Fluralaner systemic treatment of chickens results in mortality in Triatoma gerstaeckeri, vector of the agent of Chagas disease

Background: Chagas disease remains a persistent vector-borne neglected tropical disease throughout the Americas and threatens both human and animal health. Diverse control methods have been used to target triatomine vector populations, with household insecticides being the most common. As an alternative to environmental sprays, host-targeted systemic insecticides (or endectocides) allow for application of chemicals to vertebrate hosts, resulting in toxic blood meals for arthropods (xenointoxication). In this study, we evaluated three systemic insecticide products for their ability to kill triatomines. Methods: Chickens were fed the insecticides orally, following which triatomines were allowed to feed on the treated chickens. The insecticide products tested included: Safe-Guard® Aquasol (fenbendazole), Ivomec® Pour-On (ivermectin) and Bravecto® (fluralaner). Triatoma gerstaeckeri nymphs were allowed to feed on insecticide-live birds at 0, 3, 7, 14, 28 and 56 days post-treatment. The survival and feeding status of the T. gerstaeckeri insects were recorded and analyzed using Kaplan-Meier curves and logistic regression. Results: Feeding on fluralaner-treated chickens resulted 50-100% mortality in T. gerstaeckeri over the first 14 days post-treatment but not later; in contrast, all insects that fed on fenbendazole- and ivermectin-treated chickens survived. Liquid chromatography tandem mass spectrometry (LC-QQQ) analysis, used to detect the concentration of fluralaner and fenbendazole in chicken plasma, revealed the presence of fluralaner in plasma at 3, 7, and 14 days post-treatment but not later, with the highest concentrations found at 3 and 7 days post-treatment. However, fenbendazole concentration was below the limit of detection at all time points. Conclusions: Xenointoxication using fluralaner in poultry is a potential new tool for integrated vector control to reduce risk of Chagas disease.

Impacto dos fungos entomopatogênicos Metarhizium anisopliae e Beauveria bassiana no controle biológico de Rhodnius neglectus: um estudo realizado em condições de laboratório / Impact of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana on the biological control of Rhodnius neglectus: a study carried out under laboratory conditions

A doença de Chagas é uma doença negligenciada causada pelo protozoário Trypanosoma cruzi que afeta, aproximadamente, seis a sete milhões de pessoas em todo o mundo, resultando, todos os anos, em cerca de 14 mil mortes por complicações cardíacas e digestivas. A principal forma de transmissão dessa enfermidade na América Latina é vetorial, pelos triatomíneos, sendo o controle de vetores a principal medida para mitigar os casos de infecção por T. cruzi. O histórico do controle dos triatomíneos no Brasil se fundamenta, principalmente, no uso de inseticidas, fazendo-se necessário o manejo integrado de pragas como alternativa para a contenção desses vetores. Entre elas, tem sido realizada a utilização de controladores biológicos, visando auxiliar no estabelecimento de estratégias racionais e eficazes de controle de artrópodes vetores, uma vez que causam baixos danos ambientais. Diversos trabalhos consideram os fungos Beauveria bassiana e Metarhizium anisopliae patogênicos para triatomíneos, conferindolhes competência para o controle dos vetores da doença de Chagas. Dessa forma, foi testada a eficácia de produtos comerciais compostos pelos fungos M. anisopliae e B. bassiana no controle biológico de Rhodnius neglectus, como alternativa ao uso de inseticidas. As análises do potencial de B. bassiana resultaram na não eclosão de 28,3% dos ovos, na mortalidade de 8,57% das ninfas de primeiro estágio (N1) e de 24,44% dos adultos. Já M. anisopliae foi responsável pela não eclosão de 25% dos ovos, mortalidade de 21,43% das ninfas N1 e 13,33% dos adultos. Esses resultados, quando comparados ao grupo controle (30% de não eclosão de ovos, nenhuma mortalidade das ninfas e 30% de mortalidade em adultos), demonstraram a ineficácia desses fungos no controle de R. neglectus, uma vez que o grupo controle resultou em eclosão/mortalidade igual ou maior que os tratamentos com os fungos entomopatogênicos.

Chagas disease is a neglected disease caused by the protozoan Trypanosoma cruzi that affects approximately six to seven million people worldwide, resulting, every year, in about 14,000 deaths from heart and digestive complications. The main form of transmission of this disease in Latin America is vector, by triatomines, with vector control being the main measure to mitigate cases of infection by T. cruzi. The history of triatomine control in Brazil is mainly based on the use of insecticides, making integrated pest management necessary as an alternative to contain these vectors. Among them, the use of biological controllers has been carried out, aiming to help in the establishment of rational and effective strategies to control arthropod vectors, since they cause low environmental damage. Several works consider the fungi Beauveria bassiana and Metarhizium anisopliae to be pathogenic for triatomines, giving them competence to control the vectors of Chagas disease. Thus, we tested the effectiveness of commercial products composed of the fungi M. anisopliae and B. bassiana in the biological control of Rhodnius neglectus, as an alternative to the use of insecticides. Analyzes of the potential of B. bassiana resulted in the non-hatching of 28.3% of the eggs, the mortality of 8.57% of the first-stage nymphs (N1) and 24.44% of the adults. M. anisopliae was responsible for the non-hatching of 25% of the eggs, mortality of 21.43% of the N1 nymphs and 13.33% of the adults. These results, when compared to the control group (30% non-hatching of eggs, no nymph mortality and 30% mortality in adults), demonstrate the ineffectiveness of these fungi in the control of R. neglectus, since the control group resulted in hatching/mortality equal to or greater than treatments with entomopathogenic fungi.

Cytokey: desenvolvimento de uma chave de identificação com dados citogenéticos para os vetores da doença de Chagas do estado da Paraíba, Brasil / Cytokey: development of an identification key with cytogenetic data for Chagas disease vectors from the state of Paraíba

Os triatomíneos são insetos hematófagos vetores do protozoário Trypanosoma cruzi, agente etiológico da doença de Chagas (DC). Embora existam diferentes formas de transmissão do parasito, a Organização Mundial de Saúde ressalta que a vetorial seja a principal via de transmissão do T. cruzi na América Latina. No Brasil, existe cerca de 4,6 milhões de pessoas vivendo com DC, sendo os casos mais recentes de contaminação por infecção oral, a partir de barbeiros infectados e/ou fezes contaminadas que foram processados com alimentos consumidos in natura. Diversos casos de infecção oral foram registrados na região Nordeste, associados a surtos causados pelo consumo de caldo de cana ou outros alimentos. Nos estados da Paraíba (PB) e do Rio Grande do Norte (RN), por exemplo, 26 óbitos foram associados com infecção por via oral e 18 casos positivos para DC e duas mortes foram notificadas, respectivamente. Por séculos, as principais chaves de classificação se fundamentaram em chaves dicotômicas baseadas em dados morfológicos. Apenas em 2019, chaves alternativas, com base em dados citogenéticos (CytoKeys), foram propostas. Recentemente, chaves foram desenvolvidas para os estados de PE e RN. Com base no exposto, uma chave dicotômica foi desenvolvida para auxiliar na identificação das espécies de triatomíneos da PB, a partir de dados citogenéticos. Com base na chave dicotômica desenvolvida com dados citogenéticos, todas as espécies de triatomíneos notificadas na PB puderam ser diferenciadas. O desenvolvimento de chaves alternativas mostra-se de grande importância para a comunidade científica e, principalmente, os agentes de saúde que atuam no controle de vetores, auxiliando-os na correta identificação de espécies que apresentam semelhanças morfológicas (como as espécies Triatoma brasilensis e T. petrocchiae notificadas na PB).

Triatomines are hematophagous insects vectors of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease (CD). Although there are different forms of transmission of the parasite, the World Health Organization emphasizes that vector transmission is the main route of transmission of T. cruzi in Latin America. In Brazil, there are about 4.6 million people living with CD, with the most recent cases of contamination by oral infection, from infected triatomines and/or contaminated feces that were processed with food consumed in natura. Several cases of oral infection were registered in the Northeast region, associated with outbreaks caused by the consumption of sugarcane juice or other foods. In the states of Paraíba (PB) and Rio Grande do Norte (RN), for example, 26 deaths were associated with oral infection and 18 positive cases for CD and two deaths were reported, respectively. For centuries, the main classification keys were based on dichotomous keys based on morphological data. Only in 2019, alternative keys, based on cytogenetic data (CytoKeys), were proposed. Recently, keys were developed for the states of PE and RN. Based on the above, a dichotomous key was developed to assist in the identification of BP triatomine species, based on cytogenetic data. Based on the dichotomous key developed with cytogenetic data, all triatomine species reported in BP could be differentiated. The development of alternative keys is of great importance for the scientific community and, mainly, for health agents who work in vector control, helping them in the correct identification of species that present morphological similarities (such as the species Triatoma brasilensis and T .petrocchiae notified in BP).

Evaluation of triatomines infestation occurrence in home environments in the city of Taua-Ce, 2012 / Avaliação da ocorrência de infestação por triatomíneos em ambientes domiciliares no município de Tauá-Ce, 2012 / Evaluación de la ocurrencia de infestación por triatominos en ambientes domiciliarios en el municipio de Tauá-Ce, 2012

Background and Objectives: Triatomines are vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease, a parasitic disease that affects mammals and humans. The destruction or transformation of natural ecotopes has intensified, resulting in the invasion of triatomines in households, bringing risks to the population. Thus, the objective of the study was to carry out a data survey on triatomine infestation in the countryside of the city of TauaCe, in 2012. Methods: This is a descriptive/exploratory study of a quantitative nature, where the Secondary data were obtained from the Municipal Health Department (Endemic Nucleus). Results: The percentage of infestation in the 15 locations studied was 26.1%, with the most affected locations being: Sítio Central do Incra 50%, Fazenda Brôco 18.2%, Jordão 16.7%, Fazenda Bom Lugar 0%, Fazenda Riacho do Mato 40%, Fazenda Cearauai 37.5%, Sítio Riacho do Mato 30%, Fazenda Cedro 17.4%, Cachoeirinha 27%, Fazenda Várzea do Feijão 24%, Cachoeira do Júlio 41.2%, Fazenda Mutuquinha 9,4%, Sítio Várzea Grande 33.3%, Iparana 9.1% and Cachoeira do Celso 16.7%. Conclusion: The study showed that there is a significant rate of triatomine infestation in the home environment, which represents a great risk to the health of the population of Taua. Therefore, a more frequent entomological control is suggested, going beyond the period of campaigns for a better monitoring of the occurrence of these insects in the area.(AU)

Justificativa e Objetivos: Triatomíneos são vetores de Trypanosoma cruzi, agente etiológico da doença de Chagas, parasitose que atinge mamíferos e humanos. A destruição ou transformação dos ecótopos naturais tem se intensificado, resultando na invasão de triatomíneos em domicílios trazendo riscos a população. Diante do exposto, o objetivo do estudo foi realizar um levantamento de dados sobre a infestação de triatomíneos em localidades do interior do município de Tauá-Ce, em 2012. Métodos: Trata-se de um estudo descritivo/exploratório de natureza quantitativa, onde os dados secundários foram obtidos junto à Secretaria de Saúde (Núcleo de Endemias) do município. Resultados: O percentual de infestação nas 15 localidades estudadas foi de 26,1%, sendo as localidades mais afetadas: Sítio Central do Incra 50%, Fazenda Brôco 18,2%, Jordão 16,7%, Fazenda Bom Lugar 0%, Fazenda Riacho do Mato 40%, Fazenda Cearauai 37,5%, Sítio Riacho do Mato 30%, Fazenda Cedro 17,4%, Cachoeirinha 27%, Fazenda Várzea do Feijão 24%, Cachoeira do Júlio 41,2%, Fazenda Mutuquinha 9,4%, Sítio Várzea Grande 33,3%, Iparana 9,1% e Cachoeira do Celso 16,7%. Conclusão: O estudo mostrou que há um expressivo índice de infestação triatomínica em ambiente domiciliar, o que representa um grande risco a saúde da população tauaense. Sendo assim, sugere-se um controle entomológico mais frequente, ultrapassando o período de campanhas para um melhor acompanhamento da ocorrência desses insetos na região.(AU)

Justificación y Objetivos: Los triatomíneos son vectores de Trypanosoma cruzi, agente etiológico de la enfermedad de Chagas, parasitosis que afecta a mamíferos y humanos. La destrucción o transformación de los ecótopos naturales se ha intensificado, resultando en la invasión de triatomíneos en domicilios trayendo riesgos a la población. Ante lo expuesto, el objetivo del estudio fue realizar un levantamiento de datos sobre la infestación de triatomíneos en localidades del interior del municipio de Tauá-Ce, en 2012. Métodos: Se trata de un estudio descriptivo/exploratorio de naturaleza cuantitativa, donde los datos secundarios fueron obtenidos junto a la Secretaría de Salud (Núcleo de Endemias) del municipio. Resultados: El porcentaje de infestación en las 15 localidades estudiadas fue de 26,1%, siendo las localidades más afectadas: Sítio Central do Incra 50%, Fazenda Brôco 18,2%, Jordão 16,7%, Fazenda Bom Lugar 0%, Fazenda Riacho do Mato 40%, Fazenda Cearauai 37,5%, Sítio Riacho do Mato 30%, Fazenda Cedro 17,4%, Cachoeirinha 27%, Fazenda Várzea do Feijão 24%, Cachoeira do Júlio 41,2%, Fazenda Mutuquinha 9,4%, Sítio Várzea Grande 33,3%, Iparana 9,1% e Cachoeira do Celso 16,7%. Conclusión: El estudio mostró que hay un expresivo índice de infestación triatomínica en ambiente domiciliar, lo que representa un gran riesgo para la salud de la población tauaense. Siendo así, se sugiere un control entomológico más frecuente, superando el período de campañas para un mejor seguimiento de la ocurrencia de esos insectos en la región.(AU)

Laboratory Evaluation and Field Feasibility of Micro-Encapsulated Insecticide Effect on Rhodnius prolixus and Triatoma dimidiata Mortality in Rural Households in Boyacá, Colombia

Abstract: Chagas disease is a neglected vector-borne zoonosis caused by the parasite Trypanosoma cruzi that is primarily transmitted by insects of the subfamily Triatominae. Although control efforts targeting domestic infestations of Rhodnius prolixus have been largely successful, with several regions in Boyacá department certified free of T. cruzi transmission by intradomicile R. prolixus, novel native species are emerging, increasing the risk of disease. Triatoma dimidiata is the second most important species in Colombia, and conventional control methods seem to be less effective. In this study we evaluated the efficacy and usefulness of micro-encapsulated insecticide paints in laboratory conditions and its applicability in rural communities to avoid triatomine domiciliation. Laboratory conditions measured mortality at 6 months and 12 months, with an average mortality between 93­100% for T. dimidiata and 100% for R. prolixus. Evaluation of triatomine infestation in rural households was measured after one year, with an overall perception of effectiveness in reducing household domiciliation. Although triatomines were still spotted inside and around the homes, our findings demonstrate the ability of micro-encapsulated insecticide to prevent colonization inside the households when comparing infestation rates from previous years. Current control measures suggest insecticide spraying every six months, which implies great economic cost and logistical effort. Complementary triatomine control measures with insecticide spraying and micro-encapsulated insecticide paint would make public health efforts more efficient and reduce the frequency of treatment.

Evaluation of the Effectiveness of Chemical Control for Chagas Disease Vectors in Loja Province, Ecuador

The objective of this study was to evaluate the effectiveness of selective and community-wide house insecticide spraying in controlling triatomines in the subtropical areas of Loja Province, Ecuador. We designed a quasiexperimental pre­post-test without a control group to compare entomological levels before and after spraying. The baseline study was conducted in 2008. Second, third, and fourth visits were conducted in 2010, 2011, and 2012 in three rural communities. Out of the 130 domestic units (DU) visited, 41 domestic units were examined in each of the four visits. Selective and community-wide insecticide interventions included spraying with 5% deltamethrin at 25 mg/m2 active ingredient. At each visit, a questionnaire was administered to identify the characteristics of households, and DUs were searched for triatomine bugs. In addition, parasitological analysis was carried out in life triatomines. One and two rounds of selective insecticide spraying decreased the probability of infestation by 62% (pairwise odds ratios [POR] 0.38, 95% confidence interval [CI] 0.17­0.89, p = 0.024) and 51% (POR 0.49, 95% CI 0.23­1.01, p = 0.054), respectively. A similar effect was observed after one round of community-wide insecticide application in Chaquizhca and Guara (POR 0.55, CI 0.24­1.25, p = 0.155) and Bellamaria (POR 0.62, CI 0.22­1.79, p = 0.379); however, it was not statistically significant. Trypanosoma cruzi infection in triatomines (n = 483) increased overtime, from 2008 (42.9% and 8.5% for Rhodnius ecuadoriensis and Panstrongylus chinai, respectively) to 2012 (79.5% and 100%). Neither of the two spraying methodologies was effective for triatomine control in this area and our results point to a high likelihood of reinfestation after insecticide application. This underscores the importance of the implementation of physical barriers that prevent invasion and colonization of triatomines in households, such as home improvement initiatives, accompanied by a concerted effort to address the underlying socioeconomic issues that keep this population at risk of developing Chagas disease.

Dinâmica das populações de Triatoma infestans no Chaco Paraguaio: Análise genética populacional da reinfestação domiciliar após controle vetorial / Dynamics of Triatoma infestans populations in the Paraguayan Chaco: Population genetic analysis of household reinfestation following vector control

Background Although domestic infestations by Triatoma infestans have been successfully controlled across Latin America, in areas of the Gran Chaco region, recurrent post-spraying house colonization continues to be a significant challenge, jeopardizing Chagas disease vector control and maintaining active Trypanosoma cruzi transmission. Methodology/Principal findings To investigate the dynamics of triatomine reinfestation in a rural area of the Paraguayan Chaco, genetic characterization (based on 10 microsatellite loci and cytochrome B sequence polymorphisms) was performed on baseline and reinfestant T. infestans (n = 138) from four indigenous communities and adjacent sylvatic sites. House quality and basic economic activities were assessed across the four communities. Significant genetic differentiation was detected among all baseline triatomine populations. Faster reinfestation was observed in the communities with higher infestation rates pre-spraying. Baseline and reinfestant populations from the same communities were not genetically different, but two potentially distinct processes of reinfestation were evident. In Campo Largo, the reinfestant population was likely founded by domestic survivor foci, with reduced genetic diversity relative to the baseline population. However, in 12 de Junio, reinfestant bugs were likely derived from different sources, including survivors from the pre-spraying population and sympatric sylvatic bugs, indicative of gene-flow between these habitats, likely driven by high human mobility and economic activities in adjacent sylvatic areas. Conclusions/Significance Our results demonstrate that sylvatic T. infestans threatens vector control strategies, either as a reinfestation source or by providing a temporary refuge during insecticide spraying. Passive anthropogenic importation of T. infestans and active human interactions with neighboring forested areas also played a role in recolonization. Optimization of spraying, integrated community development and close monitoring of sylvatic areas should be considered when implementing vector control activities in the Gran Chaco.

Monitoramento da suscetibilidade de populações de Rhodnius neglectus (Lent, 1954) a inseticidas utilizados em ações de controle em áreas urbanas do noroeste do estado de São Paulo / Monitoring Rhodnius neglectus (Lent, 1954) populations' susceptibility to insecticide used in controlling actions in urban areas northwest of São Paulo state

Background: Chagas disease (CD) is caused by the flagellate protozoan Trypanosoma cruzi and can be carried by different species of triatomines, including Rhodnius neglectus, which is wild, well distributed in Brazil, and has formed colonies in palm trees located in urban areas of municipalities in the state of São Paulo. Chemical control has been routinely used to reduce population density, but each year, there has been an increase in species dispersion and density. This study aimed to evaluate the susceptibility of insects to insecticides used in control. Methods: The reference population was collected from Araçatuba municipality, Nilce Maia. Dilutions of deltamethrin were prepared and applied to the back of the first-stage nymphs, which were biologically synchronized. The control group received pure acetone only. Mortality was assessed after 72 h. Results: The mortality rate with respect to diagnostic dose was 100%. The susceptibility profile observed for this population showed RR50 ranging from 1.76 to 3.632. Conclusions: The populations were susceptible to the insecticides tested. It is possible that the insecticide residual effect on this ecotope has decreased the lifespan, and controlling failures may be the cause of recolonization in this environment.

Hemolymph of triatomines presents fungistatic activity against Cryptococcus neoformans and improves macrophage function through MCP-I/TNF-α increase

Triatomines are blood-feeding arthropods belonging to the subfamily Triatominae (Hemiptera; Reduviidae), capable of producing immunomodulatory and water-soluble molecules in their hemolymph, such as antimicrobial peptides (AMPs). In this work, we evaluated the antifungal and immunomodulatory activity of the hemolymph of Meccus pallidipennis (MPH) and Rhodnius prolixus (RPH) against Cryptococcus neoformans. Methods: We assessed the activity of the hemolymph of both insects on fungal growth by a minimum inhibitory concentration (MIC) assay. Further, RAW 264.7 macrophages were cultivated with hemolymph and challenged with C. neoformans. Then, their phagocytic and killing activities were assessed. The cytokines MCP-1, IFN-γ, TNF-α, IL-10, IL-12, and IL-6 were measured in culture supernatants 4- and 48-hours post-infection. Results: Both hemolymph samples directly affected the growth rate of the fungus in a dose-dependent manner. Either MPH or RPH was capable of inhibiting fungal growth by at least 70%, using the lowest dilution (1:20). Treatment of RAW 264.7 macrophages with hemolymph of both insects was capable of increasing the production of MCP-I and TNF-α. In addition, when these cells were stimulated with hemolymph in the presence of C. neoformans, a 2- and a 4-fold increase in phagocytic rate was observed with MPH and RPH, respectively, when compared to untreated cells. For the macrophage killing activity, MPH decreased in approximately 30% the number of viable yeasts inside the cells compared to untreated control; however, treatment with RPH could not reduce the total number of viable yeasts. MPH was also capable of increasing MHC-II expression on macrophages. Regarding the cytokine production, MCP-I and TNF-α, were increased in the supernatant of macrophages treated with both hemolymphs, 4 and 48 hours after stimulation. Conclusion: These results suggested that hemolymph of triatomines may represent a source of molecules capable of presenting antifungal and immunomodulatory activity in macrophages during fungal infection.(AU)

Avaliação do conhecimento sobre a doença de Chagas em escolares das zonas rural e urbana de municípios endêmicos em Minas Gerais / Assessment of knowledge about Chagas disease in schoolchildren in rural and urban areas of endemic municipalities in Minas Gerais state, Brazil

Resumo O objetivo deste estudo foi avaliar o conhecimento de escolares do ensino médio de três escolas localizadas em municípios mineiros endêmicos para a doença de Chagas e extrair informações relativas à sua percepção em relação aos aspectos gerais, biológicos, clínicos e epidemiológicos da doença, do vetor e controle entomológico da doença de Chagas, além de comparar o conhecimento dos participantes em função da localização das escolas (zona rural ou urbana). Para isso, aplicou-se um questionário semiestruturado a 68 alunos. Todos os participantes já ouviram falar a respeito da doença de Chagas, afirmando ter adquirido esse conhecimento, sobretudo, com familiares e escola. Além disso, muitos participantes demonstraram conhecer os hábitos dos vetores, tais como hematofagia e fontes alimentares. Não houve associação clara entre o perfil de urbanização e o conhecimento dos participantes. No entanto, alunos da zona urbana apresentaram menos conhecimento prático a respeito dos triatomíneos e aspectos relativos à transmissão da doença, em relação aos alunos da zona mais "ruralizada". Sugere-se o aprofundamento do tema nos currículos escolares do ensino médio e a necessidade de elaboração de ações de educação em saúde voltadas à vigilância entomológica da doença de Chagas nesses municípios e, provavelmente, em outras regiões do Brasil.

Abstract This study aimed to evaluate the knowledge of high school students from three schools located in endemic municipalities of Minas Gerais to Chagas disease and to extract information related to their perception regarding the general, biological, clinical and epidemiological aspects of the disease, vector and entomological control of Chagas disease, in addition to comparing the knowledge of participants according to the location of schools (rural or urban area). For this, a semi-structured questionnaire was applied to 68 students. All participants have heard about Chagas disease, stating that they have acquired this knowledge, especially with family members and school. In addition, many participants demonstrated to know the habits of vectors, such as hematophagy and dietary sources. There was no clear association between the urbanization profile and the participants' knowledge. However, students from the urban area presented less practical knowledge about triatoins and aspects related to the transmission of the disease, in relation to students in the most "ruralized" area. It is suggested the deepening of the theme in high school curricula and the need to develop health education actions aimed at entomological surveillance of Chagas disease in these municipalities and, probably, in other Brazilian regions.

Actualización de la distribución geográfica de triatominos en el departamento del Putumayo / Update to the geographical distribution of triatomines in the Department of Putumayo / Atualização da distribuição geográfica de triatomíneos no Departamento de Putumayo

La enfermedad de Chagas es una zoonosis producida por la infección del Trypanosoma cruzi (T. cruzi) (1), cuya principal vía de transmisión es vectorial (2). Esta enfermedad se caracteriza por ser una infección crónica que puede ocasionar daños cardiacos, digestivos y neurológicos irreversibles (3). En el departamento del Putumayo, de acuerdo con los datos del Sistema de Vigilancia Epidemiológica (SIVIGILA), entre el año 2015 y el 2020, se han notificado 19 casos de Chagas crónico y 4 casos de Chagas agudos (4). Por este motivo resulta de gran interés compartir con los lectores de la revista MedUNAB la actualización de la distribución geográfica de los triatominos, vectores de la enfermedad de Chagas, y establecer el riesgo epidemiológico que representan para la población Putumayense, donde hay hallazgos de gran importancia porque se identifican especies en municipios y localidades donde antes no se conocían. Palabras claves: Triatominae; Enfermedad de Chagas; Infección por Trypanosoma cruzi; Infecciones; Insectos Vectores; Colombia.

Chagas Disease is a zoonotic disease produced by infection with Trypanosoma cruzi (T. cruzi) (1), whose main route of transmission is vectorial (2). This disease is characterized by being a chronic infection that can cause irreversible cardiac, digestive, and neurological damage (3). In the department of Putumayo, according to data from the epidemiological surveillance system (SIVIGILA, for the Spanish original), between 2015 and 2020, 19 chronic cases and 4 acute cases of Chagas were reported (4). For this reason, it is important to share with the readers of the MedUNAB journal the update to the geographical distribution of triatomines, vectors of Chagas Disease, and to establish the epidemiological risk that they represent for the population of Putumayo, where there are findings of great importance as species are identified in municipalities and localities where they were not previously found. Keywords: Triatominae; Chagas Disease; Trypanosoma cruzi; Infections; Insect Vectors; Colombia.

A doença de Chagas é uma zoonose causada por infecção com Trypanosoma cruzi (T. cruzi) (1), cujo principal modo de transmissão é vetorial (2). Esta doença é uma infecção crônica que pode causar danos cardíacos, digestivos e neurológicos irreversíveis (3). No Departamento de Putumayo, de acordo com dados do Sistema de Vigilância Epidemiológica (SIVIGILA), entre 2015 e 2020, foram notificados 19 casos de Chagas crônica e quatro casos de Chagas aguda (4). Por esta razão, é de grande interesse compartilhar com os leitores da revista MedUNAB a atualização da distribuição geográfica dos triatomíneos, vetores da doença de Chagas, e estabelecer o risco epidemiológico que representam para a população de Putumayo, onde há descobertas de grande importância, pois são identificadas espécies em municípios e localidades onde antes eram desconhecidas. Palavras-chave: Triatominae; Doença de Chagas; Infecção por Trypanosoma cruzi; Infecções; Insetos Vetores; Colômbia.

Validation of a documentary on Chagas disease by a population living in an endemic area / Validação de um documentário sobre a doença de Chagas por uma população de área endêmica

Abstract Educational interventions may trigger actions that contribute to prevent parasitic diseases, such as Chagas disease (CD). This study aimed at investigating the impact of an instructional video named "Documentary on Chagas Disease" on knowledge about CD and its vectors displayed by a population that lives in an endemic area in Brazil, so as to validate it as an educational tool. The video was shown to 226 subjects, divided into two groups. Group 1 was composed of users of Basic Health Units (BHU) in Pelotas and Pinheiro Machado, cities located in Rio Grande do Sul (RS) state, Brazil, where CD is endemic. Group 2 consisted of students who attend three public schools located in the rural area in Pinheiro Machado, RS. Two questionnaires with questions about their knowledge about triatomines and CD were applied, before and after the documentary was shown. After the video was shown, there was significant increase in individuals' knowledge (in both groups) about "kissing bugs", their notification, the disease and its prevention. Besides, watchers considered that the quality of the material was satisfactory. Since the "Documentary on CD" can be easily accessed on the internet and was effective in teaching the population that lives in endemic areas, its use should be encouraged in places and meetings connected to health that aim at fighting against triatominae and at exposing an updated view of CD.

Resumo Intervenções educacionais podem desencadear ações que contribuam para a prevenção de doenças parasitárias, como a doença de Chagas (DC). Este estudo teve como objetivo investigar o impacto de um vídeo instrucional denominado "Documentário Doença de Chagas" no conhecimento sobre DC e seus vetores exibidos a uma população que vive em área endêmica no Brasil, para validá-lo como uma ferramenta educacional. O vídeo foi exibido para 226 indivíduos, divididos em dois grupos. O grupo 1 foi composto por usuários das Unidades Básicas de Saúde (UBS) de Pelotas e Pinheiro Machado, cidades do estado do Rio Grande do Sul (RS), Brasil, onde a DC é endêmica. O grupo 2 foi formado por estudantes que frequentam três escolas públicas localizadas na zona rural de Pinheiro Machado, RS. Dois questionários com perguntas sobre conhecimentos sobre triatomíneos e DC foram aplicados, antes e depois da exibição do documentário. Após a exibição do vídeo, houve um aumento significativo no conhecimento dos indivíduos (em ambos os grupos) sobre "triatomíneos", sua notificação, a doença e sua prevenção. Além disso, os observadores consideraram que a qualidade do material era satisfatória. Como o "Documentário DC" pode ser facilmente acessado na Internet e ser eficaz no ensino à população que vive em áreas endêmicas, seu uso deve ser incentivado em locais e reuniões relacionadas à saúde, que visam combater os triatomíneos e exibir uma informação atualizada sobre a DC.

Metaciclogénesis de Trypanosoma cruzi en Belminus ferroae (Reduviidae: Triatominae) y capacidad infectiva de las heces en condiciones de laboratorio / Metacyclogenesis of Trypanosoma cruzi in B. ferroae (Reduviidae: Triatominae) and feces infectivity under laboratory conditions

Resumen | Introducción. Belminus ferroae es un triatomino de comportamiento entomófago, sin embargo, puede alimentarse de vertebrados ocasionalmente. No se ha demostrado infección natural por Trypanosoma cruzi en esta especie, como tampoco la metaciclogénesis del parásito. Objetivo. Examinar la metaciclogénesis de T. cruzi en B. ferroae y la capacidad infectiva de las heces o sus contenidos intestinales en roedores. Materiales y métodos. Se analizaron las heces y la orina expulsadas espontáneamente por los insectos o mediante compresión abdominal o extracción del contenido intestinal a los 10, 20, 30, 40, 50 y 60 días. Se cuantificó la carga parasitaria de T. cruzi y sus formas evolutivas se identificaron con tinción de Giemsa. Asimismo, se evaluó en ratones albinos la capacidad infectiva de los tripomastigotes metacíclicos de T. cruzi obtenidos de las heces o contenidos intestinales de los especímenes infectados. Resultados. El análisis parasitológico reveló tres (15 %) insectos infectados con T.cruzi a los 30 (n=1), 40 (n=1) y 50 (n=1) días después de la infección con cargas parasitarias de hasta 1,62 x 105 tripanosomas/mm3 y porcentajes de metaciclogénesis entre el 3,5 y el 6,78 %. Conclusiones. Se demuestra por primera vez, en una especie del género Belminus, la metaciclogenésis de T. cruzi en condiciones de laboratorio y la capacidad infectiva de las heces para un huésped vertebrado.

Abstract | Introduction: Belminus ferroae is a triatominae with entomophagous behavior. However, it may occasionally feed on vertebrates. Currently, there is no evidence of natural infection with Trypanosoma cruzi or the occurrence of metacyclogenesis in this species. Objective: To test T. cruzi metacyclogenesis in B. ferroae and the infectivity of their feces or intestinal contents in rodents under laboratory conditions. Materials and methods: Twenty nymphs of B. ferroae were infected with an autochthonous strain of T. cruzi (M/HOM/VE/09/P6). Fecal and urine samples were collected from spontaneous droppings or by compressing the bugs' abdomens and, eventually, by removing their gut contents, and then examined at 10, 20, 30, 40, 50, and 60 days. We quantified T. cruzi parasitic load, as well as the evolutionary forms in feces, urine, and intestinal contents by Giemsa staining. Similarly, we evaluated the infectivity of T. cruzi metacyclic trypomastigotes in albino mice. Results: The parasitological analysis showed three insects (15%) infected with T. cruzi at 30 (n=1), 40 (n=1), and 50 (n=1) days post-infection. We observed parasitic loads of up to 1.62 x 105 trypanosomes/mm3 and metacyclogenesis percentages between 3.5% and 6.78%. Conclusions: This is the first time that T. cruzi metacyclogenesis is reported in a species of the genus Belminus under laboratory conditions and the infectivity of Belminus' feces is demonstrated on a vertebrate host.

First report of colonization by Panstrongylus megistus (Burmeister, 1835) (Hemiptera, Reduviidae, Triatominae) in the Metropolitan Region of São Paulo, Brazil / Primeiro relato de colonização por Panstrongylus megistus (Burmeister, 1835) (Hemiptera, Reduviidae, Triatominae) na Região Metropolitana de São Paulo, Brasil

Abstract We report the first known occurrence of Panstrongylus megistus (Burmeister, 1835) (Hemiptera, Reduviidae, Triatominae) in the Metropolitan Region of São Paulo, Brazil. In 2018, adult specimens were sent by residents to the competent authorities and, in the inspection of the property, a large focus associated with a marsupial nest was found. This finding reinforces the importance of the species in the state of São Paulo, serves as an alert for epidemiological surveillance and extends the species colonization area in the state of São Paulo.

Resumo Relatamos a primeira ocorrência de Panstrongylus megistus (Burmeister, 1835) (Hemiptera, Reduviidae, Triatominae) na Região Metropolitana de São Paulo, Brasil. Em 2018, espécimes adultos foram enviados por residentes e a pesquisa na propriedade constatou a presença de um grande foco associado a um ninho marsupial. Este achado reforça a importância da espécie no estado de São Paulo, serve de alerta para a vigilância epidemiológica e amplia a área de colonização da espécie no estado de São Paulo.

Triatominae (Hemiptera, Reduviidae) in homes: Report of their occurrence in the municipality of Cruzeiro do Sul, Acre, South Western Amazon

Abstract INTRODUCTION: Triatomines are hematophagous insects that are important to public health since they are the vectors of American Trypanosomiasis. The objective of this study was to describe the occurrence of triatomines in homes in Cruzeiro do Sul, Acre, Brazil. METHODS The specimens were collected by an active search inside homes and also by a passive search by the residents. RESULTS: A total of 55 triatomines were captured comprising of 5 species each of the genera Rhodnius, Eratyrus, and Panstrongylus. No colonies were detected, ruling out the possibility of domiciliation. CONCLUSIONS: Information on regional epidemiological dynamics contributes to the prevention and control of disease.

Panstrongylus rufotuberculatus (Champion, 1899) (Hemiptera, Reduviidae, Triatominae) in Rondônia, Brazil: A novel report

Abstract INTRODUCTION: This short communication presents a novel report on the occurrence of Panstrongylus rufotuberculatus in the Brazilian state of Rondônia. METHODS: Two specimens were collected inside dwellings and identified using dichotomous keys. RESULTS: The present study showed the extensive geographic distribution of P. rufotuberculatus and the increased number of species in the state of Rondônia. CONCLUSIONS: This new record of P. rufotuberculatus is important for understanding the epidemiology of Chagas disease because this species is found naturally infected with Trypanosoma cruzi. Studies on the ecology, biology, and vector-host-parasite interactions of this species are essential for surveillance programs.

History of insecticide resistance of Triatominae vectors

In the last 15 years, different types of Triatominae resistance to different insecticides have been reported; thus, resistance may be more widespread than known, requiring better characterization and delimitation, which was the aim of this review. This review was structured on a literature search of all articles from 1970 to 2015 in the PubMed database that contained the keywords Insecticide resistance and Triatominae. Out of 295 articles screened by title, 33 texts were selected for detailed analysis. Insecticide resistance of Triatomines is a complex phenomenon that has been primarily reported in Argentina and Bolivia, and is caused by different factors (associated or isolated). Insecticide resistance of Triatominae is a characteristic inherited in an autosomal and semi-dominant manner, and is polygenic, being present in both domestic and sylvatic populations. The toxicological profi le observed in eggs cannot be transposed to different stages of evolution. Different toxicological profi les exist at macro- and microgeographical levels. The insecticide phenotype has both reproductive and developmental costs. Different physiological mechanisms are involved in resistance. Studies of Triatomine resistance to insecticides highlight three defi ciencies in interpreting the obtained results: I) the vast diversity of methodologies, despite the existence of a single guiding protocol; II) the lack of information on the actual impact of resistance ratios in the fi eld; and III) the concept of the susceptibility reference lineage. Research on the biological and behavioral characteristics of each Triatominae species that has evolved resistance is required in relation to the environmental conditions of each region.

Distribution and natural infection status of synantrophic triatomines (Hemiptera: Reduviidae), vectors of Trypanosoma cruzi, reveals new epidemiological scenarios for chagas disease in the Highlands of Colombia

Updating the distribution and natural infection status of triatomine bugs is critical for planning, prioritizing, and implementing strategies to control Chagas disease (CD), especially after vector reduction programs. After carrying out a control program, the Department of Boyaca contains the highest number of Colombian municipalities certified by PAHO to be free of intradomiciliary transmission of Trypanosoma cruzi by Rhodnius prolixus. The present work describes the spatial distribution, natural infection (NI), and molecular characterization of T. cruzi in synanthropic triatomines from the Department of Boyaca in 2017 and 2018. Materials and methods: An entomological survey was conducted in 52 municipalities in Boyaca known to have had previous infestations of triatomine bugs. Insects were collected through active searches carried out by technical personnel from the Secretary of Health and community members using Triatomine Collection Stations (PITs-acronym in Spanish). For evaluation of natural infection, triatomines were identified morphologically and grouped in pools of one to five individuals of the same species collected in the same household. DNA derived from the feces of each pool of insects was analyzed by PCR for the presence of T. cruzi using primers flanking the satellite DNA of the parasite. SL-IR primers were used to differentiate TCI from the other DTUs and to identify different genotypes. The distribution of the collected triatomines was analyzed to determine any vector hotspots using spatial recreation. Results: A total of 670 triatomine bugs was collected, belonging to five species: Triatoma dimidiata (73.2%), Triatoma venosa (16.7%), Panstrongylus geniculatus (5.7%), Rhodnius prolixus (4.4%), and Panstrongylus rufotuberculatus (0.4%), from 29 of the 52 municipalities. In total, 71.6% of the bugs were collected within houses (intradomiciliary) and the rest around the houses (peridomiciliary). Triatoma dimidiata was the most widely distributed species and had the highest natural infection index (37.8%), followed by T. venosa and P. geniculatus. TcI was the only DTU found, with the TcI Dom genotype identified in 80% of positive samples and TcI sylvatic in the other insects. Spatial analysis showed clusters of T. dimidiata and T. venosa in the northeast and southwest regions of Boyaca. Conclusions: After some municipalities were certified free of natural transmission within houses (intradomiciliary transmission) of T. cruzi by R. prolixus, T. dimidiata has become the most prevalent vector present, and represents a significant risk of resurgent CD transmission. However, T. venosa, P. geniculatus, and P. rufotuberculatus also contribute to the increased risk of transmission. The presence of residual R. prolixus may undo the successes achieved through vector elimination programs. The molecular and spatial analysis used here allows us to identify areas with an ongoing threat of parasite transmission and improve entomological surveillance strategies.

Knockdown of CYP4PR1, a cytochrome P450 gene highly expressed in the integument tissue of Triatoma infestans, increases susceptibility to deltamethrin in pyrethroid-resistant insects / A eliminação do CYP4PR1, um gene do citocromo P450 altamente expresso no tecido tegumentar de Triatoma infestans, aumenta a suscetibilidade à deltametrina em insetos resistentes aos piretróides

Abstract Metabolic resistance to chemical insecticides implies a greater capacity to detoxify insecticides due to an increase in the expression of genes and/or in the activity of enzymes related to detoxification metabolism. The insect integument is known to participate as the cuticular penetration factor of resistance, but recently this tissue was also linked with metabolic resistance due to P450-dependent detoxification in the Chagas disease vector Triatoma infestans. The objectives of this study were i) to name and classify all P450s known to date in T. infestans, ii) to characterise one of them, CYP4PR1, representing the first member of a new cytochrome P450 subfamily described in insects, and iii) to investigate the potential role of CYP4PR1 in metabolic resistance to deltamethrin in T. infestans. We found that CYP4PR1 is expressed almost exclusively in the integument tissue, and its expression was not induced by deltamethrin. Knockdown of CYP4PR1 by RNA interference in pyrethroid-resistant nymphs caused a significant increment in insect mortality after topical application of two different doses of deltamethrin. These results support the role of the integument on metabolic resistance and suggest that CYP4PR1 might contribute to resistance in integument tissue of T. infestans.

Phenotypic plasticity, canalisation and developmental stability of Triatoma infestans wings: effects of a sublethal application of a pyrethroid insecticide

Abstract Background: Triatomine control campaigns have traditionally consisted of spraying the inside of houses with pyrethroid insecticides. However, exposure to sublethal insecticide doses after the initial application is a common occurrence and may have phenotypic consequences for survivors. Here, using Triatoma infestans (the main vector of Chagas disease in the Southern Cone of South America) as a model species, we quantifed the efects of exposure to a sublethal dose of pyrethroid insecticide on wing morphology. We tested if the treatment (i) induced a plastic efect (change in the character mean); (ii) altered environmental canalisation (higher individual variation within genotypes); (iii) altered genetic canalisation (higher variation among genotypes); and (iv) altered developmental stability (higher fuctuating asymmetry [FA]). Methods: Each of 25 full-sib families known to be susceptible to pyrethroid insecticides were split in two groups: one to be treated with a sublethal dose of deltamethrin (insecticide-treated group) and the other to be treated with pure acetone (control group). Wings of the emerging adults were used in a landmark-based geometric morphometry analysis to extract size and shape measurements. Average diferences among treatments were measured. Levels of variation among families, among individuals within families and among sides within individuals were computed and compared among treatments. Results: Wing size and shape were afected by a sublethal dose of deltamethrin. The treated insects had larger wings and a more variable wing size and shape than control insects. For both wing size and shape, genetic variation was higher in treated individuals. Individual variations and variations in FA were also greater in deltamethrin-treated insects than in control ones for all full-sib families; however, the patterns of shape variation associated with genetic variation, individual variation and FA were diferent. Conclusions: Insects exposed to a sublethal dose of deltamethrin presented larger, less symmetrical and less canalised wings. The insecticide treatment jointly impaired developmental stability and genetic and environmental canalisation. The divergent patterns of shape variation suggest that the related developmental bufering processes difered at least partially. The morphological modifcations induced by a single sublethal exposure to pyrethroids early in life may impinge on subsequent fight performance and consequently afect the dynamics of house invasion and reinfestation, and the efectiveness of triatomine control operations.