Degneh Efrem, Ashenafi Hagos, Kassa Tesfu, Kebede Nigatu, Shibeshi Workineh, Asres Kaleab, Terefe Getachew
College of Veterinary Medicine and Agriculture, Department of Pathology and Parasitology, Addis Ababa University, Addis Ababa, Ethiopia.
College of Veterinary Medicine and Agriculture, Department of Pathology and Parasitology, Addis Ababa University, Addis Ababa, Ethiopia.
Prev Vet Med. 2019 Jul 1;168:103-107. doi: 10.1016/j.prevetmed.2019.03.017. Epub 2019 Apr 20.
This study was conducted from May 08 to June 08, 2017 in Gidami District, Kellem Wollega Zone, Oromia Regional State, Ethiopia. The objective of the study was to assess the occurrence of trypanocidal drug resistance in naturally infected cattle in identified hot spots villages of Gidami district. An initial cross-sectional prevalence study was conducted in seven villages from November 2015 to June 2016. Based on the outcome of the cross-sectional study, Kellem and Gry Sonka villages with highest trypanosome prevalence (28% and 30.85%) respectively were selected. An abbreviated 28-day field prototocol study was used to estimate resistance to 1 mg/kg bw isometamidium chloride (ISM) and 7.0 mg/kg bw diminanzene aceturate (DA). In this study, 100 purposively selected trypanosome positive cattle were ear-tagged and allocated into two treatment groups: a group I were treated with 2% solution of 1 mg/kg bw ISM and a group II were treated with 7% solution of 7 mg/kg bw DA. The treatment day was considered as day 0 and the treated cattle were monitored for trypanosomes and packed cell volume (PCV) levels on days 14 (for DA and ISM) and 28 (for ISM) post treatment. A treatment failure rate of 25% of the cattle in the ISM treated group on days 14 and 28 were indicative of resistance, whereas in the DA treated group the response was assessed only on day 14 post-treatment. The results of the study confirmed the presence of drug resistance to the maximum recommended doses of ISM and DA in Giray Sonka and Kellem villages of Gidami district. Out of 50 trypanosome positive cattle treated with ISM, 68% had persistent infections on day 28 post-treatment. Similarly, of the 50 trypanosome positive cattle treated with 7 mg/kg bw DA, 36% had persistent trypanosomes on day 14 post treatment. Of all ISM and DA treatment failures T. congolense accounted for (70.59%; 66.67%), T. vivax (23.53%; 27.78%) and T. brucei (5.88%; 5.55%) respectively. Drug resistance has indeed been a considerable threat in all villages of Gidami district, but the situation is magnified in Giray Sonka and Kellem villages. Thus, an integrated control approach of trypanosomosis should be conducted to ensure sustainable animal health and production in the area. In addition beside tsetse control, rational use of trypanocidal drugs and control of co-infections to exploit self-cure against resistant trypanosome populations are recommended. Furthermore, extensive data on trypanocidal drug sensitivity tests using advanced molecular techniques considered as elucidative.
本研究于2017年5月8日至6月8日在埃塞俄比亚奥罗米亚州凯莱姆沃莱加区吉达米地区开展。研究目的是评估吉达米区已确定的热点村庄中自然感染牛的杀锥虫药物耐药性情况。2015年11月至2016年6月在7个村庄进行了初步的横断面患病率研究。根据横断面研究结果，分别选取锥虫患病率最高的凯莱姆村和格里·松卡村（分别为28%和30.85%）。采用为期28天的简化现场试验方案研究来评估对1mg/kg体重的氯胺胂（ISM）和7.0mg/kg体重的乙酰氨基苯胂（DA）的耐药性。在本研究中，有目的地选取100头锥虫阳性牛进行耳标标记，并分为两个治疗组：第一组用1mg/kg体重的ISM 2%溶液治疗，第二组用7mg/kg体重的DA 7%溶液治疗。治疗日被视为第0天，在治疗后第14天（针对DA和ISM）和第28天（针对ISM）对治疗的牛进行锥虫和红细胞压积（PCV）水平监测。ISM治疗组在第14天和第28天有25%的牛治疗失败率表明存在耐药性，而DA治疗组仅在治疗后第14天评估反应。研究结果证实，吉达米区的吉雷·松卡村和凯莱姆村存在对ISM和DA最大推荐剂量的耐药性。在50头用ISM治疗的锥虫阳性牛中，68%在治疗后第28天仍有持续性感染。同样，在50头用7mg/kg体重DA治疗的锥虫阳性牛中，36%在治疗后第14天仍有持续性锥虫感染。在所有ISM和DA治疗失败病例中，刚果锥虫分别占（70.59%；66.67%），活跃锥虫占（23.53%；27.78%），布氏锥虫占（5.88%；5.55%）。耐药性确实在吉达米区的所有村庄构成了相当大的威胁，但在吉雷·松卡村和凯莱姆村情况更为严重。因此，应采取锥虫病综合防控措施，以确保该地区动物健康和生产的可持续性。此外，除了采采蝇控制外，建议合理使用杀锥虫药物并控制合并感染，以利用自身治愈能力对抗耐药锥虫种群。此外，使用先进分子技术进行的杀锥虫药物敏感性试验的广泛数据被认为具有启发性。
