微量伊维菌素注射剂对牦牛皮蝇幼虫的驱除效力试验

选择当年犊牦牛154头,9月下旬用伊维菌素注射液分别按2,5,10,20μg/kg剂量注射给药,进行牦牛皮蝇幼虫的驱除效力试验,翌年3月中旬和5月下旬检查防治效果。结果:2μg/kg剂量组的平均驱净率为90.32%,平均驱虫率93.76%,5,10,20μg/kg剂量组感染率为0,驱净率和驱虫率均达100%。试验证明:伊维菌素注射液微量驱除牛皮蝇幼虫高效安全经济,最佳剂量为5μg/kg。     

伊维菌素注射剂不同剂量防治牦牛皮蝇蛆幼虫的效果调查

选择当年犊牦牛116头,9月下旬用伊维菌素注射液分别按2、5、10μg/kg剂量注射给药,进行牦牛皮蝇蛆幼虫的驱除效果试验,翌年3月中旬和5月下旬检查防治效果。结果2μg/kg剂量组的平均驱净率为90.31%,平均驱虫率93.76%,5、10μg/kg剂量组感染率为0,驱净率和驱虫率均达100%。试验证明：伊维菌素注射液微量驱除牛皮蝇蛆幼虫高效安全经济,最佳剂量为5μg/kg。耗牛是世界上生活在海拔最高处的哺乳动物。     

微量多拉菌素与伊维菌素对牦牛皮蝇幼虫驱除效力的研究

应用多拉菌素注射剂和伊维菌素浇泼剂微量给药,对自然感染皮蝇幼虫的犊牦牛进行驱虫效力研究。结果:给药后28~34d剖检和翌年3、5月份两次摸背检查远期防治效果,多拉菌素注射剂5μg/kg剂量组驱净率分别为85.0%和92.1%,驱虫率分别为93.6%、93.7%;10、20μg/kg剂量组均为100.0%。伊维菌素浇泼剂12.5μg/kg。剂量组驱净率分别为85.0%和91.2%,驱虫率分别为93.3%和93.2%;25、50μg/kg剂量组均为100.0%。对照组牦牛皮蝇1期幼虫感染率85.0%,平均感染强度29.7条;背部皮下瘤疱和皮肤虫孔的平均感染率84.1%,瘤疱和虫孔总数205个。试验证明供试两种药物使用微量驱除牦牛皮蝇1期幼虫高效安全经济,多拉菌素的最佳剂量为10μg/kg,伊维菌素的最佳剂量为25μg/kg。     

埃普利诺菌素浇泼剂对牦牛皮蝇幼虫驱除效果试验

应用埃普利诺菌素浇泼剂驱除牦牛皮蝇幼虫,并设埃普利诺菌素注射剂药物对照组和阳性对照组。结果：剖检埃普利诺菌素浇泼剂300μg/kg,400μg/kg,500μg/kg剂量组牦牛与药物对照埃普利诺菌素注射剂组及伊维菌素浇泼剂组牦牛,均未检出皮蝇1期幼虫,而阳性对照组牦牛皮蝇1期幼虫感染率35.0%,平均感染强度29.4（9～53）条。翌年3、5月份两次触摸检查牛背部皮下瘤疤和皮肤虫孔,4个药物试验组牦牛均未检出,而阳性对照组牦牛两次检查平均感染率45.16%,平均感染强度6.45个。试验证明埃普利诺菌素浇泼剂低、中、高3个剂量对寄生于牦牛的皮蝇幼虫驱净率、驱虫率均达100.0%,高效安全。     

埃谱利诺菌素注射剂微量施药驱除牦牛皮蝇幼虫的效力试验

应用埃谱利诺菌素注射剂微量给药技术,对自然感染皮蝇幼虫的犊牦牛进行驱虫效力研究。结果:给药后28~35d剖检,对照组牦牛皮蝇1期幼虫感染率65%,平均感染强度28.92条(12~39)条;埃谱利诺菌素注射剂2μg/kg.bw剂量组驱净率和驱虫率分别为85%、94.95%,5、10、20μg/kg剂量组驱净率和驱虫率均达100%;给药后分别于翌年3月中旬和5月下旬两次触摸检查远期防治效果,对照组牦牛背部皮下瘤疱和皮肤虫孔平均感染率61.67%,瘤疱和虫孔均数5.91(4~13)个;埃谱利诺菌素注射剂2μg/kg剂量组平均驱净率、驱虫率分别为90.0%和92.7%,5、10、20μg/kg剂量组平均驱净率和驱虫率均达100%。试验证明埃谱利诺菌素注射剂微量注射对牦牛皮蝇幼虫均达高效,其中使用5μg/kg.bw埃谱利诺菌素注射剂为最佳剂量。     

不同剂量的伊维菌素注射剂和浇泼剂对天祝牦牛牛皮蝇防制效果观察

通过对天祝县感染了牛皮蝇的牦牛的药物实验,确定了伊维菌素注射剂与浇泼剂在防治该病时的最低剂量。将280头牦牛随机分成7组,1~3组分别在颈部皮下注射0.1%伊维菌素注射液1μg/kg,5μg/kg和10μg/kg,4~6组分别沿背中线浇泼0.5%伊维菌素浇泼剂25μg/kg、50μg/kg和250μg/kg,将第7组设为空白对照。对前6组在11月份统一治疗。在第2年的3月份和5月份检查试验牦牛的背部瘤包,在治疗组牛的背部未发现瘤包,但在对照组牛的背部发现了三期幼虫。结果表明：1μg/kg伊维菌素注射剂和25μg/kg的浇泼剂对自然感染的牛皮蝇幼虫有较好的防治效果。     

依普菌素搽背剂对牦牛皮蝇蛆的驱虫效果及安全性试验

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剂型,选取120头1.5岁牦牛,分为3组,试验1组(50头)用依普菌素搽背剂按0.5mg/kg体重剂量经背部皮肤浇泼给药,试验2组(50头)用伊维菌素注射剂按0.2mg/kg体重剂量经皮下注射给药,试验3组为对照组。翌年5月底对全部试验牛进行牛皮蝇蛆驱除效果检查。结果:两试验组牦牛皮蝇蛆病治愈率均为98%,而对照组的感染率为100%,平均感染强度为10.9(2~21)。依普菌素搽背剂对牦牛皮蝇幼虫的驱虫率达99.54%。表明依普菌素搽背剂0.5mg/kg剂量安全,驱虫方法简单,可用于高寒牧区牦牛寄生虫病驱治。     

多拉菌素驱除绵羊消化道线虫试验

目的　肯定多拉菌素驱除绵羊消化道线虫的效果,为临床用药提供科学依据。方法　试验分5组(多拉菌素高、中、低剂量组,伊维菌素对照组及空白对照组)。依试验前后寄生虫罹患数量进行比较得出结论。结论　多拉菌素驱除绵羊消化道线虫效果确实可靠,其中高剂量组和中剂量组药物残效期达50天,推荐剂量为中剂量组为200μg/kg体重。     

多拉菌素治疗鸡体内犬蛔虫幼虫试验

为了验证多拉菌素对鸡体内犬蛔虫幼虫的治疗效果,为临床用药提供相关数据,现建立犬蛔虫幼虫感染2日龄的小鸡动物模型,将多拉菌素分别按高(300μg/kg)中(200μg/kg)低(100μg/kg)剂量作用于受感染的小鸡,并设置对照组。在给药后第1、2、3、4、5、6天剖检、分离小鸡肝、肺、肌肉、肾、心、脑等组织,用胃蛋白酶消化其组织并镜检计算减虫率,用统计学的方法分析结果,对比疗效。试验结果表明,高剂量(300μg/kg)的多拉菌素减虫率为89.77%,中剂量组的减虫率为80.12%,低剂量组的减虫率为78.43%,高剂量(300μg/kg)的多拉菌素减虫效果显著,临床用药推荐以高剂量300μg/kg效果好。     

伊维菌素注射剂防治牦牛寄生虫病的示范效果观察

应用伊维菌素注射剂,按0.2mg/kg体重剂量皮下注射给药,进行牦牛寄生虫病防治,评价对牦牛体内线虫和体外寄生虫的疗效.结果:对牦牛主要7属消化道线虫和网尾线虫的虫卵(幼虫)转阴率、减少率均达100％;毛首线虫的驱虫率86.4％;对线虫的总计驱虫率99.3％;对绵羊颚虱的杀虫率达100％.技术示范群比阳性对照群牦牛平均多增重3.9kg,幼年牦牛成活率提高1.9个百分点.示范结果证明:伊维菌素注射剂0.2mg/kg剂量一次给药,驱除牦牛体内线虫和体外虱、蝇等寄生虫,高效安全,生产效益显著.     

The efficacy of ivermectin against larvae of the screw-worm fly (Chrysomya bezziana)

An in vitro technique for screening systemic insecticides against larvae of the screw-worm fly, Chrysomya bezziana is described. Susceptibilities of screw-worm larvae of different ages to ivermectin (MK-933) were determined. Based on 24 h larval mortality, the LD50 of 1-,2-,3-,4- and 5-day larvae was 0.01, 0.02, 0.03, 0.2 and 0.4 ppm of ivermectin. LD50 based on adult emergence following treatment of 4- and 5-day larvae was 0.02 and 0.05 ppm. The LD99.9 for 4-day larvae based on 24 h larval mortality and adult emergence was 11.0 and 0.15 ppm respectively and for 5-day larvae, was 44.3 and 0.4 ppm respectively. Pen and field trials with cattle infested with screw-worm fly demonstrated the potential of ivermectin as a systemic insecticide. Dosages of 50, 100 and 200 micrograms/kg, of ivermectin administered subcutaneously to experimentally infested cattle gave complete control for 6, 12 and 14 days respectively. Ivermectin at 200 micrograms/kg caused 100% mortality of screw-worm larvae up to 2 days old at the time of treatment with 70, 64 and 21% mortality of 3-, 4- and 5-day old larvae at the time of treatment. The residual protection from a single dose of 200 micrograms/kg was 16 to 20 days. When bull calves were treated with ivermectin at a dose of 200 micrograms/kg at the time of castration and branding, none of the 77 treated animals sustained a screw-worm strike in the scrotal area compared with 47 strikes (44%) in the 106 control cattle.     

Field efficacy of minidosed pour-on ivermectin and eprinomectin against goat warble fly infestation by Przhevalskiana silenus

The efficacy of minidose of pour-on ivermectin and eprinomectin formulations against first instar larvae of Przhevalskiana silenus was observed in naturally infested goats in the Jammu region, North India. The study was performed in mid August 2011. A total of 280 goats were randomly divided in to 7 groups of 40 each. Goats of the first three groups were treated with pour-on ivermectin at dosage of 2, 5, and 200 μg/kg body weight, respectively, whereas animals of the fourth to sixth groups were treated with pour-on eprinomectin at 25, 50, and 500 μg/kg body weight, respectively. Group VII animals were kept as untreated control. The results indicated that no warbles were recorded between December 2011 and March 2012 on back of animals treated with pour-on preparations of ivermectin at dosage of 5 and 200 μg/kg body weight, respectively, and eprinomectin at dosage of 50 and 500 μg/kg body weight, respectively. Thus, it is concluded that administration of minidose of pour-on ivermectin (5 μg/kg body weight) and eprinomectin (50 μg/kg body weight) is cost effective and so can be used for warble fly control campaign in Jammu region.     

Migration of warble fly larvae in the yak and optimum timing of ivermectin treatment

Sixty yaks were autopsied to determine the migration pattern of warble fly larvae. In August, first instars were observed in the body of yak for the first time. These larvae peaked in number in October. From November to February, second instars were detected and their number peaked in January. Third instars appeared in January and peaked in March. Forty-five yaks were administered with ivermectin: 15 animals in September, 15 in October and 15 in November. Between December and June, the number of warbles was checked by palpation. Although some warbles were observed in the September- and November-treated groups, no warbles were detected in the October-treated group. Treatment of yaks with ivermectin was most effective for warble fly in October.     

Efficacy of injectable and pour-on microdose ivermectin in the treatment of goat warble fly infestation by Przhevalskiana silenus (Diptera, Oestridae)

The prophylactic efficacy of microdoses of injectable and pour-on ivermectin formulations against larval stages of Przhevalskiana silenus was assessed in naturally infected goats in the region of Calabria (southern Italy).Sixty-eight goats from two goat farms were divided into five groups: one group remained untreated, while the other four groups were treated with microdoses of ivermectin (5 and 10 microg/kg injectable formulation and 10 and 20 microg/kg pour-on formulation).The microdoses of ivermectin were fully effective in the treatment of goat warble fly infestation (GWFI) as no larvae emerged from the warbles in the treated groups, while all the larvae emerged in the control groups. Irrespective of the type of formulation used, the difference between the treated groups and the control group was statistically significant (P< 0.001). By contrast, no statistical differences were found between the goats treated with the injectable formulation and those receiving the pour-on applications, and between the two doses of the injectable and pour-on formulations used. Given the plasma concentrations it attains at its lowest dose (0.052 - 0.042 ng/ml for the injectable formulation and 0.030 ng/ml for the pour-on) the injectable formulation seems to offer the most reliable route for the administration of ivermectin microdoses and it is acceptable for milk consumption. The introduction of ivermectin in the early eighties and the use of microdoses in some cases have made it possible to control cattle hypodermosis in large areas of Europe. As with cattle hypodermosis, the administration of ivermectin microdoses in goats is particularly interesting because of the low costs involved and the low levels of residues found in goat milk; it may thus constitute the basis for GWFI control campaigns in areas where the disease is prevalent.     

Comparison of the efficacy of dermal formulations of ivermectin and levamisole for the treatment and prevention of Dictyocaulus viviparus infection in cattle

Four groups of six parasite-naive calves were infected at seven day intervals with three doses of infective larvae of Dictyocaulus viviparus. Twenty-one days after the first dose three of the groups were treated either with an injectable formulation of ivermectin at a dose rate of 200 micrograms/kg bodyweight, or with pour-on preparations of levamisole at 10 mg/kg or ivermectin at 500 micrograms/kg. On day 28 two calves from each group were slaughtered and their burdens of lungworms counted. On day 35 the remaining calves were reinfected with D viviparus infective larvae at a rate of 80 L3/kg. The levamisole preparation was 94.6 per cent effective and both ivermectin preparations were 100 per cent effective against the initial infections. The ivermectin-treated calves were protected from the reinfection which subsequently became patent in the levamisole-treated and control calves.     

Efficacy of ivermectin and levamisole against immature Dictyocaulus viviparus in cattle

Eighteen calves aged approximately three months were each infected with Dictyocaulus viviparus larvae at a rate of 30/kg bodyweight. Seven days later they were randomly allocated to three groups of six animals. Calves of group 1 were controls. Calves of group 2 were given levamisole at a dose rate of 10 mg/kg and calves of group 3 were given ivermectin at a dose rate of 200 micrograms/kg. The anthelmintic activity of these two drugs was compared using clinical, functional, parasitological and pathological parameters. The results showed that the efficacy of ivermectin, given at a therapeutic dose, against immature D viviparus was higher than that of levamisole, given at double the recommended dose.     

Anthelmhntic effects of injectable and oral paste formulations of ivermectin against 28-day infections of parascaris equorum

Efficacy of ivermectin treatment (0.2 mg/kg) against 28-day experimental infections of Parascaris equorum was determined in 18 pony foals6–17.5 weeks old. There were 6 foals in each group: nontreated control, ivermectin injectable or oral paste. In comparison with larvae found in the nontreated controls, ivermectin injectable or paste was 96.0% and 99.9% efficacious. There was a distinct difference in drug effect against the larger (ca 26mm.) vs the smaller (13–19mm) larvae by the 2 formulations of ivermectin. There were no adverse signs related to treatment of the young foals.     

Control of gastro-intestinal parasitism in sheep with ivermectin delivered via an intraruminal controlled-release capsule

The efficacy of ivermectin delivered by an intraruminal controlled-release capsule against gastro-intestinal nematodes of sheep was evaluated under controlled conditions. In seven Australian studies involving 170 Merino or Merino x Border Leicester sheep, intraruminal capsules developed for 20-40 kg or 40-80 kg sheep, and delivering 0.8 or 1.6 mg of ivermectin/day respectively for 100 days (minimum dose 20 microg/kg/day), were evaluated. Studies were designed to test the therapeutic efficacy against naturally acquired and induced infections treated at the adult and fourth larval stage, and the prophylactic efficacy against naturally acquired and induced infections with third stage infective larvae. The predominant pathogenic nematodes of sheep were represented. Two studies included known benzimidazole- and levamisole-resistant nematode strains. Sheep were necropsied for total nematode counts 21-8.5 days after treatment. The efficacy of the ivermectin controlled-release capsule was generally >99% against all nematode species tested, including those confirmed to be benzimidazole- and levamisole-resistant. High therapeutic activity was demonstrated against existing adult and fourth larval stage nematode infections at the time of treatment, and high prophylactic efficacy was shown against incoming third stage larvae of all species and strains tested.     

Efficacy of ivermectin chewable tablets and two new ivermectin tablet formulations against Dirofilaria immitis larvae in dogs.

One hundred four heartworm-free Beagles less than 1 year old were studied to determine the efficacy of ivermectin chewable tablets and of 2 other ivermectin tablet formulations against heartworm larvae. At 30 days after SC inoculation of dogs with infective Dirofilaria immitis larvae, all ivermectin formulations were given orally at dosage of 6 micrograms/kg of body weight. The ivermectin chewable tablets also were given orally at dosage of 2 and 6 micrograms/kg at 30 and 45 days, respectively, after injection of larvae. Replicates of 6 or 8 dogs in each study were formed on the basis of gender and body weight and, within replicates, were randomly allocated to treatment groups. At 30 days after injection of larvae, the additional dogs (in replicates of 8) were assigned to the control group and to the group given ivermectin chewable tablets at dosage of 6 micrograms/kg. All dogs were housed individually. Necropsy was performed approximately 5 or 6 months after larvae were administered. In both trials, all control dogs had heartworms at necropsy (University of Illinois--geometric mean, 35.0; Florida--geometric mean, 26.1). In both trials, the ivermectin chewable tablet (6 micrograms/kg) and both tablet formulations (6 micrograms/kg) given at 30 days after larval injection, and the chewable formulation (6 micrograms/kg) given at 45 days after larval injection were 100% effective (P less than 0.01) in preventing development of induced infection with D immitis.(ABSTRACT TRUNCATED AT 250 WORDS)     

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。