放牧绵羊主要寄生虫病高效低残留防治技术试验示范

为评价埃谱利诺菌素注射剂的驱虫药效与对放牧绵羊线虫病及外寄生虫病的防治示范应用效果,选择1.5岁感染线虫和部分外寄生虫的绵羊150只,设埃谱利诺菌素注射剂0.1,0.2和0.3 mg/kg体重剂量组和埃谱利诺菌素原料药对照组,进行驱虫效果评价,按0.2 mg/kg体重剂量进行规模防治技术示范,检查防治效果和考核防治效益。结果:药效试验中埃谱利诺菌素注射剂0.2 mg/kg剂量对绵羊消化道线虫虫卵转阴率和减少率分别为96.7%和99.3%,对原圆科线虫幼虫转阴率和减少率分别为90.0%和97.5%;0.3 mg/kg剂量对消化道线虫虫卵及原圆科线虫幼虫转阴率和减少率均为100.0%;0.1mg/kg剂量对消化道线虫虫卵转阴率和减少率分别为83.3%和90.4%,原圆科线虫幼虫转阴率和减少率分别为76.7%和88.9%。在冬季应用埃谱利诺菌素注射剂按0.2 mg/kg体重剂量对放牧绵羊进行规模防治技术示范,防治示范群绵羊消化道线虫虫卵转阴率和减少率分别为96.7%和97.7%;对原圆科线虫幼虫转阴率和减少率分别为93.3%和97.6%。同期检查未防治对照组绵羊虫卵EPG和幼虫数略有增加。埃谱利诺菌素注射剂0.2mg/kg剂量试验组给药后第1d绵羊体表的绵羊颚虱、足颚虱、羊蜱蝇活力旺盛;第3d绵羊颚虱、足颚虱大部分死亡干瘪,部分虫体移行到被毛表面,处于麻痹状态,活力较差;第7d检查对足颚虱的杀虫率达100%;绵羊颚虱全部死亡干瘪,杀虫率达100%;对羊蜱蝇的转阴率为83.3%。0.1mg/kg剂量,第3、7d检查杀灭效果次于上述剂量。未防治的对照组绵羊上述外寄生虫活力旺盛,感染情况与给药前无明显变化。同期检查技术示范群比未示范群每只成年羊平均少减重5.96kg、幼年羊成活率平均提高2.35个百分点。结果表明该防治技术对放牧绵羊主要寄生虫病高效安全,效益显著。     

埃谱利诺菌素注射剂对藏羊线虫与寄生期幼虫的驱虫效果

应用埃谱利诺菌素注射剂,选择自然感染线虫的1岁藏系绵羊150只,分别按0.1、0.2、0.3 mg/kg体重剂量皮下注射给药,驱除藏羊线虫,同时设伊维菌素注射剂药物对照组和阳性对照组。结果显示:①埃谱利诺菌素注射剂0.2、0.3 mg/kg体重剂量对藏羊消化道线虫虫卵转阴率分别为93.3%和100.0%,减少率分别为99.18%和100.0%;对网尾线虫幼虫转阴率和减少率均达100.0%,原圆科线虫幼虫转阴率分别为90.0%、100.0%,减少率分别为95.79%和100.0%;对线虫成虫的总计驱虫率分别为98.83%和99.96%,对线虫寄生阶段幼虫的总计驱虫率分别为96.42%和99.17%。②0.1 mg/kg剂量对线虫虫卵(幼虫)的转阴率、减少率、驱虫率均次于0.2、0.3 mg/kg体重剂量组。③对照药物伊维菌素注射剂0.2 mg/kg体重剂量对消化道线虫、原圆科线虫幼虫转阴率和减少率、对线虫成虫及其寄生阶段幼虫的总计驱虫率与同剂量埃谱利诺菌素注射剂基本一致。④藏羊皮下注射试验剂量未出现任何异常反应。试验证明埃谱利诺菌素注射剂0.2 mg/kg体重剂量驱除线虫高效安全。     

伊维菌素浇泼剂对绵羊线虫的驱虫效力与安全性试验

应用0.5%伊维菌素浇泼剂按0.3,0.4,0.5mg/kg.b w剂量对绵羊沿背中线皮肤一次浇泼给药,并以伊维菌素注射剂0.2mg/kg.b w剂量做对照。结果:伊维菌素浇泼剂0.3mg/kg,0.4mg/kg.b w剂量对消化道线虫虫卵转阴率分别为85%和90%,减少率分别为89.1%和95.9%;对原圆科线虫幼虫转阴率分别为60%和75%,减少率分别为77.2%和86.7%;0.5mg/kg.b w剂量对消化道线虫虫卵转阴率和减少率均为100%,对原圆科线虫幼虫转阴率为85%,减少率为95.4%。解剖检查结果:伊维菌素浇泼剂三种剂量对绵羊消化道、呼吸道多属线虫均有效,总计驱虫率分别为90.8%,95.6%和99.7%,伊维菌素浇泼剂0.5mg/kg.b w剂量与伊维菌素注射剂0.2mg/kg.b w剂量驱虫效果基本一致;绵羊经皮给药可耐受1.0mg/kg.b w剂量。试验证明:伊维菌素浇泼剂经皮给药驱除绵羊线虫高效安全,临床推荐剂量以0.5mg/kg.b w为宜。     

爱普利注射剂对放牧绵羊体内外寄生虫的驱虫试验

应用爱普利注射剂,选择自然感染线虫和体外寄生虫的1.5岁放牧藏系绵羊100只,分别按0.1、0.2、0.3 mg/kg.b w剂量皮下注射给药,同时设伊维菌素注射剂药物对照组和阳性对照组,评价驱除放牧绵羊体内线虫与体外寄生虫的效果。结果显示:爱普利注射剂0.2、0.3 mg/kg剂量对放牧绵羊消化道线虫虫卵转阴率分别为95.0%和100.0%,减少率分别为98.4%和100.0%;网尾线虫幼虫转阴率和减少率均达100.0%,原圆科线虫幼虫转阴率分别为90.0%和100.0%,减少率分别为96.1%和100.0%;对主要线虫虫卵(幼虫)的平均有效率分别达98.0%和100.0%;第7d对绵羊颚虱、足颚虱的转阴率、杀虫率均达100%;对羊蜱蝇的转阴率分别为90.0%和100.0%,杀虫率分别达92.3%和100%;均达到了高效。爱普利注射剂0.1 mg/kg剂量对线虫虫卵(幼虫)的转阴率、减少率及对体外寄生虫的杀虫率均次于0.2、0.3 mg/kg剂量组。对照药物伊维菌素注射剂0.2 mg/kg剂量消化道线虫虫卵转阴率、减少率分别为95.0%和97.8%;网尾线虫幼虫转阴率和减少率均达100.0%,原圆科线虫幼虫转阴率、减少率分别为85.0%和94.3%;第7d绵羊颚虱、足颚虱的转阴率、杀虫率均达100%;羊蜱蝇转阴率、杀虫率分别为80.0%和90%。阳性对照组线虫虫卵(幼虫)与给药前无明显变化、3种体外寄生虫感染情况较给药前略有增加。绵羊皮下注射3个剂量爱普利注射剂,未出现任何异常反应。试验证明爱普利注射剂3个剂量对藏系绵羊线虫虫卵(幼虫)、3种体外寄生虫均有效,其中0.2 mg/kg剂量驱除放牧绵羊线虫高效安全经济。     

伊维菌素注射剂对绵羊主要寄生虫病的防治试验

应用伊维菌素注射剂按0.2mg/kg体重剂量一次皮下注射给药,采用粪检法和体表检查法,进行放牧绵羊主要寄生虫病防治示范.结果:对绵羊主要消化道线虫虫卵转阴率、减少率分别为96.7％和99.1％,对原圆科线虫幼虫转阴率、减少率分别为89.5％和91.6％,对绵羊颚虱的杀虫率达100％.全部防治绵羊投药后未发生异常反应.应用效果证明:伊维菌素注射剂防治绵羊主要寄生虫病高效、安全、经济.     

牦牛主要寄生虫病高效低残留防治技术试验示范

为评价埃谱利诺菌素浇泼剂的驱虫效果与对牦牛线虫病及外寄生虫病的防治示范应用效果,选择1.5岁感染线虫和部分外寄生虫的牦牛150头,设埃谱利诺菌素浇泼剂0.4、0.5和0.6 mg/kg体重剂量组和埃谱利诺菌素注射剂对照组,进行驱虫效果评价;按0.5mg/kg体重剂量进行规模防治技术示范,检查防治效果和考核防治效益。结果:药效试验中埃谱利诺菌素浇泼剂0.5 mg/kg对牦牛消化道线虫虫卵转阴率、减少率分别为96.7%和99.3%,对原圆科线虫幼虫转阴率和减少率分别为90.0%和97.8%;0.6 mg/kg剂量对消化道线虫虫卵及原圆科线虫幼虫转阴率和减少率均为100.0%;0.4mg/kg剂量对消化道线虫虫卵转阴率为83.0%,减少率为90.4%,原圆科线虫幼虫转阴率和减少率分别为76.7%和88.9%。在冬季应用埃谱利诺菌素浇泼剂按0.5 mg/kg体重剂量对牦牛进行规模防治技术示范,近期防治示范群牦牛消化道线虫虫卵转阴率为96.7%,虫卵减少率为97.7%;对原圆科线虫幼虫转阴率、减少率分别为93.3%和97.6%。远期防治效果达88.5%。同期检查未防治对照组牦牛虫卵EPG和幼虫数略有增加。埃谱利诺菌素浇泼剂0.5mg/kg剂量试验组给药后第1d牦牛体表的牛颚虱活力减弱;第3d牛颚虱大部分死亡干瘪,部分虫体处于麻痹状态,活力较差;第7d检查牛颚虱全部死亡干瘪,杀灭率达100%;0.4mg/kg剂量,第3、7d检查杀灭效果次于上述剂量。而未防治的对照组牦牛上述外寄生虫活力旺盛,感染情况与给药前无明显变化。检查技术示范群比未示范群每头成年牦牛平均多增重或少减重5.76kg、幼年牛成活率平均提高2.51个百分点。结果表明该防治技术对牦牛主要寄生虫病高效安全低残留,效益显著。     

伊维菌素干混悬剂驱除绵羊寄生虫的扩大试验

应用伊维菌素干混悬剂,驱除绵羊体内线虫和体外寄生虫。结果:0.2mg/kg体重剂量对消化道主要线虫及网尾线虫的虫卵(幼虫)转阴率、减少率均为100%,原圆科线虫幼虫转阴率和减少率分别为91.3%、91.8%,对线虫的总计驱虫率98.9%:对绵羊颚虱的杀虫率为100%。结果证明:伊维菌素干混悬剂0.2mg/kg剂量一次用药,驱除绵羊主要线虫和虱等寄生虫,高效安全。     

倍克虫复合制剂对放牧绵羊线虫的驱虫效果

应用不同剂量倍克虫复合制剂(伊维菌素,丙硫苯咪唑),对放牧绵羊胃肠道线虫,肺线虫等进行驱除试验,结果表明：中剂量组(伊维菌素0．2mg／kg,丙硫苯咪唑10mg／kg)绵羊的消化道线虫虫卵转阴率达100％,减少率达100％,原圆科线虫幼虫转阴率达70％,减少率为77．35％。     

伊维菌素浇泼剂防治绵羊寄生虫病的效果观察

应用伊维菌素浇泼剂,驱除绵羊体内线虫和体外寄生虫,结果表明,0．5mg／kg体重剂量对主要7属消化道线虫和网尾线虫的虫卵（幼虫）转阴率、减少率均为100％,对原圆科线虫幼虫转阴率、减少率分别为87．59／6和91．3％,对线虫的总计驱虫率为99．04％;对绵羊颚虱的杀虫率达100％。表明伊维菌素浇泼剂0．5mg／kg剂量一次用药,驱除绵羊体内线虫和体外绵羊颚虱等寄生虫,高效安全。     

伊维菌素泼背剂对牦牛寄生虫的驱除效果试验

为选择适应于高寒牧区放牧牦牛大群驱除体内外寄生虫的理想荆型,在青海大通种牛场通过粪检选60头牦牛,随机分为3组,每组20头,试验1组用伊维菌素泼背荆接0.5 mg/kg体重剂量经背部皮肤浇泼给药,试验2组用伊维菌素注射剂按0.2 mg/kg体重剂量经皮下注射给药,试验3组为空白对照组.分析了三组不同寄生虫卵转率、虫卵减少率及驱虫率指标的变化,同时对药物的安全性进行了观察.结果试验1组消化道线虫虫卵转阴率、减少率分别为90%和99.1%,原圆科线虫幼虫转阴率、减少率分别为80%和92.8%;线虫成虫、寄生阶段幼虫的总计驱虫率分别为99.3%和98.8%;试验2组相应指标分别为90%和98.7%、80%和92.9%、99.4%和99.2%;1.2组对牛颚虱杀虫率均达100%,但对莫尼茨绦虫无效,对照组体内外寄生虫均无明显变化.表明伊维菌素泼背剂0.5 mg/kg剂量安全,驱虫效果可信,可在青海高寒地区牦牛体内外寄生虫驱虫工作中推广应用.     

祁连县牦牛主要寄生虫病高效低残留防治技术示范应用

为观察牦牛主要寄生虫病高效低残留防治技术防治示范应用效果,选择1.5岁感染线虫和部分外寄生虫的牦牛40头,应用埃谱利诺菌素注射剂,按0.2 mg/kg体重剂量进行牦牛线虫病及外寄生虫病规模防治技术示范,设埃谱利诺菌素注射剂防治组和未防治的对照组,进行防治效果检查。结果:技术示范群牦牛防治后7、14、21、28、35d对牦牛消化道线虫虫卵转阴率、减少率均达100.0%,近中期防治效果佳;对牦牛原圆科线虫幼虫的转阴率分别为61.5%、92.3%、100.0%、100.0%和100.0%,减少率分别为67.2%、96.2%、100.0%、100.0%和100.0%,近期防治效果随时间的变化而逐步提高,在21d后均达100.0%。防治后146d对牦牛消化道线虫的虫卵转阴率、减少率分别达75.0%和88.7%;对牦牛原圆科线虫幼虫转阴率、减少率分别达90.0%和87.4%,远期防治效果显著。防治后第7d牛颚虱全部死亡干瘪,转阴率达100%,对牛颚虱有高效驱杀作用。结果表明应用本项技术防治牦牛主要寄生虫病高效安全低残留,能有效降低牦牛寄生虫病的危害,在冷季保膘、保重和提高牦牛成活率等方面效益显著,牧民乐于接受使用。     

Prevalence of anthelmintic resistance on sheep farms in New Zealand

AIM: To establish the prevalence of anthelmintic resistance in parasitic nematodes on sheep farms in New Zealand. METHODS: A cross-sectional prevalence study was conducted, using a standardised faecal nematode egg count (FEC) reduction (FECR) test (FECRT) for ivermectin, at a full (0.2 mg/kg) and half (0.1 mg/kg) dose rate, and albendazole, levamisole and albendazole-levamisole in combination, on 60 lambs (n=10 per group) on farms selected from throughout New Zealand. Farms that conformed with selection criteria were chosen at random (n=80) or with a history of suspected resistance to macrocyclic lactone (ML) anthelmintics (n=32). Resistance to an anthelmintic was inferred when there was <95% reduction in FEC 7-10 days after treatment. Larval cultures were performed for all control groups and for treated groups for which resistance was evident. RESULTS: Of the farms randomly selected, 36% showed > or =95% FECR for all anthelmintics tested; resistance to ivermectin at 0.1 and 0.2 mg/kg liveweight was evident on 36% and 25% of these farms, respectively. Resistance to both ivermectin (0.2 mg/kg) and levamisole was evident on 8/80 (10%) farms, to ivermectin and albendazole on 10/80 (13%) farms, and to ivermectin, levamisole and albendazole on 6/80 (8%) farms. The prevalence of resistance to a half dose of ivermectin tended to be more prevalent on farms with a history of suspected ML resistance (p=0.06). Resistance to albendazole was seen across all the main parasite genera, and to levamisole in Nematodirus, Ostertagia (= Teladorsagia) and Trichostrongylus species. Resistance to ivermectin was dominated by Ostertagia spp, although Cooperia, Nematodirus and Trichostrongylus species were also implicated. CONCLUSION: Anthelmintic resistance in parasitic nematodes of sheep is common in New Zealand. Not only was resistance to albendazole and levamisole common, but resistance to the ML, ivermectin, was at a higher prevalence than expected. Sheep farmers and advisors in New Zealand need to re-evaluate the way they manage parasites, and more research is urgently needed if the steady decline in anthelmintic susceptibility is to be halted.     

Duration of Anthelmintic Effect of Three Formulations of Ivermectin (Oral,Injectable and Pour-on) Against Multiple Anthelmintic-Resistant <Emphasis Type="Italic">Haemonchus contortus</Emphasis> in Sheep

We report the results of investigations that were conducted in a sheep flock in Uttaranchal, India where repeated failure of anthelmintic medication was noted. The study revealed that Haemonchus contortus in sheep had developed resistance to benzimidazoles (fenbendazole, mebendazole and albendazole), imidazothiazole (levamisole) and salicylanide (rafoxanide), while it was fully susceptible to avermectins (ivermectin). Further, the suppression of nematode egg output in faeces of sheep naturally infected with multiple anthelmintic-resistant H. contortus following treatment with ivermectin tablet (0.4 mg/kg body weight (bw), orally), ivermectin injection (1% w/v, 0.2 mg/kg bw, subcutaneously) and ivermectin pour-on (0.5 w/v, 0.5 mg/kg bw) was also studied over a period of 10 weeks post treatment. It was noted that ivermectin tablet after initial clearance of infection (faecal egg count reduction 100%), could not prevent establishment of new patent natural infection for even a single day, while ivermectin pour-on and injection prevented the establishment of new infection for 7 and 14 days post treatment, respectively. Maximum protection period (duration for which mean faecal egg count of sheep reaches 500 eggs per gram of faeces or more) of 68 days was recorded in sheep treated with injectable ivermectin, followed by pour-on (60 days) and oral (53 days) preparations.     

An ivermectin tablet for sheep: Efficacy against gastro-intestinal nematodes and a bioavailability comparison with a liquid ivermectin formulation

An ivermectin tablet for o ral administration to sheep was developed for use in countries where it is customary to treat sheep with anthelmintic tablets. Tablets require no special administration equipment, and offer convenience for storage and transport. The ivermectin tablet, which delivers 10 mg of ivermectin (200 μg kg⁻¹ in a 50 kg sheep), had similar bioavailability to a liquid formulation of ivermectin (IVOMEC^® Liquid for Sheep) as determined by peak plasma ivermectin concentrations and area under the concentration curve in plasma (P>0.10). In dose confirmation trials in which nematode infections were induced in helminth-naive sheep, animals treated with the ivermectin tablet had significantly fewer adult and fourth-stage larval nematodes than untreated control sheep P<0.01 with efficacies >99% against all nematode species tested. In six field trials evaluating the efficacy of the ivermectin tablet in 240 Merino sheep, the reductions in faecal nematode egg counts ranged between 98 and 100%, as determined by comparison of pre- and post-treatment counts for the ivermectin-treated group.     

Resistance to a triple combination of broad-spectrum anthelmintics in naturally-acquired Ostertagia circumcincta infections in sheep

AIM: To measure the efficacy of two macrocyclic lactone-levamisole-benzimidazole combination drenches against naturally-acquired abomasal nematode infections on a sheep farm in the North Island, New Zealand. METHODS: Eighteen lambs carrying naturally-acquired worm burdens were removed from pasture and randomly allocated to one of three equal-sized groups, consisting of an untreated control group and two treatment groups. One treatment group was given a single oral dose of a triple-combination anthelmintic administered at the manufacturer's recommended dose rate of 0.2 mg/kg ivermectin, 7.5 mg/kg levamisole and 5.0 mg/kg albendazole. The other treatment group received a similar dose of another triple-combination drench consisting of 0.2 mg/kg abamectin, 8.0 mg/kg levamisole and 4.5 mg/kg oxfendazole. Worm counts were carried out post mortem on the abomasa of all animals in all groups, 10 days after treatment. RESULTS: While the abamectin-levamisole-oxfendazole combination was highly effective against all three abomasal nematode species present, the ivermectin-levamisole-albendazole combination was not. In the latter instance, a reduction of only 78% was achieved against infections of Ostertagia (=Teladorsagia) circumcincta. CONCLUSIONS: These results provide evidence of resistance to an ivermectin-levamisole-albendazole combination drench by O. circumcincta. CLINICAL RELEVANCE: Besides representing the first confirmed report of resistance to a combination drench consisting of three broad-spectrum anthelmintics, the present results provide further evidence of the continuing escalation of multiple anthelmintic resistance in sheep nematodes in New Zealand.     

Multiple species of nematodes resistant to ivermectin and a benzimidazole-levamisole combination on a sheep farm in New Zealand

AIM: To confirm the presence of multiple anthelmintic resistance on a sheep farm in New Zealand. METHODS: Three groups of 10 weaned Romney-cross lambs were treated either with an oral dose of ivermectin (0.2 mg/kg), or a benzimidazole/levamisole (BZ/LEV) combination (4.75 albendazole and 7.5 mg/kg levamisole), or were left untreated. Ten days later, animals were necropsied, and adult worms recovered and identified from the abomasa and small intestines. Pre- and post-treatment faecal nematode egg counts (FEC) were recorded, and larval cultures were performed. RESULTS: In a faecal egg count reduction test (FECRT), adjusted to reflect pre- and post-treatment larval culture results, ivermectin resistance was detected in Teladorsagia (Ostertagia), Trichostrongylus and Haemonchus spp, while BZ/LEV combination- resistant Teladorsagia and Trichostrongylus spp were also present. Adult worm counts confirmed these results, and identified the species involved as Teladorsagia circumcincta, Trichostrongylus colubriformis and H. contortus. CONCLUSION: Multiple, multi-generic anthelmintic resistance was confirmed on a sheep property in New Zealand. This included the first confirmed case of ivermectin resistance in T. colubriformis from sheep in New Zealand.     

阿苯达唑干混悬剂驱除绵羊线虫的效力与安全性试验

应用阿苯达唑干混悬剂按10mg/kg、15mg/kg、20mg/kg剂量驱除绵羊线虫,并设药物对照组和空白对照组。粪检结果:阿苯达唑干混悬剂三个试验剂量组对羊消化道线虫虫卵转阴率分别为83.3%、93.3%和96.7%,减少率分别为95.2%、98.8%和99.9%;对原圆科线虫幼虫转阴率分别为63.3%、83.3%和93.3%,减少率分别为76.1%、87.5%和94.2%。剖检结果:三个剂量组对线虫的总计驱虫率分别为96.9%、98.3%和99.4%。阿苯达唑原料药15mg/kg剂量对羊消化道线虫虫卵转阴率、减少率分别为90%和98.5%,对原圆科线虫幼虫转阴率、减少率分别为83.3%和86.9%,总计驱虫率98.5%。绵羊能耐受80mg/kg剂量。试验证明:阿苯达唑干混悬剂的驱虫活性及安全性与阿苯达唑原料药、片剂等无明显差异,均有良好驱虫效果,临床驱除绵羊线虫使用剂量以15mg/kg为宜,干混悬剂使用方法简便,特别适用于高原牧区,具有推广价值。