首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Amitraz and its active metabolite BTS2 7271 were given intravenously to ponies and sheep at equimolar doses of 1 mg/kg and 0.68 mg/kg, respectively, and the plasma concentrations of amitraz and BTS27271 estimated at various times thereafter. Amitraz was hydrolysed to BTS2 7271 in both species. Amitraz was undetectable in sheep plasma after approximately 5 min but persisted in the plasma of ponies for at least 90 min. The persistence of unmetabolized amitraz in ponies may have implications for the toxicity of amitraz in that species. The primary and secondary disposition half-lives of amitraz in ponies were 2 and 39 min, respectively. BTS27271 was distributed rapidly outside the plasma in both species with a primary disposition half-life of 4.4 min in sheep and 5.9 min in ponies. The secondary disposition half-lives were 51 and 55 min, respectively. The secondary phase of the disposition of BTS27271 was similar whether BTS27271 was given directly or derived by hydrolysis from amitraz. However, significant differences were evident in the primary phase of the disposition of BTS27271. Sheep demonstrated a larger apparent volume of distribution of BTS27271 than ponies and more rapid body clearance.  相似文献   

2.
SUMMARY Amitraz topically applied as an 0.025 or 0.05% aqueous suspension once or twice weekly for up to 8 weeks cured 3 cases of generalised squamopapular to pustular demodectic mange and effectively controlled the condition in a fourth dog. Three of these dogs were Dobermans in which the disease was refractory to standard therapy with ronnel. A single wash in 0.025% amitraz suspension was sufficient to cure each of 5 dogs affected with localised demodecosis within 2 to 4 weeks. At these dose levels the drug is non toxic and non irritant to skin and mucous membranes. Recommendations for the use of amitraz include a thorough prewash of the entire skin surface with soap and water followed by application of the drug suspension with vigorous scrubbing, the compound then being allowed to dry on the animal' skin. The availability of amitraz therapy appears to provide a favourable prognosis for the control of severe long standing mange in the dog.  相似文献   

3.
Southern cattle tick, Boophilus microplus, control in the Mexican tropics is based on the application by spray, dip or pour-on of acaricides. In Mexico the first report of ticks resistant to amitraz was reported in 2002. Amitraz resistance affecting the cattle industry of Yucatan State, Mexico, has not been investigated. A cross-sectional study was carried out in order to investigate the possible association between management risk factors and the prevalence of B. microplus ticks resistant to amitraz in Yucatan, Mexico. Ninety-eight cattle farms were randomly selected and a sample of 20–30 engorged B. microplus females was collected from at least 10 cattle from each farm. Collected ticks were taken to the laboratory where the larval progeny were obtained. The modified larval immersion test was used to detect ticks resistant to amitraz. A discriminating dose of 0.0002% amitraz was used. A questionnaire was applied on each collaborating farm. For the statistical analysis a 2 × 2 contingency table was used to identify potential risk factors. The prevalence of farms with B. microplus resistant to amitraz was 19.40%. However, even though tick resistance to amitraz is a present problem there was no evidence that it was associated with the risk factors analyzed in this survey.  相似文献   

4.
Amitraz is a formamidine compound used as a topical acaricide mainly in dogs and cattle. In an initial attempt to explain some of its side-effects, the actions of amitraz were studied on the cardiovascular and respiratory systems in thiopentone/methoxyflurane-anaesthetized dogs. In separate experiments, amitraz, at doses of 1, 2 and 5 mg/kg i.v., dissolved in DMSO, increased blood pressure for 1 hour. Heart rate decreased initially then showed a dose-related return towards control values. Tidal volume, respiratory rate and respiratory minute volume all showed initial transient depression. Hyperventilation was a feature after high doses of amitraz. Cumulative doses of amitraz of 0.5, 1, 2, 5 and 10 mg/kg i.v., at intervals of 5 min, increased blood pressure. Heart rate decreased at lower doses but increased slightly after higher doses. Five minutes after injection, cardiac index had returned to control values while total peripheral resistance showed a dose-related increase. The mechanism of action of amitraz in dogs cannot be determined from these results; however, other reports have described an alpha 2-adrenoceptor agonist action of this formamidine compound.  相似文献   

5.
Controlled laboratory studies have shown that a metaflumizone plus amitraz combination (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) applied topically is effective for the treatment and control of fleas and ticks on dogs. Two studies were conducted to determine the distribution of both metaflumizone and amitraz in the plasma and hair of dogs following treatment at the minimum recommended dose of approximately 20mg/kg of each active ingredient. Six purpose-bred, adult Beagle dogs were used in each study. Plasma or hair samples were collected from each dog just prior to dosing and periodically through 56 days after treatment. Samples were analyzed by HPLC methods validated for the simultaneous determination of metaflumizone and amitraz. Amitraz was detectable (>3.2ng/ml) but not quantifiable (<50ng/ml) in only two plasma samples, collected 1 and 2 days post-treatment from different dogs. Metaflumizone concentrations in plasma were generally detectable (>1.0ng/ml) but not quantifiable (<50ng/ml). Measurable levels were found in one dog 7 days post-treatment, increasing to a maximum of four dogs at 42 days after dosing, with a metaflumizone range of 59-138ng/ml. Analysis of hair samples indicated that both metaflumizone and amitraz were widely distributed at basically similar levels in the hair within 1-day after administration, reaching maximum concentrations between 2 and 7 days post-treatment. Low but quantifiable levels of both compounds were still present on hair at the end of the 56-day study. These studies indicate that the ectoparasitic activity is due to exposure of the parasites to metaflumizone and amitraz on the surface of the host (hair and/or skin), not to exposure via the circulatory system of the host.  相似文献   

6.
Acaricide resistance is a major problem that hinders the control of the tropical cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), in many parts of the world where cattle production continues to suffer severe economic losses to tick infestation. Deltamethrin and amitraz have been used alone to control R. microplus in New Caledonia for the past decade, and tick populations have developed resistance to both acaricides. A study was conducted to evaluate the effectiveness of deltamethrin and amitraz mixtures, through in vitro laboratory bioassays and in vivo on-animal efficacy trials, for the control of resistant R. microplus on cattle at two dairy farms in New Caledonia. Results of laboratory bioassays using modified larval packet tests (LPT) revealed up to 16.59-fold resistance to deltamethrin, and up to 5.86-fold resistance to amitraz. Significant synergism was observed when amitraz was used as a synergist in deltamethrin bioassays. Amitraz significantly increased deltamethrin toxicity to tick larvae, while deltamethrin was much less effective on amitraz toxicity. Synergism of amitraz by deltamethrin only occurred when the deltamethrin concentration was relatively high. Results of on animal efficacy trials of deltamethrin and amitraz alone and mixtures of both at different concentrations revealed a similar pattern of synergism. Adding amitraz to a deltamethrin formulation led to dramatic increases of percent reduction of both immature and adult ticks. In contrast, adding deltamethrin to an amitraz formulation did not increase control efficacy. Results from this study may lead to the adoption of an acaricide mixture strategy for the control of pyrethroid-resistant R. microplus in New Caledonia and elsewhere.  相似文献   

7.
Knockdown and persistence efficacies of a pour-on containing Amitraz 1% and Cypermethrin 1% and a spray dip containing 12.5% Amitraz were compared. Knock-down and persistence efficacies of the Amitraz spray dip against Rhipicephalus (Boophilus) decoloratus and Amblyomma hebraeum were significantly higher for the duration of the trial than those of the pour-on. In the case of Rhipicephalus appediculatus and Rhipicephalus evertsi evertsi, efficacy was significantly higher on Days 2 and 5. Resistance testing prior to the start of the trial indicated that R. (B.) decoloratus was resistant to both Cypermethrin and Amitraz, yet in the case of the spray dip excellent efficacy results were obtained. It is thought that the cattle's scruffy winter coat may have hindered the spread of the pour-on, but that the thorough wetting and especially the higher concentration of active ingredient applied via the spray dip allowed this formulation to be effective. These results show that under certain conditions a spray dip containing 12.5% Amitraz may be more effective than a pour-on containing 1% Amitraz and 1% Cypermethrin, despite apparent in vitro resistance.  相似文献   

8.
Amitraz, atropine, glycopyrrolate and morphine (but not its derivatives, meperidine [pethidine], oxymorphone and butorphanol) produced similar effects on clinically observed intestinal functions and significantly prolonged intestinal transit, as assessed with polyethylene glycol (PEG). However, their mechanisms of action, particularly on intestinal transport (fluid movement), may differ widely. Loperamide appeared to exert a preferential action on intestinal transport rather than motility, as there was no significant delay in PEG transit. The action of amitraz in perturbing smooth muscle coordination and enhancing absorption involved, at least partially, an alpha 2 adrenergic component susceptible to yohimbine. Naloxone, an opiate antagonist, did not influence amitraz responses but induced the return of intestinal sounds and defecation after a refractory period in morphine-dosed ponies. The results suggest potential clinical applications in horses for loperamide in diarrhoea therapy, for alpha 2 adrenergic antagonists in obstruction and ileus and, possibly, of amitraz-like agents in reducing fluid losses in diarrhoea.  相似文献   

9.
The aim of this study was to determine the contribution of alpha 2- and alpha 1-adrenoceptor agonist activity of the formamidine, amitraz, on peripheral circulation in the dog. Intra-arterial injections of amitraz (0.25-5.0 micrograms/kg) produced a dose-dependent increase in perfusion pressure in the autoperfused hind limbs of methoxyflurane-anaesthetized dogs. A constant blood flow to the hind limbs was maintained using a peristaltic pump. Intravenous phentolamine (0.5 mg/kg), prazosin (35 micrograms/kg) and yohimbine (10 micrograms/kg) in separate experiments antagonized the vasoconstrictor actions of amitraz and produced a parallel shift to the right of the amitraz dose-response curve. Cumulative doses of amitraz (0.5-15 micrograms/kg) given by intracisterna magna (i.c.m.) injections reduced mean arterial pressure and heart rate in a dose-dependent manner. Similar responses were produced by intravenous amitraz but at much higher doses. In separate experiments amitraz-induced hypotension (doses up to 25 micrograms/kg i.c.m.) was prevented by pre-treatment with yohimbine (30 micrograms/kg i.c.m.) but not prazosin (20 micrograms/kg i.c.m.). Both antagonists partially inhibited the bradycardia produced by amitraz. It is concluded that amitraz stimulates alpha 1- and alpha 2-adrenoceptors to produce vascular constriction. The central hypotensive action of amitraz appears to be mediated by alpha 2-adrenoceptors; however, both receptor subtypes appear to be stimulated to produce bradycardia.  相似文献   

10.
OBJECTIVE: To compare the efficacies of amitraz and fipronil for prevention of experimental and natural infestations of Rhipicephalus sanguineus. DESIGN: Prospective study. ANIMALS: 30 dogs. PROCEDURE: In 3 trials, dogs were allocated to 3 groups of 10 each. In trial 1, dogs were experimentally infested on day--1, and on day 0 were fitted with an amitraz-impregnated collar, treated topically with fipronil, or not treated. Ticks were counted daily until day 7, when viability of ticks and their progeny was determined. In trial 2, dogs were treated on day 0 and experimentally infested on days 7, 8, 10, and 13. Ticks were counted on days 8, 10, 13, and 18, and viability of ticks and their progeny was determined on day 18. In trial 3, dogs were exposed weekly to a tick-infested environment from day--3 to day 70. Dogs were treated on day 0, and ticks were counted and removed weekly from day 3 to day 77. RESULTS: Fipronil and amitraz were acaricidal and inhibited attachment and feeding. Amitraz had a significantly greater effect than fipronil on numbers of live, feeding ticks, egg hatchability, and larval viability, indicating partial ability to interrupt the tick life cycle. In field conditions, amitraz remained effective over the entire observation period. CLINICAL IMPLICATIONS: Amitraz had stronger and more sustained effects against tick infestation than fipronil.  相似文献   

11.
Amitraz, a formamidine insecticide, is used topically in the treatment of demodicosis and other ectoparasitic infestations. When 3.78 L (containing 2.1 g) of amitraz (twice the recommended concentration) was applied to 5 dogs 4 hours before glucose (0.6 g/kg of body weight) was administered IV, plasma glucose concentration increased, but the increase in plasma insulin concentration, which usually follows IV administered glucose, was suppressed. The results suggested that amitraz induced hyperglycemia at least partly by inhibiting insulin release.  相似文献   

12.
A novel spot-on formulation containing metaflumizone plus amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated for efficacy against sarcoptic mange mites in naturally infested dogs. Sixteen dogs were allocated to two equal groups and were housed individually. Eight of the dogs were treated topically with metaflumizone plus amitraz at the proposed minimum dose rate (20mg/kg of each of metaflumizone and amitraz, at a dose volume of 0.133ml/kg) on Days 0 and 28. The other eight were treated with metaflumizone plus amitraz at the proposed minimum dose rate on Days 0, 14, 28 and 42. To enumerate Sarcoptes scabiei mites, skin scrapings were taken on each of Days 2, 14, 28, 42 and 56. Clinical signs of mange and the extent of sarcoptic lesions were evaluated on each dog when scrapings were made. Evaluation of the efficacy of the treatment was based on the absence of mites supported by the absence of clinical signs associated with canine sarcoptic mange. Treatment with metaflumizone plus amitraz at the minimum proposed dose rate at monthly (two treatments) or two-weekly (four treatments) intervals resulted in a rapid reduction of mites and improved clinical signs. The overall cure rates at Day 56, based on zero mite counts and/or resolution of clinical signs were 75% and 83% of dogs for the monthly and two-weekly regimens, respectively.  相似文献   

13.
The purpose of this study was to determine the effect of amitraz selection pressure on the development of resistance in field populations of Boophilus microplus in the Mexican tropics. Three farms (FA(1), FA(2) and FA(3)) in Yucatan, Mexico, were selected in this study. Amitraz was applied as a whole body sprays to all cattle on each farm for tick control once monthly for 15 months. From each farm, 20-30 B. microplus engorged females were collected every 3 months. The modified larval immersion test was used to test susceptibility of B. microplus to amitraz. Larvae were exposed to serial dilutions of amitraz. Probit analysis was used to determine lethal dose at 50% mortality and associated 95% confidence limits. The resistance factors found in the three farms during the 15 months of amitraz selection pressure were FA(1) (1, 2, 4, 4 and 13), FA(2) (1, 6, 23, 21 and 22) and FA(3) (2, 13, 2, 6 and 6). It is concluded that amitraz selection pressure on field populations of B. microplus increased the resistance level in all populations studied in the Mexican tropics.  相似文献   

14.
Amitraz has been shown to be successful in controlling mange and lice infestations on pigs which had failed to respond to diazinon and gamma-BHC, respectively, and by the use of a prophylactic programme to maintain pig herds mange free. In addition, trials have indicated the elimination of psoroptic mange from sheep by applying the compound to the animal using either conventional or less conventional methods of treatment. Mixed infections of Chorioptes spp., Psoroptes spp. and Sarcoptes spp., in cattle have also been controlled using spray applications of amitraz, where in some cases organochlorine, organophosphorus and organotin compounds had failed. In a pilot study a heavy infestation of chorioptic mange was controlled on a calf using a pour-on formulation of amitraz.  相似文献   

15.
Amitraz is a rapidly acting acaricide that has been in use for the control of cattle ticks for more than 30 years. Resistance against amitraz was first reported in Boophilus microplus in Australia in 1980 but has been slow to spread in comparison to resistance against synthetic pyrethroids. The most recent estimate of prevalence of amitraz resistance in Australia is 10.8%. In Mexico, the development and distribution of amitraz appears to have been more rapid and the prevalence has been estimated to be 19.4% in Yucatan state. In New Caledonia, about 10% of properties were confirmed to have amitraz resistance. There is little reliable information on the prevalence of amitraz resistance in southern Africa. Risk factors have been identified, but the small sample sizes in the studies that have attempted to identify risk factors using survey data suggest caution in their interpretation. Regional variation in prevalence has been reported, as has a positive relationship with frequency of acaricide application. There is evidence to suggest that in Australia, amitraz resistance might have emerged on a small number of properties and been disseminated by cattle movements. There is also some evidence to suggest that amitraz resistance can diminish in the field when selection pressure is not applied. The mode of inheritance of amitraz resistance is uncertain and it has been suggested that it is a polygenic trait. The mechanism of amitraz resistance is unknown. Two possibilities have been proposed: octopamine receptor and monoamine oxidase. There is some equivocal support for both possibilities. The larval packet test bioassay is the most reliable method of diagnosing amitraz resistance in B. microplus, and this test has been modified by Miller to provide more accuracy and repeatability. Molecular tests are in development but will not eliminate the need for the bioassay.  相似文献   

16.
A novel spot-on formulation containing metaflumizone plus amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated for efficacy against demodectic mange mites in naturally infested dogs. Sixteen dogs were allocated to two equal groups and individually housed. Eight of the dogs were treated topically with metaflumizone plus amitraz at the proposed minimum dose rate (20mg/kg of each of metaflumizone and amitraz, 0.133ml/kg) on Days 0, 28, and 56. The other eight were treated with metaflumizone plus amitraz at the proposed minimum dose rate on Days 0, 14, 28, 42, 56, and 70. Mite numbers were estimated from skin scrapings taken on Days -3 to -1, 28, 56, and 84. Clinical signs of mange and the extent of demodectic lesions on each dog were evaluated when skin scrapings were conducted. Efficacy of the treatment was based on a reduction in mite numbers and an assessment of the clinical signs associated with canine demodectic mange. Treatment at monthly or two-weekly intervals for 3 months resulted in a rapid reduction in mite numbers (>94 and >99% for the monthly and two-weekly treatments, respectively) and an improvement in clinical signs. Success rates, based on zero mite counts in skin scrapings at Day 84 were 42.9 and 62.5% of dogs for the monthly and two-weekly regimens, respectively.  相似文献   

17.
Amitraz, an acaricide used to control ectoparasites in animals has a complex pharmacological activity, including α2-adrenergic agonist action. The purpose of this research was to investigate the possible antinociceptive and/or sedative effect of amitraz in horses. The sedative effect of the intravenous (i.v.) injection of dimethylformamide (DMF, 5 mL, control) or amitraz (0.05, 0.10, 0.15 mg/kg), was investigated on the head ptosis test. The participation of α2-adrenergic receptors in the sedative effect provoked by amitraz was studied by dosing yohimbine (0.12 mg/kg, i.v.). To measure the antinociception, xylazine hydrochloride (1 mg/kg, i.v., positive control) and the same doses of amitraz and DMF were used. A focused radiant light/heat directed onto the fetlock and withers of a horse were used as a noxious stimulus to measure the hoof withdrawal reflex latency (HWRL) and the skin twitch reflex latency (STRL). The three doses of amitraz used (0.05, 0.10 and 0.15 mg/kg) provoked a dose-dependent relaxation of the cervical muscles. The experiments with amitraz and xylazine on the HWRL showed that after i.v. administration of all doses of amitraz there was a significant increase of HWRL up to 150 min after the injections. Additionally, there was a significant difference between control (DMF) and positive control (xylazine) values up to 30 min after drug injection. On the other hand, the experiments on the STRL show that after administration of amitraz at the dose of 0.15 mg/kg, a significant increase in STRL was observed when compared with the control group. This effect lasted up to 120 min after injection. However, no significant antinociceptive effect was observed with the 0.05 and 0.10 mg/kg doses of amitraz or at the 1.0 mg/kg dose of xylazine.  相似文献   

18.
OBJECTIVE: To determine the survival time of Mycobacterium avium subsp paratuberculosis in amitraz-based cattle dip fluid derived from an active dip site in northern New South Wales. PROCEDURE: Following inoculation of triplicate 5 L containers with faeces (0.5 g/L) from a clinical case of bovine paratuberculosis, samples collected up to 8 weeks after inoculation were examined by conventional and radiometric culture. M a paratuberculosis colonies were enumerated on solid media. RESULTS AND CONCLUSIONS: M a paratuberculosis survived in amitraz cattle dip fluid for up to 2 weeks, but not 3 weeks. Where 1% of solids in dip fluid is derived from a clinical case of paratuberculosis, dip fluid may contain viable M a paratuberculosis for at least 2 weeks. These findings have implications for the management of cattle dip sites.  相似文献   

19.
Angora goats heavily infested with Chorioptes bovis were dipped one time in either 0.05% amitraz, 0.27% coumaphos, 0.05% fenvalerate, or 0.03% lindane. Control of the mites by the single dips was evaluated for 21 days. Amitraz caused 98% mortality of the mites initially. Both coumaphos and lindane caused greater than 85% mortality at 3 days, but mite numbers increased rapidly thereafter. Only fenvalerate killed all of the mites.  相似文献   

20.
双甲脒防治桑树害虫朱砂叶螨的研究   总被引：2，自引：2，他引：0  
双甲脒(Amitraz,Mitac)对朱砂叶螨的毒性比三氯杀螨醇(Dicofol)对照慢,但总毒性比对照强。室内24小时后测得的LC_(50)值分别为38.0ppm和25.1ppm在48小时后测得的LC_(50)分别为8.9ppm和17.2ppm。双甲脒对朱砂叶螨卵有很好的杀灭作用,用50ppm浓度即可以全部杀死,效果高于对照。田间防效:用20％双甲脒1500倍(133ppm)喷药后第四天和第八天分别为92.36％和99.01％,高于对照;田间对朱砂叶螨持效期11天左右。对家蚕的残毒期约为10天。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号