A simplified molecular tool for detecting the Chagas etiological agent using a vector feces sample in field conditions.

Triatomine bugs are vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease in the American continent. Here, we have tested a loop-mediated isothermal amplification (LAMP) test for a direct detection of T. cruzi in feces of Triatoma infestans, the main vector of this parasite in the Southern Cone of America. The analytical evaluation showed positive results with samples of triatomine feces artificially inoculated with DNA from strains of T. cruzi corresponding to each Discrete Typing Units (I-VI), with a sensitivity of up to one parasite per reaction. Conversely, the reaction yielded negative results when tested with DNA from Trypanosoma rangeli and other phylogenetically related and unrelated organisms. In triatomines captured under real field conditions (from urban households), and defined as positive or negative for T. cruzi using the reference microscopy technique, the LAMP test achieved a concordance of 100 %. Our results demonstrate that this LAMP reaction exhibits excellent analytical specificity and sensitivity without interference from the fecal matrix, since all the reactions were conducted without purification steps. This simple molecular diagnostic technique can be easily used by vector control agencies under field conditions.

Applicability of Traps for Collecting Mosquito Immatures (Diptera: Culicidae) for Entomological Surveillance of Arbovirus Vectors in a Remnant of the Atlantic Forest, Rio de Janeiro State, Brazil.

Diverse larval habitats significantly influence female mosquito oviposition. Utilizing traps that simulate these habitats is helpful in the study of the bioecology and characteristics of pathogen-transmitting species during oviposition. This study evaluated the feasibility of different traps in natural environments by comparing sampling methods and detecting the oviposition of epidemiologically important mosquitoes, with emphasis on Haemagogus species, in a fragment of the Atlantic Forest in Silva Jardim, Rio de Janeiro State, Brazil. Monthly collections were conducted from March 2021 to October 2023 using four types of traps: plastic containers, tires, bamboo, and sapucaia. Immatures were collected from these traps using a pipette, placed in plastic bags, and transported to the laboratory. Tire was the most efficient trap, showing the highest mosquito abundance (n = 1239) and number of species (S = 11). Conversely, the plastic container trap exhibited the lowest diversity (H = 0.43), with only two species and a low mosquito abundance (n = 26). The bamboo trap captured six species and recorded the second-highest diversity index (H = 1.04), while the sapucaia trap captured five species and had the third-highest diversity index (H = 0.91). Of the total immatures collected, 1817 reached adulthood, comprising 13 species, two of which are vectors of the sylvatic yellow fever virus: Haemagogus leucocelaenus and Haemagogus janthinomys. In conclusion, detecting key vectors of the sylvatic yellow fever virus in Brazil highlights the need for ongoing entomological and epidemiological surveillance in the study area and its vicinity. These efforts are crucial for monitoring vector presence and activity, identifying potential transmission hotspots, and devising effective control and prevention strategies.

Long-Term Trends in Mosquito Vector Populations and Their Impact on Yellow Fever Outbreaks in Atlantic Forest Fragments of Rio De Janeiro, Brazil (2016-2021).

Among all living beings, mosquitoes account for the highest number of human fatalities. Our study aimed to determine mosquito egg abundance fluctuation from 2015 to 2020, in order to observe which years had the highest mosquito vector densities and whether they coincided with yellow fever virus outbreaks in both human and nonhuman primates. The study area included Atlantic Forest fragments in the state of Rio de Janeiro. Studies from the Diptera Laboratory at FIOCRUZ were selected and compared along a timeline period of the field collections. The highest peak in egg abundance from the analyzed studies was observed from 2016 to 2017 and from 2015 to 2016. The lowest egg abundance was during the collection periods from 2018 to 2019 and 2019 to 2020. The species with the highest abundance throughout all the periods of the studies analyzed was Haemagogus leucocelaenus, representing 87% of all epidemiological species identified. The species with the lowest abundance was Hg. Janthinomys, representing only 1%. Monitoring the population of mosquitoes is imperative for disease surveillance, as the rise in specimens of various vector species directly impacts the occurrence of yellow fever cases in both nonhuman primates and human populations.

Variety is the spice: The role of morphological variation of Triatoma infestans (Hemiptera, Reduviidae) at a macro-scale.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi (Chagas, 1909). One of the primary vectors of T. cruzi in South America is Triatoma infestans (Klug, 1834). This triatomine species is distributed across a huge latitudinal gradient, inhabiting domiciliary , peridomiciliary , and wild environments. Its wide geographic distribution provides an excellent opportunity to study the relationships between environmental gradients and intraspecific morphological variation. In this study, we investigated variations in wing size and shape in T. infestans across six ecoregions. We aimed to address the following questions: How do wing size and shape vary on a regional scale, does morphological variation follow specific patterns along an environmental or latitudinal gradient, and what environmental factors might contribute to wing variation? Geometric morphometric methods were applied to the wings of 162 females belonging to 21 T. infestans populations, 13 from Argentina (n = 105), 5 from Bolivia (n = 42), and 3 from Paraguay (n = 15). A comparison of wing centroid size across the 21 populations showed significant differences. Canonical Variate Analysis (CVA) revealed significant differences in wing shape between the populations from Argentina, Bolivia, and Paraguay, although there was a considerable overlap, especially among the Argentinian populations. Well-structured populations were observed for the Bolivian and Paraguayan groups. Two analyses were performed to assess the association between wing size and shape, geographic and climatic variables: multiple linear regression analysis (MRA) for size and Partial Least Squares (PLS) regression for shape. The MRA showed a significant general model fit. Six temperature-related variables, one precipitation-related variable, and the latitude showed significant associations with wing size. The PLS analysis revealed a significant correlation between wing shape with latitude, longitude, temperature-related, and rainfall-related variables. Wing size and shape in T. infestans populations varied across geographic distribution. Our findings demonstrate that geographic and climatic variables significantly influence T. infestans wing morphology.

Relationship between genetic diversity and morpho-functional characteristics of flight-related traits in Triatoma garciabesi (Hemiptera: Reduviidae).

BACKGROUND: Triatoma garciabesi, a potential vector of the parasitic protozoan Trypanosoma cruzi, which is the causative agent of Chagas disease, is common in peridomestic and wild environments and found throughout northwestern and central Argentina, western Paraguay and the Bolivian Chaco. Genetic differentiation of a species across its range can help to understand dispersal patterns and connectivity between habitats. Dispersal by flight is considered to be the main active dispersal strategy used by triatomines. In particular, the morphological structure of the hemelytra is associated with their function. The aim of this study was to understand how genetic diversity is structured, how morphological variation of dispersal-related traits varies with genetic diversity and how the morphological characteristics of dispersal-related traits may explain the current distribution of genetic lineages in this species. METHODS: Males from 24 populations of T. garciabesi across its distribution range were examined. The cytochrome c oxidase I gene (coI) was used for genetic diversity analyses. A geometric morphometric method based on landmarks was used for morpho-functional analysis of the hemelytra. Centroid size (CS) and shape of the forewing, and contour of both parts of the forewing, the head and the pronotum were characterised. Length and area of the forewing were measured to estimate the aspect ratio. RESULTS: The morphometric and phylogenetic analysis identified two distinct lineages, namely the Eastern and Western lineages, which coincide with different ecological regions. The Eastern lineage is found exclusively in the eastern region of Argentina (Chaco and Formosa provinces), whereas the Western lineage is prevalent in the rest of the geographical range of the species. CS, shape and aspect ratio of the hemelytra differed between lineages. The stiff portion of the forewing was more developed in the Eastern lineage. The shape of both portions of the hemelytra were significantly different between lineages, and the shape of the head and pronotum differed between lineages. CONCLUSIONS: The results provide preliminary insights into the evolution and diversification of T. garciabesi. Variation in the forewing, pronotum and head is congruent with genetic divergence. Consistent with genetic divergence, morphometry variation was clustered according to lineages, with congruent variation in the size and shape of the forewing, pronotum and head.

Experiencias del personal de salud sobre la implementación de prácticas de protección contra COVID-19 en la Argentina / Experiences of protection against COVID-19

El objetivo de este estudio fue indagar sobre experiencias y percepciones del personal de salud (PDS) de la Argentina en la implementación de protocolos para su protección durante la pandemia por COVID-19. Se realizó una encuesta al PDS a nivel nacional, relevando datos sociodemográficos, de protocolos, recursos y aspectos psicosociales. Se analizaron 2010 encuestas. El 76,4% fueron mujeres, 43 años de edad media, 35% médicos/as y 72,7% del subsistema público. El 37,2% aumentó su carga horaria y el 22,5% presentaba algún factor de riesgo, de quienes 20,4% tuvo licencia o reasignación de tareas. Se establecieron protocolos sobre uso de equipos de protección personal (EPP) en 91% de las instituciones y otras temáticas en menor medida. La claridad de los mismos fue bien valorada y hubo entrenamiento en el 60,8% de los casos. La conformidad con la disponibilidad y calidad del EPP fue variable, con mejor valoración en el subsector privado. El 60,4% tuvo necesidad de obtener EPP por medios propios. El 48,4% de los encuestados siguió los protocolos de uso de EPP, variando según grupos de riesgo. El indicador global de valoración institucional fue 6,45/10 (IC 95% 6,38-6,53). El 87,2% del PDS dijo haber sentido angustia y esto se relacionó con peor comunicación con superiores y peor valoración institucional. De este estudio surgen dificultades en la implementación de los nuevos cuidados, y la necesidad de intensificar esfuerzos en recursos y organización institucional para mejorar las condiciones de trabajo.

During the COVID-19 pandemic, health personnel (HP) faced changes in their working conditions due to exposure to the virus and increased demand for attention. This study inquires on the experiences and perceptions of HP in Argentina about the implementation of protocols for their protection. A survey including information on sociodemographic characteristics, protocols, resources and psychological aspects was performed for HP all over the country. Two thousand and ten surveys were analyzed: 76.4% female, mean age 43 years old, 35% physician, 72.7% public institutions. Hours of work increased for 37.2%, 22.5% had at least one risk factor, of which 20.4% had leave or re-assigned tasks. Protocols about use of personal protective equipment (PPE) were established by 91% of institutions and less frequently about other topics. Clarity of protocols was well evaluated, and in 60.8% of cases trainament was performed. Approval about access and quality of PPE was variable, with better performance on private institutions. 60.4% of the HP had to obtain PPE by their own means. 48.4% of the participants followed protocols on PPE, being this variable according to groups of risk. The global index for institutional valuation was 6.45/10 (CI 95%, 6.38-6.53). HCP expressed fear or anxiety in 87.2% of the cases, and this was related to worse communication with superiors and worse institutional valuation. This study raises difficulties on the implementation of new protocols and the need to reinforce efforts on resources and institutional organization, to improve working conditions for HP

Urban infestation by Triatoma infestans (Hemiptera: Reduviidae), an overlooked phenomena for Chagas disease in Argentina

Vector-borne transmission of Chagas disease in urban areas of Argentina has been an overlooked phenomena. We conducted the first comprehensive cross-sectional study of domestic infestation with Triatoma infestans and vector infection with Trypanosoma cruzi in a metropolitan area of San Juan, Argentina. Our results document the occurrence of T. infestans infected with T. cruzi in human sleeping quarters. In this urban setting, we also show that infestation was associated with construction materials, the presence of chickens, cats and a large number of dogs that can provide blood meals for the vector. Our findings reveal new challenges for vectorial control agencies.

A motorized vehicle-mounted sprayer as a new tool for Chagas disease vector control / Equipamiento aspersor montado en vehículos como nueva herramienta para el control vectorial de la enfermedad de Chagas / Equipamento aspersor montado em veículo como ferramenta nova para o controle vetorial da doença de Chagas

Abstract: Residual insecticide spraying still is the main tool used to suppress house infestations with Chagas disease vectors. While manual compression sprayers (MCS) have traditionally been used in Latin America, Mendoza's vector control program from Argentina introduced the use of a modified motorized vehicle-mounted sprayer (VMS) with apparent advantages over MCS. We conducted a randomized intervention trial to evaluate the effectiveness and selected components of the performance of MCS and VMS. We assessed house infestation by Triatoma infestans in 76 previously-infested houses at 0, 1, 4 and 12 months postintervention. Infestations were reduced substantially, with no significant differences between treatments. End-point infestations were restricted to peridomiciles. Although VMS required less time to complete the house spraying than MCS, both treatments had similar performance and did not suppress infestations completely. The main relative advantages of VMS were a reduced physical effort, especially under harsh field conditions, and potential gains in spray coverage per unit of time.

Resumen: El empleo de insecticida residual es todavía la principal herramienta para suprimir la infestación domiciliaria por triatominos, vectores de la enfermedad de Chagas. Mientras los aspersores manuales activados por compresión han sido utilizados tradicionalmente en América Latina, el programa de control vectorial de la provincia de Mendoza, Argentina, introdujo el uso de un equipamiento aspersor montado en un vehículo, aparentemente con ventajas respecto al aspersor manual. Realizamos un ensayo de intervención aleatorizado para evaluar la efectividad y los componentes seleccionados del desempeño de los dos equipamientos. Evaluamos la infestación por Triatoma infestans en 76 vivendas, previamente infestados a 0, 1, 4 y 12 meses tras la intervención. Las infestaciones se redujeron substancialmente, sin diferencia significativa entre las dos técnicas. Las infestaciones finales se limitaban al peridomicilio. El equipamiento montado en el vehículo llevaba menos tiempo para completar la aplicación, comparado con el equipamiento manual, pero los dos tratamientos tuvieron un desempeño semejante y dejaron de suprimir completamente las infestaciones. Las principales ventajas del equipamiento montado en vehículo fueron: la reducción del esfuerzo físico, principalmente en condiciones adversas en el campo, y potenciales beneficios en términos de cobertura de pulverización por unidad de tiempo.

Resumo: A aplicação de inseticida residual ainda é a principal medida para suprimir a infestação domiciliar por triatomíneos, vetores da doença de Chagas. Enquanto os aspersores manuais acionados por compressão têm sido utilizados tradicionalmente na América Latina, o programa de controle vetorial da Província de Mendoza, Argentina, introduziu o uso de um equipamento aspersor montado em veículo, aparentemente com vantagem em relação ao aspersor manual. Realizamos um estudo randomizado de intervenção para avaliar a efetividade e os componentes selecionados do desempenho dos dois equipamentos. Avaliamos a infestação por Triatoma infestans em 76 domicílios previamente infestados a 0, 1, 4 e 12 meses pós-intervenção. As infestações foram reduzidas substancialmente, sem diferença significativa entre as duas técnicas. As infestações finais eram limitadas ao peridomicílio. O equipamento montado em veículo levava menos tempo para completar a aplicação, comparado com o equipamento manual, mas os dois tratamentos tiveram desempenho semelhante e deixaram de suprimir completamente as infestações. As principais vantagens do equipamento montado em veículo foram redução do esforço físico, principalmente em condições adversas em campo, e potenciais ganhos em termos de cobertura de borrifação por unidade de tempo.

The eco-epidemiology of Triatoma infestans in the temperate Monte Desert ecoregion of mid-western Argentina

BACKGROUND The eco-epidemiological status of Chagas disease in the Monte Desert ecoregion of western Argentina is largely unknown. We investigated the environmental and socio-demographic determinants of house infestation with Triatoma infestans, bug abundance, vector infection with Trypanosoma cruzi and host-feeding sources in a well-defined rural area of Lavalle Department in the Mendoza province. METHODS Technical personnel inspected 198 houses for evidence of infestation with T. infestans, and the 76 houses included in the current study were re-inspected. In parallel with the vector survey, an environmental and socio-demographic survey was also conducted. Univariate risk factor analysis for domiciliary infestation was carried out using Firth penalised logistic regression. We fitted generalised linear models for house infestation and bug abundance. Blood meals were tested with a direct ELISA assay, and T. cruzi infection was determined using a hot-start polymerase chain reaction (PCR) targeting the kinetoplast minicircle (kDNA-PCR). FINDINGS The households studied included an aged population living in precarious houses whose main economic activities included goat husbandry. T. infestans was found in 21.2% of 198 houses and in 55.3% of the 76 re-inspected houses. Peridomestic habitats exhibited higher infestation rates and bug abundances than did domiciles, and goat corrals showed high levels of infestation. The main host-feeding sources were goats. Vector infection was present in 10.2% of domiciles and 3.2% of peridomiciles. Generalised linear models showed that peridomestic infestation was positively and significantly associated with the presence of mud walls and the abundance of chickens and goats, and bug abundance increased with the number of all hosts except rabbits. MAIN CONCLUSIONS We highlight the relative importance of specific peridomestic structures (i.e., goat corrals and chicken coops) associated with construction materials and host abundance as sources of persistent bug infestation driving domestic colonisation. Environmental management strategies framed in a community-based programme combined with improved insecticide spraying and sustained vector surveillance are needed to effectively suppress local T. infestans populations.

Triatoma jatai sp. nov. in the state of Tocantins, Brazil (Hemiptera: Reduviidae: Triatominae)

Triatoma jatai sp. nov. is the first new species of triatomine to be described in the state of Tocantins, in the northern region of Brazil. It was caught on rock outcrops in the wild environment and, more recently, invading homes. While T. jatai sp. nov. is morphologically similar to Triatoma costalimai, it is distinguished by its general colouring, differences in the blotches on the connexivum, wing size in females and external structures of the male genitalia. The type series has been deposited in the Entomological Collection and Herman Lent Collection, Oswaldo Cruz Institute-Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.

Comparative biology of the two sister species of Triatominae (Hemiptera: Reduviidae) / Biologia comparativa de duas espécies irmãs de Triatominae (Hemiptera: Reduviidae)

INTRODUCTION: Triatoma pseudomaculata and T. wygodzinskyi (Hemiptera: Reduviidae: Triatominae) are two Brazilian vectors of Chagas disease. The first is an arboricolous species in sylvatic environment and considered a vector of T. cruzi in peridomestic structures; the second, a rupicolous species in the wild environment of no epidemiological importance. In order to test the assumption that sister species share biological traits, comparative studies of their development cycle and blood ingestion were conducted. METHODS: Eggs laid by five field females of each species were randomly selected. The nymphs were observed daily and fed on mice weekly. The time required to pass through the different stages to adulthood was recorded in days. The triatomines were weighed individually before and after feeding. The mortality rate according to each nymphal stage was calculated. RESULTS AND CONCLUSIONS: Analysis of the results shows that they display only minor biological differences even though they exhibit a distinct ecology. This suggests that the biological traits are important criteria to determine the relationship between species.

INTRODUÇÃO: Triatoma pseudomaculata e T. wygodzinskyi (Hemiptera: Reduviidae: Triatominae) são dois vetores Brasileiros da doença de Chagas. A primeira é uma espécie arborícola em ambiente silvestre e considerada vetor do T. cruzi em estruturas peridomesticas. A segunda é rupícola em ambientes silvestres e sem importância epidemiológica. Com o objetivo de testar a hipótese que espécies irmãs compartilham características semelhantes, realizamos um estudo comparativo do ciclo biológico e ingesta alimentar. MÉTODOS: Ovos pertencentes a cinco fêmeas de cada espécie provenientes do campo foram selecionados aleatoriamente. As ninfas foram observadas diariamente e alimentadas com camundongos semanalmente. O tempo requerido para passar até o estágio adulto foi registrado em dias. Os triatomíneos foram pesados individualmente antes e depois da alimentação. A mortalidade de cada estágio foi calculada. RESULTADOS E CONCLUSÕES: Analise dos resultados mostram que eles exibem pequenas diferencias biológicas apesar de apresentarem diferenças marcantes quanto a sua ecologia. Isso sugere que as características biológicos são critérios importantes para determinar a relação entre as espécies.