Effect of cypermethrin on the control of lesser mealworm (Alphitobius diaperinus) and broiler performance / Efeito da cipermetrina no controle de cascudinho (Alphitobius diaperinus) sobre o desempenho de frangos de corte

This study analysed the effectiveness of using different levels of a product based on 6% cypermethrin and 2% citronella on broiler production and control the lesser mealworm (Alphitobius diaperinus). A total of 648 one-day-old chicks (Cobb®) which were allocated to one of three treatments (no application of the commercial product - control, and two concentrations of the product 2.00 and 3.33g/m2) in eight replicates with 27 birds each. The commercial product, which was based on cypermethrin was applied in the chambers with an atomizer. The lesser mealworm population was sampled weekly (1, 7, 14, 21, 28, 35 and 42 days of the experiment) using traps, at three points (front, middle and back) inside the pen. The performance, carcass and cut yields were evaluated. At 21, 28, 35 and 42 days of the experiment, the number of lesser mealworm adults and larvae was lower in the treatment groups involving 2.00 and 3.33g/m2 of the product than in the control group. On the first and 14th days of the study, the number of lesser mealworms adults was lower in the group treated with 3.33g/m2 of the product compared to the control group, although the results did not differ statistically from those obtained with 2.00g/m2 of the product. In conclusion, the application of the commercial product at both concentrations (2.00 and 3.33g/m2) was effective in combating Alphitobius diaperinus adults and larvae, and the performance was not influenced by treatments.(AU)

Este estudo analisou a eficácia do uso de diferentes níveis de um produto à base de cipermetrina a 6% e citronela a 2%, na produção de frangos de corte e no controle do cascudinho (Alphitobius diaperinus). Um total de 648 pintos de um dia de idade (Cobb®) foram distribuídos em três câmaras com os tratamentos (sem aplicação do produto comercial - controle, e duas concentrações do produto comercial - 2,00 e 3,33g/m2) em oito repetições com 27 aves cada. O produto comercial a base de cipermetrina foi aplicado nas câmaras com um atomizador. A população de cascudinho foi amostrada semanalmente (1, 7, 14, 21, 28, 35 e 42 dias do experimento) usando armadilhas, em três pontos (frente, meio e fundo) de cada parcela. Foram avaliados o desempenho, rendimentos de carcaça e cortes. Aos 21, 28, 35 e 42 dias do experimento, o número de adultos e larvas de cascudinho foi menor nos grupos de tratamento envolvendo 2,00 e 3,33g/m2 do produto quando comparado ao grupo controle. No primeiro e no 14º dia do estudo, o número de cascudinhos adultos foi menor no grupo tratado com 3,33g/m2 do produto em comparação ao grupo controle, embora os resultados não tenham diferido estatisticamente daqueles obtidos com 2,00g/m2 do produto. A conversão alimentar de 1 a 21 dias de idade foi significativa, com os melhores resultados para essa variável quando aplicado 3,33g do produto por metro quadrado e no tratamento controle. Em conclusão, a aplicação do produto comercial em ambas as concentrações (2,00 e 3,33g/m2) foi eficaz no combate a adultos e larvas de Alphitobius diaperinus e, não influenciou o desempenho.(AU)

Avaliação da efetividade do uso de coleiras impregnadas com deltametrina no controle da leishmaniose visceral no município de Votuporanga, Estado de São Paulo, Brasil, 2014 ­ 2016 / Evaluation of the effectiveness of using deltamethrinimpregnated collars to control visceral leishmaniasis in the municipality of Votuporanga, State of São Paulo, Brazil, 2014 ­ 2016

O objetivo deste artigo é apresentar os principais resultados do Projeto de Inovação Tecnológica em Saúde realizado entre 2014 e 2015, destacando-se o uso de coleiras impregnadas com deltametrina a 4% em cães em uma região endêmica para leishmaniose visceral (LV), o município de Votuporanga, São Paulo, Brasil. Neste município, anterior à realização do projeto, eram registrados muitos casos caninos e humanos da doença, com elevada taxa de letalidade. Durante o projeto, foram monitorados cerca de 16,5 mil cães, examinadas 25.700 amostras de sangue, considerando-se as perdas e as entradas de novos animais durante os quatro inquéritos sorológicos. Após sua finalização, verificou-se uma diminuição da prevalência e incidência de LV canina, assim como do número de casos humanos. A diminuição dos casos caninos foi correlacionada positivamente aos casos humanos no período de 2011 a 2016 (Correlação de Pearson de 0.914, p-valor<0.05). Além disso, a análise espacial dos resultados corrobora a diminuição ou desaparecimento da concentração de casos caninos e, consequentemente, de fontes e de infecção nas áreas endêmicas à medida que avançaram no tempo e espaço as diferentes etapas de desenvolvimento do projeto. Apesar da drástica redução na incidência da LV canina, ainda permaneceram algumas áreas críticas. Os resultados delineados sugerem a revisão de protocolos e manuais demonstrando a efetividade do uso das coleiras como medida preventiva e potencial no controle da LV. (AU)

This paper aims to present the main results of the Health Technology Innovation Project carried out between 2014 and 2015, which evaluates the use of 4% deltamethrin-impregnated collars in dogs, in an endemic region for visceral leishmaniasis (VL), the municipality of Votuporanga, São Paulo, Brazil. Before this project, Votuporanga had notified canine and human cases of the disease, with a high case fatality rate. We monitored approximately 16.5 thousand dogs, 25,700 blood samples analyzed, considering losses and entrances of new animals during the four serological surveys. After the project, the prevalence and incidence of canine VL decreased as well as the number of human cases. We found a positive correlation between the decrease of infected dogs and human cases from 2011 to 2016 (Pearson correlation of 0.914, p-value <0.05). Furthermore, the spatial analysis of the results indicated areas with canine cases concentration that decreased its intensity or disappeared concomitantly to the project levels in the space-time. Despite the drastic reduction in the incidence of canine VL, some critical areas remain. The current results suggest the review of protocols and manuals demonstrating the effectiveness of the use of collars as a preventive measure and potential in the control of VL. (AU)

Avaliação da efetividade do uso de coleiras impregnadas com deltametrina no controle da leishmaniose visceral no município de Votuporanga, Estado de São Paulo, Brasil, 2014 – 2016 / Evaluation of the effectiveness of using deltamethrinimpregnated collars to control visceral leishmaniasis in the municipality of Votuporanga, State of São Paulo, Brazil, 2014 – 2016

O objetivo deste artigo é apresentar os principais resultados do Projeto de Inovação Tecnológica em Saúde realizado entre 2014 e 2015, destacando-se o uso de coleiras impregnadas com deltametrina a 4% em cães em uma região endêmica para leishmaniose visceral (LV), o município de Votuporanga, São Paulo, Brasil. Neste município, anterior à realização do projeto, eram registrados muitos casos caninos e humanos da doença, com elevada taxa de letalidade. Durante o projeto, foram monitorados cerca de 16,5 mil cães, examinadas 25.700 amostras de sangue, considerando-se as perdas e as entradas de novos animais durante os quatro inquéritos sorológicos. Após sua finalização, verificou-se uma diminuição da prevalência e incidência de LV canina, assim como do número de casos humanos. A diminuição dos casos caninos foi correlacionada positivamente aos casos humanos no período de 2011 a 2016 (Correlação de Pearson de 0.914, p-valor<0.05). Além disso, a análise espacial dos resultados corrobora a diminuição ou desaparecimento da concentração de casos caninos e, consequentemente, de fontes e de infecção nas áreas endêmicas à medida que avançaram no tempo e espaço as diferentes etapas de desenvolvimento do projeto. Apesar da drástica redução na incidência da LV canina, ainda permaneceram algumas áreas críticas. Os resultados delineados sugerem a revisão de protocolos e manuais demonstrando a efetividade do uso das coleiras como medida preventiva e potencial no controle da LV.

This paper aims to present the main results of the Health Technology Innovation Project carried out between 2014 and 2015, which evaluates the use of 4% deltamethrin-impregnated collars in dogs, in an endemic region for visceral leishmaniasis (VL), the municipality of Votuporanga, São Paulo, Brazil. Before this project, Votuporanga had notified canine and human cases of the disease, with a high case fatality rate. We monitored approximately 16.5 thousand dogs, 25,700 blood samples analyzed, considering losses and entrances of new animals during the four serological surveys. After the project, the prevalence and incidence of canine VL decreased as well as the number of human cases. We found a positive correlation between the decrease of infected dogs and human cases from 2011 to 2016 (Pearson correlation of 0.914, p-value <0.05). Furthermore, the spatial analysis of the results indicated areas with canine cases concentration that decreased its intensity or disappeared concomitantly to the project levels in the space-time. Despite the drastic reduction in the incidence of canine VL, some critical areas remain. The current results suggest the review of protocols and manuals demonstrating the effectiveness of the use of collars as a preventive measure and potential in the control of VL.

Efficacy of commercial synthetic pyrethroids and organophosphates associations used to control Rhipicephalus (Boophilus) microplus in Southern Brazil / Eficácia de associações comerciais entre piretroides sintéticos e organofosforados utilizados no controle de Rhipicephalus (Boophilus) microplus na Região Sul do Brasil

Abstract This study evaluated the acaricidal efficiency of synthetic pyrethroids (SP) associated with organophosphates (OP) against Rhipicephalus (Boophilus) microplus populations in the state of Rio Grande do Sul, Southern Brazil. Ticks were collected in 54 cattle farms and tested using in vitro adult immersion test against four commercially available acaricide mixtures of SP and OP. Only one of four acaricides, comprising a mixture of cypermethrin, chlorpyrifos, and fenthion, had a mean efficiency higher than 95%, and was effective in 94.44% (51/54) of the cattle farms tested. The acaricide with a mixture of cypermethrin, chlorpyrifos, and citronelall had the lowest mean efficiency (62.11%), and was effective in 29.62% (16/54) of cattle farms tested. Furthermore, R. (B.) microplus in Southern Brazil exhibited differing degrees of resistance to SP and OP mixtures. The results suggest that the presence of fenthion contributes to the higher efficiency of the formulation with this active principle. This is possibly due to its recent commercial availability, as tick populations have been lower challenged with this product. Monitoring the resistance of ticks to carrapaticides is essential to maximize the efficiency of these products in the control of R. (B.) microplus.

Resumo Este estudo avaliou a eficiência acaricida de piretroides sintéticos (SP) associados a organofosforados (OP) sobre populações de Rhipicephalus (Boophilus) microplus no estado do Rio Grande do Sul, Brasil. Carrapatos foram coletados em 54 fazendas de bovinos, testados in vitro pelo teste de imersão de teleóginas, contra quatro associações acaricidas comercialmente disponíveis de SP e OP. Apenas um dos quatro acaricidas, constituído por associação de cipermetrina, clorpirifós e fenthion, teve eficiência média superior a 95%, sendo eficaz em 94,44% (51/54) das fazendas testadas. O acaricida com associação de cipermetrina, clorpirifós e citronelal teve menor eficiência média (62,11%), sendo efetivo em 29,62% (16/54) das fazendas testadas. Além disso, o R. (B.) microplus no sul do Brasil, apresentou diferentes graus de resistência às associações de SP e OP. Os resultados sugerem que a presença do fenthion contribui para a maior eficiência da formulação com esse princípio ativo. Possivelmente, isso ocorre em função da sua recente introdução no mercado, já que as populações de carrapatos foram pouco desafiadas com este produto. Monitorar a resistência dos carrapatos aos carrapaticidas é fundamental para maximizar a eficiência desses produtos no controle de R. (B.) microplus.

Where do these bugs come from? Phenotypic structure of Triatoma infestans populations after control interventions in the Argentine Chaco

House re-invasion by native triatomines after insecticide-based control campaigns represents a major threat for Chagas disease vector control. We conducted a longitudinal intervention study in a rural section (Area III, 407 houses) of Pampa del Indio, northeastern Argentina, and used wing geometric morphometry to compare pre-spray and post-spray (re-infestant bugs) Triatoma infestans populations. The community-wide spraying with pyrethroids reduced the prevalence of house infestation by T. infestans from 31.9% to < 1% during a four-year follow-up, unlike our previous studies in the neighbouring Area I. Two groups of bug collection sites differing in wing shape variables before interventions (including 221 adults from 11 domiciles) were used as a reference for assigning 44 post-spray adults. Wing shape variables from post-spray, high-density bug colonies and pre-spray groups were significantly different, suggesting that re-infestant insects had an external origin. Insects from one house differed strongly in wing shape variables from all other specimens. A further comparison between insects from both areas supported the existence of independent re-infestation processes within the same district. These results point to local heterogeneities in house re-infestation dynamics and emphasise the need to expand the geographic coverage of vector surveillance and control operations to the affected region.

Controle da leishmaniose visceral no município de Porteirinha, estado de Minas Gerais, no período de 1998 a 2003 / Control of visceral leishmaniasis in the town of Porteirinha, state of Minas Gerais, Brazil, from 1998 to 2003

INTRODUÇÃO: No município de Porteirinha, Estado de Minas Gerais, foram registrados 23 casos humanos de leishmaniose visceral (LV) nos anos de 1998 e 1999. MÉTODOS: Foi realizado um estudo envolvendo a tríade de ações preconizadas no controle da LV. Pacientes com leishmaniose humana foram tratados e cães sorologicamente positivos foram eutanasiados, trimestralmente. O inseticida piretróide α-cipermetrina foi aplicado nos bairros onde casos humanos foram registrados. RESULTADOS: Houve uma redução da soroprevalência canina e de flebotomíneos capturados, após a implementação das medidas de controle, refletindo na diminuição de casos humanos de leishmaniose visceral. CONCLUSÕES: Os resultados mostraram a eficiência destas medidas quando empregadas em conjunto.

INTRODUCTION: In the town of Porteirinha, State of Minas Gerais, 23 human cases of visceral leishmaniasis (VL) in 1998 and 1999 were recorded. METHODS: A study was conducted involving the triad of action recommended for the control of VL. Patients were treated and serologically positive dogs were euthanized quarterly. The pyrethroid insecticide α-cypermethrin was applied in the neighborhoods where human cases were recorded. RESULTS: A reduction in canine seroprevalence and sand flies occurred following the implementation of control measures, reflecting in a reduction in human cases of VL. CONCLUSIONS: The results show the efficiency of such control measures when used in association.

Comparative performance of imagicides on Anopheles stephensi, main malaria vector in a malarious area, southern Iran.

BACKGROUND & OBJECTIVES: Jiroft district has subtropical climate and prone to seasonal malaria transmission with annual parasite index (API) 4.2 per 1000 in 2006. Anopheles stephensi Liston is a dominant malaria vector. The monitoring of insecticide susceptibility and irritability was conducted using discriminative dose as described by WHO. METHODS: The IV instar larvae were collected from different larval breeding places and transported to the temporary insectary, fed with Bemax and then 2-3 days-old emerged and sugar-fed adults were used for susceptibility and irritability tests employing WHO methods and kits to organochlorine (OC) and pyrethroid (PY) insecticides. RESULTS: Mortality rates of field strain of An. stephensi were 91.3 +/- 0.14 and 90 +/- 0.47% to DDT and dieldrin, respectively at one hour exposure time but was susceptible to all pyrethroids tested. The average number of take-offs per min per adult was 2.09 +/- 0.13 for DDT, 0.581 +/- 0.05 for dieldrin, 1.85 +/- 0.08 for permethrin, 1.87 +/- 0.21 for lambda-cyhalothrin, 1.53 +/- 0.13 for cyfluthrin, and 1.23 +/- 0.1 for deltamethrin. INTERPRETATION & CONCLUSION: Currently, deltamethrin is being used for indoor residual spraying against malaria vectors in the endemic areas of Iran. The findings revealed that the main malaria species is susceptible to all pyrethroids including deltamethrin, permethrin, cyfluthrin and lambda-cyhalothrin but was tolerant to DDT and dieldrin. This report and the finding are coincided with results of previous studies carried out during 1957-61 in the same area. Irritability tests to OC and PY insecticides revealed the moderate level of irritability to DDT compared to pyrethroids and dieldrin. Monitoring for possible cross-resistance between OC and PY insecticides should come into consideration for malaria control programme.

Efecto de dosis única intraperitoneal de cipermetrina en la corteza cerebral somatosensorial de ratones CF- 1 / Effect of a single doses intraperitoneal of cypermethrin in brain somatosensory area of mice CF-1

La cipermetrina es un pesticida ampliamente utilizado en agricultura y en salud pública. Sus efectos histopatológicos a nivel de sistema nervioso central han sido poco estudiados, aún cuando se han demostrado casos de intoxicación en humanos, con importante compromiso neurológico. El propósito de este trabajo es conocer los efectos de una dosis única intraperitoneal de cipermetrina sobre la morfología neuronal de corteza somatosensorial (láminas superficiales y profundas) de ratones CF-1. 35 ratones fueron separados en tres grupos: control (n=5), control vehículo (n=15) y experimental (n=15); los dos últimos grupos sacrificados los días 1, 8, 18, 26 y 35, en grupos de a tres. Los encéfalos fueron removidos, fijados, y procesados con técnica de rutina, para un análisis morfométrico. Análisis estadístico con Kruskal Walli's test. Fueron evidenciadas alteraciones morfológicas correspondientes a muerte neuronal en todas las láminas estudiadas, a los distintos intervalos de tiempo.

The cypermethrin is a pesticide widely used in agriculture and public health. Their histopathological effects at central nervous system level, little have been studied, even though has demonstrated cases of poisoning in humans with important neurological commitment. The aim of this work is to know the effects a intraperitoneal single dose of cypermethrin on neuronal morphology of somatosensory cortex (superficial and deep laminae) of mice CF-1. 35 mice were separated in three groups: control (n=5), control vehicle (n=15) and experimental (n=15); the two last sacrificed groups 1, 8, 18, 26 and 35 days, three animals per group. The brain were removed, fixed, and process with routine technique, for a morphometric analysis. Statistical analysis with Kruskal Wallís test. We demonstrated corresponding morphologic alterations until death neuronal, in all studied laminae, at the different time intervals.

Controle da leishmaniose visceral em meio urbano: estudo de intervenção randomizado fatorial / Control of visceral leishmaniasis in urban areas: randomized factorial intervention trial

O objetivo deste trabalho foi avaliar a efetividade do controle vetorial e da eliminação de cães infectados na incidência de infecção por Leishmania chagasi. Um estudo de intervenção comunitário foi realizado em Teresina entre 1995 e 1996. A área foi dividida em 34 lotes alocados aleatoriamente a 4 tipos de intervenção: 1) borrifação intradomiciliar e de anexos residenciais; 2) borrifação intradomiciliar e eliminação de cães infectados; 3) combinação de borrifação intradomiciliar e de anexos e eliminação canina; 4) apenas borrifação intradomiciliar. Em comparação com lotes que receberam apenas borrifação intradomiciliar, a eliminação canina diminui em 80 por cento a incidência de infecção. A borrifação de anexos, associada ou não à eliminação canina, não apresentou efeito significativo. A proteção oferecida pela remoção de cães infectados sugere que esta estratégia pode reduzir o pool de fontes de infecção para flebotomíneos.

The objective of this study was to evaluate the effect of vector control and elimination of infected dogs on the incidence of infection with Leishmania chagasi. A randomized community intervention trial was carried out in Teresina between 1995 and 1996. The area was divided in 34 blocks randomically allocated to 4 types of intervention: 1) spraying houses and animal pens with insecticide; 2) spraying houses and eliminating infected dogs; 3) combination of spraying houses and animal pens, and eliminating infected dogs, and 4) only spraying houses. In comparison to blocks receiving only household spraying, culling dogs decreased in 80 percent the incidence of infection. Spraying animal pens, associated or not with culling dogs, showed no significant effect. The protection offered by culling dogs suggests that this strategy might reduce the source of infection for the vector.

Comparative field evaluation of residual-sprayed deltamethrin WG and deltamethrin WP for the control of malaria in Pahang, Malaysia.

The bioefficacy of indoor residual-sprayed deltamethrin wettable granule (WG) formulation at 25 mg a.i./m2 and 20 mg a.i./m2 for the control of malaria was compared with the current dose of 20 mg/m2 deltamethrin wettable powder (WP) in aboriginal settlements in Kuala Lipis, Pahang, Malaysia. The malaria vector has been previously identified as Anopheles maculatus. The assessment period for the 20 mg/m2 dosage was six months, but for the 25 mg/m2 dosage, the period was 9 months. Collections of mosquitoes using the bare-leg techniques were carried out indoors and outdoors from 7:00 PM to 7:00 AM. All mosquitoes were dissected for sporozoites and parity. Larval collections were carried out at various locations to assess the extent and distribution of breeding of vectors. A high incidence of human feeds was detected during May 2005 and a low incidence during January 2005 for all the study areas. Our study showed that deltamethrin WG at 25 mg/m2 suppressed An. maculatus biting activity. More An. maculatus were caught in outdoor landing catches than indoor landing catches for all the study areas. The results indicate that 25 mg/m2 WG is good for controlling malaria for up to 9 months. Where residual spraying is envisaged, the usual two spraying cycles per year with 20 mg/m2 deltamethrin may be replaced with 25 mg/m2 deltamethrin WG every 9 months.

Ultra low volume aerosol application of deltacide (deltamethrin 0.5% w/v, S-bioallethrin 0.71% w/v & piperonyl butoxide 8.9% w/v) against mosquitoes.

BACKGROUND & OBJECTIVE: Insecticide in the form of space spray as an ultra low volume (ULV) aerosol are used during epidemics of vector borne diseases. Deltacide, a formulation comprising of three chemicals viz., deltamethrin 0.5 per cent w/v, S-bio-allethrin 0.71 per cent w/v and piperonyl butoxide 8.9 per cent w/v is suitable for ULV application. As this combination is found to be effective in preventing resistance development tackling the population, which had already developed resistance and cause immediate mortality, its synergistic effect was tested in Peet Grady chamber, against three species of mosquitoes, viz., Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. METHODS: Blood fed females were exposed to ULV application of deltacide in a Peet Grady chamber at four dosages viz., 0.005, 0.01, 0.02 and 0.04 ml/m2 and examined for knockdown activity at 10 min interval for 60 min. Thereafter, the mosquitoes were removed from the chamber and maintained in another room having controlled temperature (28+/-2 degrees C) and humidity (60-75%) and observed for recovery, if any, and the per cent knockdown was calculated. Mortality rate after 24 h of holding period was also determined from moribund and dead adults. RESULTS: Pairwise comparison showed that the effect of deltacide spray varied significantly (P<0.001) among the three species tested. The effectiveness was significantly higher in Ae. aegypti, when compared with that of Cx. quiquefasciatus (P<0.001) and An. stephensi (P<0.05). However, there was no significant difference in the efficacy of deltacide between Cx. quiquefasciatus and An. stephensi. All species of mosquitoes became inactive i.e., knocked down completely within 60 min of exposure at all the dosages tested and mortality observed was 100 per cent after 24 h of exposure. INTERPRETATION & CONCLUSION: Deltacide when tested in the form of ULV cold aerosol, the dosage 0.01 ml/m2 was effective against both Ae. aegypti, and An. stephensi, and 0.02 ml/m2 against Cx. quiquefasciatus, causing 100 per cent mortality. The efficacy of ULV application of deltacide against vector mosquitoes needs to be assessed under field conditions.

Evaluation of bifenthrin treated mosquito nets against anopheline and culicine mosquitoes.

BACKGROUND AND OBJECTIVES: The main rural malaria vector Anopheles culicifacies has developed resistance to dichloro diphenyl trichloroethane (DDT), hexachloro cyclo hexane (HCH) and malathion in the state of Haryana in northern India. An alternative synthetic pyrethroid insecticide bifenthrin was therefore evaluated on mosquito nets against anopheline and culicine mosquitoes, in two villages Jagdishpur and Garh Mirakpur of Community Health Center (CHC) Badhkhalsa in district Sonipat, Haryana state. METHODS: Two formulations of bifenthrin, suspension concentrate (SC) and micro-emulsion (ME) were compared with micro-capsule suspension (CS) of lambdacyhalothrin. The impact of three doses of bifenthrin (10, 25 and 50 mg/m(2)) impregnated on mosquito nets was compared with lambdacyhalothrin (25 mg/m(2)) and untreated control. Quality assessment of treatment on treated nets was carried out by residue analysis and the persistence of the insecticide on nets was determined by contact bioassays. Efficacy of treated nets on mosquito density was assessed by calculating mosquito entry rate, immediate mortality, delayed mortality and excito-repellency to the insecticides. RESULTS: In susceptibility tests An. culicifacies was susceptible to bifenthrin (0.1% test papers) and to lambdacyhalothrin (0.05% test papers). Bioassays on treated nets against A. culicifacies recorded 100 per cent mortality up to tenth fortnight for all the doses of impregnation with bifenthrin (SC and ME) and lambdacyhalothrin (CS). Ring-net bioassays against An. culicifacies showed median knock-down time between 3.1 to 11.4 min. Behavioural indices were also studied for anopheline and culicine mosquitoes. The reduction in entry rates of anopheline and culicine mosquitoes into the rooms with treated nets compared to control indicated good efficacy with all the formulations and doses of the insecticides. INTERPRETAION AND CONCLUSION: Indoor (immediate) mortality of mosquitoes with bifenthrin ME formulation was relatively lower compared to SC fomulation of bifenthrin and based on delayed mortility and continued susceptibility in bioassays, bifenthrin ME at the rate of 10 mg/m(2) dose was found suitable for the impregnation of mosquito nets for phase III trial.

Bioaccumulation of fenvalerate technical grade in different organs of the frog Haplobatrachus tigerinus (Daudin).

Bioaccumulation studies of fenvalerate were conducted on Indian bullfrog Haplobatrachus tigrinus (Daudin) after exposure to sublethal intraperitoneal dose of technical grade fenvalerate (1/3 LD50 i.e. 116.66 microg/kg body weight) at 3, 6, 12, 24, 48 and 72 hours schedule. The tissues viz., muscle, liver, kidney, testis, brain, and whole body accumulation was analysed for residue estimations. In all the tissues, analysed maximum residue was recovered in the initial stages of exposure (3 and 6 hours). However, in brain the residues remained up to 72 hours. In the whole body, analysis after 3 hours of exposure 78.65% residue was recovered and by the time 72 hours passed only, 9.4% residue was recovered. The decline in residue levels along with the period of exposure indicates the fast acting nature of fenvalerate and metabolites.

Baixa aderência e alto custo como fatores de insucesso do uso de mosquiteiros impregnados com inseticida no controle da malária na Amazônia Brasileira / Low adherence and high cost as failure factors of impregnated bed nets with inseticide for malaria control in the Brazilian Amazon

Em 1992, durante um ensaio com mosquiteiros impregnados com deltametrina, condurido em Porto Murtinho, município de Costa Marques, Rondônia, na Amazônia Brasileira, analisou-se a aderência e os fatores econômicos capazes de reduzir o impacto do uso de mosquiteiros impregnados sobre a morbidade da malária. Os mosquiteiras impregnados tiveram excelente receptividade pela populaçäo local. No entanto, a aderência foi muito baixa, principalmente pelos adultos maiores de 15 anos de idade e, durante a estiagem. O preço do mosquiteiro impregnado foi calculado em US$18,83 para casal e, em US$13,82, para solteiro. Apesar das vantagens econômicas do emprego dos mosquiteiras impregnados em larga escala, desde que subsidiados pelas agências governamentais, a baixa aderência verificada, aliada aos fatores epidemiológicos locais, näo permitem indicar o uso de mosquiteiros impregnados como medida de proteçäo em massa na Amazônia

Flit-gun sprayer characteristics

Six flit-gun sprayers were tested for possible use in mosquito adulticide programs where inexpensive nonmotorized application technology may be required. An analysis of variance for differences in droplets ≤ 24 microns (µ), droplets ≥ 48 µ, droplets/cm2, volume median diameters, and mosquito mortality is provided. As shown by these data, good results can be achieved with this equipment.

Se pusieron a prueba seis atomizadores de compresión activados a mano a fin de evaluar su utilidad para programas de exterminio de mosquitos adultos en que se necesiten tecnologías no motorizadas de bajo costo. Se hace un análisis de la varianza en cuanto a partículas ≤ 24 y ≥ 48 micras (µ), partículas/cm2, diámetro del volumen mediano, y número de mosquitos muertos. Los datos confirman que pueden obtenerse buenos resultados con aparatos de este tipo.

Laboratory evaluation on the toxic effects of bednets impregnated with permethrin against malaria mosquitos.

In the laboratory, bednets impregnated with 250mg ai/m2 and 500mg ai/m2 permethrin caused respectively the mean mortalities of 86.6% within 13 months and 87.2% within 17 months on laboratory-bred An. sinensis, while they caused average mortalities of 58.3% within 4 months and 73.8% within 10 months on An. dirus respectively. The bioassay results of KT50 and LT50 on the two species showed that KT50 is shorter than LT50 after exposure to the treated bednets. The ratio is 1:2.16 - 1:3.05. It was observed Anopheles had obviously secondary knocked down after exposure to the treated bednets and there is obvious resurgent after Anopheles have been knocked down. When the temperature goes up the resurgence gets shorter, the resurgence rate gets higher and the mortality gets lower. It showed that permethrin has stronger knocking down effect than killing effect.

Estudo sobre o uso de mosquiteiros impregnados com deltametrina em uma área endêmica de malária na Amazônia Brasileira / Study regarding the value of mosquito-nets impregnated with deltamethrin in malaria endemic area in Amazon region of Brazil

Uma investigação sobre mosquiteiros impregnados com deltametrina foi efetuada no município de Costa Marques, Rondônia, em 1992. Em fevereiro de 1992, em um grupo de 20 moradias na localidade de Porto Murtinho, situada à margem direita do Rio São Miguel, foram instalados mosquiteiros impregnados e, em outro grupo de 20 casas, na mesma localidade, mosquiteiros não impregnados. Um grupo controle de 20 residências, sem usar mosquiteiros de qualquer tipo, foi escolhido na localidade de Aguas Francas, às margens da BR-429, que liga Costa Marques a Presidente Medici, Rondônia. Os mosquiteiros fechados, de pano de algodão, foram impregnados pelo método da borrifação, ou "spray", com deltametrina, na dosagem de 20mg/m². Após distribuídos os mosquiteiros em fevereiro de 1992, foram feitas revisões clínicas, parasitológicas e entomológicas, a cada dois meses, até fevereiro de 1993, completando um ano de observação. Os resultados dessas revisões pós intervenção foram comparados com a situação pré-intervenção em cada grupo e, entre os grupos de mosquiteiros impregnados e de não impregnados. Os mosquiteiros impregnados se comportaram de modo semelhante aos não impregnados, sem modificar os índices de infecção na época de baixa transmissão. A análise multivariada, por idade e títulos de anticorpos, mostrou uma proteção significantemente maior para o grupo com mosquiteiros impregnados contra o risco de infecção, apenas na estação de alta transmissão, quando os mosquiteiros foram usados mais regularmente. Não houve diferença no efeito de ambos os tipos de mosquiteiros na prevenção de elevadas parasitemias. A redução da prevalência de malária em Porto Murtinho em 1992, comparada ao ano anterior, reflete a diminuição progressiva dos indíces malariométricos em Rondônia e em Costa Marques, desde 1987. Ao fim do estudo, houve diminuição da prevalência de esplenomegalia em ambos os grupos com mosquiteiros. O uso de mosquiteiros impregnados diminuiu especificamente a prevalência de esplenomegalia em maiores de 5 anos de idade, mas a regressão de esplenomegalia só foi observada em pessoas acima de 15 anos, a faixa etária menos acometida pela doença na época de alta transmissão, apesar de ter sido a que menos fez uso regular dos mosquiteiros. Houve uma recuperação da taxa normal de hematócrito em menores de 15 anos de idade, com mosquiteiros impregnados...

Tratamiento de la pediculosis capitis en niños con permetrina al 1 por ciento en champú o loción / Treatment of pediculosis capitis in children with 1 percent permethrin shampoo or lotion

A clinical and entomological trial was carried out in 88 head louse (pediculus humanus capitis) infested children treated with a single dose of 1 percent permethrin shampoo or lotion. The sex distribution was 47 males and 41 females with ages ranging between 5 and 14 years old. In order to assess the efficiency of treatments, search for adult forms, nymphs and eggs (nits) of the parasite was performed in each of the children, before and after treatment (30 minutes, 7 days and 21 days). The entomological evaluations consisted in stereoscopic and microscopic examination of a mean of 12 hair samples taken from the retroauricular and occipital regions of each of the children, the biological condition of eggs, viable (inmature, mature), dead ans empty, was recorded. The cure rates, both clinical and entomological, obtained were 91,5 percent for shampoo and 95.2 percent for lotion. No adverse reactions with the 2 formulations used were reported. In conclusion, 1 percent permethrin shampoo or lotion is an effective and safe treatment for pediculosis capitis