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Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) is the vector of multiple arboviruses. To evaluate the association between environmental factors and the oviposition activity of Ae. aegypti in Argentina, data on the presence and abundance of eggs were collected using ovitraps, between September of 2018 and May of 2019, in the cities of Villa María, Río Cuarto and Salsipuedes (Córdoba province, Argentina). We analysed the relationships between oviposition and five environmental factors: Temperature, precipitation, vegetation cover, human population density and distance to sites with a potential high density of larval habitats, like cemeteries and trash dumps. Environmental factors' data were collected using satellite image products. The oviposition activity was randomly distributed in three cities. Using generalized linear mixed models, we show that the house where each ovitrap was placed was a source of variability in oviposition, suggesting the relevance of microsite factors and the importance of domestic control actions. Ae. aegypti oviposition was positively correlated with night-time temperature of the previous 3 weeks, and in a context-dependent manner, it was positively correlated with human population density, vegetation cover and precipitation. The consistency and magnitude of these relationships varied between cities, indicating that oviposition is related to a complex system of environmental variables.

This is an ecological study that investigated the influence of environmental, socioeconomic characteristics and changes in land use and cover on the occurrence of Tegumentary Leishmaniasis (TL) in the city of Montes Claros. The relationships between the number of cases of TL, which occurred between 2012 and 2019, in each census sector and the standardized covariates (Number of properties, altitude, Brazilian Deprivation Index, Normalized Difference Vegetation Index (NDVI), proportion of sector (PS) deforested, PS that underwent other anthropic alterations and unaltered PS) were evaluated with ecological Bayesian Models. Four multivariate models were constructed, with similar quality of adjustments, but Model 1 was the most parsimonious. Model 1 revealed that for each one-unit increase of standard deviation (SD) in the log of the number of properties, at the altitude and root of the deforested PS, corresponds to an increase of 44%, 34% and 24.5% in the number of cases of TL, respectively. The variable NDVI, included in models 3 and 4, was positively associated with the increase in the number of TL cases, being that for each one-unit increase in the NDVI was verified an increase of 21.3% and 20.2% respectively in the models. This study showed that the spatial distribution of TL cases in the city of Montes Claros occurs in a heterogeneous way and our findings support the hypothesis that socio-environmental characteristics and deforestation influence the occurrence of this disease in the studied area. Thus, these factors must be considered for the development of disease control strategies.

We assume that because of the self-correction nature of the scientific knowledge, every published study will be revised by somebody that will replicate it and, eventually, publish a correction. Therefore, the process will discard errors and keep successes to build the established scientific knowledge. However, because of questionable research practices, the process does not work as well as expected, and has driven a reproducibility and replicability crisis (although some will deny such crisis). This document considers in general the state-of-the-art of the problem and presents a local example (at least as a proof of concept) showing that questionable research practices are more prevalent than we think. I conclude calling for spaces to reflect on the problem and I suggest ideas to reduce the impact of its causes, especially important for the training of young researchers.

Triatoma guasayana (Hemiptera, Reduviidae), considered a secondary vector of Chagas disease, invades rural dwellings through flight dispersal during the warm season in semi-arid Chaco of Argentina. The objective of this study was to define and compare morphometrics features in the relative body size and wing shape of T. guasayana related to temperature and rainfall between spring, summer and end of summer. A total of 188 adults were collected in rural communities in the northwest of the province of Córdoba (central Argentina). Relative body size [body length (mm) / wing length (mm)] and 11 landmarks on the right wing were recorded. The temperature ( °C) and precipitation (mm) data were extracted from the MODIS sensor and Terra Climate dataset, respectively. Correlations between climatic variables and morphological variation were analyzed using Partial Least Square (PLS). Males at the end of summer were smaller than those at spring or summer (F = 4.48; df = 2; p = 0.01), whereas females were similar in relative body size at all seasons (F = 0.76; df = 2; p = 0.47). The PLS in males showed a correlation between wing shape and temperature (r = 0.48; p = 0.03) and precipitation (r = 0.50; p = 0.02) while in females only the temperature was the correlation significant (r = 0.35; p = 0.03). Triatoma guasayana has elongated and thin wings in spring that become short and wide at the end of summer. The morphotype of early summer could allow sustained long-duration flights, while the morphotype of end of summer would be related to short flights, correlated with the dispersive behavior of the species. The results in this study suggest that wing morphology of T. guasayana has phenotypic plasticity, and that temperature and rainfall could be considered modulator factors during the developmental stage.

Flight is the main form of dispersion for adult triatomines. It is postulated here that some body morphological parameters vary in T. guasayana according to a greater or lesser wing development, which would allow to estimate their flight capacity. Furthermore, there are observations which allow to suggest that the wings alone would not present the entirety of the information on the flight ability of an insects. It is postulated here that some body morphological parameters vary in T.guasayana according to a greater or lesser wing development. The study aims to verify the hypothesis that the variation of the wing phenotype in triatomines is accompanied by variations of other body structures, particularly the head. Geometric morphometry of heads, thorax width and wing length of T.guasayana brachypterous and macropterous was used. The results allow to confirm that there is a relationship between the wing condition of T. guasayana and other variables – unrelated to wings – that can be associated with flight capacity. The shape of the head changes with the wing condition. The results obtained suggest that the diversity of wing morphotypes imply a diversity in head conformation, suitable for flight: macropterous have a greater distance between eyes and shorter heads, while brachy or micropterous exhibit smaller eyes and larger heads. For the first time, brachypterous individuals of T.guasayana are recorded here, posing the existence of a pronounced alary polymorphism in this species. Identifying these markers in triatomines is of special importance to understand the processes of domicile recolonization after vector control campaigns.

The contribution of the geospatial tools to the vector control activities of Chagas disease is very clear for the academic and technology-prone communities, but not so much for the state-dependent health agents (national or provincial) that are ultimately responsible for disease control in Latin America. In spite of many published scientific papers during the last 20 years on the use of geospatial tools for the surveillance and control of Chagas disease, that I started contributing to more than 20 years ago (Gorla et al., 1997), health systems did not widely adopt these tools in their daily routines. The lack of technically skilled personnel within the health agencies may have been one of the causes of the adoption failure. In some other cases, one can identify products of the academic/technical communities that do not give enough attention to study designs that in the end discourages the end-users to adopt the tools. Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina

The epidemiological scenario in central Argentinian Chaco region shows persistence of Triatoma infestans domestic populations in endemic areas, with control interventions historically affected by the economic instability of the region. Considering this situation, we aimed to (i) update the information regarding to the diversity of triatomines present in domestic, peridomestic and sylvatic environments in departments historically endemic of the Chaco region, (ii) to report the occurrence of secondary vectors of Chagas disease invading domestic environments and (iii) to discuss the possible sources of dispersal of these sylvatic species towards anthropic habitats. Between November 2017 and March 2020, we visited fourteen rural communities of northwest Cordoba province (central Argentina). Entomological data were collected through community vector surveillance in domiciles, active search in peridomiciles and the use of light and yeast traps in sylvatic environments. Seven Triatominae species were captured invading domiciles (T. guasayana, T. garciabesi, T. platensis, T. delpontei, T. breyeri, Panstrongylus guentheri and T. infestans). T. guasayana and T. garciabesi were the species with the highest number of captures. The 32 % of the peridomiciles registered infestation with T. infestans (n ​​= 355), mostly in chicken coops and goat pens. In sylvatic environments, T. garciabesi, T. guasayana, T. infestans and P. guentheri were collected. Only one adult specimen of T. infestans was positive for the presence of Trypanosoma cruzi. Our results suggest that the persistence of T. infestans populations in peridomiciles continues to be a serious challenge for control programs, whereas the finding of secondary vectors of Chagas disease actively invading domiciles emphasizes the need to implement new strategies for entomological surveillance.

Background: For several years, the wild populations of Triatoma infestans, main vector of Trypanosoma cruzi causing Chagas disease, have been considered or suspected of being a source of reinfestation of villages. The number of sites reported for the presence of wild T. infestans, often close to human habitats, has greatly increased, but these data are scattered in several publications, and others obtained by our team in Bolivia have not been published yet. Methodology/principal findings: Herein is compiled the largest number of wild sites explored for the presence of T. infestans collected with two methods The standardized methods aimed to determine the relationship between wild T. infestans and the ecoregion, and the directed method help to confirm the presence/absence of triatomines in the ecoregions. Entomological indices were compared between ecoregions and an environmental niche modelling approach, based on bioclimatic variables, was applied. The active search for wild T. infestans in Bolivia suggests a discontinuous distribution from the Andean valleys to the lowlands (Chaco), while the models used suggest a continuous distribution between the two regions and very large areas where wild populations remain to be discovered. The results compile the description of different habitats where these populations were found, and we demonstrate that the environmental niches of wild and domestic populations, defined by climatic variables, are similar but not equivalent, showing that during domestication, T. infestans has conquered new spaces with wider ranges of temperature and precipitation. Conclusions/significance: The great diversity of wild T. infestans habitats and the comparison of their ecological niches with that of domestic populations confirm the behavioural plasticity of the species that increase the possibility of contact with humans. The result of the geographical distribution model of the wild populations calls for more entomological vigilance in the corresponding areas in the Southern Cone countries and in Bolivia. The current presentation is the most comprehensive inventory of wild T. infestans-positive sites that can be used as a reference for further entomological vigilance in inhabited areas. Fil: Brenière, Simone Frédérique. Pontificia Universidad Catolica del Ecuador; Ecuador. INTERTRYP - Cirad; Francia Fil: Buitrago, Rosio. INTERTRYP - Cirad; Francia. Instituto Nacional de Laboratorios de Salud; Bolivia Fil: Waleckx, Etienne. Universidad Autónoma de Yucatán; México Fil: Depickère, Stéphanie. INTERTRYP - Cirad; Francia. Instituto Nacional de Laboratorios de Salud; Bolivia. Universidad Mayor de San Andrés; Bolivia Fil: Sosa, Victor. INTERTRYP - Cirad; Francia. Gobierno Autónomo Departamental de Santa Cruz. Dirección de Recursos Naturales. Secretaria de Desarrollo Sostenible y Medio Ambiente; Bolivia Fil: Barnabé, Christian. INTERTRYP - Cirad; Francia Fil: Gorla, David Eladio. Comision Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Universidade de Bras?lia. Faculdade de Medicina. Departamento de Patologia. Bras?lia, DF, Brasil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Laborat?rio de Geoprocessamento. Ananindeua, PA, Brasil. Al? Meio Ambiente e Geoprocessamento Ltda. Belo Horizonte, MG, Brasil. Universidad Nacional de C?rdoba. Instituto de Altos Estudios Espaciales Mario Gulich. Consejo Nacional de Investigaciones Cient?ficas y T?cnicas. C?rdoba, AR. Funda??o Oswaldo Cruz. Centro de Pesquisas Ren? Rachou. Laborat?rio de Triatom?neos e Epidemiologia da Doen?a de Chagas. Belo Horizonte, MG, Brasil. BACKGROUND: Triatoma sordida and Triatoma pseudomaculata are frequently captured triatomine species in the Brazilian savannah and caatinga biomes, respectively, and in Brazilian domiciles. OBJECTIVES: This study identified eco-epidemiological changes in Chagas disease in northern Minas Gerais state, Brazil, and considered the influence of environmental shifts and both natural and anthropogenic effects. METHODS: Domicile infestation and Trypanosoma cruzi infection rates were obtained from triatomines and sylvatic reservoirs during the following two time periods: the 1980s and 2007/2008. Entomological and climatic data with land cover classification derived from satellite imagery were integrated into a geographic information system (GIS), which was applied for atmospheric correction, segmentation, image classification, and mapping and to analyse data obtained in the field. Climatic data were analysed and compared to land cover classifications. RESULTS: A comparison of current data with data obtained in the 1980's showed that T. sordida colonised domiciliary areas in both periods, and that T. pseudomaculata did not colonise these areas. There was a tendency toward a reduction in T. cruzi infection rates in sylvatic reservoirs, and of triatomines captured in both households and in the sylvatic environment. T. sordida populations have reduced in the sylvatic environment, while T. pseudomaculata showed an expanding trend in the region compared to counts observed in the 1980's in the sylvatic environment. This may be related to high deforestation rates as well as gradual increases in land surface temperature (LST) and temperatures along the years. MAIN CONCLUSIONS: Our results suggest a geographical expansion of species into new biomes as a result of anthropogenic and climatic changes that directly interfere with the reproductive and infection processes of vectors.

Background Mepraia gajardoi and Mepraia spinolai are endemic triatomine vector species of Trypanosoma cruzi, a parasite that causes Chagas disease. These vectors inhabit arid, semiarid and Mediterranean areas of Chile. Mepraia gajardoi occurs from 18° to 25°S, and M. spinolai from 26° to 34°S. Even though both species are involved in T. cruzi transmission in the Pacific side of the Southern Cone of South America, no study has modelled their distributions at a regional scale. Therefore, the aim of this study is to estimate the potential geographical distribution of M. spinolai and M. gajardoi under current and future climate scenarios. Methods We used the Maxent algorithm to model the ecological niche of M. spinolai and M. gajardoi, estimating their potential distributions from current climate information and projecting their distributions to future climatic conditions under representative concentration pathways (RCP) 2.6, 4.5, 6.0 and 8.5 scenarios. Future predictions of suitability were constructed considering both higher and lower public health risk situations. Results The current potential distributions of both species were broader than their known ranges. For both species, climate change projections for 2070 in RCP 2.6, 4.5, 6.0 and 8.5 scenarios showed different results depending on the methodology used. The higher risk situation showed new suitable areas, but the lower risk situation modelled a net reduction in the future potential distribution areas of M. spinolai and M. gajardoi. Conclusions The suitable areas for both species may be greater than currently known, generating new challenges in terms of vector control and prevention. Under future climate conditions, these species could modify their potential geographical range. Preventive measures to avoid accidental human vectorial transmission by wild vectors of T. cruzi become critical considering the uncertainty of future suitable areas projected in this study.

Reports of triatomine infestation in urban areas have increased. We analysed the spatial distribution of infesta-tion by triatomines in the urban area of Diamantina, in the state of Minas Gerais, Brazil. Triatomines were obtainedby community-based entomological surveillance. Spatial patterns of infestation were analysed by Ripley?s K func-tion and Kernel density estimator. Normalised difference vegetation index (NDVI) and land cover derived from sat-ellite imagery were compared between infested and uninfested areas. A total of 140 adults of four species were cap-tured (100 Triatoma vitticeps, 25 Panstrongylus geniculatus, 8 Panstrongylus megistus, and 7 Triatoma arthurneivaispecimens). In total, 87.9% were captured within domiciles. Infection by trypanosomes was observed in 19.6% of 107examined insects. The spatial distributions of T. vitticeps, P. geniculatus, T. arthurneivai, and trypanosome-positivetriatomines were clustered, occurring mainly in peripheral areas. NDVI values were statistically higher in areasinfested by T. vitticeps and P. geniculatus. Buildings infested by these species were located closer to open fields,whereas infestations of P. megistus and T. arthurneivai were closer to bare soil. Human occupation and modificationof natural areas may be involved in triatomine invasion, exposing the population to these vectors. Fil: Dias, João Victor Leite. Instituto Oswaldo Cruz; Brasil Fil: Queiroz, Dimas Ramon Mota. Universidade Federal dos Vales do Jequitinhonha e Mucuri; Brasil Fil: Martins, Helen Rodrigues. Universidade Federal dos Vales do Jequitinhonha e Mucuri; Brasil Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Pires, Herton Helder Rocha. Universidade Federal dos Vales do Jequitinhonha e Mucuri; Brasil Fil: Diotaiuti, Liléia. Instituto Oswaldo Cruz; Brasil

Triatoma infestans (Hemiptera: Reduviidae) is a vector of the Trypanosoma cruzi parasite, causative agent of Chagas disease. During the last decade, vector control activities have been systematically carried out in northwestern Argentina, an endemic region for this disease. The general aim of this study to evaluate was spatio-temporal variation of infestation by T. infestans in rural communities of Los Llanos in La Rioja province. We estimated house infestation using two sampling methods: passive and active. Passive collection was conducted with community participation collecting triatomines. Six passive collections were carried out in 397 houses during the warm season between 2014 and 2017. Active collection of T. infestans was thoroughly performed by trained staff for 60 minutes and was carried out once in March 2016. The estimate of intradomestic infestation did not show significant differences between both collection methods (p = 0.39). However, passive collection method had lower sensitivity than active collection method for the estimation of peridomestic infestation and intradomestic colonization (PDI: p< 0.01; ID colonization: p< 0.01). The results obtained with passive collection methods showed that the infestation in the study area was spatially heterogeneous and temporally variable. Intradomiciliary infestation decreased over time (14.4% to 7.9%, p

Trypanosoma cruzi, the causative agent of Chagas disease, is transmitted to mammals - including humans - by insect vectors of the subfamily Triatominae. We present the results of a compilation of triatomine occurrence and complementary ecological data that represents the most complete, integrated and updated database (DataTri) available on triatomine species at a continental scale. This database was assembled by collecting the records of triatomine species published from 1904 to 2017, spanning all American countries with triatomine presence. A total of 21815 georeferenced records were obtained from published literature, personal fieldwork and data provided by colleagues. The data compiled includes 24 American countries, 14 genera and 135 species. From a taxonomic perspective, 67.33% of the records correspond to the genus Triatoma, 20.81% to Panstrongylus, 9.01% to Rhodnius and the remaining 2.85% are distributed among the other 11 triatomine genera. We encourage using DataTri information in various areas, especially to improve knowledge of the geographical distribution of triatomine species and its variations in time.

Background Insecticide spraying efficiently controls house infestation by triatomine bugs, the vectors of Trypanosoma cruzi. The strategy, however, is ineffective against sylvatic triatomines, which can transmit Chagas disease by invading (without colonizing) man-made structures. Despite growing awareness of the relevance of these transmission dynamics, the drivers of house invasion by sylvatic triatomines remain poorly understood. Methods/Findings About 12,000 sylvatic triatomines were caught during routine surveillance in houses of Tocantins state, Brazil, in 2005–2013. Using negative binomial regression, information-theoretic model evaluation/averaging, and external model validation, we investigated the effects of regional (Amazon/Cerrado), landscape (preservation/disturbance), and climate covariates (temperature, rainfall) on the municipality-aggregated numbers of house-invading Rhodnius pictipes, R. robustus, R. neglectus, and Panstrongylus geniculatus. House invasion by R. pictipes and R. robustus was overall more frequent in the Amazon biome, tended to increase in municipalities with more well-preserved land, and decreased in rainier municipalities. Across species, invasion decreased with higher landscape-disturbance levels and in hotter-day municipalities. Invasion by R. neglectus and P. geniculatus increased somewhat with more land at intermediate disturbance and peaked in average-rainfall municipalities. Temperature effects were more pronounced on P. geniculatus than on Rhodnius spp. Conclusions We report widespread, frequent house invasion by sylvatic triatomines in the Amazon–Cerrado transition. Our analyses indicate that readily available environmental metrics may help predict the risk of contact between sylvatic triatomines and humans at coarse geographic scales, and hint at specific hypotheses about climate and deforestation effects on those vectors–with some taxon-specific responses and some seemingly general trends. Thus, our focal species appear to be quite sensitive to higher temperatures, and might be less common in more heavily-disturbed than in better-preserved environments. This study illustrates, in sum, how entomological routine-surveillance data can be efficiently used for Chagas disease risk prediction and stratification when house-colonizing vectors are absent., Author summary Triatomine bugs are the vectors of Chagas disease, still a key public health concern in the Americas. Insecticide spraying efficiently controls house infestation by triatomines, but is useless against sylvatic bugs–which can transmit the disease by simply invading human residences. Although this behavior is common, the drivers of house invasion by wild triatomines remain poorly understood. Using municipality-aggregated data from routine surveillance, we investigated whether and how some major environmental factors affect house invasion by four triatomine species across the transition between Amazon rainforests and Cerrado savannahs in Brazil. We found that house invasion (i) is widespread, (ii) varies by region for some species, (iii) is overall less frequent in areas with higher levels of landscape disturbance, and (iv) is less common in hotter and in rainier sites. Although the effects of landscape disturbance and climate differed somewhat among bug species, the general approach we describe here may help advance Chagas disease risk assessment when house-colonizing vectors are absent.

Triatoma infestans is the main vector of Trypanosoma cruzi in Bolivia. The species is present both in domestic and peridomestic structures of rural areas, and in wild ecotopes of the Andean valleys and the Great Chaco. The identification of areas persistently showing low and high house infestation by the vector is important for the management of vector control programs. This study aimed at analyzing the temporal and spatial distribution of house infestation by T. infestans in the Toro Toro municipality (Potosi, Bolivia) between 2009 and 2014, and its association with environmental variables. House infestation and T. infestans density were calculated from entomological surveys of houses in the study area, using a fixed-time effort sampling technique. The spatial heterogeneity of house infestation was evaluated using the SatScan statistic. Association between house infestation with Bioclim variables (Worldclim database) and altitude was analyzed using a generalized linear model (GLM) with a logit link. Model selection was based on the Akaike information criteria after eliminating collinearity between variables using the variable inflation factor. The final model was used to create a probability map of house infestation for the Toro Toro municipality. A total of 73 communities and 16,489 house evaluation events were analyzed. Presence of T. infestans was recorded on 480 house evaluation events, giving an overall annual infestation of 2.9% during the studied period (range 1.5-5.4% in 2009 and 2012). Vector density remained at about 1.25 insects/ house. Infestation was highly aggregated in five clusters, including 11 communities. Relative risk of infestation within these clusters was 1.7-3.9 times the value for the regional average. Four environmental variables were identified as good descriptors of house infestation, explaining 57% of house infestation variability. The model allowed the estimation of a house infestation surface for the Toro Toro municipality. Conclusion: This study shows that residual and persistent populations of T. infestans maintain low house infestation, representing a potential risk for the transmission of T. cruzi in these communities, and it is possible to stratify house infestation using EV, and produce a risk map to guide the activities of vector control interventions in the municipality of Toro Toro (Potosi, Bolivia). Fil: Espinoza Echeverria, Jorge. Centro de Pesquisas Rene Rachou; Brasil Fil: Rodriguez, Antonio Nogales. Servicio Nacional de Salud. Programa Nacional de Chagas; Bolivia Fil: Cortez, Mirko Rojas. Salud y Medioambiente; Bolivia Fil: Diotaiuti, Liléia Gonçalves. Centro de Pesquisas Rene Rachou; Bolivia Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina

Control of Triatominae (Hemiptera, Reduviidae) is a primary component of strategies to halt the transmission of Chagas disease, along with serological screening of blood donors to reduce the likelihood of transmission through infected blood transfusions. In the early 1990s, an estimated 80% of Chagas disease cases were attributed to transmission from triatomine vectors. 1 Since 1991, a series of multinational initiatives have focused on elimination of the domestic vector populations throughout the endemic areas of Latin America. Largely as a result of these initiatives, transmission rates have been steadily reduced, with corresponding reductions in infection prevalence. Current estimates suggest that around 7 million people are infected, down from the 1984 estimate of 24 million 2 ; annual transmission rates are probably fewer than 50,000 new cases per year. 3,4 The geographical distribution of domestic vector populations has been drastically reduced, especially Triatoma infestans in Southern Cone countries and Rhodnius prolixus in Central America. Uruguay, Chile, and Brazil, together with several provinces and departments of Argentina, Bolivia, and Paraguay, have been formally declared free of transmission due to T. infestans. Costa Rica, El Salvador, Honduras, Guatemala, and Nicaragua have recently been declared free of transmission due to R. prolixus and/or its elimination. In addition, there has been steady progress in blood donor screening, with coverage now approaching 100% in most of the endemic countries. But this is not to say that the task of controlling Chagas disease is concluded. Rates of transmission due to domestic vectors remain high in several regions, most notably the Gran Chaco region of Argentina, Bolivia, and Paraguay, as well as parts of the Andean Pact countries and Mexico. Even in those regions where the main domesticvector populations have been eliminated, there is a consistent requirement to maintain surveillance with focal interventions against potential new domestic nfestations.There is not only a risk of repopulation by the main vector species but also a risk of other species invading domestic habitats and either establishing new domestic colonies or provoking accidental transmission (e.g., through contamination of food or drink) without necessarily establishing new colonies. This, in conjunction with declining public health interest in Chagas disease as the apparent control successes become more widely discussed, imposes a need for additional strategies invector surveillance and control that can be sustained as a matter of routine over the long term. Current strategies, based on large-scale campaigns of indoor residual spraying (IRS) against established vector populations, are still required in many areas, but will need to become progressively more focal and guided by a sustainable surveillance system integrated with routine public health vigilance. Such techniques are available, and the strategies are being developed. Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Hashimoto, K.. Freelance Global Health Consultant; Japón

Fil: Amelotti, Ivana. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de Anillaco; Argentina

Goat production is an important economic activity for rural communities in the Gran Chaco of Argentina. Goat corrals are important for the survival of peridomestic populations of Triatoma infestans. This study evaluated the impact of modifying the traditional structure of goat corrals on T. infestans populations and goat productivity in the region of Los Llanos (La Rioja). Thirty-nine experimental corrals were constructed and 57 traditional corrals were used as controls. We evaluated the infestations of the control and experimental corrals for five years following construction of the structures. The results showed that the new structures did not prevent the colonization, although it enhanced the detection of infestation at low densities of T. infestans. No significant difference was found in T. infestans population abundance between control and experimental corrals, probably because of the different detectability in the two types of structures, especially among the small nymphs. Although goat productivity average was higher in experimental than in control corrals, no significant difference was found because of high variability. The new structures can be used as a complement to promote the development of rural communities. Acceptability and adoption of the new corrals by the owners was high, as the enclosures offered better protection for the goats, increased growth of kids and facilitated herd handling.

Triatomines are the vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease, the main endemic disease affecting five to seven million people in Latin America. Besides Triatoma infestans, the most important T. cruzi vector in the Gran Chaco region, other triatomine species associated with sylvatic birds and mammals are responsible for the maintenance of the wild cycle of T. cruzi. The present study aimed at evaluating the house invasion by sylvatic triatomine species in rural communities of the Los Llanos region (La Rioja, Argentina) and its association with environmental variables. House invasion by flying adult triatomines was recorded by trained collectors that surveyed over 377 houses distributed over 73 localities in a 56,600 km2 study region, between October, 2014 and February, 2015. The result of the study showed the frequent house invasion by adult triatomines: 26.3% houses were infested in 53% of the localities. Seven sylvatic triatomine species were collected, with T. guasayana and T. garciabesi among the most abundant. House invasion by triatomine species showed no spatial aggregation and was not associated with temperature, precipitation, or vegetation cover at the spatial scale considered in the present study. House invasion by the epidemiologically important T. infestans is a concern of rural communities. Besides constituting a latent, although low, risk, the presence of these species negatively interferes with the vigilance activities of the provincial Chagas disease program. Fil: Cavallo, María José. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Provincia de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. ; Argentina; Argentina Fil: Amelotti, Ivana. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Provincia de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. ; Argentina; Argentina Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina

Background A number of studies published during the last 15 years showed the occurrence of insecticide resistance in Triatoma infestans populations. The different toxicological profiles and mechanisms of resistance to insecticides is due to a genetic base and environmental factors, being the insecticide selective pressure the best studied among the last factors. The studies on insecticide resistance on T. infestans did not consider the effect of environmental factors that may influence the distribution of resistance to pyrethroid insecticides. To fill this knowledge gap, the present study aims at studying the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables. Methodology/Principal Findings A total of 24 articles reporting on studies that evaluated the susceptibility to pyrethroids of 222 field-collected T. infestans populations were compiled. The relationship between resistance occurrence (according to different criteria) with environmental variables was studied using a generalized linear model. The lethal dose that kills 50% of the evaluated population (LD50) showed a strong linear relationship with the corresponding resistance ratio (RR50). The statistical descriptive analysis of showed that the frequency distribution of the Log (LD50) is bimodal, suggesting the existence of two statistical groups. A significant model including 5 environmental variables shows the geographic distribution of high and low LD50 groups with a particular concentration of the highest LD50 populations over the region identified as the putative center of dispersion of T. infestans. Conclusions/Significance The occurrence of these two groups concentrated over a particular region that coincides with the area where populations of the intermediate cytogenetic group were found might reflect the spatial heterogeneity of the genetic variability of T. infestans, that seems to be the cause of the insecticide resistance in the area, even on sylvatic populations of T. infestans, never before exposed to pyrethroid insecticides, representing natural and wild toxicological phenotypes. The strong linear relationship found between LD50 and RR50 suggest RR50 might not be the best indicator of insecticide resistance in triatomines., Author Summary The elimination of T. infestans in wide areas of the Southern Cone countries of South America and good results in other vector control initiatives showed the high susceptibility of triatomines to pyrethroid insecticides. Despite the constant efforts of vector control, the success was not complete in several areas of the Gran Chaco region of Argentina, Bolivia and Paraguay and parts of the Inter-Andean Valleys of Bolivia, and southern Peru, where persistent populations of domestic and wild T. infestans still persist. Additionally, high levels of insecticide resistance leading to control failures were described in the biogeographic region of the Gran Chaco, within the area of persistent house reinfestation after insecticide application. The influence of environmental variables on the geographic distribution of triatomine was previously studied for several species, showing significant correlations between Triatominae species occurrence and a number of environmental variables. We investigated the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables. This study shows that pyrethroid resistance in T. infestans causing control failures is a highly localized event, spatially associated with the putative dispersion origin of the species, the location of the intermediate cytogenetic group, and with a particular combination of environmental variables, near the border between Argentina and Bolivia. The strong linear relationship found between LD50 and RR50 suggest RR50 might not be the best indicator of insecticide resistance in triatomines.

Chagas disease is the most important endemic disease in Latin America, mainly transmitted by Triatoma infestans in the Southern Cone countries of South America. Dogs are one of themain domestic reservoirs of Trypanosoma cruzi, the etiological agent of Chagas disease. The presence of dogs in rural households of endemic areas significantly increases the likelihood of the vectorial transmission of the parasite.We studied the mortality and blood intake of T. infestans exposed to dogs treated with different doses and formulations of fipronil. Two doses, two formulations, and different distances to the application point of fipronil were compared. Third instar nymphs of T. infestans were fed at different time intervals after the insecticide application up to 45 days post-application. No significant difference was found between the blood intake of nymphs fed on control and treated dogs with different doses and formulations (p>0.05). The spray formulation showed lower effect and persistence than the spot-on formulation. The mortality rate caused by the spot-on formulation in the 26.8-mg active ingredient (a.i.)/kg dose was higher (48 %) than with the13.4-mg a.i./kg dose (25 %), 24 h after the insecticide application. The effect was highly heterogeneous among replicates of the same treatment. The mortality rate of nymphs fed over the point of the insecticide application was higher than the mortality of nymphs fed over places 12 cm apart from the fipronil application point, suggesting that the distribution of fipronil over the dog body is lower than the needed one to obtain a persistent triatomicide effect. Fil: Amelotti, Ivana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina Fil: Catala, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina

Triatoma infestans, one of the main vectors of Trypanosoma cruzi, is strongly associated with rural human ecotopes. Infested peridomestic places could act as a source of house infestation as a result of the movement of vectors among habitats. The quantitative study of phenotypic traits and nutritional variables could be informative about the population structure and the relative mobility of vectors. This is the first approach toward analyzing the phenetic characteristics of T. infestans and the relationship with their potential role to invade and colonize other habitats in the arid Chaco region. This article compares the phenotypic structure of T. infestans populations living in chicken coops and goat corrals, analyzing the geometric morphometry of wings and heads, antennal phenotypes, and the nutritional status of 257 adults and nymphs. The study area remained untreated with insecticides during the 15 years before the present study. The insects collected in peridomestic structures located in two zones 80 km apart exhibited significant differences in their morphotypes, suggesting an environmental effect and/or the absence of individual exchange between zones. The population structure was clear in T. infestans from goat corrals and chicken coops in one zone and less pronounced in the other. These results suggest the existence of a different rate of individual exchange among ecotopes within each zone. Morphometric variables of heads and wings were significantly correlated in insects collected in goat corrals but not in chicken coops, suggesting a habitat effect and supporting the hypothesis of different canalization forces that affect the two organs. The nutritional status of adults indicated a low dispersal probability with zonal differences. This article provides the first combined morphometric analysis of the head of adults and fifth instar nymphs in triatomines and the first combined analysis of head and wing in T. infestans.

The effect of exposing Triatoma infestans to chickens treated with cypermethrin pour-on combined with piperonyl butoxide (PBO) was studied. Four groups of treated chickens and one control group were used. Each treatment received 1 or 2 ml of the cypermethrin formulation with and without PBO. Independent groups of nymphs were fed 1, 7, 15, 30, and 45 d after the treatment application. Blood intake was estimated after each feeding occasion. Up to 15 d after the pour-on application, high mortality was observed in all nymphs fed on treated chickens (93% +/- 12), and lower than the nymphs of the control group (33% +/- 15). After 30 d of the pour-on application, there was significantly different mortality between the treatment with 1 ml (80% +/- 9) and 2 ml (96% +/- 5); no difference was observed between groups with or without PBO addition. After 45 d of the pour-on application, the treatments did not show significant differences (77% +/- 7), although all treatments showed higher mortality than the control group (10% +/- 9). Up to 45 d after the pour-on application, blood intake by nymphs exposed to treated chickens (0.85 +/- 0.96 mg/nymph) was lower than blood intake by nymphs exposed to control chickens (6.7 +/- 5 mg/nymph). This study shows that cypermethrin pour-on produces high mortality and reduces the blood intake of third-instar nymphs of T. infestans up to 45 d after the insecticide application to chickens. PBO did not produce a detectable effect.

The Bolivian Chaco is part of the endemic region of Chagas disease and an area where pyrethroid resistant Triatoma infestans (Hemiptera: Reduviidae) populations has been reported. The World Health Organization identified these resistant populations as an important focus for research. The objective of this study was to evaluate the residual effect of a micro-encapsulated formulation containing organophosphate active ingredients and a juvenile hormone analogue (Inesfly 5A IGR) on the mortality of T. infestans. Studies took place in rural houses of the Bolivian Chaco that were treated up to 34 months before and evaluated the susceptibility to pyrethroids of the offspring of field collected insects. Thirty houses were randomly selected within three communities to carry out wall bio-assays with T. infestans nymphs. Mortality was recorded 24, 48 and 72 h after wall contact. Eggs laid by females collected in the area were used to obtain first-instar nymphs and carry out pyrethroid susceptibility tests. The wall bio-assays showed that the micro-encapsulated insecticide eliminates T. infestans populations and produces detectable mortality of insects exposed to walls treated 34 months prior to the tests. The discriminant dose of deltamethrin (0.01 mg/mL) showed 65% nymph survival, whereas at the highest tested dose (1.0 mg/mL) 14% of the nymphs survived. These results show that Inesfly 5A IGR is an appropriate tool for the elimination of intradomestic and peridomestic populations of T. infestans resistant to pyrethroids.

In this study, predictive models of geographic distribution patterns of Triatoma pseudomaculata (Tps) and T. wygodzinskyi (Twy) were carried out. They were based on biophysical variables estimated from information provided by the satellite remote sensors AVHRR (Advanced Very High Resolution Radiometer) and MODIS (MODerate-resolution Imaging Spectroradiometer). Our goal was to analyze the potential geographic distribution of Tps and Twy and to assess the performance of three predictive models (one for each species and one for both species together) based on temperature, vapour pressure deficit, vegetation and altitude. The geographic distribution analysis shows that all models performed well (>85.7% of overall correct classification of presence and absence point data). The MODIS-based models showed lower correct classifications than the AVHRR-based models. The results strongly suggest that environmental information provided by remote sensors can be successfully used in studies on the geographic distribution of poorly understood Chagas disease vector species. Fil: Carbajal de la Fuente, Ana Laura. Fundación Oswaldo Cruz; Brasil Fil: Porcasi Gomez, Ximena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina Fil: Noireau, F.. Centre National de la Recherche Scientifique. Institut de Recherche pour le Développement; Francia. Universidad Mayor de San Simón; Bolivia Fil: Diotaiuti, Liléia. Fundación Oswaldo Cruz; Brasil Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina

Triatoma infestans (Klug) is the main vector of Trypanosoma cruzi, etiologic agent of Chagas disease. The phenotype of the species varies at different geographic scales. The objective of this study was to compare the antennal phenotype of spatially close T. infestans populations and to evaluate its usefulness as a marker of exchange of individuals between populations. The antennal phenotype of 190 T. infestans from Argentina and Bolivia was analyzed using uni- and multivariate techniques. This study shows heterogeneity of the antennal phenotypes of closely related T. infestans populations living in different habitats. Specimens collected in a goat corral and a rabbit cage in La Rioja (Argentina) were dissimilar to the specimens collected in the nearby intradomestic environment. Similarly, specimens from peridomestic corrals in Cochabamba (Bolivia) were different from the intradomestic and sylvatic specimens, indicating some degree of isolation between these populations. In contrast, T. infestans collected in chicken coops and the intradomestic environment were similar, in all studied regions, suggesting a frequent exchange of individuals between the two habitats and/or because of the similarity of the habitat due to the presence of chickens in the intradomestic environment. We propose that each habitat affects in a particular mode the insect morphology and these changes could be used to identify recolonizing T. infestans. These results support the hypothesis of different degrees of isolation between intradomestic and peridomestic habitats. Within this context, special attention should be given to chicken coops and other close peridomestic structures in relation to the recolonization process of domestic habitats by T. infestans.

Vectorial transmission of Chagas disease has been strongly reduced in most parts of the Southern Cone countries of South America, except in the Gran Chaco region of Argentina, Bolivia, and Paraguay. Given periodical interruptions of the vector control programmes in the endemic region of the Gran Chaco of Argentina, the vectorial transmission of the disease has been increasing during the last years. From the beginning of 2004, the provincial Ministry of Health of La Rioja, Argentina, started a vector control programme to cover the rural houses of the Los Llanos area in the southwestern area of the Gran Chaco region. This article reports the result of a standardized entomological survey and insecticide application against Chagas disease vectors in the intra and peridomestic structures of the rural houses of Los Llanos. A total of 4062 houses were inspected, of which 46.8% were found to be infested by Triatoma infestans. Infestation by vector species other than T. infestans was less than 0.5%(T. eratyrusiformis and T. platensis). Intradomestic infestation was found in 27.2%, whereas peridomestic infestation was found in 39.3% of the houses. The lowest figure of intradomestic infestation was 6.6% (Department F Varela), and the highest value of intradomestic infestation was 45.1% (Department Independencia). In spite of the demonstrated success of vector control elsewhere, this study shows that the vector populations are susceptible to pyrethroid insecticides in the southern area of the Gran Chaco of Argentina, that there still are regions where rural houses show heavy infestation by T. infestans associated with big peridomestic structures and that the vectorial transmission of the Chagas disease will continue, unless a sustained and well organized vector control effort is installed in the region.

Peridomestic structures are considered the main sites where Triatoma infestans (Hemiptera: Reduviidae) remain and disperse, representing the first risk factor for intradomestic invasion, even after vector control activities. This study analyzed T. infestans dispersal during vector control interventions in six rural houses of the arid Chaco (La Rioja, Argentina). Flying and walking dispersers were captured during five months of two consecutive warm seasons after insecticide spraying of intra- and peridomiciles. These data were compared with previous published data in the same scenario but without insecticide spraying in peridomiciles. Recorded climatic conditions were favorable for active dispersion during the study. Total number of T. infestans dispersers moving among domestic habitats decreased after insecticide spraying. Sylvatic triatomines T. guasayana, T. eratyrusiformis, T. garciabesi, and T. platensis, not targeted by insecticide spraying, were captured simultaneously within peridomestic areas and showed higher invasion pressure than T. infestans. Adult T. infestans peridomestic populations showed high nutritional status, indicating low dispersion probability. Some peridomiciles remained infested at the end of the study. However, no intradomiciles were recolonized. These results suggest that there is a low probability of intradomestic recolonization by active dispersion from peridomiciles during 15 months post-spraying. Fil: Abrahan, Luciana Beatriz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Provincia de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. ; Argentina; Argentina Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Catala, Silvia Susana. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Provincia de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. ; Argentina; Argentina

Triatominae insects are vectors for Trypanosoma cruzi, the Chagas disease parasite, and their flying behaviour has epidemiological importance. In Triatominae, the flying capacity shows striking differences among species, but also within species between sexes or individuals. In Triatoma infestans, it has been shown that an important proportion of individuals could have wings but no flying muscles. In other species, no clear relationships could be observed between wing lenght and flying behaviour. If wing presence or size is not a warrant of the flying behaviour, which other parts of the body could be taken as a reliable witness of this important function? Fil: Hernández, María Laura. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Provincia de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. ; Argentina; Argentina Fil: Dujardin Jean Pierre. Institut de Recherches pour le Développement; Francia Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Provincia de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. ; Argentina; Argentina Fil: Catala, Silvia Susana. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. - Provincia de la Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de la Rioja. ; Argentina; Argentina

Background: Triatomines (Hemiptera, Reduviidae) are vectors of Trypanosoma cruzi, the causative agent of Chagas disease, one of the most important vector-borne diseases in Latin America. This study compares the environmental niche spaces of Triatoma brasiliensis and Triatoma melanica using ecological niche modelling and reports findings on DNA barcoding and wing geometric morphometrics as tools for the identification of these species. Methods: We compared the geographic distribution of the species using generalized linear models fitted to elevation and current data on land surface temperature, vegetation cover and rainfall recorded by earth observation satellites for northeastern Brazil. Additionally, we evaluated nucleotide sequence data from the barcode region of the mitochondrial cytochrome c oxidase subunit I (CO1) and wing geometric morphometrics as taxonomic identification tools for T. brasiliensis and T. melanica. Results: The ecological niche models show that the environmental spaces currently occupied by T. brasiliensis and T. melanica are similar although not equivalent, and associated with the caatinga ecosystem. The CO1 sequence analyses based on pair wise genetic distance matrix calculated using Kimura 2-Parameter (K2P) evolutionary model, clearly separate the two species, supporting the barcoding gap. Wing size and shape analyses based on seven landmarks of 72 field specimens confirmed consistent differences between T. brasiliensis and T. melanica. Conclusion: Our results suggest that the separation of the two species should be attributed to a factor that does not include the current environmental conditions. However, as the caatinga is a biome that has existed in the area for at least the last 18,000 years, past conditions might have had an influence in the speciation process. The DNA Barcoding approach may be extended to these members of the subfamily Triatominae.

Background: Triatoma virus (TrV) is the only entomopathogenous virus identified in triatomines. We estimated the potential geographic distribution of triatomine species naturally infected by TrV, using remotely sensed and meteorological environmental variables, to predict new potential areas where triatomines infected with TrV may be found. Methods: Detection of TrV infection in samples was performed with RT-PCR. Ecological niche models (ENM) were constructed using the MaxEnt software. We used 42 environmental variables derived from remotely sensed imagery (AVHRR) and 19 bioclimatic variables (Bioclim). The MaxEnt Jackknife procedure was used to minimize the number of environmental variables that showed an influence on final models. The goodness of fit of the model predictions was evaluated by the mean area under the curve (AUC). Results: We obtained 37 samples of 7 species of triatomines naturally infected with TrV. Of the TrV positive samples, 32% were from sylvatic habitat, 46% came from peridomicile habitats and 22% from domicile habitats. Five of the seven infected species were found only in the sylvatic habitat, one species only in the domicile and only Triatoma infestans was found in the three habitats. The MaxEnt model estimated with the Bioclim dataset identified five environmental variables as best predictors: temperature annual range, mean diurnal range, mean temperature of coldest quarter, temperature seasonality and annual mean temperature. The model using the AVHRR dataset identified six environmental variables: minimum Land Surface Temperature (LST), minimum Middle Infrared Radiation (MIR), LST annual amplitude, MIR annual amplitude annual, LST variance and MIR variance. The potential geographic distribution of triatomine species infected by TrV coincides with the Chaco and the Monte ecoregions either modelled by AVHRR or Bioclim environmental datasets. Conclusions: Our results show that the conditions of the Dry Chaco ecoregion in Argentina are favourable for the infection of triatomine species with TrV, and open the possibility of its use as a potential agent for the biological control of peridomestic and/or sylvatic triatomine species. Results identify areas of potential occurrence that should be verified in the field., Facultad de Ciencias Veterinarias, Centro de Estudios Parasitológicos y de Vectores

Mepraia spinolai and Mepraia gajardoi (Hemiptera, Reduviidae) are only found in the arid regions of northern Chile. Mepraia is the only genus of Triatominae with marked wing polymorphism. Females of both species are micropterous, males of M. spinolai may be micropterous, brachypterous or macropterous, while males of M. gajardoi are always brachypterous. Because of this wing polymorphism, Mepraia can be used as a model to analyze morphological adaptations related to the flying activity and evolutionary relationships in the Triatominae. The study presented here analyses the antennal phenotype of the Mepraia species and carries out a comparison with the two species of Triatoma included in the spinolai complex (Triatoma eratyrusiformis and Triatoma breyeri). The analysis of the antennal phenotype of Mepraia showed a marked intraspecific phenotypic variability related with sex and wing condition. The number and length of multiporous trichoid sensilla (TH) on the pedicel are significantly higher and longer in winged males and are strongly reduced in females. The great length of the TH sensillum is an infrequent characteristic within Triatominae. The results show that phenetic distances between sexes are greater than between the two species. Similarity between the Mepraia species and T. eratyrusiformis was found as they all show long bristles (BR) and TH and two sized basiconic receptors (BA), a pattern that have not been observed in other species of Triatominae. These characters are not present in T. breyeri.

Fil: Gleiser, Raquel M.. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja; Argentina

Triatomines (Hemiptera, Reduviidae) are bloodsucking insects involved in the transmission of Trypanosoma cruzi, the causative agent of Chagas disease, an important public health problem in Latin America. The triatomine species found in sylvatic habitats generally play a limited epidemiological role compared to domestic species, but they may act as a reinfestation source of dwellings after insecticide spraying and have to be carefully considered in control strategies of Chagas disease transmission. The objectives of this work were to carry out a survey of the sylvatic triatomine species colonizing Furnariidae nests in a typical area of the Chaco region of Argentina during the winter and to study the parasites and natural enemies associated with the collected triatomines. Sixty-three triatomine specimens were collected from Furnariidae nests (Coryphistera alaudina and Phacellodomus sibilatrix) randomly selected within the study area. Fifty-four were identified as Psammolestes coreodes, seven as Triatoma platensis, and two as Triatoma infestans. Specimens of T. infestans and T. platensis were found in one nest. The first finding of instar nymphs of T. infestans x T. platensis in a sylvatic habitat is reported. For the first time, sylvatic collected specimens of T. platensis were found infected by T. cruzi. Triatoma virus was found in one Ps. coreodes specimen. Fil: Marti, Gerardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica de Anillaco; Argentina Fil: Echeverria, Maria Gabriela. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Microbiología. Cátedra de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Waleckx, E.. Centre National de la Recherche Scientifique. Institut de Recherche Pour Le Developpement; Francia Fil: Susevich, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina Fil: Balsalobre, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica de Anillaco; Argentina

Spatial and temporal changes in the abundance of adult female Aedes (Ochlerotatus) albifasciatus (Macquart) were studied using CDC miniature light traps at 7 sites along an 80-km transect parallel to the southern shore of Mar Chiquita Lake (central Argentina) during the rainy seasons between 1994 and 1997. Abundance was greatest and most variable at sites near larval habitats. Rainfall and an index combining rainfall and temperature predicted adult female abundance near larval habitats 7-15 d in advance. The spatial distribution of population abundance seemed to be influenced strongly by local factors, because temporal change at sampling sites located >10 km apart was asynchronous.

Surges in the size of adult populations of the flood-water mosquito Aedes albifasciatus can produce important economical losses because of the way this species irritates livestock. Although this species is also the main vector of west equine encephalitis in Argentina, little is known about the factors affecting its population dynamics, as it is difficult to obtain data on its abundance over a large area. However, the results of intensive study of the mosquito in a few sites might reasonably be extrapolated to a regional scale by the use of remotely sensed data. The adult, larval and pupal stages of Ae. albifasciatus were sampled at five field sites to the south of Mar Chiquita Lake, either once a month (during the dry, cold season) or once a fortnight (during the warm, rainy season), between August 1992 and April 1993. The measured abundance of adults or pre-adults and a meteorological coefficient useful for the estimation of larval abundance each showed significant correlation with various statistics derived from normalized-difference, vegetation indices (NDVI) calculated from satellite (NOAA-AVHRR) imagery. A linear discriminant analysis, using data on NDVI, rainfall and temperature, accurately identified periods with and without pre-adults. The satellite imagery was also useful in the estimation of larval abundance and consequently could be used to predict adult abundance 7 days in advance. Even though the satellite data employed have poor spatial resolution, their high temporal resolution makes them very useful in studies of the population dynamics of mosquitoes in general, at least once the relevant variables and their relationships with mosquito breeding and survival have been identified.

Triatoma infestans (Reduviidae: Triatominae, "kissing bug") is the main insect vector of Trypanosoma cruzi, the causative agent of Chagas disease, a chronic trypanosomiasis infecting 10 million people world-wide. This hematophagous bug feeds on diurnal and nocturnal species during each host's quiescent time. As the hosts are also its major predators, kissing bugs are subjected to dual selective pressures from a single source. Therefore, synchronization of feeding with the host's behavior is critical to the insects' survival. We show that nonphotic signals linked to the host eclipse the role of light and dark as the primary circadian zeitgeber for these bugs, although light still strongly inhibits locomotor behavior directly. In nature, this combination provides the insect with great flexibility in organizing physiology and behavior: anticipating a quiescent host or avoiding its potential predation while remaining directly responsive to immediate environmental conditions. Manipulation of nonphotic entrainment could be a useful chronobiotic tool in the control of Chagas disease.

The presence of Triatoma infestans in habitats treated with insecticides constitutes a frequent problem in endemic areas. Basing our study on the hypothesis that descendants of a residual population should be more similar to the pre-treatment population than to any other, we compared the indications of two quantitative morphological approaches. This study seeks to find the origin of 247 T. infestans from three populations found in two chicken coops and a goat corral after treatment with insecticides. The results obtained by quantitative morphology suggest that the T. infestans found between three-34 months after the application of insecticides formed mixed populations with insects derived from residual foci and neighbouring habitats. Our analyses also showed the presence of a phenotype which does not resemble neither the pre-treatment phenotype nor the one from neighbouring populations, suggesting the presence of a particular post-treatment phenotype. The heads size showed some variations in males from different populations and remained unchanged in females, which reinforces the hypothesis of an intraspecific competition for food with priority for females. This article presents, for the first time, the combined analysis of geometric morphometry of heads and antennal phenotypes to identify the composition of reinfesting populations. Fil: Hernández, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica de Anillaco; Argentina; Fil: Dujardin, Jean Pierre. Centre National de la Recherche Scientifique. Institut de Recherche pour le Développement; Francia; Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica de Anillaco; Argentina; Fil: Catala, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica de Anillaco; Argentina

We analyzed the variability of susceptibility to deltamethrin in putatively susceptible Triatoma infestans Klug (Hemiptera: Reduviidae), and evaluated the sample size implications on the hypotheses used in the current World Health Organization protocol for the measure of insecticide resistance in Triatominae. Following the protocol, using topical application of deltamethrin to unfed first instar nymphs of T. infestans, we found that susceptibility showed significant differences between offspring from different females, a significant association with female age, and significant interaction female × female age. Considering individual female data, three patterns of nymphal mortality were identified: one showed a strong positive relation between nymphal mortality and their mother's age, another showed high mortality with low variability and the third showed intermediate mortality with high variability along female age. The analysis suggests revision of the World Health Organization protocol for resistance detection in Triatominae, not only to take into consideration the sources of variation in susceptibility, but also the effects of sample size in relation to the significance and power probabilities of the test. Fil: Amelotti, Ivana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina Fil: Romero, Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina Fil: Catala, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina Fil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina