四种药物防治小尾寒羊消化道线虫的效果观察

为了探讨小尾寒羊消化道线虫发病规律和药物防治效果,筛选驱虫效果最佳药物,试验随机选取小尾寒羊600只,分为芬苯达唑粉组、伊维菌素注射液组、阿苯达唑伊维菌素预混剂组、多拉菌素注射液组和生理盐水对照组,每组各120只。每组在试验前7天进行粪便虫卵检查,用药开始后,在每次用药的第7天分别进行粪便虫卵检查1次,在整个试验期间共检查4次。粪便虫卵检查采用饱和盐水漂浮法,计算粪便虫卵数、每克被检粪样中虫卵数量(EPG),比较每个试验组每个检查阶段的虫卵转阴率。结果表明:各组试验羊在用药7 d后虫卵转阴率由高到低依次为阿苯达唑伊维菌素预混剂组、伊维菌素注射液组、芬苯达唑粉组、多拉菌素注射液组,分别为92.5%、90.8%、90.0%和89.1%,阿苯达唑伊维菌素预混剂防治效果确实可靠,药效持续时间长,优于其他试验组。说明临床用药在防治小尾寒羊消化道线虫方面,阿苯达唑伊维菌素预混剂防治该病效果优于其他试验药物,值得推广应用。     

芬苯哒唑控释丸对绵羊消化道线虫的临床驱虫效果观察

近年来,国内外为防治家畜蠕虫病研制出了高效、低毒、广谱的驱虫新药和新剂型.用中国农科院上海家畜寄生虫病研究所研制的芬苯哒唑长效控释丸,作为首选驱虫药来研究其对羊线虫的临床驱虫效果,为防治羊线虫病提供可靠的依据.芬苯哒唑是一种苯丙咪唑类广谱驱线虫药物,该药对羊血矛线虫、奥斯特线虫、毛圆线虫、古柏线虫、细颈线虫、仰口线虫、夏伯特线虫、食道口线虫、毛首线虫、网尾线虫的成虫及幼虫均有高效杀灭作用,并具有抑制雌虫排卵作用,但有关其临床上的有效用药剂量说法不一.为探讨该药一次有效使用剂量,以方便临床应用,于2004年9月份进行了不同剂量芬苯哒唑对自然感染线虫病羊的驱虫效果比较试验,现将试验过程与结果报道如下.     

芬苯哒唑干粉混悬剂对绵羊肝片吸虫的驱除试验

芬苯哒唑是一种广谱驱虫药，对不同动物线虫的驱除效果已有大量报道，但对羊肝片吸虫的驱除效果却资料有限。为了验证芬苯哒唑干粉混悬剂对绵羊自然感染肝片吸虫的驱除效果，并确定适宜的使用剂量，笔者于2000年8月进行了本项试验。     

芬苯哒唑长效控释丸在山羊体内的药物动力学研究

本试验用反相高效液相法测定芬苯哒唑长效控释丸在山羊体内的药物动力学。在血浆中测到芬苯哒唑代谢产物亚砜和砜，其平均浓度分别为７．１７±１．５４ｍｇ／ｍｌ和３．８６±１．０３ｎｇ／ｍｌ，但未测出原药浓度。在瘤胃液中测出的芬苯哒唑平均浓度为２１９．００±１３０．８３ｎｇ／ｍｌ。结果表明芬苯哒唑长效控释九可以在山羊体内恒定释放药物１１０天以上。     

猪鞭虫病的防治

为了深入研究猪鞭虫病的防治,笔者在确诊120头病猪为猪鞭虫病后,在其饲料中加入伊维菌素—芬苯哒唑预混剂和广谱抗生素氟苯尼考,加入剂量分别为500g/t、100g/t,疗程持续5～7d。结果发现,除15头病死猪进行焚烧外,其余105头病猪用药3d后,粪便中的虫体清晰可见,而用药7d后,105头病猪已逐步恢复正常。选用伊维菌素—芬苯哒唑预混剂和广谱抗生素氟苯尼考可有效驱除病猪体内的虫体;同时,通过加大消毒和清洗力度,来保证养殖场的环境,也可从根本上杜绝猪鞭虫病的发生。     

芬苯达唑微晶体临床药效学试验

本试验以家兔为试验动物,观察芬苯达唑微晶体对动物肠道寄生虫的影响。50只人工感染猪蛔虫的家兔随机分成5组,每组10只,第Ⅰ组、Ⅱ组按体重5 mg/kg、10mg/kg不同剂量的芬苯达唑微晶体对家兔口服饲喂驱虫,同时第Ⅲ组、Ⅳ组按体重10mg/kg芬苯达唑及0.2 mg/kg伊维菌素口服给药作药效对照,并设空白组,分别于用药前3d和用药后5d取粪便进行虫卵计数。结果表明,各剂量组药物对肠道蛔虫虫卵减少率分别为99.6%,100%,98.8%,99.7%,虫卵转阴率分别为100%、100%、90%、90%,芬苯达唑微晶体组对兔肠道寄生虫驱除作用要优于其他用药各组,10 mg/kg体重最佳,表明芬苯达唑微晶体能提高芬苯达唑的驱虫效果,提高其生物利用度。     

奥苯哒唑驱除奶牛寄生蠕虫的效果观察

奥苯哒唑(Oxibendazole)是一种广谱高效的驱虫药,已广泛用于兽医临床,尤其是对动物消化道中寄生虫体作用更加明显。国内学者的研究表明,该药对犊牛新蛔虫的驱除率达100%;对鸡蛔虫和异刺线虫驱除效果均达99%以上;对猪蛔虫远期驱虫效果一直保持100%。我们选择了在自然状态下感染有蠕虫的奶牛,确定奥苯哒唑的驱除效果,为指导临床用药提供依据。1材料与方法1.1药品江苏金坛县兽药厂生产,100mg/片,批号:20010714。1.2试验牛只选择某奶牛场,经粪便学检查证明消化道蠕虫自然感染较高者作为试验用牛。为了便于饲养管理和牛的品种、体重、合群性的一…     

3种驱虫药对陕北白绒山羊消化道线虫的驱虫效果比较

为了更好地了解常用驱虫药的驱虫效果,选择陕北白绒山羊开展驱虫研究。试验选取3种市场常用驱虫药(伊维菌素注射液、芬苯达唑粉、伊维菌素芬苯达唑预混剂),应用饱和食盐水漂浮法和虫卵计数法对陕北白绒山羊的消化道线虫驱虫前后的感染情况进行检测。结果表明,伊维菌素注射液组驱虫后虫卵转阴率为6.25%,感染强度由766.7降低至233.3;芬苯达唑组驱虫后虫卵转阴率为31.25%,感染强度由766.7降低至100;伊维菌素芬苯达唑预混剂组驱虫后虫卵转阴率为50%,感染强度由766.7降低至167.0。建议在陕北白绒山羊生产中将伊维菌素芬苯达唑预混剂作为消化道线虫的首选驱虫药。     

抗蠕虫特效新药──芬苯哒唑

芬苯哒唑是近年来国际最新最优的广谱、高效、低毒、低残留的动物用抗蠕虫药物。对马、牛、羊、猪、犬、猫、禽、鹿、食肉猛禽等动物胃肠道多数线虫的成虫、幼虫、虫卵和吸虫成虫、幼虫,以及线虫等均有很强的驱杀作用。临床应用证明,芬苯哒唑对如下蠕虫具有强大杀灭作用：①牛、羊的血矛线虫、奥斯特他线虫、毛圆线虫、古柏线虫、细颈线虫、仰口线虫、夏伯物线虫、食道口线虫、毛首线虫、网尾线虫的成虫及幼虫;扩展莫尼茨绦虫、贝氏莫尼茨绦虫。②马的副蛔虫、尖尾线虫的成虫和幼虫、胎生普氏线虫、普通圆形线虫、无齿圆线虫、小型圆形线…     

甲醇试剂对芬苯哒唑紫外鉴别试验的影响

<正>芬苯哒唑为苯并咪唑类,具有广谱驱虫作用。线虫对其敏感,对绦虫、吸虫也有较强的作用,对血吸虫无效,是当前动物应用最多而最广的药物。芬苯哒唑及制剂已收载到《中国兽药典》一部,在检验实践中发现,甲醇试剂的质量影响芬苯达唑紫外鉴别,为此,我们用分析纯甲醇和色谱纯甲醇作溶剂时对紫外鉴别在218nm波长测定最大吸收时产生移位情况及原料紫外鉴别测定溶液浓度每1ml中含7μg进行了试验,现将试验结果报告如     

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.     

Effect of fenbendazole and ivermectin on development of strongylate nematode eggs and larvae in calf feces.

Thirty-nine weaned steer calves (mean weight 284 kg) were maintained under dry-lot conditions and assigned (based on fecal nematode egg count) to one of three treatment groups of 13 animals each as follows: control (no treatment), fenbendazole (5 mg kg-1), and ivermectin (0.2 mg kg-1). Fecal samples were collected 12 h before treatment, at treatment, and 12, 24, 48 and 72 h after treatment for determination of nematode eggs per gram, and (after culture) infective larvae per gram and population distribution. The effect of treatment on egg development was observed in feces collected 12 and 24 h after treatment. There was essentially no difference in efficacy, based on egg counts, of fenbendazole and ivermectin. Egg count was reduced 100% by both anthelmintics at 72 h after treatment. Viability, based on percent of eggs reaching the infective larval stage, of developing stages at 12, 24, and 48 h after fenbendazole treatment was 0.1%, 1.1%, and 0%; after ivermectin treatment the corresponding values were 23.7%, 30.1%, and 28.6%, respectively. Fenbendazole treatment resulted in little or no development of eggs and/or larvae in feces deposited 12 and 24 h after treatment, whereas development proceeded normally (compared with the control group) in ivermectin treated feces. Population distribution of infective larvae was predominantly Haemonchus and Cooperia with some Ostertagia and Oesophagostomum.     

Macrocyclic lactone-resistant Parascaris equorum on stud farms in Canada and effectiveness of fenbendazole and pyrantel pamoate

The aims of studies in 2002 and 2003 on three farms with 76 foals naturally infected with Parascaris equorum were to (i) identify if the nematode was resistant to ivermectin and moxidectin, and (ii) confirm the effectiveness of fenbendazole and pyrantel pamoate for the parasite. Twelve clinical trials, each with a Fecal Egg Count Reduction Test, were conducted on two Thoroughbred and one Standardbred farms in southwestern Ontario, Canada. In each trial, Parascaris eggs/g feces were estimated for each foal pre- and post-treatment using the Cornell-Wisconsin double flotation and Cornell-McMaster dilution techniques. On each farm and for each trial, foals were randomized into treatment groups. Treatments were ivermectin, moxidectin, fenbendazole, pyrantel pamoate administered at the manufacturers' recommended dosages, and some foals were untreated. The overall efficacy for ivermectin was 33.5% (19 foals) and for moxidectin 47.2% (28 foals). Fenbendazole (16 foals) and pyrantel pamoate (21 foals) were highly effective for P. equorum each at 97.6%. For fenbendazole, 15 foals had 100% and for pyrantel pamoate 17 foals had >97% with 14 at 100%.     

放牧绵羊主要寄生虫病药物防治技术试验与示范效果观察

为评价伊维菌素注射剂的驱虫效果与对放牧绵羊线虫病及外寄生虫病的防治示范效果,选择1.5岁感染线虫和部分外寄生虫的绵羊150只,设伊维菌素注射剂0.1,0.2和0.3mg/kg体重剂量组和伊维菌素片剂对照组,进行驱虫效果评价;在冬季应用伊维菌素注射剂按0.2mg/kg体重剂量对放牧绵羊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:药效试验中伊维菌素注射剂0.2mg/kg对绵羊消化道线虫虫卵转阴率和减少率分别为93.3%,99.3%,对原圆科线虫幼虫转阴率和减少率分别为90.0%和96.1%;0.3mg/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76.7%,88.6%,原圆科线虫幼虫转阴率和减少率分别为66.7%和86.1%。防治示范群绵羊消化道线虫虫卵转阴率为93.3%,虫卵减少率为96.8%;对原圆科线虫幼虫转阴率和减少率分别为90.0%和96.2%。同期检查未防治对照组虫卵EPG和幼虫数略有增加。技术示范群比未示范群每只成年羊平均多增重5.47kg、幼年羊成活率平均提高2.1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。     

Efficacy of avermectin B1 given orally against equine intestinal strongyles and Onchocera microfilaria

Three groups of horses and ponies (N = 13, 13 and 12) were treated with ivermectin paste (0.2 mg/kg p.o.), avermectin B1 solution (0.2 mg/kg p.o.), or fenbendazole suspension (10 mg/kg via nasogastric tube). The avermectin B1 was a 1% solution in a propylene glycolglycerol formal base. Faecal strongyle egg counts were performed before, and 14, 28, 42, 56 and 70 d, after treatment. Full-thickness skin biopsies from the neck, pectoral and umbilical regions were examined for Onchocera microfilaria before treatment, and again 14 and 70 d later. Ivermectin therapy produced a significant (P less than 0.01) decrease in mean strongyle egg counts 14, 28, 42 and 56 d after treatment. Avermectin B1 therapy resulted in significant (P less than 0.01) decreases in mean strongyle egg counts 14, 28 and 42 d after treatment. All horses given ivermectin or avermectin B1 had zero strongyle egg counts 14 and 28 d after treatment. Fenbendazole failed to significantly decrease strongyle egg counts. Both ivermectin and avermectin B1 resulted in zero microfilaria counts in all horses 14 d after treatment. On day 70 the percentage decrease in microfilaria counts were 100% and 99.6% respectively. Fenbendazole failed to significantly decrease microfilaria counts. The oral administration of this formulation of avermectin B1 appeared to be highly efficacious against intestinal strongyles and Onchocera microfilaria. The duration of anti-strongyle activity was, however, significantly (P less than 0.01) shorter than that of ivermectin paste.     

Resistance of Teladorsagia circumcincta in goats to ivermectin in the Netherlands

Resistance of Teladorsagia circumcincta in goats to ivermectin In 2005, suspected ivermectin resistance of gastrointestinal nematodes was investigated in 17 goats on a farm in the Netherlands, using a faecal egg count reduction test combined with faecal larval cultures. Eight goats were treated orally with 0.2 mg/ kg ivermectin on 1 August 2005 and the other nine goats served as untreated controls. Faeces were collected from all goats on 1 August and on 12 August. Faecal egg counts were reduced by 80.6% in goats receiving ivermectin. On the basis of faecal larval cultures and the egg counts, ivermectin was found to be 100% effective against Haemonchus contortus, 15.0% effective against Teladorsagia circumcincta, and 93.3% effective against Trichostrongylus spp. The effect of levamisole and oxfendazole on gastrointestinal nematodes was also evaluated. Nine goats were treated subcutaneously with 5 mg/kg levamisole and seven goats orally with 4.5 mg/kg oxfendazole on 12 September On the basis of faecal egg counts performed on 12 and 22 September, levamisole reduced the total egg count by 95.4% and oxfendazole reduced the egg count by 85.8%. Differentiation of pooled faecal larval cultures revealed that levamisole was 99.9% effective against H. contortus, 81.9% effective against T. circumcincta, and 99.5% against Trichostrongylus spp. Oxfendazole was 75.5% effective against H. contortus, 33.2% effective against T. circumcincta, and 100% effective against Trichostrongylus spp. On 28 October the nine goats that were still present on the farm were orally treated with 0.4 mg/kg ivermectin. Faecal egg counts and differentiation of pooled larval cultures of faecal samples collected on 28 October and 9 November, respectively, revealed that total egg counts were reduced by 93.1%. Ivermectin was 49.1% effective against T. circumcincta but 100% effective against H. contortus and Trichostrongylus spp. Thus H. contortus appears to be resistant to oxfendazole and T. circumcinta appears to be resistant to oxfendazole and ivermectin. This is the first documented case of ivermectin resistance of a gastrointestinal nematode of small ruminants in the Netherlands.     

Field efficacy of ivermectin plus praziquantel oral paste against naturally acquired gastrointestinal nematodes and cestodes of horses in North America and Europe

The efficacy of an oral formulation of ivermectin plus praziquantel in the reduction of nematode and cestode egg counts in horses was assessed in 273 horses under field conditions at 15 sites in North America (n = 6) and Europe (n = 9). Horses were confirmed by fecal examination to have natural infections of strongyles (100%) and tapeworms (76%). Replicates of four horses were formed at each site, and in each replicate three animals received ivermectin (0.2 mg/kg body weight) plus praziquantel (1 mg/kg body weight) oral paste and one animal remained untreated or received vehicle paste. Fecal samples were collected for fecal nematode and cestode egg counting before and 7, 8, 9, 14, 15, and 16 days after treatment. Horses treated with ivermectin plus praziquantel oral paste had significantly (P <.01) lower posttreatment strongylid and cestode egg counts (reductions of 98% or more) than controls. Combined site analyses revealed that 95% or 96% of the horses positive for cestode eggs before treatment that were treated with ivermectin plus praziquantel were negative for cestode eggs at each posttreatment fecal examination. No adverse reactions attributable to ivermectin plus praziquantel oral paste treatments were observed. The results of the studies demonstrated that ivermectin plus praziquantel paste was highly effective in reducing egg shedding by gastrointestinal nematodes and cestodes, and no adverse reactions were observed in horses treated under field conditions.     

Survey for drug-resistant gastrointestinal nematodes in 13 commercial sheep flocks.

The prevalence of drug-resistant ovine parasites in the United States has not been widely reported. Thirteen flocks, typical of commercial sheep production units, were selected for survey. Four anthelmintics (fenbendazole, ivermectin, pyrantel pamoate, and levamisole) were tested for their ability to reduce herd mean pretreatment fecal egg count. If a properly dosed and administered drug failed to reduce herd mean pretreatment fecal egg count by 80%, it was considered ineffective in that flock, and the presence of parasites resistant to that drug was inferred. Fenbendazole administration changed pretreatment fecal egg counts by +9% to -100%. On the basis of the aforementioned definition, drug resistance existed in 6 of 13 flocks. Posttreatment larval culture indicated that Haemonchus contortus survived administration of fenbendazole. Levamisole, pyrantel pamoate, and ivermectin reduced pretreatment fecal egg count by -83% to -100%; resistance to these products was not evident in the flocks surveyed.     

Comparison of ivermectin and thiabendazole for treatment of naturally occurring nematode infections of goats in Kenya

The anthelmintic activity of thiabendazole (TBZ) at 88 mg kg-1 and ivermectin at 0.2 mg kg-1 was examined in goats with naturally-acquired nematode infections. In one experiment, a herd of 450 does was treated with TBZ or ivermectin at 4-week intervals for 9 months and efficacy was measured by reduction in faecal egg counts after each treatment. In a second experiment, 100 kids were treated with ivermectin and effectiveness measured at 2 and 4 weeks after treatment by comparison of their egg counts with those of nontreated controls. In a third experiment, efficacy of treatment with TBZ and ivermectin was determined by recovery of parasites at necropsy in a controlled test with 15 kids. The results indicated that TBZ generally did not reduce egg counts and only removed 19% of Haemonchus contortus in the controlled test. The efficacy of ivermectin approached 100% for reduction in egg counts and elimination of H. contortus. Species of Ostertagia, Trichostrongylus, Nematodirus and Oesophagostomum also were present in some subjects, but not in sufficient numbers to evaluate effectiveness of treatment.     

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.