An 80-Year-Old Woman with Alzheimer Disease and Accidental Poisoning with Pyrethroid Pesticide Successfully Treated with Intravenous Lipid Emulsion.

BACKGROUND Pesticides are commonly used in the agricultural industry. Overdose can be lethal due to its effects generating closure of the voltage-gated sodium channels in the axonal membranes. Most case reports of toxicity refer to skin exposure and there are very few that refer to effects due to its oral intake. CASE REPORT We report the case of an elderly woman with Alzheimer disease who accidentally swallowed 50 g of Lambda Cyhalothrin (GOLPE 5 M E®), a pyrethroid of medium toxicity containing a cyano group. It severely harmed the woman's health, causing severe central nervous system depression and refractory vasodilated shock requiring the use of vasopressors. Its management was challenging, requiring orotracheal intubation, vasopressors, and admission to the Intensive Care Unit (ICU). The emergency care team decided to use intravenous lipid emulsion, which clearly helped with the recovery and successful discharge of the patient. CONCLUSIONS The use of intravenous lipid emulsion for the treatment of pyrethroid poisoning can lead to successful outcomes, as described in this case report.

In vitro and in vivo effects of chlorpyrifos and cypermethrin on blood cholinesterases in sheep.

The combination of the organophosphate (OP) chlorpyrifos (CPF) and the pyrethroid cypermethrin (CPM) is commonly marketed as pour-on formulations for the control of sheep lice, ked, and blowflies. CPF irreversibly inhibits acetylcholinesterases (AChE), while pyrethroids are not AChE inhibitors. However, combinations of pyrethroids with OPs showed a highly synergistic effect on AChE inhibition. Thus, the aim of the current work was to evaluate in vitro and in vivo the inhibitory potency of both pesticides, alone and in combination with AChE and butyrylcholinesterase (BChE) activities in sheep blood. In vitro, IC50 values were similar after CPF or CPF plus CPM incubations. The pour-on coadministration of recommended doses of CPF and CPM did not cause a significant inhibition of AChE and BChE in sheep blood. Only slight percentages of inhibition of their catalytic activities were observed when both drugs were given at 4-fold higher dose rates. The lower systemic availability of topical administration of OPs in sheep may help to explain the lower degree of inhibition of blood AChE and BChE in vivo. The results emerged from this research are a further contribution to the knowledge of the risks of implementing higher dosage regimens of OPs-containing antiparasitic formulations.

Seasonal Effects and the Impact of In-Hive Pesticide Treatments on Parasite, Pathogens, and Health of Honey Bees.

Honey bee, Apis mellifera (L.; Hymenoptera: Apidae), populations are in decline and their losses pose a serious threat for crop pollination and food production. The specific causes of these losses are believed to be multifactorial. Pesticides, parasites and pathogens, and nutritional deficiencies have been implicated in the losses due to their ability to exert energetic stress on bees. While our understanding of the role of these factors in honey bee colony losses has improved, there is still a lack of knowledge of how they impact the immune system of the honey bee. In this study, honey bee colonies were exposed to Fumagilin-B, Apistan (tau-fluvalinate), and chlorothalonil at field realistic levels. No significant effects of the antibiotic and two pesticides were observed on the levels of varroa mite, Nosema ceranae (Fries; Microsporidia: Nosematidae), black queen cell virus, deformed wing virus, or immunity as measured by phenoloxidase and glucose oxidase activity. Any effects on the parasites, pathogens, and immunity we observed appear to be due mainly to seasonal changes within the honey bee colonies. The results suggest that Fumagilin-B, Apistan, and chlorothalonil do not significantly impact the health of honey bee colonies, based on the factors analyzed and the concentration of chemicals tested.

Efficacy profile of Cypermethrin and Chlorpyrifos based acaricides on Rhipicephalus microplus control on cattle in the rearing phase, naturally infested and exposed to tick fever agents in central Brazil.

The objective of this work was to evaluate the efficacy of two cypermethrin- and chlorpyrifos-based acaricides in controlling Rhipicephalus microplus in a naturally infested bovine herd and in in vitro tests, as well as to monitor the animals for tick fever. Male bovines in the rearing phase were used, with 30 Brangus and 30 Nellore animals naturally infested. The groups were composed as follows: 15 Nellore treated, 15 Nellore control, 15 Brangus treated and 15 Brangus control. Every 18 days, the animals were monitored for tick count, acaricide treatment, weight, blood pack cell volume, and clinical signs. For in vitro tests, the larval packet test, adult immersion test and DNA amplification for tick fever diagnosis were performed. In the first animal treatment period, product 1 (cypermethrin, 15 g + chlorpyrifos, 25 g + citronellal, 1 g) was used; in the second period, product 2 (cypermethrin, 15 g + chlorpyrifos, 30 g + fenthion, 15 g) was used. In Brangus animals, the mean efficacy was 35.1% and 95.8% in the first and second periods, respectively, for the same animals. For Nellore animals, the efficacy in periods one and two was 51% and 97.1%, respectively. The in vitro results showed efficacy above 95% for the two challenged acaricides. The Brangus animals showed a high production of ticks associated with the presence of tick fever agents, which could generate risks for the disease's enzootic stability.

Sensitivity assessment of sea lice to chemotherapeutants: Current bioassays and best practices.

Traditional bioassays are still necessary to test sensitivity of sea lice species to chemotherapeutants, but the methodology applied by the different scientists has varied over time in respect to that proposed in "Sea lice resistance to chemotherapeutants: A handbook in resistance management" (2006). These divergences motivated the organization of a workshop during the Sea Lice 2016 conference "Standardization of traditional bioassay process by sharing best practices." There was an agreement by the attendants to update the handbook. The objective of this article is to provide a baseline analysis of the methodology for traditional bioassays and to identify procedures that need to be addressed to standardize the protocol. The methodology was divided into the following steps: bioassay design; material and equipment; sea lice collection, transportation and laboratory reception; preparation of dilution; parasite exposure; response evaluation; data analysis; and reporting. Information from the presentations of the workshop, and also from other studies, allowed for the identification of procedures inside a given step that need to be standardized as they were reported to be performed differently by the different working groups. Bioassay design and response evaluation were the targeted steps where more procedures need to be analysed and agreed upon.

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.

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)

Investigação da ocorrência de reações adversas com uso de coleira impregnada por deltametrina a 4% em cães / Investigation of occurrence of adverse reactions with the use of collar impregnated by deltamethrin 4% in dogs

A deltametrina é um inseticida do grupo dos piretróides tipo II muito utilizada como ectoparasiticida na veterinária em várias formas de aplicação tópica, como banho, spray, solução para aplicação no dorso e coleira. A coleira impregnada com deltametrina a 4% (CD4%), além de sua indicação contra carrapatos, tem sido recomendada também contra as picadas dos flebótomos transmissores da Leishmaniose. Alguns relatos têm sido descritos de ingestão e intoxicação, além de reações cutâneas com o uso da CD4%, porém, até o presente momento não há um estudo controlado sobre a possibilidade destes eventos em cães. O objetivo deste trabalho foi investigar em cães a ocorrência de reações adversas à CD4%. Foram utilizados 33 cães mantidos em baias coletivas do canil da UNOESTE, divididos em 3 grupos com 11 animais cada, sendo o grupo A de fêmeas adultas (utilização da coleira conforme a indicação do fabricante), grupo B de machos adultos (utilização da coleira não seguindo a indicação do fabricante) e grupo C de fêmeas jovens (utilização da coleira conforme a indicação do fabricante, porém com um período de adaptação). Os animais foram observados com relação às possíveis reações adversas ou alérgicas com preenchimento de ficha clínica e dermatológica diariamente durante 15 dias e depois três vezes por semana até completar 4 meses, tempo recomendado de permanência da coleira com eficácia pelo fabricante. Dos 33 cães, 39,4% (13) retiram a coleira, sendo 9 fêmeas (3 do grupo A e 6 do grupo C) e 4 machos (grupo B). Dos 13 animais que retiram a coleira, 18,2% ingeriram a mesma, 4 fêmeas (grupo C) e 2 machos (grupo B). Nenhum animal apresentou reação alérgica ou adversa à coleira, inclusive naqueles que ingeriram a mesma. Não houve a ocorrência de ectoparasitas durante o período de observação. [...](AU)

Deltamethrin is an insecticide of the group of type II pyrethroids widely used as the ectoparasiticide in various veterinary topical application forms, such as bath, spray solution for application on the back and collar. The impregnated with deltamethrin to 4% (CD4%) collar, and his statement against ticks, has also been recommended against the bites of sandflies transmission of leishmaniasis. Some reports have been described for ingestion and poisoning, and skin reactions with the use of CD4%, but so far there is not a controlled study on the possibility of these events study in dogs. The objective of this study was to investigate the occurrence of adverse reactions to CD4%. Thirty-three dogs kept in collective cages in the kennel UNOESTE, divided into 3 groups of 11 animals each, with group A of adult females (use the collar as indicated by the manufacturer), group B adult male (do not use the collar following the indication of manufacturer) and group C of young females (use the collar as indicated by the manufacturer, but with an adjustment period). The animals were observed with respect to possible adverse or allergic reactions to completion of clinical dermatology and record daily for 15 days and then three times a week until at least 4 months time recommended staying with the leash effectiveness by the manufacturer. Of the 33 dogs, 39.4% (13) remove the collar, 9 females (3 group A and group C 6) and 4 males (group B). Of the 13 animals that pull the collar, 18.2% ingested the same, 4 females (group C) and 2 males (group B). No animal showed adverse or allergic reaction to the collar, even in those who ate the same. There was no occurrence of ectoparasites during the period of observation. [...](AU)

Investigação da ocorrência de reações adversas com uso de coleira impregnada por deltametrina a 4% em cães / Investigation of occurrence of adverse reactions with the use of collar impregnated by deltamethrin 4% in dogs

A deltametrina é um inseticida do grupo dos piretróides tipo II muito utilizada como ectoparasiticida na veterinária em várias formas de aplicação tópica, como banho, spray, solução para aplicação no dorso e coleira. A coleira impregnada com deltametrina a 4% (CD4%), além de sua indicação contra carrapatos, tem sido recomendada também contra as picadas dos flebótomos transmissores da Leishmaniose. Alguns relatos têm sido descritos de ingestão e intoxicação, além de reações cutâneas com o uso da CD4%, porém, até o presente momento não há um estudo controlado sobre a possibilidade destes eventos em cães. O objetivo deste trabalho foi investigar em cães a ocorrência de reações adversas à CD4%. Foram utilizados 33 cães mantidos em baias coletivas do canil da UNOESTE, divididos em 3 grupos com 11 animais cada, sendo o grupo A de fêmeas adultas (utilização da coleira conforme a indicação do fabricante), grupo B de machos adultos (utilização da coleira não seguindo a indicação do fabricante) e grupo C de fêmeas jovens (utilização da coleira conforme a indicação do fabricante, porém com um período de adaptação). Os animais foram observados com relação às possíveis reações adversas ou alérgicas com preenchimento de ficha clínica e dermatológica diariamente durante 15 dias e depois três vezes por semana até completar 4 meses, tempo recomendado de permanência da coleira com eficácia pelo fabricante. Dos 33 cães, 39,4% (13) retiram a coleira, sendo 9 fêmeas (3 do grupo A e 6 do grupo C) e 4 machos (grupo B). Dos 13 animais que retiram a coleira, 18,2% ingeriram a mesma, 4 fêmeas (grupo C) e 2 machos (grupo B). Nenhum animal apresentou reação alérgica ou adversa à coleira, inclusive naqueles que ingeriram a mesma. Não houve a ocorrência de ectoparasitas durante o período de observação. [...]

Deltamethrin is an insecticide of the group of type II pyrethroids widely used as the ectoparasiticide in various veterinary topical application forms, such as bath, spray solution for application on the back and collar. The impregnated with deltamethrin to 4% (CD4%) collar, and his statement against ticks, has also been recommended against the bites of sandflies transmission of leishmaniasis. Some reports have been described for ingestion and poisoning, and skin reactions with the use of CD4%, but so far there is not a controlled study on the possibility of these events study in dogs. The objective of this study was to investigate the occurrence of adverse reactions to CD4%. Thirty-three dogs kept in collective cages in the kennel UNOESTE, divided into 3 groups of 11 animals each, with group A of adult females (use the collar as indicated by the manufacturer), group B adult male (do not use the collar following the indication of manufacturer) and group C of young females (use the collar as indicated by the manufacturer, but with an adjustment period). The animals were observed with respect to possible adverse or allergic reactions to completion of clinical dermatology and record daily for 15 days and then three times a week until at least 4 months time recommended staying with the leash effectiveness by the manufacturer. Of the 33 dogs, 39.4% (13) remove the collar, 9 females (3 group A and group C 6) and 4 males (group B). Of the 13 animals that pull the collar, 18.2% ingested the same, 4 females (group C) and 2 males (group B). No animal showed adverse or allergic reaction to the collar, even in those who ate the same. There was no occurrence of ectoparasites during the period of observation. [...]

Caracterização e distribuição da resistência a deltametrina de populações silvestres e domésticas de Triatoma infestans da Bolívia

A persistência do Triatoma infestans e a transmissão contínua de Trypanosoma cruzinos Vales Inter-Andinos e no Grande Chaco da Bolívia são de grande importância. Na última década, focos silvestres desta espécie foram descritos em amplas áreas, na qual o alcance das estratégias de controle do vetor é limitado, sendo frequentes os relatos de resistência do T. infestans a inseticidas, que incluem populações silvestres e domésticas. O presente estudo teve como objetivo caracterizar o perfil de suscetibilidade (1) e hereditariedade (2) de populações silvestres e domésticas de T. infestans da Bolívia à deltametrina, bem como descrever a área de distribuição das populações resistentes a diferentes piretróides na América do Sul (3). 1) Foram avaliadas nove populações de T. infestans silvestres e domésticas do Grande Chaco e dos Vales Inter-Andinos da Bolívia. Três amostras silvestres de T. infestans(dark morph) do Chaco (Santa Cruz) foram suscetíveis a deltametrina (RR50 de <2), com 100% de mortalidade em resposta a dose diagnóstica (DD). A população doméstica de Villa Montes do Grande Chaco (Tarija) apresentou altos níveis de resistência (RR50 = 129,12 e 0% DD).

Do mesmo modo, as populações domésticas dos Vales Inter-Andinos (Cochabamba) apresentaram RR50 > 9, sendo as populações silvestres menos suscetíveis, com RR50 >5 do que SRL. 2) Cruzamentos experimentais foram realizados entre uma colônia suscetível RR50=0,62 (S), uma resistente RR50=129,12 (R) e com susceptibilidade reduzida RR50=5,04 (SR), em ambas as direções (♀x♂ e ♂x♀). O modo de herança do caráter resistente foi determinado pelo grau de dominância (DO) e dominância efetiva (DML). A hereditariedade (h2) foi estimada a partir da colônia R selecionada durante duas gerações, utilizando a dose diagnóstica (10 ng.i.a./ninfa).

O resultado para DO e DML (<1) indica que a resistência é um caráter de dominância incompleta e de herança autossômica. A Dose Letal 50% (DL50) para F1 de ♀Sx♂R e ♂Sx♀R foi de 0,74 e 3,97 respectivamente, revelando efeito de diluição da resistência inicialmente observada. Por outro lado, foi observado um incremento da RR50 de 2,25 vezes (F1) e 26,83 vezes (F2) na população selecionada em comparação com a colônia parental. 3) Foi compilado um total de 24 artigos que avaliaram a suscetibilidade a diferentes piretróides em 222 populações de T. infestans coletadas no campo dos países de Argentina, Bolívia, Brasil e Paraguai. A relação entre resistência aos inseticidas (avaliada por critérios diferentes) e diferentes variáveis ambientais foi estudada utilizando modelo linear generalizado. A DL50 mostrou uma forte relação linear com a RR50. Análise estatística descritiva demonstrou que a distribuição de frequência da Log (DL50) é bimodal, sugerindo a existência de dois grupos estatísticos (um grupo de menor e outro com maior Log (DL50). Finalmente, o modelo significativo incluindo 5 variáveis ambientais referentes a temperatura e precipitação, revelou concentração das populações com altas DL50 sobre a região identificada como o centro de dispersão de T. infestans. Os dados obtidos neste estudo contribuem com informações sobre a variabilidade do perfil de resistência, ocorrência e distribuição de populações resistentes na Bolívia

Integrated control of an acaricide-resistant strain of the cattle tick Rhipicephalus microplus by applying Metarhizium anisopliae associated with cypermethrin and chlorpyriphos under field conditions.

The efficacy of the fungus Metarhizium anisopliae to control ticks has been shown in several in vitro experiments. However, few studies have been undertaken in field conditions in order to demonstrate the applicability of its use as a biological control of ticks and its combination with chemical acaricides. The aim of the present study was to evaluate the efficacy of M. anisopliae to control an acaricide-resistant strain of Rhipicephalus microplus under laboratory and field conditions. First, the compatibility of M. anisopliae strain (TIS-BR03) with commercial acaricides and its potential to control the cattle tick were evaluated in vitro. In general, acaricide treatments had mild effects on fungus viability. In the field experiment, the median of treatment efficacy with acaricide only, M. anisopliae only and combination of M. anisopliae with acaricide were 71.1%, 56.3% and 97.9%, respectively. There is no statistical difference between groups treated with M. anisopliae and acaricide alone. Thus, in this work we have demonstrated the applicability of M. anisopliae use associated or not with chemical acaricides on field conditions in order to control an acaricide-resistant strain of the cattle tick R. microplus.

Efficacy of the treatments used for the control of Caligus rogercresseyi infecting Atlantic salmon, Salmo salar L., in a new fish-farming location in Region XI, Chile.

Caligus rogercresseyi is the most important parasite affecting Atlantic salmon and rainbow trout farming in sea water in Chile. After the outbreaks of the infectious salmon anaemia recorded in Region X from 2007, the salmon industry has expanded southwards to Region XI, where 60% of Atlantic salmon in Chile is now produced. In parallel with the relocation of salmon production, sea lice infestation has also spread to Region XI, and today C. rogercresseyi is the most serious threat to the salmon-farming industry in this region. The results obtained through a year of monitoring between September 2007 and August 2008 on a farm located in the 'Las Guaitecas Archipelago' in Region XI (44°S; 74°W) showed that treatments with emamectin benzoate and deltamethrin did not give the expected control of Caligus. Failures of the treatments were associated with the loss of sensitivity recorded for C. rogercresseyi to emamectin benzoate in Region X. In addition, a major influence was the lack of delousing coordination measures with the neighbouring farms sharing the same area in that period.

Triatomicidal effect of new spot-on formulations applied to poultry in semi-field conditions.

Chagas disease is an endemic disease affecting ten million people in the American continent. Produced by a parasite transmitted by triatomine insects, the main actions for reducing the incidence of this disease are focused on the control of insect vectors. This type of control has produced highly effective results within rural homes, but not in peridomestic areas (kitchens, warehouses, hen houses and other buildings not attached to the houses). The object of the present study was to assess the triatomicidal effect of new spot-on formulations developed by our laboratory in a semi-rural environment. The active ingredients of the formulations were ß-cypermethrin, pyriproxyfen, or ß-cypermethrin + pyriproxyfen. All formulations were applied to hens and tested in miniature replicas of rural households where experimental populations of Triatoma infestans, the main vector of Chagas disease in Argentina, had been previously released. The experimental populations exposed to formulations containing ß-cypermethrin or ß-cypermethrin + pyriproxyfen were noticeably reduced compared to non-treated control groups. However, no differences were observed between the effects produced by ß-cypermethrin alone and ß-cypermethrin + pyriproxyfen. Pyriproxyfen alone produced no significant reduction in the experimental populations of T. infestans. These results suggest that spot-on application of ß-cypermethrin could be a useful complementary tool for controlling triatomine insects in the peridomestic areas of rural homes.

A long-lasting topical deltamethrin treatment to protect dogs against visceral leishmaniasis.

To develop long-lasting, topical pour-on insecticides for dogs to control zoonotic visceral leishmaniasis, two deltamethrin-based formulations (emulsifiable concentrate [EC] and suspension concentrate [SC]) were tested for their efficacy against the phlebotomine sandfly Lutzomyia longipalpis Lutz & Neiva (Diptera: Psychodidae), vector of Leishmania infantum Nicolle (Kinetoplastida: Trypanosomatidae). The entomological outcomes tested were anti-feeding effect (proportion of female sandflies unfed), lethal effect (24-h female sandfly mortality) and these two effects combined, and the insecticide persistence time at 50% (residual activity, RA50) and 80% (RA80) efficacy. On initial application, the proportions of female flies that demonstrated anti-feeding activity or were killed were similar for both formulations, at 0.93 (95% confidence interval [CI] 0.856-0.977) vs. 0.81 (95% CI 0.763-0.858) (anti-feeding) and 0.86 (95% CI 0.787-0.920) vs. 0.76 (95% CI 0.698-0.817) (24-h mortality) for EC and SC, respectively. The RA(50) rates for anti-feeding and mortality caused by the EC formulation were 4.7 months (95% CI 4.18-5.84) and 2.5 months (95% CI 2.25-2.90), respectively, compared with 1.1 months (95% CI 0.96-1.15) and 0.6 months (95% CI 0.50-0.61), respectively, for the SC formulation. The RA(50) for the combined anti-feeding and mortality effects of EC was 5.2 months (95% CI 4.73-5.96), compared with only 0.9 months (95% CI 0.85-1.00) for the SC formulation. The four- to six-fold superior residual activity of the EC formulation was attributed to the addition of a solvent-soluble resin in the formulation which improved fur adhesion and acted as a reservoir for the slow release of the active ingredient. These results identify the potential of such a low-cost formulation to reduce the inter-intervention interval to 5-6 months, similar to that recommended for deltamethrin-impregnated dog collars or for re-impregnation of conventional bednets, both of which are currently used to combat Leishmania transmission. Finally, a novel bioassay was developed in which sandflies were exposed to fur from treated dogs, revealing no detectable tolerance (24-h mortality) in wild-caught sandflies to the insecticide formulations up to 8 months after the initiation of communitywide application of the insecticides to dogs.

Pediculosis hasta 2008 / Pediculosis until 2008

La pediculosis es una patología cuya prevalencia está en aumento en todo el mundo. En parte, esto se debe a las dificultades que presentan los tratamientos disponibles. Los pediculicidas químicos usados actualmente son piretrinas (permetrina 1% es la más usada), malatión 0,5%, lindano 1% (cuestionado debido a su neurotoxicidad e impacto ambiental) e ivermectina (sin aprobación de la Food and Drug Administration). Si bien existe una creciente evidencia sobre el desarrollo de resistencia a estos pediculicidas, es importante considerar la correcta realización de los tratamientos o la presencia de una reinfección antes que el desarrollo de resistencia propiamente dicho, razón por la cual es recomendable que el problema sea abordado en forma conjunta por el equipo de salud, la escuela y la familia. Actualmente se investigan nuevas opciones terapéuticas más seguras y eficaces como, por ejemplo, métodos físicos, aceites esenciales y derivados vegetales, nuevos insecticidas o la incorporación formal de opciones como la ivermectina, para lo cual aún se requiere más investigación que aporte evidencia de mejor calidad metodológica.

Head lice is a condition whose prevalence is increasing worldwide, probably because of the difficulties that available treatments present. Chemicals pediculicides currently in use are pyrethrins (1% permethrin is the most widely used), 0.5% malathion, 1% lindane (questioned because of its neurotoxic effects and their environmental impact) and ivermectin (not yet approved by the Food and Drug Administration). While there is increasing evidence of growing development of resistance to these pediculicides, it is important to consider the proper conduct of the treatments or the presence of reinfection before considering the real development of resistance, for these reasons a global assessment that includes the health equipe, the school and the family is desirable. New therapeutic options, both safe and effective, are being investigated. They include physical methods, products derived from essential oils and herbal products, new insecticides and ivermectin, which requires further research to provide evidence of better quality.

Demodectic mange in fattening pigs in São Paulo, Brazil.

An investigation was conducted of mange in five Large White adult sows refractory to pyrethroid treatment (cypermethrin 15%). The most important clinical signs consisted of erythema, hyperkeratosis, alopecic macules, micaceous scaling, follicular pluging, and numerous comedones, especially on the facial region. Skin samples were scraped and punched. Elongate mites were found that were classified as Demodex sp., according to the morphological and histopathological characteristics. The protein, vitamin, and mineral levels contained in the rations were considered to be lower than those recommended to attend the requirements of fattening pigs. Adjustment of the rations was adopted, and the treatment of animals with ivermectin premix (450g/tonne of food) daily orally for a further 7 days was prescribed. The success of treatment was observed 15 days after adoption of these measures, when the beginning of remission of signs was observed. No mites were found on scrapings or biopsy punches after the treatment of the sows.

Pyrethroid-impregnated curtains for Chagas' disease control in Venezuela.

The use of insecticide treated materials for the control of Chagas' disease transmission is potentially a cost-effective and sustainable option where vectors are sylvatic. A study was undertaken in two rural Chagas' disease endemic communities (96 households) of Trujillo State, Venezuela. After a baseline study (including a short questionnaire survey, assessment of housing conditions, vector behaviour and preferences in vector protection), 37 households were chosen at random for protection by impregnated or non-impregnated curtains. During the 30-day entomological study vector collection of triatomine bugs were conducted in the early morning. The protective efficacy of curtains was determined by the number of vectors found dead or alive in control and experimental houses. It was found that house infestation of Chagas' disease vectors was high (60% of houses) in spite of good-quality houses due to a re-housing programme. The vectors were sylvatic (mainly Rhodnius robustus) and entered the houses at night. More than half the population (52%) preferred curtains to bednets for Chagas' disease protection. Users of pyrethroid-impregnated curtains were well protected as no living triatomines were found in bedrooms of houses with impregnated curtains compared to houses with non-impregnated curtains where an average of 4/7 vectors were found alive in bedrooms. In houses with impregnated curtains 21/30 triatomines died within 72 h; the triatomines which survived were found exclusively in rooms where no impregnated curtains had been placed. In houses with non-impregnated curtains 20% (6/30) of vectors died, probably due to rough handling. It is concluded that pyrethroid-impregnated curtains represent an important option for the reduction or even elimination of man-vector contact and thus of Chagas' disease transmission in areas where species of small triatomine bugs such as Rhodnius prolixus and R. robustus are the main vectors.

Effects of partial housing improvement and insecticide spraying on the reinfestation dynamics of Triatoma infestans in rural northwestern Argentina.

The long-term effects on domiciliary reinfestation by Triatoma infestans of smoothing the plaster of indoor walls prior to insecticide application (in Amamá village) relative to only insecticide application (in Trinidad-Mercedes villages) were evaluated in rural northwestern Argentina from 1992 to 1997. All domestic and peridomestic areas of each house were sprayed with 2.5% suspension concentrate deltamethrin at 25 mg/m(2) in October 1992, and infestations were assessed by various methods every 6 months. Domiciliary infestation decreased from 72-88% in 1992 to 6-17% in late 1995, to increase moderately thereafter without returning to baseline rates. Peridomestic sites were the first in becoming reinfested, and reached more abundant T. infestans populations than domiciliary areas. Domiciliary infestation rates and bug abundances were not significantly different between communities during surveillance. Domiciliary infestation rates in well-plastered houses were very low (5-9%) and approximately stable until 1996, but in houses with regular or bad plaster they consistently increased from 5 to 19-21% in both communities. Logistic multiple regression analysis showed that the likelihood of domestic infestation assessed through householders' collections was significantly and positively associated with the occurrence of an infested peridomestic site in the respective house, the occurrence of high-density domestic infestations before interventions, and well-plastered walls in 1996. Combining insecticide spraying and partial improvement of walls controlled domestic infestations and transmission of Trypanosoma cruzi effectively, but was not sufficient to eliminate T. infestans from the study area or increase the effectiveness of careful chemical control.

Demodecidosis: ¿comensalismo o parasitismo? / Demodecidosis: commensalism o parasitism?

Con el objeto de evaluar la importancia que tiene el hallazgo de Demodex sp. en dermatología humana, se realizó el presente estudio de casos y controles, completando con análisis químico del parásito. Los casos presentaban rosácea o eccematide seborreica, mientras que los controles, piel normal. Las muestras fueron extraídas del rostro mediante aplicación de cintas adhesivas transparentes sobre la piel, las que luego se adhirieron a portaobjetos para buscar el artrópodo por microscopía. El hallazgo de un solo parásito fue suficiente como criterio de positividad. Además se realizó análisis espectrofotométrico de los parásitos, por fluorescencia de rayos X. El 36,6 por ciento de los casos presentó Demodex sp. asociado con dermatitis perioral, rosácea, eccematide seborreica y en conducto nasal asociado a Staphylococcus aureus. Solamente en el 3,3 por ciento de los controles se demostró la presencia del parásito. Odds Ratio: 16,79; X²:8,44; p: 0,0036, límite de confianza 95 por ciento. El análisis espectrométrico por fluorescencia de rayos X, demostró presencia de: calcio, titanio, hierro, azufre, fósforo, cobre, níquel, zinc, potasio, cloro, magnesio, aluminio y silicio en los artrópodos, correspondiendo al cobre y al hierro los picos de mayor intensidad. Luego del tratamiento para Demodex sp. se produjo remisión de los cuadros. Se concluye que existe asociación estadísticamente significativa entre las dermatopatías mencionadas y Demodex sp. El cobre y el hierro de los parásitos podrían, eventualmente, contribuir a agravar los cuadros por reacciones alérgicas (AU)