, São Paulo, Brazil.
Parasitol Int. 2013 Feb;62(1):1-6. doi: 10.1016/j.parint.2012.07.001. Epub 2012 Jul 15.
The aim of this work was to determine the resistance level of Haemonchus contortus isolated from the Santa Inês flock of the Embrapa (Brazilian government's Agricultural Research Company), Southeast Livestock Unit (CPPSE), as well as to determine costs of characterizing and maintaining this isolate in host donors. Forty-two male Santa Inês lambs were experimentally infected with 4000 H. contortus infective larvae of the field isolate of CPPSE, called Embrapa2010, and divided into six treatment groups, which received triclorfon, albendazol plus cobalt sulfate, ivermectin, moxidectin, closantel and levamisole phosphate, as well as a negative control group (water). Egg per gram (EPG) counts were performed at 0, 3, 7, 10 and 14 days post treatment when the animals were slaughtered for parasite count. The data were analyzed using the RESO statistical program, considering anthelmintic resistance under 95% of efficacy. EPG and worm count presented a linear and significant relation with 94% determination coefficient. The susceptibility results obtained by RESO through both criteria (EPG and worm count) were equal, except for closantel, showing that the isolate Embrapa2010 is resistant to benzimidazoles, macrocyclic lactones and imidazothiazoles. The need of a control group did not appear to be essential since the result for susceptibility in the analyses with or without this group was the same. Suppression in egg production after treatment did not occur in the ivermectin and moxidectin groups. In the control group, the establishment percentage was just 12.5 because of the low number of third-stage larvae, resistance (innate and infection immunity) of the animals studied plus good nutrition. Drug classes presented similar efficacy between adults and immature stages. The costs for isolate characterization were calculated for 42 animals during 60 days. The total cost based on local market rates was approximately US$ 8000. The precise identification of Brazilian isolates and their establishment in host donors would be useful for laboratorial anthelmintic resistance diagnoses through in vitro tests, which has an annual cost of approximately US$ 2500 for maintenance in host donors.
这项工作的目的是确定从巴西农牧业研究公司（Embrapa）东南部牲畜单位（CPPSE）的圣伊内斯羊群中分离出的捻转血矛线虫的抗药水平，并确定在宿主供体中鉴定和维持该分离株的成本。42只雄性圣伊内斯羔羊被实验性感染了4000条来自CPPSE田间分离株（称为Embrapa2010）的捻转血矛线虫感染性幼虫，并分为六个治疗组，分别接受敌百虫、阿苯达唑加硫酸钴、伊维菌素、莫西菌素、氯氰碘柳胺和磷酸左旋咪唑治疗，以及一个阴性对照组（水）。在治疗后0、3、7、10和14天进行每克粪便虫卵数（EPG）计数，之后宰杀动物进行寄生虫计数。使用RESO统计程序分析数据，将驱虫效果低于95%视为抗驱虫药。EPG和虫体计数呈现线性且显著的关系，决定系数为94%。通过RESO根据两种标准（EPG和虫体计数）获得的药敏结果相同，但氯氰碘柳胺除外，这表明Embrapa2010分离株对苯并咪唑类、大环内酯类和咪唑噻唑类药物具有抗性。似乎不需要对照组，因为有或没有该组的分析中的药敏结果是相同的。伊维菌素和莫西菌素组在治疗后未出现产卵抑制。在对照组中，由于三期幼虫数量少、所研究动物的抗性（先天和感染免疫）以及良好的营养，定殖率仅为12.5%。不同药物类别在成虫和未成熟阶段的疗效相似。计算了60天内42只动物的分离株鉴定成本。根据当地市场价格计算的总成本约为8000美元。巴西分离株的精确鉴定及其在宿主供体中的建立对于通过体外试验进行实验室驱虫药抗性诊断将是有用的，在宿主供体中维持该诊断每年的成本约为2500美元。
