Identifying Current and Missing Knowledge in the Control of Pyrethroid-Resistant Triatoma Infestans, Vector of Chagas Disease

Triatomines are blood-sucking bugs that occur mainly in Latin America. They are vectors of Trypanosoma cruzi, the parasite that causes Chagas disease. Chemical control of Chagas disease´s vectors by using pyrethroid insecticides has been highly successful for the elimination of domestic infestation and consequently the reduction of the vector transmission. However, at the beginning of the 2000s a decrease in the effectiveness of the chemical control of triatomines was detected in several areas from Argentina and Bolivia, particularly in the Gran Chaco eco-region. During the last 15 years, several studies demonstrated the evolution of insecticide resistance in Triatoma infestans and established the presence of different toxicological profiles, the autosomal inherence of resistance, the biological costs of deltamethrin resistance, the expression of deltamethrin resistance thorough the embryonic development, and the main mechanisms of resistance (target-site insensitivity and metabolic detoxification of insecticides). The emergence of pyrethroid resistance coupled with the usual difficulties in sustaining adequate rates of insecticide applications emphasize the need of incorporating other tools for integrated vector and disease control, such as the proposal of the organo-phosphorus insecticide fenitrothion as an alternative chemical strategy for the management of the resistance because it was effective against pyrethroid-resistant populations in laboratory and semi-field trials. New studies on the current situation of presence and spread of resistant populations of triatomines and the acceptance of the use of alternative insecticides are critical requirements in the implementation of strategies for the management of resistance and for the rational design of campaigns oriented to reducing the vector transmission of Chagas’ disease.Fil: Roca Acevedo, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin

Primer registro de colonias domésticas de la variante cromática oscura de Triatoma infestans (Hemiptera: Reduviidae)

Triatoma infestans (Klug) es el principal vector de la enfermedad de Chagas en el sur de Sudamérica. Aunque esta especie muestra una morfología y un patrón cromático similar a través de su distribución geográfica, algunas variantes melánicas han sido descriptas. La mayoría de estas variantes fueron reconocidas como parte de poblaciones silvestres, que evidenció una distribución silvestre de T. infestans mayor a la esperada. Este trabajo informa la presencia de ocho adultos y quince individuos inmaduros de T. infestans melánicos en unidades domiciliarias en el Gran Chaco argentino. Este es el primer registro de colonias domésticas de la variante cromática oscura de T. infestans.Triatoma infestans (Klug) is the main vector of Chagas disease in southern South America. Although this species shows a similar morphology and chromatic pattern throughout its geographical distribution, some melanic variations have been described. Most of these variants were recognized as part of wild populations constituting evidence of a wild distribution for T. infestans greater than the expected. This paper reports the presence of eight adults and fifteen immature individuals of melanic T. infestans in domiciliary units of Argentine Gran Chaco. This is the first report of domestic colonies of the dark chromatic morph of T. infestans.Fil: Lobbia, Patricia Alejandra. Ministerio de Salud. Dirección de Enfermedades Transmisibles por Vectores. Centro de Referencia de Vectores; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Álvarez, Rodrigo. Ministerio de Salud. Dirección de Enfermedades Transmisibles por Vectores. Centro de Referencia de Vectores; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Mougabure Cueto, Gastón Adolfo. Ministerio de Salud. Dirección de Enfermedades Transmisibles por Vectores. Centro de Referencia de Vectores; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin

Head lice were also affected by COVID-19: a decrease on Pediculosis infestation during lockdown in Buenos Aires

Pediculosis is a worldwide disease affecting school-aged children produced by the presence of the head louse, Pediculus humanus capitis De Geer, an obligate ectoparasite on the human scalp feeding exclusively on blood. Transmission occurs primarily through direct physical head-to-head contact. In March 2020, the World Health Organization (WHO) declared the COVID-19 outbreak as a pandemic. COVID-19 is caused by SARS-CoV-2, a variant of the coronavirus. Therefore, on March 18, 2020, the Argentinean government established mandatory isolation for an indefinite period. This obligatory isolation interrupted regular classes avoiding direct contact between children, thus affecting the dispersal route of individuals and the evolution of head louse populations. In this study, we evaluated through an online survey how confinement affected the prevalence of lice during lockdown compared to the situation prior to confinement. The survey allowed to discriminate the different control strategies, the number of treatments, and the amount of insects recorded by parents. Data of 1118 children obtained from 627 surveys were analyzed. As the main result, it was observed that prevalence of lice decreased significantly from before (69.6%) to during (43.9%) COVID-19 lockdown. Moreover, head lice infestation was more effectively controlled in households with up to 2 children in comparison to households with 3 or more children. This is the first study that analyzed the prevalence of head lice during COVID-19 pandemic. In addition, this work demonstrated the impact of social distance in the population dynamics of head lice and how it could affect the control strategies in the future.Fil: Galassi, Federico Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Ortega Insaurralde, Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Adjemian, Victor. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Gonzalez Audino, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Toloza, Ariel Ceferino. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin

Respuesta de Pediculus humanus capitis (Phthiraptera: Pediculidae) a volátiles del cuero cabelludo humano y a sus componentes aislados

Elpiojo de la cabeza Pediculus humanuscapitis (De Geer) es un ectoparásito humano cosmopolita que causa lapediculosis, una de las infestaciones humanas más frecuentes (Toloza et al.,2009). La infestación de piojos es molesta y puede causar picazón, pérdida desueño y sanción social (Burgess et al., 2004). El mecanismo de cómo los piojosreconocen a su anfitrión y las señales implicadas son poco conocidas, así comolos compuestos químicos que están implicados en este comportamiento. En esteestudio se evaluó utilizando un T-olfatómetro, la respuesta de los piojos de lacabeza al olor del cuero cabelludo humano. Además, identificamos los componentesvolátiles emanados por la cabeza humana y evaluamos la actividad atractiva orepelente de sus componentes principales puros. Los volátiles se recogieron através de SPME (fibra) y los compuestos se analizaron por CG-MS. Se identificaron veinticuatro componentes en el olor delcuero cabelludo humano, de los cuales los cuatro principales fueron: nonanal,sulcatona, geranilacetona y ácido palmítico. Los piojos de la cabeza fueronaltamente atraídos por las muestras volátiles del cuero cabelludo humano, yfueron atraídos o repelidos por los componentes principales individuales segúnsu masa. Un hallazgo significativo de nuestro estudio fue demostrar que laactividad nonanal depende de la masa del compuesto que es repelente a altasconcentraciones y atrae a bajas concentraciones.Fil: Galassi, Federico Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Toloza, Ariel Ceferino. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Gonzalez Audino, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina1as Jornadas de la Unidad de Investigación y Desarrollo Tecnológico para la DefensaArgentinaUnidad de Investigación y Desarrollo Estratégico para la Defens

International recommendations for an effective control of head louse infestations

Head louse infestations continue to be a concern of public health in most countries, including the most developed ones. The present recommendations are intended to inform and stress the role and impact of the different authorities, institutions, industry, and the public in the control of head lice in order to reduce the prevalence of this parasite. We encourage health authorities to pursue more effective methods to correctly identify such infestations, and evaluate existing and new pediculicides, medical devices, louse repellents, and louse- and nit-removal remedies. Pediculicides and medical devices must have verifiable claims in the instructions for use and should be tested periodically to document current levels of resistance by lice to the active ingredients and to the formulated products. Where the prevalence of lice is claimed to be epidemic, children should be periodically evaluated objectively to document the actual level of prevalence. Continuing education for health providers and the general population promises to correct misinformation regarding the biology, prevention, and management of lice. Parents should regularly inspect their children for head lice and treat as necessary. Health authorities are encouraged to eliminate policies and practices that rely upon school exclusion as a means to reduce incidence and prevalence, e.g., the ‘no-nit’ policy which lacks scientific justification, and are counterproductive to the health and welfare of childrenFil: Mumcuoglu, Kosta Y.. The Hebrew University of Jerusalem; IsraelFil: Pollack, Richard J.. Harvard University; Estados UnidosFil: Reed, David L.. University Of Florida. Florida Museum Of History; Estados UnidosFil: Barker, Stephen C.. University of Queensland; AustraliaFil: Gordon, Shirley. Florida Atlantic University; Estados UnidosFil: Toloza, Ariel Ceferino. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Taylan Ozkan, Aysegul. Hitit University; Turquía. Near East University; ChipreFil: Chosidow, Olivier. Hôpital Henri Mondor; FranciaFil: Habedank, Birgit. German Environment Agency; AlemaniaFil: Ibarra, Joanna. Community Hygiene Concern; Reino UnidoFil: Meinking, Terri L.. Global Health Associates of Miami; Estados UnidosFil: Vander Stichele, Robert H.. Heymans Institute of Pharmacology; Bélgic

Baş biti enfestasyonlarının etkin kontrolü için uluslararası tavsiyeler

Baş biti enfestasyonları, en gelişmiş olanlar da dâhil olmak üzere çoğu ülkede halk sağlığını ilgilendiren bir sorun olmaya devam etmektedir. Makalede sunulan tavsiyeler, bu parazitin prevalansını azaltmak amacıyla baş biti kontrolünde farklı otoritelerin, kurumların, endüstrinin ve kamunun rollerini ve etkilerini vurgulamayı ve bilgilendirmeyi amaçlamaktadır. Sağlık yetkililerini, bu tür enfestasyonların doğru şekilde tespit edilmesi; mevcut ve yeni pedikülositler, tıbbi cihazlar, repellentler, bit ve yumurta giderici ürünlerin değerlendirilmesi amacıyla daha etkili yöntemler iz açıklamalara sahip olmalı ayrıca aktif bileşenlere ve formüle ürünlere karşı bitlerin direnç seviyelerinin mevcut durumunu belgelemek için periyodik olarak test edilmelidir. Bit yaygınlığının salgın düzeyine ulaştığı iddiaları ortaya atıldığında, gerçek yaygınlık düzeyinin kanıtlanması amacıyla çocuklar periyodik aralıklarla objektif olarak değerlendirilmelidir. Sağlık hizmeti sunanlar ve toplum geneli için düzenlenen sürekli eğitimlerle bitlerin biyolojisi, önlenmesi ve kontrolü konusundaki yanlış bilgilerin düzeltilmesi sağlanabilir. Ebeveynler, çocuklarını baş biti açısından düzenli olarak kontrol etmeli ve gerektiğinde tedavi etmelidir. Sağlık yetkilileri, vakaları ve yaygınlığı azaltmada bir araç olarak kullanılan ancak bilimsel gerekçesi olmadığı gibi çocukların sağlığı ve huzuruna da ters etki yapan “sirkeye geçit yok- no-nit politikası” tarzında çocukları okuldan uzaklaştırmaya dayalı politika ve uygulamaların ortadan kaldırılması için mücadele etmelidir.lemeye teşvik etmeyi umuyoruz. Pedikülositler ve tıbbi cihazlar, kullanım talimatlarında doğrulanabilirHead louse infestations continue to be a concern of public health in most countries, including the most developed ones. The present recommendations are intended to inform and stress the role and impact of the different authorities, institutions, industry, and the public in the control of head lice in order to reduce the prevalence of this parasite. We encourage health authorities to pursue more effective methods to correctly identify such infestations, and evaluate existing and new pediculicides, medical devices, louse repellents, and louse and nit-removal remedies. Pediculicides and medical devices must have verifiable claims in the instructions for use and should be tested periodically to document current levels of resistance by lice to the active ingredients and to the formulated products. Where the prevalence of lice is claimed to be epidemic, children should be periodically evaluated objectively to document the actual level of prevalence. Continuing education for health providers and the general population promises to correct misinformation regarding the biology, prevention, and management of lice. Parents should regularly inspect their children for head lice and treat as necessary. Health authorities are encouraged to eliminate policies and practices that rely upon school exclusion as a means to reduce incidence and prevalence, e.g., the ‘no-nit’ policy which lacks scientific justification, and are countFil: Mumcuoğlu, Kosta Y.. The Hebrew University; IsraelFil: Pollack, Richard J.. Harvard University. Harvard School of Public Health; Estados UnidosFil: Reed, David. University Of Florida. Florida Museum Of History. Departamento Of Biology; Estados UnidosFil: Barker, Stephen. The University of Queensland; AustraliaFil: Gordon, Shirley. Florida Atlantic University (fau);Fil: Toloza, Ariel Ceferino. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Taylan Özkan, Ayşegül. Tobb University Of Economics And Technology; TurquíaFil: Chosidow, Olivier. Hopital Henri Mondor; FranciaFil: Habedank, Birgit. German Environment Agency; AlemaniaFil: Ibarra, Joanna. Community Hygiene Concern; Reino UnidoFil: Meinking, Terri L.. Global Health Association Of Miami; Estados UnidosFil: Stichele, Robert Vander. University of Ghent; Bélgic

Demographic effects of deltamethrin resistance in the Chagas disease vector Triatoma infestans. Medical and Veterinary Entomology

Triatoma infestans (Heteroptera: Reduviidae) Klug is the main vector of Chagas disease in Latin America. Resistance to deltamethrin was reported in Argentina and recently associated with reproductive and longevity trade‐offs. The objectives of the present study were to describe the demographic consequences of deltamethrin resistance in T. infestans and to establish possible target stages for chemical control in susceptible and resistant colonies. A stage‐classified matrix model was constructed based on the average stage length for susceptible, resistant and reciprocal matings' progeny. The differences between colonies were analysed by prospective and retrospective analysis. The life table parameters indicated reduced fecundity, fertility and population growth in resistant insects. The retrospective analysis suggested the latter was associated with lower reproductive output and increased fifth‐instar nymph stage length. The prospective analysis suggested that the adult stage should be the main target for insecticide control. Although, fifth‐instar nymphs should also be targeted when resistance has been detected. The presented results show demographic effects of deltamethrin resistance in T. infestans. While the older stages could be the main targets for chemical control, this approach is impeded by their higher tolerance to insecticides. It is concluded that the different mode of action insecticides would be more effective than a dose increase for the control of deltamethrin‐resistant T. infestans.Fil: Germano, Mónica Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin

Reproductive and developmental costs of deltamethrin resistance in the Chagas disease vector Triatoma infestans

Effective chemical control relies on reducing vector population size. However, insecticide selection pressure is often associated with the development of resistant populations that reduce control success. In treated areas, these resistant individuals present an adaptive advantage due to enhanced survival. Resistance can also lead to negative effects when the insecticide pressure ceases. In this study, the biological effects of deltamethrin resistance were assessed in the Chagas disease vector Triatoma infestans. The length of each developmental stage and complete life cycle, mating rate, and fecundity were evaluated. Susceptible and resistant insects presented similar mating rates. A reproductive cost of resistance was expressed as a lower fecundity in the resistant colony. Developmental costs in the resistant colony were in the form of a shortening of the second and third nymph stage duration and an extension of the fifth stage. A maternal effect of deltamethrin resistance is suggested as these effects were identified in resistant females and their progeny independently of the mated male's deltamethrin response. Our results suggest the presence of pleiotropic effects of deltamethrin resistance. Possible associations of these characters to other traits such as developmental delays and behavioral resistance are discussed.Fil: Germano, Mónica Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentin

Stage-dependent expression of deltamethrin toxicity and resistance in triatoma infestans (hemiptera: Reduviidae) from Argentina

Triatoma infestans Klug (Hemiptera: Reduviidae) is the main vector of Chagas disease in Latin America.This insect has been controlled with pyrethroids since the 1980s, although the emergence of resistance to deltamethrin has decreased control success in some areas of the Gran Chaco ecoregion.The response of T. infestans to deltamethrin was evaluated per developmental stage. In addition, we evaluated the possible stage-dependent expression of deltamethrin resistance.The bioassays were conducted by topical application of the insecticide in acetone.The drop size, age at the time of exposure, and mortality measuring time were standardized per stage. The lethal dose of deltamethrin moderately increased with the developmental stage.The resistance to deltamethrin was expressed in every instar, and was the highest in the fourth- and fifth-instar nymphs.While increasing, weight plays a relevant role in lethal dose stage dependency, a number of contributing factors such as degradative metabolism are probably involved in the variability of insecticide effect and resistance described for different T. infestans developmental stages. Possible explanations for these differences and their implications on resistance management and chemical control are discussed.Fil: Germano, Mónica Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Picollo, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin