Evaluation of 65% permethrin spot-on and deltamethrin-impregnated collars for canine Leishmania infantum infection prevention

During the 2004 and 2005 sand fly seasons, we evaluated the efficacy of a 65% spot-on solution of permethrin (Exspot, Schering & Plough) and deltamethrin-impregnated collar (Scalibor, Intervet) in reducing Leishmania infantum infection, in a canine leishmaniasis (CanL) endemic region (Liguria) in Italy. Immunofluorescent assay (IFA) revealed that three of 120 dogs (2.5%) treated with a 65% spot-on solution of permethrin, as three of 119 dogs (2.5%) treated with deltamethrin-impregnated collar have shown seroconversion after sand fly season. On the contrary, seroconversion was 15% in 188 untreated control dogs. Treatment reduced the risk of infection by 84%. The difference in treated dogs and control ones is highly significant (chi2 = 12.4; P = 0.0004). Our results show that treatment with 65% spot-on solution of permethrin and the deltamethrin-impregnated collar are effective in reducing the risk of acquiring L. infantum infection.     

Neurotoxic implications of the agonistic action of CS-syndrome pyrethroids on the N-type Ca(v)2.2 calcium channel

BACKGROUND: Cismethrin (T-syndrome) and deltamethrin (CS-syndrome) pyrethroids have been previously shown to increase membrane depolarization and calcium influx, but only deltamethrin increased Ca(2+)-dependent neurotransmitter release from rat brain synaptosomes. Deltamethrin's action was blocked by omega-conotoxin GVIA, delineating a separate action at N-type Ca(v)2.2 channels that is consistent with the in vivo release of neurotransmitter. It is hypothesized that other CS-syndrome pyrethroids will elicit similar actions at presynaptic nerve terminals.RESULTS: Nine additional pyrethroids were similarly examined, and these data were used in a cluster analysis. CS-syndrome pyrethroids that possessed alpha-cyano groups, cypermethrin, deltamethrin and esfenvalerate, all caused Ca(2+) influx and neurotransmitter release and clustered with two other alpha-cyano pyrethroids, cyfluthrin and cyhalothrin, that shared these same actions. T-syndrome pyrethroids, bioallethrin, cismethrin and fenpropathrin, did not share these actions and clustered with two non-alpha-cyano pyrethroids, tefluthin and bifenthrin, which likewise did not elicit these actions. Deltamethrin reduced peak current of heterologously expressed wild-type Ca(v)2.2, increased peak current of T422E Ca(v)2.2 and was 20-fold more potent on T422E Ca(v)2.2 than on wild-type channels, indicating that the permanently phosphorylated form of Ca(v)2.2 is the preferred target.CONCLUSIONS: Ca(v)2.2 is directly modified by deltamethrin, but the resulting perturbation is dependent upon its phosphorylation state. The present findings may provide a partial explanation for the different toxic syndromes produced by these structurally distinct pyrethroids.     

三角帆蚌稚蚌培育阶段摇蚊幼虫的药物杀灭试验

为杀灭三角帆蚌(Hyriopsis cumingii)稚蚌培育池中的摇蚊幼虫,以吡喹酮、伊维菌素、阿维菌素、氰戊菊酯等8种常用水产杀虫药,进行稚蚌培育池中摇蚊幼虫杀灭效果试验,再对筛选出的药物进行急性毒性试验,并据此进行稚蚌培育池中杀灭摇蚊幼虫的药物应用试验.结果显示:溴氰菊酯是稚蚌培育池杀灭摇蚊幼虫的理想药物;在平均...     

Deltamethrin resistance in the sea louse Caligus rogercresseyi (Boxhall and Bravo) in Chile: bioassay results and usage data for antiparasitic agents with references to Norwegian conditions

The sea louse Caligus rogercresseyi is a major threat to Chilean salmonid farming. Pyrethroids have been used for anticaligus treatments since 2007, but have shown reduced effect, most likely due to resistance development. Pyrethroid resistance is also a known problem in Lepeophtheirus salmonis in the Northern Hemisphere. This study describes the development of deltamethrin resistance in C. rogercresseyi based on bioassays and usage data for pyrethroids in Chilean aquaculture. These results were compared to bioassays from L. salmonis from Norway and to Norwegian usage data. Available deltamethrin bioassay results from 2007 and 2008, as well as bioassays from Norway, were collected and remodelled. Bioassays were performed on field‐collected sea lice in region X in Chile in 2012 and 2013. Bioassays from 2007 were performed prior to the introduction of pyrethroids to the Chilean market. Both the results from 2008 and 2012 showed an increased resistance. Increased pyrethroid resistance was also indicated by the increased use of pyrethroids in Chilean aquaculture compared with the production of salmonids. A similar trend was seen in the Norwegian usage data. The bioassay results from Chile from 2012 and 2013 also indicated a difference in the susceptibility to deltamethrin between male and female caligus.     

固相萃取-高效薄层色谱测定茶叶中甲氰菊酯和溴氰菊酯残留

本文建立了简便快速测定茶叶中甲氰菊酯和溴氰菊酯残留的固相萃取-高效薄层色谱分析方法。以乙腈为提取剂, 活性炭固相萃取柱和中性氧化铝固相萃取柱串联净化,高效薄层色谱检测。 结果表明,在给定色谱条件下甲氰菊酯（Rf= 0.49 ）和溴氰菊酯（Rf=0.64）的最小检测限分别为20.0ng和10.0ng。 茶叶中甲氰菊酯和溴氰菊酯的添加回收率为94.8-108% 和90.5-102%（添加浓度0.50-10.0 mg/kg）,相对标准偏差为1.71-6.22% 和3.82-6.39%。 本文所建立方法的准确性、精确性均满足农药残留分析的要求。     

溴氰菊酯对加州腔蚓的急性中毒效应

于不同时间地点观察加州腔蚓在溴氰菊酯浓度为40mg／kg、20mg／kg、10mg／kg、5mg／kg、2．5mg／kg土壤中的急性中毒症状、异常行为及死亡状况,结果发现：与低浓度相比,高浓度（≥20mg／kg）下蚯蚓环带红肿、粘液分泌、身体翻滚等症状出现的时间较短,不足7min,在浓度为2．5mg／kg时上述症状出现的时间最长,约为60min;蚯蚓中毒翻滚持续时间,在40mg／kg浓度下最短,为233．1min,在2．5-10mg／kg浓下时持续最长,约600min;蚯蚓中毒致死时间,在40mg／kg和5mg／妇浓度下达极值,分别为317．9min和2140min,前者死亡时体重下降9．48％,后者死亡时体重下降近30％。统计分析表明：溴氰菊酯对加州腔蚓的急性毒性效应与中毒时间和农药剂量存在相关性。     

马尾松毛虫幼虫血淋巴羧酸酯酶的诱导及其与抗菌物质的相关性研究

报道了用低剂量溴氰菊酯注射处理马尾松毛虫５龄幼虫后对血淋巴羧酸酯酶的诱导效果及其与抗菌物质诱导活性的关系。在诱导２４ｈ、羧酸酯酶活性好增加２０．４％、４８ｈ达到高峰,增加约３８．１％,７２ｈ后为２３．２％,幼虫血淋巴中羧酸酯酶和抗菌物质的诱导活性变化动态相似,但两者的活力高峰存在时相位差,前者在诱导后４８ｈ、后者在６０ｈ。     

Genetics and evidence for an esterase-associated mechanism of resistance to indoxacarb in a field population of diamondback moth (Lepidoptera: Plutellidae)

Bioassays (at generation G2) with a newly collected field population (designated CH3) of Plutella xylostella L. from farmers' fields in the Cameron Highlands, Malaysia, indicated resistance ratios of 813-, 79-, 171-, 498- and 1285-fold for indoxacarb, fipronil, spinosad, deltamethrin and Bacillus thuringiensis toxin Cry1Ac respectively compared with a laboratory susceptible population (Lab-UK). At G2 the field-derived population was divided into two subpopulations: one was selected (G2 to G7) with indoxacarb (indoxa-SEL), while the second was left unselected (UNSEL). A significant reduction in the resistance ratio for each compound was observed in UNSEL at G8. For indoxa-SEL, bioassays at G8 found that selection with indoxacarb gave a resistance ratio of 2594 compared with Lab-UK and of 90 compared with UNSEL. The toxicity of fipronil, spinosad and deltamethrin was not significantly different in indoxa-SEL at G8 compared with G2 but was significantly greater than UNSEL at G8. The toxicity of Cry1Ac was significantly reduced in indoxa-SEL at G8 compared with G2 but was also significantly greater than UNSEL at G8. This suggests that indoxacarb selection maintained resistance to these compounds in the indoxa-SEL population. Synergist studies indicated that resistance to indoxacarb in indoxa-SEL was esterase associated. Logit regression analysis of F1 reciprocal crosses between indoxa-SEL and Lab-UK indicated that resistance to indoxacarb was inherited as an autosomal, incompletely recessive (D(LC) = 0.35) trait. Tests of monogenic inheritance suggested that resistance to indoxacarb was controlled by a single locus.