Efficacy of 1.25% amitraz solution in the treatment of generalized demodicosis (eight cases) and sarcoptic mange (five cases) in dogs

Eight dogs with generalized demodicosis and five with sarcoptic mange were treated with 1.25% amitraz solution applied weekly and associated with an antidote treatment (atipamezol, 0.1 mg kg⁻¹ IM once: and yohimbine 0.1 mg kg⁻¹ once daily for 3 days, orally). Results of skin scrapings were used to determine whether therapy should be continued or stopped. The median number of treatments for demodicosis and sarcoptic mange was three (range 2–5) and two (range 1–3), respectively. Some side-effects were observed but all were stopped with antidote treatment; no failure or relapses occurred at 6–36 months after treatment.     

New method using quantitative PCR to follow the tick blood meal and to assess the anti-feeding effect of topical acaricide against Rhipicephalus sanguineus on dogs

A 28-day study was conducted to assess the dynamic of blood feeding by Rhipicephalus sanguineus ticks on dogs treated or not with a novel topical combination of fipronil, amitraz and (S)-methoprene. Dogs were infested weekly through exposure to ticks in crates for 4 h. Ticks were then counted in the crates at 2 h and 4 h post dog exposure. Ticks were also counted and removed from the dogs at 2 h, 4 h, 6 h, 12 h and 24 h post tick exposure. The inhibition of blood feeding was assessed by both tick quantification and designing and performing a quantitative PCR (qPCR) to detect the canine hydroxymethylbilane synthase (HMBS) gene in ticks. The percentage of repellency sensu lato based on the ticks collected in crates at 2 h varied from 4.7% at day 28 to 48.3% at day 7. The immediate mortality rate of the ticks expelled at 2 h varied from 1.5% at day 21 to 31.7% at day 7. The efficacy calculation showed that the acaricidal combination started to kill ticks in as little as 2 h. The average efficacy reached 90.0% at 12 h post crate challenges and 100% at 24 h post exposure in crates. The inclusion of an internal amplification control was used to ensure that no significant template-derived PCR inhibition (≤6.2%) affected the overall results. The reduction of blood feeding was significant at 4 h (>80.0%) and >99.0% at 24 h post tick exposure in the crate. The high repellency rate and the lethal efficacy of CERTIFECT^® resulted in significantly fewer live attached ticks, consequently reducing blood intake and fluid exchanges.     

Survival of Mycobacterium avium subsp paratuberculosis in amitraz cattle dip fluid

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.     

Treatment protocols for demodicosis: an evidence-based review

Publications discussing the treatment of demodicosis in the dog and cat are reviewed. Based on the evidence in the literature, amitraz rinses at 0.025-0.06% every 7-14 days, and oral daily ivermectin at 300 micro g kg(-1), milbemycin at 2 mg kg(-1) and moxidectin at 400 micro g kg(-1), respectively, can all be recommended for the treatment of generalized canine demodicosis. Ivermectin and moxidectin should be initiated at lower doses and patients monitored for possible adverse effects during therapy. In cats, 2% lime sulfur dips and amitraz rinses at 0.0125-0.025% have been used successfully.     

蜂蜜中双甲脒残留量检测方法

本文建立了蜂蜜中双甲脒残留量的气相色谱分析方法,并对萃取溶剂及衍生化试剂等８进行了讨论。蜂蜜中的双脒经水解、净化和衍生化后,用气相色谱－电子捕获检测器测定。其回收率为９０．５％￣１００．１％,变异系数１．６４％￣４．４０％,最低检测浓度为０．００２５ｍｇ／ｋｇ。     

Acaricide resistance and synergism between permethrin and amitraz against susceptible and resistant strains of Boophilus microplus (Acari: Ixodidae)

The control of the southern cattle tick, Boophilus microplus (Canestrini), in Mexico and many other countries relies on chemical acaricides. Boophilus microplus has developed resistance to all major classes of acaricides in recent years. To gain a better understanding of the resistance and to develop resistance management strategies that benefit both Mexican ranchers and USDA's cattle fever tick eradication program (CFTEP), the authors used larval bioassay techniques to determine levels of resistance to permethrin and amitraz and then evaluated synergism between these two acaricides in one susceptible laboratory tick strain and four resistant strains originating from Mexico and Brazil. To examine mechanisms of resistance to permethrin in these strains, the frequency of a mutated sodium channel gene was determined using a PCR assay. The tick strains from Mexico and Brazil demonstrated 49.4- to over 672.2-fold resistance to permethrin, and up to 94.5-fold resistance to amitraz. While the San Roman strain from Mexico was the most permethrin-resistant strain, the Santa Luiza strain from Brazil was the most amitraz-resistant strain. A significant correlation was found between the permethrin resistance ratio and the allelic frequency of the sodium channel mutation. Significant synergism between permethrin and amitraz was found when one acaricide was tested in the presence of another. Synergism ratios ranged from 1.5 to 54.9 when amitraz was tested as a synergist for permethrin. Similar synergism ratios were obtained when permethrin was tested as a synergist for amitraz. Permethrin caused virtually no mortality in the San Roman strain, even at the highest concentration (3294 microg cm(-2)). Adding amitraz (11.0 microg cm(-2)) to permethrin led to a dramatic increase in larval mortality, even at very low concentrations of permethrin.     

气相色谱法检测柑桔中痕量双甲脒

本文研究了应用气相色谱法测定柑桔中痕量双甲脒残留物的分析方法。对样品预处理的方法进行探索，最终选择出较为理想的提取试剂，并对定量检测条件作了较详细的研究。