共查询到20条相似文献，搜索用时 31 毫秒
1.
Effectiveness of morantel tartrate and naphthalophos against levamisole resistantOstertagia in sheep
Adult worms from a levamisole resistant population ofOstertagia consisting ofO. circumcincta andO. trifurcata showed no dose response to morantel tartrate. The lowest dose rate of 2.2 mg/kg removed 30.8% of worms while the highest dose rate of 17.6 mg/kg removed 39.2%. A dose response was obtained against naphthalophos and the LD50 and LD95 were determined as 12.54 mg/kg and 23.25 mg/kg respectively. It was concluded that the strain was cross resistant to morantel tartrate but not to naphthalophos. 相似文献
2.
J D Kelly C A Hall H V Whitlock H G Thompson N J Campbell I C Martin 《Research in veterinary science》1977,22(2):161-168
Observations of erratic anthelmintic activity of fenbendazole against known standardised thiabendazole-resistant strains of Haemonchus contortus and Trichostrongylus colubriformis in sheep were investigated. Fenbendazole at a dose rate of 10 mg/kg body weight was administered by oral, intra-ruminal or intra-abomasal routes, and was most effective against both resistant strains following intra-ruminal administration. In addition thiabendazole, oxibendazole, fenbendazole, parbendazole and mebendazole plus two unrelated compounds, levamisole and morantel tartrate, were used at one and a half times their suggested or recommended therapeutic dose rate against thiabendazole-resistant strains of H contortus and T colubriformis in sheep; each drug being administered by the intra-ruminal or intra-abomasal routes. Fenbendazole was more effective against both strains following intra-ruminal administration. Parbendazole was more effective against the resistant strain of T colubriformis following intra-ruminal administration. At the dose rate chosen for the other benzimidazoles used against these resistant strains, there was no difference in anthelmintic efficacy due to route of administration. Levamisole was highly effective against both resistant strains, irrespective of the route of administration. In the groups treated with morantel tartrate, the results obtained were difficult to interpret due to mortalities and a highly variable response in the surviving sheep. Fenbendazole, thiabendazole and mebendazole when used at their suggested or recommended therapeutic dose rate in sheep, were highly effective against known thiabendazole-susceptible strains of H contortus and T colubriformis following both intra-ruminal or intra-abomasal administration. 相似文献
3.
Two field strains of Trichostrongylus colubriformis were tested by in vitro and in vivo methods for resistance to morantel, levamisole and thiabendazole and compared with an anthelmintic-naive laboratory-passaged strain (McM). One field strain (TAS) was isolated from a dairy goat herd which had experienced severe helminthiasis despite intensive anthelmintic usage. The other (BCK) was isolated from sheep which had been treated solely with levamisole over a 6-year period. The BCK strain had very high levels of both levamisole and morantel resistance. In contrast the TAS strain was resistant to morantel but highly susceptible to levamisole. This finding is contrary to the expectation that selection with morantel automatically confers resistance to levamisole, the converse of which was shown to apply in the BCK strain. Although the TAS strain was exposed to levamisole prior to isolation, examination of the drug's pharmacokinetics in goats indicated that it exerted little if any anthelmintic effect, and therefore selection pressure, on the parasite population. This study suggests that the mechanism of levamisole resistance covers a wide spectrum, and embraces that for morantel. It also suggests that in order to conserve the effectiveness of the levamisole/morantel group of broad spectrum anthelmintics, morantel should be used to the exclusion of levamisole until resistance is detected, at which time levamisole may be introduced to re-establish high levels of control. 相似文献
4.
ANTHELMINTIC RESISTANCE IN TRICHOSTRONGYLUS COLUBRIFORMIS 总被引：1，自引：0，他引：1
L. K. Hotson B.V.Sc. Ph.D. N.J. Campbell B.V.Sc. M. G. Smeal B.V.Sc. 《Australian veterinary journal》1970,46(8):356-360
Resistance to thiabendazole has been found in two strains of Trichostrongylus colubriformis from sheep. These strains occurred in flocks on research properties where the anthelmintic had been used at frequent intervals for experimental purposes for several years. The LD50 values for the resistant strains were approximately 70 mg/kg and 125 mg/kg respectively, compared with an expected value from published reports of less than 10 mg/kg for susceptible strains. Apparent cross-resistance to the related benzimidazole compound parbendazole was observed at the normal therapeutic dose rate of 20 mg/kg in sheep. Both anthelmintics depressed egg-production in resistant female worms at normal therapeutic dose-rates. Both dl-tetramisole and pyrantel tartrate were effective against one of the benzimidazole-resistant strains of T. colubriformis, but the efficiency of the latter anthelmintic was less than that normally expected against benzimidazole-susceptible strains. 相似文献
5.
N C Sangster H V Whitlock I G Russ M Gunawan D L Griffin J D Kelly 《Research in veterinary science》1979,27(1):106-110
Field strains of Trichostrongylus colubriformis and Ostertagia circumcincta, designated PF4 and PF5 respectively, were recovered from a farm on which the sole use of levamisole over a preceding 12 year period led to the development of anthelmintic resistance. The results of field observations and preliminary critical trials in both Merino and crossbred sheep showed that both species have varying degrees of resistance to three major anthelmintics; levamisole, morantel tartrate and thiabendazole. Mean worm count reductions for adult T colubriformis (PF4) for therapeutic doses of morantel tartrate, thiabendazole and levamisole in crossbreds were 45.7 per cent, 97.3 per cent and zero respectively, and for Merinos 80.7 per cent, 88.3 per cent and 92.0 per cent respectively. Against O circumcincta the corresponding reductions for crossbreds were 51.4 percent, 95.4 per cent and 20.3 per cent and for Merinos, 52.5 per cent, 73.1 per cent and 29.8 per cent. There was no statistically significant difference in the responses of both parasite species to either levamisole or morantel. This result suggests that resistance to the two chemically unrelated drugs may be co-inherited. 相似文献
6.
The paper describes a method for detecting levamisole and morantel tartrate resistance by determining the percentage of paralysed third stage larvae in serial dilutions of anthelmintic. Levamisole resistantOstertagia spp. had a smaller proportion of larvae undergoing tonic paralysis in either levamisole or morantel tartrate than did a non-resistant strain. The dose response thus obtained for a strain of worms can be tested statistically against strains which are known to be resistant or non-resistant.Commonwealth of Australia 相似文献
7.
The anthelmintic efficacy of 6 non-benzimidazole compounds and thiabendazole against standardised, benzimidazole resistant strains of H. contortus and T. colubriformis in sheep was determined using a controlled test. All compounds were administered intraruminally at their recommended therapeutic dose rates and 4 of the compounds were also assessed at half their recommended therapeutic dose rates. Levimisole at a dose of 6.4 mg/kg body weight, morantel at 4.4 mg/kg and 8.8 mg/kg, naphthalophos at 6.25 mg/kg and 12.5 mg/kg, rafoxanide at 7.5 mg/kg and phenothiazine at 530 mg/kg were 98% or more effective in removing adult infections of benzimidazole resistant H. contortus. Rafoxanide at 3.75 mg/kg, phenothiazine at 265 mg/kg and carbon tetrachloride at 0.05ml/kg were less effective, removing 80%, 73% and 72% respectively of the benzimidazole resistant H. contortus worm burdens. Against the benzimidazole resistant T. colubriformis levamisole at 6.4 mg/kg, and morantel at 4.4 mg/kg and 8.8 mg/kg removed 99%, 68% and 86% respectively of the adult infections. All other anthelmintics had little or no efficacy at the dose rates tested. Thiabendazole at 44 mg/kg had no significant effect against these strains of H. contortus and T. colubriformis. Several non-benzimidazole anthelmintics have shown high efficacy in this experiment and should be suitable for treating infections with benzimidazole resistant H. contortus. Of the anthelmintics tested, only levamisole and morantel show high efficacy against benzimidazole resistant T. colubriformis. 相似文献
8.
Summary Netobimin was tested for efficacy against Haemonchus contortus using 7 groups of 5 parasite‐free lambs of six month age. The lambs in group 1 and 2 were infected with 10,000 larvae of a benzimidazole susceptible strain and those in groups 3–7 with the same dose of a resistant strain. The following treatment scheme was applied 21 days after infection: lambs in groups 2 and 4 ‐ 7.5 mg kg‐1 netobimin, in group 5 ‐ 20 mg kg‐1 netobimin, in group 6 ‐ 5 mg kg‐1 oxfendazole and in group 7 ‐ 3.8 mg kg‐1 albendazole. The lambs in groups 1 and 3 remained untreated. All lambs were slaughtered 28 days after infection. Egg counts decreased in all lambs after treatment, but increased again in lambs in groups 4, 6 and 7. There was a slight increase in lambs in group 5, while those in group 2 remained negative. Post‐mortem worm counts showed a reduction of 99.8 per cent in lambs in group 2 compared to those in group 1. In lambs in group 4–7 the reduction of worm counts was respectively 40.9, 89.5, 24.7 and 40.7 per cent compared to those in group 3. Egg development assays carried out 20 days after infection showed an average LD50 of 0.46 mg ml‐1 thiabendazole for the resistant strain. After treatment (day 27) the LD50 was 0.53, 0.48, 0.58, 0.56 and 0.47 in lambs in the groups 3–7. It is concluded that netobimin and other (pro) ‐benzimidazoles should not be used in cases of benzimidazole resistance and that levamisole, pyrantel tartrate or ivermectin are preferable. 相似文献
9.
L. F. Le Jambre 《Australian veterinary journal》1979,55(2):65-67
Adult worms from a population of Ostertagia consisting of 88% O. circumcincta and 12% O. trifurcata were found to survive a double drench (14 mg/kg) of levamisole. An anthelmintic assay on this population found that against levamisole the LD50 was 11.95 mg/kg and the LD99 was 67.75 mg/kg. Three benzimidazoles were also tested against this population and the LD50 and LD99 were respectively thiabendazole 11.8 and 144.9 mg/kg, oxfendazole 0.17 and 6.10 mg/kg and albendazole 0.08 and 2.55 mg/kg. The percentage of worms killed by the recommended dose rate was levamisole 24%; thiabendazole 91%; oxfendazole 99% and albendazole 99%. 相似文献
10.
P.B. McKenna 《New Zealand veterinary journal》2013,61(11):198-199
A controlled slaughter trial was undertaken to evaluate the efficacy of ivermectin (0.2 mg/kg) and levamisole (8 mg/kg) against a morantel-resistant field strain of Trichostrongylus colubriformis in sheep. Mean worm count reductions of greater than 99% were recorded with both anthelmintics. The apparent contradiction between the high efficacy of levamisole and the common belief that resistance to levamisole and morantel is co-inherited, is discussed. 相似文献
11.
SUMMARY Following the apparent failure of levamisole to control infections of Haemonchus contortus in sheep at Lawes in south eastern Queensland, a strain of this parasite was isolated at the Animal Research Institute, Yeerongpilly. This strain was used to infect sheep at Yeerongpilly and the Merrindale Research Station, Victoria where four experiments to classify the resistance pattern of the parasite were carried out. Resistance to thiabendazole was first suspected in 1969, and these experiments confirmed that resistance to this drug was still present. They also showed that a strong degree of resistance had been developed to both levamisole and morantel tartrate. Other benzimidazole anthelmintics and also the organophosphorus compound naphthalophos were only moderately effective against the original isolate but rafoxanide, nitroxynil and phenothiazine were almost 100% effective. Other highly effective chemicals were disophenol and closantel. After passaging the strain for four generations with both levamisole and albendazole, resistance to both naphthalophos and the newer benzimidazole anthelmintics increased dramatically. This is the first report of a field strain of H. contortus exhibiting resistance to benzimidazole, non-benzimidazole and organophosphorus anthelmintics. 相似文献
12.
Six populations of H. contortus were selected for a study of thiabendazole resistance from a collection of 40 populations made during a survey of the efficiency of thiabendazole on the Northern Tablelands of New South Wales. Based on survey results, 3 of these populations were considered susceptible and the remaining 3 were considered resistant. However, when these populations were compared with a known susceptible strain on the ability of their eggs to hatch in a solution containing thiabendazole and 0.1% NaCl all 6 had significantly greater LC50's. The resistance ratios of the LC50 for each of the 6 populations to that of the known susceptible strain were 5.1, 4.3, 3.2, 3.1, 2.3, and 1.6 respectively. Following dosing of their host with 44 mg/kg thiabendazole the resistance ratios of the survivors increased to 5.4, 5.1, 4.7, 4.4, 3.1 and 2.4. Eggs produced by the F1 generation of the worms surviving 44 mg/kg thiabendazole did not revert back to the lower LC50's of the unselected parents. Rather the LC50 remained at a level near that of a known highly resistant strain of H. contortus. 相似文献
13.
In order to study the reliability of the larval paralysis test as an in vitro assay for the detection of resistance of nematodes to levamisole and morantel tartrate, the influence of different parameters was evaluated using resistant and susceptible Ostertagia ostertagi strains. The operator, the sample (10% of the larvae present in the suspension), the incubation time (24, 48 or 72 h), the incubation temperature (20 or 25 degrees C) and the observation period of the larvae (5 or 15 s) had no statistically significant influence on the test results. Statistical differences were obtained only when L3 larvae of different ages (1 or 2 months) were used. Reversibility of the paralysis did not occur when concentrations of levamisole of less than or equal to 200 micrograms ml-1 or morantel tartrate of less than 2000 micrograms ml-1 were used. The reproducibility of the test was fairly good, with a mean standard deviation of 21.3% for the LC50 values. Morantel resistance in a strain of O. ostertagi was not confirmed as such by the larval paralysis test. The resistance factor was less than or equal to 1, in spite of an efficacy of morantel of 77.4% as shown in vivo. 相似文献
14.
McKenna PB 《New Zealand veterinary journal》1985,33(11):198-199
A controlled slaughter trial was undertaken to evaluate the efficacy of ivermectin (0.2 mg/kg) and levamisole (8 mg/kg) against a morantel-resistant field strain of Trichostrongylus colubriformis in sheep. Mean worm count reductions of greater than 99% were recorded with both anthelmintics. The apparent contradiction between the high efficacy of levamisole and the common belief that resistance to levamisole and morantel is co-inherited, is discussed. 相似文献
15.
Two strains of Ostertagia circumcincta were isolated from sheep in Great Britain; one (CVL strain) from a breeding flock maintained at the Central Veterinary Laboratory, the other (H2 strain) from a commercial flock in southern England. Their resistance to benzimidazole anthelmintics was assessed by means of in vitro egg hatch assays and slaughter trials. In vitro egg hatch assays gave calculated ED50 estimates of 0.799 micrograms thiabendazole/ml for the CVL strain and 0.794 micrograms thiabendazole/ml for the H2 strain, compared with ED50 estimates of 0.038 micrograms thiabendazole/m and 0.036 micrograms thiabendazole/ml for two known susceptible strains of O circumcincta. There was a 40.7, 28.4 and 66.9 per cent reduction in the group mean worm burdens of lambs infected with the CVL strain following treatment with thiabendazole, fenbendazole and oxfendazole, respectively, and 23.8, 0.0, 79.6, 52.7, 99.9 and 100 per cent reduction in the group mean worm burdens of lambs infected with the H2 strain following treatment with thiabendazole, fenbendazole, oxfendazole, albendazole, levamisole and ivermectin, respectively. Detailed field histories for both strains are given. 相似文献
16.
The in vitro activities of thiabendazole, levamisole, pyrantel, morantel and ivermectin against Oesophagostomum spp., the nodular worm of pigs, were determined and compared. The study was carried out using isolates of O. dentatum and O. quadrispinulatum, which had been defined in vivo. Infective larvae were exposed to the anthelmintics for 24 h and then placed in a micromotility meter. All the treatments significantly reduced the motility of the ensheathed L3 larvae, but the micromotility meter was not able to differentiate between anthelmintic resistant and anthelmintic susceptible isolates. 相似文献
17.
A controlled slaughter trial was undertaken to compare the efficacies of oxfendazole (5 mg/kg), morantel citrate (10 mg/kg), levamisole (8 mg/kg) and ivermectin (0.2 mg/kg) against experimentally induced infections of adult Haemonchus contortus, Ostertagia spp., Trichostrongylus colubriformis and Cooperiacurticei in sheep and goats. Ivermectin and oxfendazole achieved similar levels of efficacy in both hosts against all four worm genera as did levamisole and mortantel against H. contortus and C. curticei. Against Ostertagia spp. and T. colubriformis, however, the latter two drugs were less effective in goats than sheep. Neither the numbers of Ostertagia spp. removed from goats by levamisole (81% reduction) nor the numbers of T. colubriformis removed from goats by morantel (56% reduction) were statistically significant (P>0.05). 相似文献
18.
S. Manna D. Bhattacharyya T. K. Mandal S. Dey 《Journal of veterinary science (Suw?n-si, Korea)》2006,7(2):133-136
This study examined the effect of deltamethrin on some of the neuropharmacological paradigms in a rat brain such as the motor co-ordination test using a rotarod, the pentobarbitone-induced sleeping time and pentylenetetrazole (PTZ)-induced convulsion as well as the gamma aminobutyric acid (GABA) level. Albino Wistar rats were used as the experimental animals. Different neuropharmacological paradigms such as the motor co-ordination by the rotarod, pentobarbitone-induced sleeping time and the PTZ-induced convulsion were examined after administering deltamethrin orally at two doses, 150 mg/kg (LD50) and 15 mg/kg (1/10 LD50). The GABA level in the rat brain was estimated by HPLC after a single oral dose of 150mg/kg deltamethrin. Deltamethrin significantly reduced the motor coordination, decreased the onset time and increased the sleeping time duration induced by pentobarbitone. In addition, it also decreased the onset time and increased the duration of convulsions induced by PTZ at 150 mg/kg (LD50) and 15 mg/kg (1/10 LD50), respectively. Further deltamethrin administration decreased the GABA levels in the cerebellum as well as in the whole brain (except the cerebellum) significantly at the LD50 dose level. There was some correlation between the effect of deltamethrin on the central GABA levels and its neuropharmacological effects. 相似文献
19.
A comparison was made of the effects on worm egg output from groups of sheep treated with either thiabendazole or levamisole at 3 dose rates in different weight categories of weaned lambs. Neither thiabendazole at 79.8 mg/kg nor levamisol at 12.8 mg/kg completely prevented worm egg output by treated sheep. Over all dose rates thiabendazole was significantly more effective than levamisole. The data indicated that dose rates may need to be increased for use in strategic control schemes for helminthiasis. 相似文献
20.
T J Newby T A Yazwinski B L Presson T E Greenway H M Holtzen M J Bischoff H E Featherstone 《American journal of veterinary research》1985,46(12):2437-2439
Two groups of 10 parasite-free calves were maintained either for 2 weeks on a pasture grazed by nonmedicated cattle (pasture A) or for 3 weeks on a pasture grazed by morantel sustained-release bolus-treated cattle (pasture B) for the preceding 2 years. After a 4-week holding period to allow for maturation of acquired gastrointestinal nematodes, 5 calves from each group were administered a therapeutic dose (10 mg/kg of body weight) of morantel tartrate. All calves were necropsied 1 week later, and the abomasal and small intestinal nematodes were isolated, identified, and enumerated. A comparison of efficacies between nonmedicated and morantel tartrate-treated calves of each pasture demonstrated that morantel was equally effective against the gastrointestinal nematode infections, regardless of infection source (ie, pasture A vs pasture B). The overall nematode reductions due to morantel tartrate treatment of calves that grazed pastures A and B were 98% and 96%, respectively. It was concluded that the sensitivity of gastrointestinal nematodes to morantel tartrate was not diminished in calves maintained on pasture B, which had been stocked with morantel sustained-release bolus-treated calves for the preceding 2 grazing seasons. 相似文献