Search

Background: Tanzania has experienced outbreaks of dengue fever in major cities. The main vectors of the dengue virus in Tanzania are Aedes aegypti mosquitoes. The control of this mosquito vector is based on insecticide, and yet, the insecticide susceptibility of this species is not well known in many places in Tanzania. Conversely, the breeding habitats mostly preferred by this species are not well documented in the study area. Therefore, the present study aimed to determine the pyrethroid insecticide susceptibility status and breeding habitats preference of Ae. aegypti mosquito in the three sites from three districts in Mwanza, Tanzania. The assessment of Ae. aegypti mosquito 24-h percentage mortality was based on WHO criteria. Results: A total of 850 Ae. aegypti were exposed to three pyrethroid insecticides. In Bwiru site, 100% mortality was observed for all three pyrethroids, indicating full susceptibility. At Igekemaja and Mwagagala villages, Ae. aegypti were resistant to all the three pyrethroid insecticides tested. In Igekemaja, there were variations in Ae. aegypti mortality rates induced by different insecticides, with mortality rates ranging from 72% for alphacypermethrin to 86% for deltamethrin. Although the mortality rates were lower than in Bwiru site, they were still substantial and statistically significant. The mortality rates in Mwagagala were lowest across the three insecticides, with mortality rates ranging from 60% for deltamethrin to 86% for alphacypermethrin. In Mwagagala, the Ae. aegypti mosquitoes were less susceptible to the insecticides tested. Aedes aegypti mosquito prefer breeding in abandoned old tires in urban area and in small containers and uncovered water storage containers in rural settings. Conclusion: The study has revealed pyrethroid insecticide susceptibility status and breeding habitats of Ae. aegypti in the rural and urban settings in Mwanza, Tanzania. The study findings imply the need for public health interventions with focus on community education on mosquito control. [ABSTRACT FROM AUTHOR]

Culex quinquefasciatus Say 1823 (Diptera: Culicidae), a vector of lymphatic filariasis and various arboviruses, is the most abundant mosquito owing to its breeding capacity in polluted stagnant water. Alphacypermethrin (C22H19Cl2NO3) is a highly effective synthetic pyrethroid insecticide, used for the management of agricultural pests as well as vector control. In this study, two strains of Cx. quinquefasciatus were reared in the laboratory with the same genetic background, one strain was selected against alphacypermethrin (AS) and another strain was devoid of insecticide treatment and reared as susceptible (S) for 15 generations. It was observed that the sub-lethal exposure to insecticide led to a low fecundity rate, less hatchability, longer larval developmental time, low pupation rate, and less emergence rate but no significant differences in sex ratio. AS strain showed 37.4-fold, 2.85-fold, fivefold, and 8.6-fold higher activity in comparison to S strain in monooxygenases, alphaesterases, betaesterases, and glutathione-S-transferases activity respectively, implying the role of detoxifying enzyme in metabolic resistance development. This study was conducted to elucidate the sub-lethal effects of insecticide on the life history traits of the exposed strain and their association with metabolic resistance which would ultimately help to design vector control programs against insecticide resistance. [ABSTRACT FROM AUTHOR]

Abstract Background Tanzania has experienced outbreaks of dengue fever in major cities. The main vectors of the dengue virus in Tanzania are Aedes aegypti mosquitoes. The control of this mosquito vector is based on insecticide, and yet, the insecticide susceptibility of this species is not well known in many places in Tanzania. Conversely, the breeding habitats mostly preferred by this species are not well documented in the study area. Therefore, the present study aimed to determine the pyrethroid insecticide susceptibility status and breeding habitats preference of Ae. aegypti mosquito in the three sites from three districts in Mwanza, Tanzania. The assessment of Ae. aegypti mosquito 24-h percentage mortality was based on WHO criteria. Results A total of 850 Ae. aegypti were exposed to three pyrethroid insecticides. In Bwiru site, 100% mortality was observed for all three pyrethroids, indicating full susceptibility. At Igekemaja and Mwagagala villages, Ae. aegypti were resistant to all the three pyrethroid insecticides tested. In Igekemaja, there were variations in Ae. aegypti mortality rates induced by different insecticides, with mortality rates ranging from 72% for alphacypermethrin to 86% for deltamethrin. Although the mortality rates were lower than in Bwiru site, they were still substantial and statistically significant. The mortality rates in Mwagagala were lowest across the three insecticides, with mortality rates ranging from 60% for deltamethrin to 86% for alphacypermethrin. In Mwagagala, the Ae. aegypti mosquitoes were less susceptible to the insecticides tested. Aedes aegypti mosquito prefer breeding in abandoned old tires in urban area and in small containers and uncovered water storage containers in rural settings. Conclusion The study has revealed pyrethroid insecticide susceptibility status and breeding habitats of Ae. aegypti in the rural and urban settings in Mwanza, Tanzania. The study findings imply the need for public health interventions with focus on community education on mosquito control.

We report on the sensing of a hazardous pesticide alphacypermethrin (ACM) using electrochemical technique through a nanocomposite film modified electrode. The nanocomposite film comprising of octadecylamine, chitosan, polyvinyl alcohol-silver nanowires and haemoglobin, shortly (OCPAH), was prepared by Langmuir–Blodgett (LB) film deposition technique on various substrates and electrodes. The composite LB film was characterised by UV-visible spectroscopy and scanning electron microscopy, which confirms the stable and multilayer film. The LB film modified electrode was used for sensing ACM pesticide by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV) techniques. The achieved sensing parameters such as limit of detection as 14 nM, 5 nM and 10 nM; linear range as 10–100 nM, 10–40 nM and 50–100 nM/10–100 nM; and sensitivity as 0.418 µA/nM/cm2, 0.259 µA/nM/cm2 and 0.271 µA/nM/cm2 for CV, DPV and SWV techniques, respectively. The reported sensor is found to have stability of 74% upto 20 cycles, the relative standard deviation (RSD) value for metal ion/organic interference species as 2% and for real samples are within 1.4% using CV technique. The reported nanocomposite-based ACM pesticide sensor will open up new options for research on LB film nanocomposite-based sensing of different organophosphorus groups of pesticides. [ABSTRACT FROM AUTHOR]

Simple Summary: Turkestan cockroaches are primarily outdoor nuisance pests in many parts of the world. The application of pesticide sprays in and around areas where cockroaches aggregate is a common practice in trying to reduce their populations. Intensive pesticide treatments can lead to pesticide runoff into water sources, such as rivers, lakes, streams, and dwells. Insecticide-based paints offer an alternative option for long-term efficacy in controlling cockroaches with diminished environmental impacts. In this study, pyrethroid-based paints applied to concrete, metal, and PVC—common surfaces where cockroaches reside—were demonstrated to kill and repel Turkestan cockroach nymphs. The pyrethroid alphacypermethrin produced the highest mortality most rapidly. The lethal and repellency effects of these paints may help prevent the establishment of Turkestan cockroaches around buildings. These results support the use of insecticide-paint technologies in areas where Turkestan cockroaches are a dominant pest. The Turkestan cockroach, Periplaneta lateralis (Walker), is an invasive urban pest prevalent in dry areas of the southwestern United States. Treatment with liquid spray formulations containing insecticides is the most conventional method to decrease Turkestan cockroach population abundance around buildings. Intensive application of insecticide treatments near natural environments has prompted concerns regarding the impacts on non-target aquatic and terrestrial ecosystems. Technologies embedding insecticides in a paint matrix have successfully been used for the long-term reduction in disease-vector populations in tropical areas. Here, we evaluated the potential effectiveness of three pyrethroid-based paints against Turkestan cockroach nymphs on common surfaces inhabited by this species. Turkestan cockroaches continuously exposed for 1 h to 1-month aged alphacypermethrin and deltamethrin paints applied to concrete, metal, or PVC caused moderate to high mortality. Evaluations using choice boxes indicated that deltamethrin and transfluthrin paints had combined lethal and repellent effects on cockroaches. Alphacypermethrin also caused repellency and killed cockroaches rapidly. We discuss the implications of these findings on cockroach control practices. [ABSTRACT FROM AUTHOR]

Abstract Background Optimising insecticide use and managing insecticide resistance are important to sustain gains against malaria using long-lasting insecticidal nets (LLINs). Restricting insecticides to where mosquitoes are most likely to make multiple contacts could reduce the quantity of insecticide needed to treat the nets. Previous studies have shown that nets partially treated with a pyrethroid insecticide had equivalent mortality compared to a fully treated net. This study compared the efficacy of: (i) whole Interceptor® G2 nets (IG2; a dual-active LLIN containing alpha-cypermethrin and chlorfenapyr), (ii) nets with roof panels made of IG2 netting, (iii) nets with side panels made of IG2 netting and (iv) whole untreated nets as test nets. Methods The study was conducted in cow-baited experimental huts, Moshi Tanzania, using a four-arm Latin square design. Test nets had 30 holes cut in panels to simulate a typical net after 2–3 year use. The trial data were analysed using generalized linear models with mortality, blood-feeding, exophily and deterrence against wild free-flying Anopheles arabiensis as outcomes and test nets as predictors. Results Mortality was significantly higher in the nets with roof IG2 [27%, P = 0.001, odds ratio (OR) = 51.0, 95% CI = 4.8–546.2), side IG2 (44%, P

Background: Optimising insecticide use and managing insecticide resistance are important to sustain gains against malaria using long-lasting insecticidal nets (LLINs). Restricting insecticides to where mosquitoes are most likely to make multiple contacts could reduce the quantity of insecticide needed to treat the nets. Previous studies have shown that nets partially treated with a pyrethroid insecticide had equivalent mortality compared to a fully treated net. This study compared the efficacy of: (i) whole Interceptor® G2 nets (IG2; a dual-active LLIN containing alpha-cypermethrin and chlorfenapyr), (ii) nets with roof panels made of IG2 netting, (iii) nets with side panels made of IG2 netting and (iv) whole untreated nets as test nets. Methods: The study was conducted in cow-baited experimental huts, Moshi Tanzania, using a four-arm Latin square design. Test nets had 30 holes cut in panels to simulate a typical net after 2–3 year use. The trial data were analysed using generalized linear models with mortality, blood-feeding, exophily and deterrence against wild free-flying Anopheles arabiensis as outcomes and test nets as predictors. Results: Mortality was significantly higher in the nets with roof IG2 [27%, P = 0.001, odds ratio (OR) = 51.0, 95% CI = 4.8–546.2), side IG2 (44%, P < 0.001, OR = 137.6, 95% CI = 12.2–1553.2] and whole IG2 (53%, P < 0.001, OR = 223.0, 95% CI = 19.07–2606.0) nettings than the untreated (1%) nets. Mortality was also significantly higher in the whole IG2 net compared to the net with roof IG2 netting (P = 0.009, OR = 4.4, 95% CI = 1.4–13.3). Blood feeding was 22% in untreated, 10% in roof IG2, 14% in side IG2 and 19% in whole IG2 nets. Exiting was 92% in untreated, 89% in roof IG2, 97% in side IG2 and 94% whole IG2 nets. Conclusion: The results show that although the roof-treated IG2 net induced greater mortality compared to untreated nets, its efficacy was reduced compared to whole IG2 nets. Therefore, there was no benefit to be gained from restricting dual-active ingredient IG2 netting to the roof of nets. [ABSTRACT FROM AUTHOR]

Long-lasting insecticidal nets (LLINs) are being promoted by World Health Organization (WHO) as key vector control tool for the prevention and control of malaria and other vector-borne diseases. A laboratory study was conducted to evaluate the bio-efficacy of a new alphacypermethrin LN (HILNET®) against insecticide-susceptible Anopheles culicifacies s.l.. This study presents the observations on (a) regeneration time, the period required to regenerate insecticide in the LLIN after three consecutive WHO standard washes in a single day to deplete the insecticide on the net surface, and (b) wash resistance of the LLIN to retain bio-efficacy up to 20 repeated washes at intervals corresponding to the regeneration time in days. In the present evaluation, the regeneration time of HILNet® was determined as 2 days. Wash resistance studies of HILNet® showed a knockdown rate of 100% up to 15 washes and 97% at the 20th wash and complied with the criteria of WHO knockdown rate of ≥ 95%. The mean active ingredient content from 0 to 20 washes was in the range of 5.8 to 6.04 g/kg and met the WHO criteria of the product claim (± 25% g/kg). The insecticide un-impregnated control net has shown no detectable levels of alphacypermethrin. In this evaluation, HILNet® fulfilled the WHO laboratory (phase I) efficacy criteria based on the rates of knockdown up to 20 standard WHO washes. [ABSTRACT FROM AUTHOR]

Abstract Background African horse sickness (AHS) is of importance to health and international trade in horses worldwide. During export from and transit through AHS endemic countries or zones, physical and chemical measures to protect horses from the vectors of AHS virus (AHSV) are recommended by the World Organization for Animal Health. Protection of containerized air transport systems for horses (jet stalls) with alphacypermethrin insecticide-treated high density polyethylene mesh is effective in reducing the Culicoides midge vector attack rate. In order to determine the effect of this mesh on jet stall ventilation and horse welfare under temperate climatic conditions, jet stall microclimate, clinical variables and faecal glucocorticoid metabolite (FGM) levels of 12 horses were monitored during overnight housing in either a treated or untreated stall in two blocks of a 2 × 3 randomized crossover design. Results Temperature difference between the treated stall and outside was significantly higher than the difference between the untreated stall and outside at 1/15 time points only (P = 0.045, r = 0.70). Relative humidity (RH) difference between the treated stall and outside did not differ from the untreated stall and outside. Temperature and RH in the treated stall were highly and significantly correlated with outside temperature (r = 0.96, P

Although the chemical control against leishmaniasis began in 1953 in Brazil, little information is available on how this strategy has affected populations of phlebotomine sandflies in the field. The objective of this study was to analyze the susceptibility profile of four populations of phlebotomine sandflies to the insecticide alpha-cypermethrin. Sandflies collected in field in four Brazilian municipalities were evaluated using CDC bottles in different concentrations of alpha-cypermethrin. A total of 1,186 phlebotomine sandflies were used in the bioassays. The LD50 ranged from 1.48 to 2.57 ug/mL in the field populations. For a dose of 5 ug/mL of alpha-cypermethrin, the LT50 and LT95 ranged from 17.9 to 27.5 minutes, and LT95 from 39.7 to 61.5 minutes, respectively. All the populations studied were highly susceptible to the insecticide alpha-cypermethrin. Routine studies are needed to detect changes in sandflies susceptibility to insecticides. [ABSTRACT FROM AUTHOR]

Two pyrethroids, deltamethrin (D) and alphacypermethrin (AC), have been used as commercial products for tick control worldwide. However, the effects of sublethal doses of these compounds on various tick species and their developmental stages have not been fully explored yet, although such knowledge could contribute to a more effective application of both pyrethroids and simultaneous reduction of their costs and undesirable side effects, including the harmful impact on other organisms and environmental contamination. This study investigates the effect of sublethal concentrations of D and AC applied to engorged females on the fecundity, development of eggs and larvae, and the number of offspring in the Ixodes ricinus (L.) tick, which is the most important vector of tick-borne diseases of humans in Europe. After detachment from rabbit's skin, fully engorged I. ricinus females were treated with 20 μl of pyrethroid solutions at five concentrations from 0.01562 to 0.25% and kept at 28 °C and 75% relative humidity. The impact of the pyrethroids on maturation and development of eggs as well as development of larvae was assessed based on parameters of the preoviposition and oviposition periods and the course of embryogenesis and egg hatch. The investigations have shown that both tested acaricides reduce the reproductive rate in I. ricinus females by inhibition of egg development and disturb embryonic development and larval hatch. Females did not lay eggs at concentrations higher than 0.0625% AC and 0.125% D. The lower concentrations of both pyrethroids disturbed or inhibited the embryogenesis and egg hatch in I. ricinus. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kirkuk University for Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

introduction. Despite the increased rates of infestations with[i] I. ricinus (Ir)[/i] and [i]D. reticulatus (Dr)[/i] ticks observed over the last decade, no effective control methods have been developed so far. The resent study was focused on assessment of the action of pyrethroids on these both tick species. materials and method. The different doses of four pyrethroids, i.e. deltamethrin – D (K-Othrine), permethrin – P (Copex WP), cypermethrin – C (Kordon 10WP), and alphacypermethrin – AC (Alfasekt 5SC) were tested. The LD50 for each tested compound was also determined for both tick species. Unengorged and engorged (maintained on rabbit skin) tick females were sprayed with 20ml of 0.01563–0.50% solutions of the tested preparations. results. The investigations showed that sensitivity of Ir and Dr to the tested pyrethroids, but the effects exerted by the different doses varied between both tick species and between engorged and unengorged females in these species. The strongest toxic effect on unengorged and engorged Ir and Dr females was exerted by D, whereas the effect of AC was weaker. The LD 50 (in µg/1 g b.w.) of D, AC, C, and P for unengorged Ir and Dr females was, respectively, 55.4 and 25.5, 105.2 and 48.5, 225.9 and 197.7, and 553.8 and 380.8. In the case of engorged Ir and Dr females, the LD50 of AC, D, C, and P reached a value of 0.9453 and 0.2310, 1.0428 and 1.3533, 3.489 and 6.5662, and 8.3955 and 7.3940, respectively. conclusions. The differences between the effects of the tested pyrethroids and their different doses on Ir and Dr highlight the necessity for development of a strategy for control of the tick species in different regions, based on investigations of their sensitivity to chemical compounds.

Intention of this research was to develop an analytical technique for analysis of alphacypermethrin (ACYM). It is a pyrethroid insecticide used in agriculture for destroying harmful insects and for killing malaria vector as a public health program. To measure residues of the ACYM in some vegetable samples, a novel method is developed for determination of ACYM. Literatures reveal minimum information about the spectrophotometric determination of ACYM. When ACYM is brominated, it forms dibromoalphacypermethrin which reacts with potassium iodide and potassium iodate in the presence of starch to form blue color dye. The dye show highest absorbance at λmax = 625 nm. Parameters which effect on the reaction were studied and conditions were optimized. Linear calibration curve was obtained from 40 to 120 µg mL-1 ACYM and lower detection limit was 10 µg mL-1. This method was applied on some vegetables and fruit samples for the determination of ACYM. [ABSTRACT FROM AUTHOR]

Background: African horse sickness (AHS) is of importance to health and international trade in horses worldwide. During export from and transit through AHS endemic countries or zones, physical and chemical measures to protect horses from the vectors of AHS virus (AHSV) are recommended by the World Organization for Animal Health. Protection of containerized air transport systems for horses (jet stalls) with alphacypermethrin insecticide- treated high density polyethylene mesh is effective in reducing the Culicoides midge vector attack rate. In order to determine the effect of this mesh on jet stall ventilation and horse welfare under temperate climatic conditions, jet stall microclimate, clinical variables and faecal glucocorticoid metabolite (FGM) levels of 12 horses were monitored during overnight housing in either a treated or untreated stall in two blocks of a 2 x 3 randomized crossover design. Results: Temperature difference between the treated stall and outside was significantly higher than the difference between the untreated stall and outside at 1/15 time points only (P = 0.045, r = 0.70). Relative humidity (RH) difference between the treated stall and outside did not differ from the untreated stall and outside. Temperature and RH in the treated stall were highly and significantly correlated with outside temperature (r = 0.96, P < 0.001) and RH (r = 0.95, P < 0.001), respectively. No significant differences were detected between rectal temperatures, pulse and respiratory rates of horses in the treated stall compared to the untreated stall. Mean FGM concentrations for horses housed in the treated stall peaked earlier (24 h) and at a higher concentration than horses housed in the untreated stall (48 h), but were not significantly different from baseline. No significant difference was detected in FGM concentrations when the treated and untreated stall groups were compared at individual time points up to 72 h after exiting the jet stall. Conclusions: Alphacypermethrin-treated HDPE mesh could be used under temperate climatic conditions to protect horses in jet stalls against AHSV vectors, without compromising jet stall microclimate and horse welfare. [ABSTRACT FROM AUTHOR]

Introduction & Objectives: A laboratory study was carried out to investigate the insecticidal, irritant and anti-feeding effects of nets treated with various pyrethroids against susceptible and highly pyrethroid resistant strains of An. stephensi. Materials & Methods: Tests were carried out inside a mosquito cage measuring 25×25×25 cm where mosquitoes were offered the opportunity to feed blood on an arm through the top face of the cage which had been pyrethroid treated. Results: With all the pyrethroids tested, the resistant strain spent a longer time in contact with a treated net, which was in contact with a human arm, than did the susceptible strain. With permethrin the resistant strain fed significantly more successfully through the treated netting than did the susceptible strain. With deltamethrin there was a non-significant tendency in the same direction in comparing the two strains. However, with alphacypermethrin there was a non-significant tendency in the reverse direction. After 15 min in the cage which tested for the ability to feed through a pyrethroid treated net, observed mortality was higher with the susceptible than the resistant strain. Conclusion: Thus there was no sign that the longer resting of the resistant strain on treated netting would compensate for the fact that a higher dose was needed to kill this strain. Such compensation had been suggested with the West African An. gambiae where treated nets continue to work well against a highly resistant wild population. However this does not seem to apply to our resistant An. stephens

Background: Long-lasting insecticidal nets (LN) are an effective tool for malaria prevention. The World Health Organization Pesticide Evaluation Scheme has established evaluation criteria to facilitate registration for public use. A household randomised trial was conducted in Tanzania according to WHOPES Phase III procedures to evaluate the alpha-cypermethrin coated Interceptor® LN (BASF) over three years’ use. Outcomes were calibrated against results of Phase II experimental hut trials. Methods: Interceptor LN (200 mg/m2 alpha-cypermethrin) and conventionally treated nets CTN (40 mg/m2 alpha-cypermethrin) were randomly distributed to 934 households. At 6-monthly intervals, household surveys recorded net use, durability, adverse effects, user acceptance and washing practices. Concurrently, 30 nets of each type were collected and tested for knock-down and kill of Anopheles gambiae mosquitoes in cone and tunnel bioassays. Alpha-cypermethrin content of nets was assessed annually. Results: At 12 months 97 % of Interceptor LN met the efficacy criteria by cone or tunnel test; this pass rate declined to 90 % at 24 months and 87 % at 36 months. In contrast only 63 % of CTN met the efficacy criteria at 12 months, 14 % at 24 months and 0 % at 36 months. The alpha-cypermethrin content at 36 months on Interceptor LN was 20 % (42 ± 13 mg/m2) of the initial content but on CTNs only 4 % (1.3 ± 1.6 mg/m2) remained. Interceptor LN was reported to be used year-round and washed 4.3 times/year. A few recalled facial tingling during the first days of use but this did not deter usage. The average number of holes at 36 months was 18, hole area per net was 229 cm2 and hole index was 332. Insecticide content and cone bioefficacy of LN and CTN after 36 months’ use were similar to that of LN and CTN used in earlier Phase II hut trials, but while the 20 times washed LN tested in experimental huts gave adequate personal protection the 20 times washed CTN did not. Conclusions: More than 80 % Interceptor LN fulfilled the WHOPES Phase III criteria at 36 months and thus the LLIN was granted full WHO recommendation. Phase III outcomes at 36 months were anticipated by Phase II outcomes after 20 standardized washes. [ABSTRACT FROM AUTHOR]

The aims of this study were to assess the efficacy of alphacypermethrin (ACYP) on pediculosis due to Haematopinus tuberculatus and to evaluate the influence of the treatment on productive and reproductive performance in buffaloes (Bubalus bubalis) reared in an intensive system. The trial was performed on 56 pluriparous buffaloes at 86.8 ± 8.1 d in milk. The animals underwent individual louse count and were divided into 2 homogenous groups according to louse count, age, number of lactations, days in milk, live BW, BCS, pregnancy status, and milk yield. Group A (n = 28) was treated by a pour-on formulation of ACYP, and Group S (n = 28) was treated by pour-on saline solution. Individual louse counts were performed weekly on 10 buffaloes in each group. Feed intake was recorded daily and the total mixed ration, individual ingredients, and orts were analyzed to calculate DM ingestion. Individual milk yield was recorded daily and milk samples were analyzed at the beginning of the trial, after 4 wk, and at the end of the trial to assess milk composition. Individual BCS was also evaluated simultaneously. Finally, the animals underwent synchronization of ovulation starting 4 wk after treatment and the pregnancy rate and the calving-conception interval were evaluated. Data were analyzed by the Mann-Whitney test and ANOVA for repeated measures. The infestation was constant in Group S, whereas no lice were present in Group A throughout the study. Daily DMI was similar in the 2 groups (16.7 ± 0.4 vs. 16.3 ± 0.3 kg/d in Group A vs. Group S, respectively), although buffaloes in Group A showed higher (P < 0.05) BCS score at the end of the trial (7.39 ± 0.1 vs. 7.14 ± 0.1 in Group A vs. Group S, respectively). The average milk yield/buffalo was higher (P < 0.05) in Group A compared to Group S (10.58 ± 0.1 vs. 10.39 ± 0.1 kg in Group A vs. Group S, respectively) and this was mainly due to the higher milk production recorded in buffaloes at less than 75 d in milk (11.81 ± 0.1 vs. 11.45 ± 0.1 kg in Group A vs. Group S, respectively). Despite of a similar fertility rate (90.5 vs. 80.9% in Group A vs. Group S, respectively), a lower (P < 0.05) calving-conception interval was recorded in Group A compared to Group S (118 ± 16 vs. 177 ± 16 d in Group A vs. Group S, respectively). In addition to the pour-on treatment against pediculosis, productive and reproductive performance were also improved. This represents a significant improvement in dairy buffalo herd management. [ABSTRACT FROM AUTHOR]

Introduction. Despite the increased rates of infestations with I. ricinus (Ir) and D. reticulatus (Dr) ticks observed over the last decade, no effective control methods have been developed so far. The present study was focused on assessment of the action of pyrethroids on these both tick species. Materials and method. The different doses of four pyrethroids, i.e. deltamethrin - D (K-Othrine), permethrin - P (Copex WP), cypermethrin - C (Kordon 10WP), and alphacypermethrin - AC (Alfasekt 5SC) were tested. The LD50 for each tested compound was also determined for both tick species. Unengorged and engorged (maintained on rabbit skin) tick females were sprayed with 20 ml of 0.01563-0.50% solutions of the tested preparations. Results. The investigations showed that sensitivity of Ir and Dr to the tested pyrethroids, but the effects exerted by the different doses varied between both tick species and between engorged and unengorged females in these species. The strongest toxic effect on unengorged and engorged Ir and Dr females was exerted by D, whereas the effect of AC was weaker. The LD50 (in μg/1 g b.w.) of D, AC, C, and P for unengorged Ir and Dr females was, respectively, 55.4 and 25.5, 105.2 and 48.5, 225.9 and 197.7, and 553.8 and 380.8. In the case of engorged Ir and Dr females, the LD50 of AC, D, C, and P reached a value of 0.9453 and 0.2310, 1.0428 and 1.3533, 3.489 and 6.5662, and 8.3955 and 7.3940, respectively. Conclusions. The differences between the effects of the tested pyrethroids and their different doses on Ir and Dr highlight the necessity for development of a strategy for control of the tick species in different regions, based on investigations of their sensitivity to chemical compounds. [ABSTRACT FROM AUTHOR]

Floating row covers or insect-proof nets with fine mesh are effective at protecting vegetable crops against aphids but negatively impact plant health, especially under warm conditions. Furthermore, in control of cabbage insect pests, aphid parasitoids cannot enter the fine-mesh nets, leading to frequent aphid outbreaks. To surmount these difficulties, a 40-mesh-size repellent net treated with alphacypermethrin was studied in laboratory and field tests. Results showed both irritant and repellent effects of the alphacypermethrin-treated net on Myzus persicae (Sulzer) (Hemiptera: Aphididae) and its parasitoid Aphidius colenumi (Haliday) (Hymenoptera: Braconidae). Under field conditions, there were no pests on cabbage protected with the repellent net. The repellent net allowed combining a visual and repellent barrier against aphids. Because of this additive effect, repellent nets allowed covering cabbage permanently with adequate protection against all pests. [ABSTRACT FROM AUTHOR]

Traditional systems account for 95 % of the livestock produced in Burkina Faso. Tick infestation hampers livestock productivity in this area. However, little information exists on tick-control practices used by livestock farmers. We interviewed 60 stockbreeders working in traditional farming systems to obtain the first data on tick-control practices. Sixteen farmers (27 %) did not use conventional practices: seven removed ticks by hand or plastered cattle with dung or engine oil; nine farmers treated cattle with crop pesticides. Forty-four farmers (73 %) used mainly synthetic pyrethroids (SP; either alphacypermethrin or deltamethrin in 20 and 18 farms, respectively) and occasionally amitraz (N = 6). Intervals between treatments varied significantly depending on the chemical used: most farmers using crop pesticides (100 %), amitraz (100 %) or alphacypermethrin (80 %) adjusted tick-control to tick-burden, whereas farmers using deltamethrin tended more to follow a tick-control schedule. Perception of tick-control effectiveness significantly varied among practices: tick-control failures were more frequently reported by farmers using alphacypermethrin (55 %) than by those using either other conventional acaricides (17 %) or crop pesticides (0 %). We investigated whether this could indicate actual development of SP-resistance in cattle ticks. First, using the larval packet test technique, we confirmed that the computation of LC and LC was repeatable and remained stable across generations of the Rhipicephalus (Boophilus) geigyi Houndé laboratory strain. We then collected from the field fully-engorged female R. geigyi to evaluate the SP-resistance relative to the Houndé reference strain. We did not detect any case of SP-resistance in the field-derived R. geigyi ticks. [ABSTRACT FROM AUTHOR]

Background In Morocco, the main strategies of leishmaniasis vector control are based on environmental modifications. Use of local residual indoor spraying with synthetic pyrethroids is often envisaged. The need to evaluate this control method is essential. The current study was conducted to determine the efficacy of an alphacypermethrin IRS program against leishmaniasis vectors in an endemic area in the north of Morocco. Methods The survey was conducted in four neighbouring localities in three different districts in northern Morocco: Ait Chaib and Aichoun in Sefrou district, Bouassem (Boulmane) and Lmrouj (Taounate). Indoor residual spraying with alphacypermethrin at a dose of 30 mg/m² was used in Ait Chaib and Lmrouj localities during 2010, 2011 and 2012, while localities of Aichoun and Bouassem were taken as control. In the four studied areas, sand flies were collected bimonthly from April to November in 2011 and 2012, using sticky traps, to determine their abundance and feeding pattern. Alphacypermethrin IRS were evaluated for their residual effect using the WHO cone bioassay test. Leishmaniasis incidence was estimated by passive and active case detection in each study area. Results Significant reductions in leishmaniasis incidence and in gravidity rate were observed when comparing sprayed and unsprayed localities. The residual activity of alphacypermethrin at the concentration used lasted 10 weeks after spraying. However, the abundance of sand flies was not significantly affected by alphacypermethrin IRS. Conclusion This study indicated that IRS has a significant impact on leishmaniasis transmission; therefore it could be recommended as an effective tool for leishmaniasis control in areas with high leishmaniasis transmission. [ABSTRACT FROM AUTHOR]

Alphacypermethrin is a highly active pyrethroid insecticide effective against a wide range of pests in agriculture, public health and animal husbandry. In this study, doses of 4, 8, 16 and 32 mg/kg alphacypermethrin were prepared in corn oil (10%) and orally administered to four experimental groups (n = 10; 5 male and 5 female in each group) by gavage once daily for 90 days. Mortality and clinical findings together with behavioural changes in rats were observed daily, weekly and monthly during the study period. Death occurred in all experimental groups. No statistical difference was found in mean lifetimes between the control and 4 mg/kg group for both genders (p>0.05). However, mean lifetimes of 8, 16 and 32 mg/kg groups were statistically different from the control and 4 mg/kg groups (p<0.05) for both gender. Also, mean lifetimes of 8 mg/kg group were statistically different from the 16 and 32 mg/kg groups for both gender (p<0.05). Similar as other Type II pyrethroids, typical symptoms were seen in dead animals approximately 3 hours after the last dose. Alphacypermethrin caused reduction of body weights and feed consumption. In addition, it caused catatonia in two male rats in the 4 mg/kg group. No significant changes were determined in other observed behaviours. These findings indicate that the vehicle (corn oil) has a great influence on the toxicity of alphacypermethrin. Also, this research may be beneficial for the risk analysis of alphacypermethrin as well as a base for further research in this area. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined the potential neurobehavioral effects of topical alphacypermethrin in rats. The study included 40 adult Wistar rats that were randomly divided into four groups. Three groups were given 100, 200 and 300 milligrams per kilogram (mg/kg) b.w pyrethroid, while the last group received 70 percent alcohol. During the study period, weekly examination of pain sensitivity, motor coordination, body weights, locomotor activities and catatonia were made, while mortality and clinical signs were observed on a daily basis. The study found no clinical, behavioral and hematological change in rats treated with topical alphacypermethrin.

The application of insecticides and/or chemical growth regulators for the control of arthropod-induced silvertop (whitetop) and/or lodging in seed crops of common bent (syn. browntop, US: colonial bentgrass, Agrostis capillaris L. syn. A.tenuis Sibth.) ‘Leikvin’ was investigated in 12 on-farm trials laid out according to five different experimental plans in SE Norway from 1993 to 1997. Seed yields on plots sprayed with insecticides were significantly higher than on unsprayed control plots in three out of nine trials; however, these seed yield increases were poorly correlated with silvertop frequencies which varied from 1 to 60% on untreated plots. Differences between various insecticides (two pyrethroids and one organophosphorus compound) and single versus split applications were mostly not significant. While seed yields on plots sprayed with ethephone (‘Cerone’, 0.5 kg a.i. ha-1) were not significantly different from those on unsprayed control plots, chlormequat chloride (‘CCC 750’, 1.0 or 2.0 kg a.i. ha-1 plus surfactant) minimized lodging and increased seed yield by 21% on average for five trials. When chlormequat chloride and the pyrethroid α-cypermethrin were combined in a tank mixture including surfactant at the crop growth stage Z 31-32, the effects of the two products were mostly additive. Based on these results, the application of the growth regulator chlormequat chloride (1.0 kg a.i. ha-1) is now recommended in Norwegian seed production of common bent. Although the effects of insecticides were often not significant, seed growers are further advised to add an insecticide (e.g., α-cypermethrin, 150 g a.i. ha-1) to the growth regulator as a precaution against silvertop, which otherwise seems to appear quite randomly in seed production of common bent. [ABSTRACT FROM AUTHOR]

Photodegradation of alphacypermethrin ((RS)-α cyano-3-phenoxy benzyl (1RS) cis-3-(2,2,dichlorovinyl)-2,2-dimethyl cyclopropane carboxylate) was studied as a thin film on glass surface and on black and red soil surfaces. A number of photoproducts from glass surfaces have been isolated, characterized and identified by gas chromatography-mass spectroscopy (GC-MS). However, only two of them viz. 3-phenoxy benzyl alcohol and [2,2-dichlorovinyl-3(2,2,dimethyl) cyclopropane carboxylate] could be identified from both the soil. Rate of photodegradation on glass and soil surface under UV and sunlight followed first order kinetics with significant correlation coefficients. The rate of photodegradation was greater on black than on red soil. [ABSTRACT FROM AUTHOR]

Insecticide-treated bednets (ITNs) are commonly used as a means of personal protection from malaria transmission by anopheline mosquitoes (Diptera: Culicidae). Long-lasting insecticidal nets (LLINs) have special treatments intended to remain effective after many washes. The present trials assessed the efficacy and wash-resistance of several production batches of PermaNet™ (polyester net coated with polymer resin containing pyrethroid insecticide deltamethrin 55 mg ai/m2) against malaria vectors in Pakistan, Iran and Tanzania compared to ITNs conventionally treated with alphacypermethrin 15 or 20 mg ai/m2, or deltamethrin 25 or 50 mg ai/m2. Insecticidal efficacy of the nets before and after repeated washing (using W.H.O. recommended and traditional local washing procedures) was monitored through contact bioassays withAnophelesand by experimental hut and outdoor platform tests. Local washing regimes gradually reduced the insecticidal efficacy of conventionally treated nets, but they were not exhausted, even after 21 washes. Using a more rigorous laboratory washing method, insecticide was more readily stripped from conventionally treated nets. PermaNet retained high efficacy after 21 washes, giving more than 97% mortality ofAnophelesin contact bioassays with 3-min exposure. Using the more sensitive bioassay criterion of‘median time to knockdown’, PermaNet showed no loss of insecticidal activity againstAnophelesafter washing repeatedly in 2 out of 6 trials; whereas in a further three trials knockdown activity of PermaNet and conventional ITNs declined at comparable rates. Higher mortality levels ofAnophelesin contact bioassays did not always translate to superiority in experimental hut or enclosed platform trials. In only one of four comparative field trials did PermaNet out-perform conventional ITNs after washing: this was in the trial of PermaNet 2.0– the product with improved quality assurance. Because PermaNet and conventionally treated nets were both quite tolerant of local washing procedures, it is important in field trials to compare LLINs with conventional ITNs washed an equivalent number of times. Our comparison of PermaNet 2.0 against conventionally treated deltamethrin nets (CTDN) in Pakistan demonstrated superior performance of the LLIN after 20 washes in phase I and phase II bioassays, and this was corroborated by chemical assays of residual deltamethrin. Although PermaNet 2.0 has received WHOPESinterim recommendationfor malaria control purposes, its performance should be monitored in everyday use throughout its lifespan in various cultural settings to assess its durability and long-term effectiveness for malaria prevention and control. As many millions of conventionally treated nets are already in routine use, and these will require regular re-treatment, programme strategies should be careful to preserve the effectiveness of ITNS before and after establishing the reliability of LLINs in long-term use. [ABSTRACT FROM AUTHOR]

The joint action of pyrethroids deltamethrin and cypermethrins in combination with organophosphates ethion, profenofos, chlorpyrifos, quinalphos, and triazophos was studied on putatively resistant field populations of Helicoverpa armigera from Pakistan by using a leaf-dip method. Ethion produced a good potentiation with deltamethrin, cypermethrin, alphacypermethrin, and zetacypermethrin, whereas profenofos, chlorpyrifos, quinalphos, and triazophos exhibited an antagonism with deltamethrin as well as cypermethrins. Implications of using mixtures for counteracting insecticide resistance are discussed. [Copyright &y& Elsevier]

The efficacy against mosquitoes (Diptera: Culicidae) of a bednet treated with carbamate insecticide [carbosulfan capsule suspension (CS) 200 mg/m2] was compared with four types of pyrethroid-treated nets in veranda-trap huts at Yaokoffikro near Bouaké, Côte d'Ivoire, where the malaria vector Anopheles gambiae Giles carries the kdr gene (conferring pyrethroid resistance) at high frequency and Culex quinquefasciatus Say is also pyrethroid resistant. Pyrethroids compared were lambdacyhalothrin CS 18 mg/m2, alphacypermethrin water dispersible granules (WG) 20 mg/m2, deltamethrin 50 mg/m2 (Permanet™) and permethrin emulsifiable concentrate (EC) 500 mg/m2. Insecticidal power and personal protection from mosquito bites were assessed before and after the nets were used for 8 months and hand washed five times in cold soapy water. Before washing, all treatments except permethrin significantly reduced blood-feeding and all had significant insecticidal activity against An. gambiae. The carbosulfan net gave significantly higher killing of An. gambiae than all pyrethroid treatments except the Permanet. Against Culex spp., carbosulfan was more insecticidal and gave a significantly better protective effect than any of the pyrethroid treatments. After washing, treated nets retained various degrees of efficacy against both mosquito genera – but least for the carbosulfan net. Washed nets with three types of pyrethroid treatment (alphacypermethrin, lambdacyhalothrin, permethrin) gave significantly higher mortality rates of Culex than in huts with the same pyrethroid-treated nets before washing. After five washes, the Permanet™, which is sold as a long-lasting insecticidal product, performed no better than the other nets in our experimental conditions. [ABSTRACT FROM AUTHOR]

The impact of use of bed-nets treated with alphacypermethrin, at 20 mg (ai)/m2, in comparison to untreated nets or no nets on malaria vectors and malaria incidence was studied in tribal villages of Malkangiri district, Orissa state, India, which are highly endemic for falciparum malaria. Treated or untreated nets were supplied to the villagers in June 1999 and the nets were re-treated in September 1999, just before the rise in vector abundance and malaria incidence. The seasonal pattern of indoor resting Anopheles fluviatilis females was similar in all the three groups of villages before the start of intervention and the indoor resting catches were not significantly different between treatment-groups (two-way ANOVA, F=1.53; d.f.=(2, 78); P=0.2). During intervention, the indoor resting catches differed significantly among treatment groups (two-way ANOVA, F=38.9; d.f.=(2, 66); P<0.005). There was a 99% reduction in the indoor resting catches of An. fluviatilis in villages with treated nets and 61% reduction in villages with untreated nets compared with no-net villages. Comparison between villages with and without treated nets showed that there was 97% reduction in indoor resting catches in villages with treated nets. Pair-wise comparison showed that the reductions between villages with and without nets as well as between villages with treated and untreated nets were significant (Dunnett’s C-test, P<0.05). The indoor resting catches of Anopheles culicifacies did not differ significantly among the three groups of villages either before (F=0.99; d.f.=(2, 121); P=0.4) or during intervention (F=0.21; d.f.=(2, 66); P=0.8). Bioassay with 3 min exposure to treated bed nets showed 100% mortality of An. culicifacies for 2 months and with An. fluviatilis for 4.5 months after which tests were not carried out. In villages with treated nets, the Annual Parasite Incidence (API) significantly declined (P<0.05) by about 65.7% and prevalence of infection among children (<15 years) declined by 57.1%, whereas in villages with untreated nets, there was only 34% reduction in API and 13% in the prevalence of infection. In villages with treated nets, there was 48% reduction in API and 64% in prevalence of infection compared with villages with untreated nets. The impact of use of treated bed nets on other arthropod pests lasted for at least 1.5 months. After 1.5 months, observations on arthropod pests were not continued. The use rate of treated nets varied from 49.8 to 93.7% in three seasons and about 68.3% of treated bed nets and 60% of untreated nets were in good condition 1 year after distribution. Out of 489 users of treated net, five people complained of a burning sensation on the face (skin irritation) for 5 days following the distribution of treated nets. There were no other complaints of any discomfort in using the treated nets. The use of alphacypermethrin treated bed nets at 20 mg (ai)/m2 can be one of the options for reducing the vector abundance and incidence of malaria in this area. [Copyright &y& Elsevier]

Abstract Insecticide-treated bedding materials (sheets and blankets) could be protective against vectors of malaria and leishmaniasis - especially in complex emergencies, epidemics and natural disasters where people are more likely to sleep in exposed situations. Comparison of cotton top-sheets impregnated with different pyrethroids (permethrin 500 mg/m2 , deltamethrin 25 mg/m2 or alphacypermethrin 25 mg/m2 ) for effectiveness against mosquitoes (Diptera: Culicidae) was undertaken in a refugee camp in Pakistan. Predominant species encountered were Anopheles stephensi Liston, An. pulcherrimus Theobald, An. nigerrimus Giles, Culex quinquefasciatus Say, Cx. tritaeniorhynchus Giles and other culicine mosquitoes. All three pyrethroid treatments performed significantly better than the untreated sheets in deterrence and killing of mosquitoes. No significant differences were found between the three insecticides tested in terms of entomological effect. Washing of the treated sheets greatly reduced their effectiveness. In a user acceptance study conducted among 88 families (divided into four groups), six families complained of irritation of the skin and mucous membranes. Of these reports, one was from the placebo group (using untreated sheets) and the other five (5/22 = 23%) from families using deltamethrin-treated sheets. All families allocated to permethrin and alphacypermethrin groups declared an appreciation for the intervention and reported no side-effects. Ten of the placebo group disliked the intervention, citing no prevention of mosquito biting as the reason. Side-effects associated with deltamethrin indicate that alphacypermethrin and permethrin are more appropriate first choice insecticides for treatment of sheets and blankets. [ABSTRACT FROM AUTHOR]

We conducted a community-randomized controlled trial in Pakistan to determine the efficacy of indoor residual spraying with alphacypermethrin ('Fendona', Cyanamid, NJ, USA), applied at 25 mg/m2, to prevent falciparum and vivax malaria. Wettable powder (WP) and suspension concentrate (SC) formulations were tested against an unsprayed control in an irrigated rice-growing area of Sheikhupura district, Punjab province. The study area of 180 km2 was divided into nine sectors, which were assigned at random to control, WP, or SC treatments in replicates of 3. Sentinel villages were selected from each sector for entomological and disease monitoring. Malaria was monitored by fortnightly active case detection (ACD) and by cross- sectional parasite surveys on schoolchildren. Mosquito populations were monitored by space spraying of rooms and by cattle-landing catches. The spray campaign took place in June 1997 and covered 96% of compounds. During the 7 months after spraying, the incidence of falciparum malaria was 95% lower and that of vivax malaria 80% lower in WP-sprayed than unsprayed sectors. Similar results were obtained for sectors sprayed with the SC formulation. Cross-sectional surveys gave estimates of efficacy comparable to those obtained by ACD. Anopheles culicifacies was 80% less abundant and A.stephensi, the predominant anopheline, was up to 68% less abundant in sprayed areas over the 7-month period. Reductions in anopheline parous rates indicated that the single-spray treatment was effective for the entire transmission season. Sprayed surfaces lacked odour, which contributed to the popularity of the campaign. Alphacypermethrin is a promising insecticide for the control of malaria in Pakistan and South Asia generally. [ABSTRACT FROM AUTHOR]

SummaryThe efficacy of various pyrethroid insecticides for use on odour-baited targets to control tsetse was compared in Zimbabwe. Formulations were applied to cotton cloth and polyester net and, at various intervals, the materials were bio-assayed by exposing fed female Glossina pallidipes (Austen) (Diptera: Glossinidae) to cloth for 45 s or by inducing them to collide briefly with net. Trial formulations were compared with deltamethrin suspension concentrate (s.c.), the insecticide currently used in tsetse control operations in Zimbabwe. Applying 0.8% suspension of alphacypermethrin to cloth or net produced high mortalities for 9 months which was similar in performance to 0.4% suspension of deltamethrin s.c. Deltamethrin s.c. and β-cyfluthrin s.c. applied to cloth as 0.1% suspensions were equally effective, producing high mortalities for 2 months during the wet season, and 0.8% suspension of β-cyfluthrin was effective for 12 months. Suspensions of 0.1% lambdacyhalothrin capsule suspension or 0.1% lambdacyhalothrin wettable powder were significantly less effective than 0.1% deltamethrin s.c. Chemical analyses showed that increasing the concentration of insecticide applied to material increased the initial amount of insecticide on the material and decreased the subsequent rate of loss; 0.1% suspension of β-cyfluthrin s.c. applied to cloth produced an initial concentration of ≈ 280 mg/m2 which declined by 94% in 12 months whereas 0.8% suspension showed no significant decrease in concentration (mean = 1304 mg/m2) over the same period. For controlling tsetse by means of pyrethroid-treated targets, it is suggested that β-cyfluthrin s.c. is as effective as deltamethrin s.c. but that alphacypermethrin s.c. should be used at twice the concentration of deltamethrin s.c. to obtain the same performance. [ABSTRACT FROM AUTHOR]

Abstract Adult mosquitoes, Anopheles gambiae Giles and Culex quinquefasciatus Say (Diptera: Culicidae), were exposed for 3 min to replicate samples of polyester netting cut from replicate bednets treated with pyrethroid insecticide formulations at the recommended concentration (alphacypermethrin SC at 40 mg ai/m2 ; cyfluthrin EW at 50 mg ai/m2 ; deltamethrin WT at 25 mg ai/m2 ), or treated with only a quarter of those dosages. After 4 months domestic use of the bednets in Malawi, chemical assays showed that pyrethroid deposits on the netting were somewhat less than the target concentrations. Comparing the pyrethroid bioassay results with Anopheles at both treatment concentrations, deltamethrin gave significantly higher mortality (99.7–100%) than the other compounds (alphacypermethrin 94–96%, cyfluthrin 80–89%). Culex bioassay mortality was lower (alphacypermethrin 56–74%; cyfluthrin 63–65%; deltamethrin 50–81%) and results with the three pyrethroid insecticides at their recommended doses did not differ significantly. [ABSTRACT FROM AUTHOR]

We sprayed, in three groups of Domiciliary Units, 10 and 15 g of alphacypermethrin and 31.3 g of cypermethrin per pump of 10 liters, equivaling, if applied on 250 [squared meters), respectiveliy, to 60 and 40 mg of a alphacypermethrin [per squared meter] and 125,2 mg of cypermethrin [per squared meter]. The invasion, colonization and cumulative indices in the houses and the positivity index in shelters near houses were very low and similar in the three groups, in the 15 months of evaluation, indicating that alphacypermethrin can replace cypermethrin. Triatoma infestans predominated in the Domiciliary Units before treatment and T. brasiliensis and T. pseudomaculata predominated after it.