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Background Triatomine bugs transmit Chagas disease across Latin America, where vector control-surveillance is increasingly decentralized. Locally run systems often deal with highly diverse native-vector faunas—plus, in some areas, domestic populations of non-native species. Flexible entomological-risk indicators that cover native and non-native vectors and can support local decision-making are therefore needed. Methods We present a local-scale entomological-risk score (“TriatoScore”) that leverages and builds upon information on the ecology-behavior and distribution-biogeography of individual triatomine bug species. We illustrate our approach by calculating TriatoScores for the 417 municipalities of Bahia state, Brazil. For this, we (i) listed all triatomine bug species recorded statewide; (ii) derived a “species relevance score” reflecting whether each species is native/non-native and, if native, whether/how often it invades/colonizes dwellings; (iii) mapped each species’ presence by municipality; (iv) for native vectors, weighted presence by the proportion of municipal territory within ecoregions occupied by each species; (v) multiplied “species relevance score” × “weighted presence” to get species-specific “weighted scores”; and (vi) summed “weighted scores” across species to get municipal TriatoScores. Using standardized TriatoScores, we then grouped municipalities into high/moderate/low entomological-risk strata. Results TriatoScores were higher in municipalities dominated by dry-to-semiarid ecoregions than in those dominated by savanna-grassland or, especially, moist-forest ecoregions. Bahia’s native triatomines can maintain high to moderate risk of vector-borne Chagas disease in 318 (76.3%) municipalities. Historical elimination of Triatoma infestans from 125 municipalities reduced TriatoScores by ~ 27% (range, 20–44%); eight municipalities reported T. infestans since Bahia was certified free of Trypanosoma cruzi transmission by this non-native species. Entomological-risk strata based on TriatoScores agreed well with Bahia’s official disease-risk strata, but TriatoScores suggest that the official classification likely underestimates risk in 42 municipalities. Of 152 municipalities failing to report triatomines in 2006–2019, two and 71 had TriatoScores corresponding to, respectively, high and moderate entomological risk. Conclusions TriatoScore can help control-surveillance managers to flexibly assess and stratify the entomological risk of Chagas disease at operationally relevant scales. Integrating eco-epidemiological, demographic, socioeconomic, or operational data (on, e.g., local-scale dwelling-infestation or vector-infection frequencies, land-use change and urbanization, housing conditions, poverty, or the functioning of control-surveillance systems) is also straightforward. TriatoScore may thus become a useful addition to the triatomine bug control-surveillance toolbox. Graphical abstract

Background: Neglected tropical diseases are a growing threat to global health, and endemic Chagas disease has emerged as one of the most important health problems in America. The main strategy to prevent Trypanosoma cruzi transmission is chemical control of vectors. This study presents a descriptive analysis of synanthropic triatomines before and after the implementation of a vector-control program in Bahia, Brazil. Methods: Descriptive analysis and geospatial statistics were performed on triatomine data, (1) the relative abundance and (2) proportional spatial distribution, from Bahia during two periods: (A) 1957 to 1971 and (B) 2006 to 2019. Results: We observed a decrease in the relative abundance of Panstrongylus megistus (A: n=22.032, 61.9%; B: n=1.842, 1.0%) and Triatoma infestans (A: n=1.310, 3.7%; B: n=763, 0.43%), as well as an increase in the relative abundance of T. sordida (A: n=8.314, 23.4%, B: n=146.901, 81.6%) and T. pseudomaculata (A: n=894, 2.5%, B: n=16.717, 9.3%). Conclusions: Our results indicate a clear reduction in the occurrence of P. megistus and T. infestans (last record in 2015) and an increase in the relative abundance and geographical distribution of T. sordida and T. pseudomaculata after 40 years of the vector-control program. The high frequency of other triatomine species in the municipalities of the state of Bahia and their abundance in recent years highlight the need to reinforce permanent entomological surveillance actions to prevent Chagas disease.

INTRODUCTION: We aimed to study intraspecific variation in Triatoma costalimai, a potential vector of Chagas disease present in Brazil and Bolivia. METHODS: We analyzed phenotypic (connexivum color patterns, wing morphometrics) and genetic variation (16S mtDNA) of three Brazilian T. costalimai populations. We compared 16S sequences with those of putative Bolivian T. costalimai and its sister species, T. jatai. RESULTS: Brazilian populations had different connexivum color patterns and forewing shapes. A 16S mtDNA haplotype network showed a clear separation of Brazilian T. costalimai from both T. jatai and Bolivian T. costalimai. CONCLUSIONS: We report considerable variability in T. costalimai populations.

Background: Entomological indicators are essential to guide surveillance and control of vector-borne diseases. Indicators of Chagas disease vector surveillance such as infestation, colonization, and density depend on wide surveys performed by trained health agents that are difficult to maintain in endemic countries; now, surveillance is mainly based on community participation. Thus, the development of an index that aggregates variables of vectorial potential and occurrence and triatomine species may be useful. Objective: To develop an index for triatomine bug surveillance. Methods: The index was developed based on entomological surveillance data from the State of Bahia, Brazil, between 2006 and 2019. For each triatomine species, the following data were analyzed: a) relative abundance; b) geographic distribution, c) proportion of nymphs; d) Trypanosoma cruzi infection; e) human contact/ blood meal sources. Values ​​were assigned to each of these variables and the sum of the values ​​generated the index (TriatoIndex = Ti) that ranged from 0 to 15. Subsequently, the municipalities' Ti value was calculated, based on the sum of the Ti values ​​of the species registered in each municipality. RESULTS: From the 26 species of triatomines in Bahia, 20 (77%) presented Ti Triatoma infestans (15), T. sordida (14), T. brasiliensis (13), T. pseudomaculata (12), T. melanica (10), and T. juazeirensis (10) presented the highest values ​​of Ti in the studied area. The Ti values ​​in the municipalities in the central and northeastern regions of Bahia were high; these areas were considered hotspots for the occurrence of the main important vectors. Conclusions: The index presented takes into account the geographical distribution and vectorial potential of triatomines within the region. TriatoIndex is a promising tool for targeted surveillance of T. cruzi vectors.

Background: This study presents a descriptive analysis of the occurrence of synanthropic triatomine species in the state of Bahia, before and after the implementation of the vector control program. Methods: Occurrence and number of collected specimens in the municipalities were analyzed in two periods: (A) 1957 to 1971, before systematic vector control actions; and (B) 2006 to 2019, after the certification of interruption of Chagas disease transmission by Triatoma infestans. Results: In total, 17 species were recorded during period A and 21 during period B. Panstrongylus megistus was the most frequent species in period A (42%), while Triatoma pseudomaculata (42%) and T. sordida (38%) were more frequent in period B. In period A, T. infestans was found in 26 (9%) municipalities, and in period B it was found in 7 (2%). During period B, most triatomines (88%) were captured at the peridomestic habitats, with a predominance of T. sordida (85%). Species with greatest relative abundance within the household were T. sordida (49%), T. brasiliensis (27%), and T. pseudomaculata (15%). Conclusions: We have observed a clear reduction in the occurrence of P. megistus and T. infestans and an increase in the relative abundance and geographical distribution of T. sordida and T. pseudomaculata after 40 years of the vector-control program. High frequency of other triatomine species in the municipalities of the state of Bahia and a great abundance of T. sordida in recent years, highlight the need to reinforce permanent entomological surveillance actions for Chagas disease.

Background The identification of Trypanosoma cruzi and blood-meal sources in synanthropic triatomines is important to assess the potential risk of Chagas disease transmission. We identified T. cruzi infection and blood-meal sources of triatomines caught in and around houses in the state of Bahia, northeastern Brazil, and mapped the occurrence of infected triatomines that fed on humans and domestic animals. Methods Triatominae bugs were manually captured by trained agents from the Epidemiologic Surveillance team of Bahia State Health Service between 2013 and 2014. We applied conventional PCR to detect T. cruzi and blood-meal sources (dog, cat, human and bird) in a randomized sample of triatomines. We mapped triatomine distribution and analyzed vector hotspots with kernel density spatial analysis. Results In total, 5906 triatomines comprising 15 species were collected from 127 out of 417 municipalities in Bahia. The molecular analyses of 695 triatomines revealed a ~10% T. cruzi infection rate, which was highest in the T. brasiliensis species complex. Most bugs were found to have fed on birds (74.2%), and other blood-meal sources included dogs (6%), cats (0.6%) and humans (1%). Trypanosoma cruzi-infected triatomines that fed on humans were detected inside houses. Spatial analysis showed a wide distribution of T. cruzi-infected triatomines throughout Bahia; triatomines that fed on dogs, humans, and cats were observed mainly in the northeast region. Conclusions Synanthropic triatomines have a wide distribution and maintain the potential risk of T. cruzi transmission to humans and domestic animals in Bahia. Ten species were recorded inside houses, mainly Triatoma sordida, T. pseudomaculata, and the T. brasiliensis species complex. Molecular and spatial analysis are useful to reveal T. cruzi infection and blood-meal sources in synanthropic triatomines, identifying areas with ongoing threat for parasite transmission and improving entomological surveillance strategies.

Visceral leishmaniasis is a public health problem in Brazil. This disease is endemic in most of Bahia state, with increasing reports of cases in new areas. Ecological niche models (ENM) can be used as a tool for predicting potential distribution for disease, vectors, and to identify risk factors associated with their distribution. In this study, ecological niche models (ENMs) were developed for visceral leishmaniasis (VL) cases and 12 sand fly species captured in Bahia state. Sand fly data was collected monthly by CDC light traps from July 2009 to December 2012. MODIS satellite imagery was used to calculate NDVI, NDMI, and NDWI vegetation indices, MODIS day and night land surface temperature (LST), enhanced vegetation index (EVI), and 19 Bioclim variables were used to develop the ENM using the maximum entropy approach (Maxent). Mean diurnal range was the variable that most contributed to all the models for sand flies, followed by precipitation in wettest month. For Lutzomyia longipalpis (L. longipalpis), annual precipitation, precipitation in wettest quarter, precipitation in wettest month, and NDVI were the most contributing variables. For the VL model, the variables that contributed most were precipitation in wettest month, annual precipitation, LST day, and temperature seasonality. L. longipalpis was the species with the widest potential distribution in the state. The identification of risk areas and factors associated with this distribution is fundamental to prioritize resource allocation and to improve the efficacy of the state's program for surveillance and control of VL.

International audience; The yellow fever virus (YFV) caused a severe outbreak in Brazil in 2016-2018 that rapidly spread across the Atlantic Forest in its most populated region without viral circulation for almost 80 years. A comprehensive entomological survey combining analysis of distribution, abundance and YFV natural infection in mosquitoes captured before and during the outbreak was conducted in 44 municipalities of five Brazilian states. In total, 17,662 mosquitoes of 89 species were collected. Before evidence of virus circulation, mosquitoes were tested negative but traditional vectors were alarmingly detected in 82% of municipalities, revealing high receptivity to sylvatic transmission. During the outbreak, five species were found positive in 42% of municipalities. Haemagogus janthinomys and Hg. leucocelaenus are considered the primary vectors due to their large distribution combined with high abundance and natural infection rates, concurring together for the rapid spread and severity of this outbreak. Aedes taeniorhynchus was found infected for the first time, but like Sabethes chloropterus and Aedes scapularis, it appears to have a potential local or secondary role because of their low abundance, distribution and infection rates. There was no evidence of YFV transmission by Aedes albopictus and Aedes aegypti, although the former was the most widespread species across affected municipalities, presenting an important overlap between the niches of the sylvatic vectors and the anthropic ones. The definition of receptive areas, expansion of vaccination in the most affected age group and exposed populations and the adoption of universal vaccination to the entire Brazilian population need to be urgently implemented.

to evaluate, under simulated field conditions, the efficacy of pyriproxyfen (juvenile hormone), novaluron (chitin inhibitor) and spinosad (biolarvicide) in controlling Aedes aegypti.periodic exposition of Ae. aegypti larvae collected in Itabuna, BA, Brazil, to recipients treated with larvicides and comparison of residual effect of treatment with the Rockefeller strain.the inhibitory effect on adult emergence after 60 days was spinosad 89.5%, novaluron 96.5% and pyriproxifen 75.4% for Itabuna larvae, with no statistical difference (p=0.412) between treatments; spinosad and novaluron had a higher percentage of mortality in the larval stage, 98.8% and 97.9% respectively; pyriproxyfen showed higher mortality (95.1%) in the pupal stage.the three larvicides demonstrated similar control; however, pyriprofyxen might give a false impression of breeding ground positivity as it acts at the pupal stage, compromising the indicators of infestation that are strategic parameters for control actions.avaliar, em condições simuladas de campo, a eficácia do pyriproxyfen (hormônio juvenil), do novaluron (inibidor de quitina) e do spinosad (biolarvicida) no controle do Aedes aegypti.exposição periódica de larvas de Ae. aeypti obtidas em Itabuna a recipientes tratados com os larvicidas, e comparação do efeito residual do tratamento com cepa Rockfeller.o efeito inibitório na emergência de adultos, após 60 dias, foi de 89,5% spinosad, 96,5% novaluron e 75,4% pyriproxifen para larvas de Itabuna, não havendo diferença estatística (p=0,412) entre os tratamentos; spinosad e novaluron apresentaram maior percentual de mortalidade na fase larval, 98,8% e 97,9% respectivamente; pyriproxifen apresentou mortalidade maior na fase pupal, 95,1%.os três larvicidas apresentaram controle semelhante; no entanto, o pyriproxifen pode deixar a falsa impressão de positividade dos criadouros, por agir em fase pupal, comprometendo os indicadores de infestação que são parâmetros estratégicos para as ações de controle.evaluar en condiciones simuladas de campo la eficacia del piriproxifén (hormona juvenil), novaluron (inhibidor de quitina) y spinosad (biolarvicida) en el control del Ae. Aegypti.exposición periódica de larvas obtenidas de Itabuna, BA, Brasil, a recipientes tratados con larvicida y comparación del efecto residual con cepa Rockefeller.el efecto inhibidor en la emergencia de adultos, después de 60 días, fue de 89,5% spinosad, 96,5% novaluron y 75,4% piriproxifén para larvas de Itabuna, no habiendo diferencia estadística (p=0,412) entre los tratamientos; spinosad y novaluron presentaron mayor mortalidad en la fase larval, 98,8% y 97,9% respectivamente; piriproxifén presentó mayor mortalidad en la fase de pupa, 95,1%.los tres larvicidas fueron eficaces en el control de larvas de Ae. Aegypti; sin embargo, piriproxifén puede dejar falsa positividad de los criaderos, por actuar en fase de pupa, comprometiendo los indicadores de infestación, parámetros estratégicos para las acciones de control.

Para determinar a prevalência de geo-helmintíases e identificar fatores associados a sua ocorrência, foram realizados inquéritos coprológicos em amostra de crianças entre 5 e 14 anos de idade, residentes em dez municípios brasileiros com baixo Índice de Desenvolvimento Humano. Aplicou-se questionário aos responsáveis, obtendo-se informações sócio-econômicas e ambientais e foi feita coleta de fezes. Estimaram-se prevalências de geohelmintos segundo variáveis de interesse e se avaliaram os fatores de risco mediante regressão logística multinível. Das 2.523 crianças estudadas, 36,5% eram portadoras de um ou mais geohelmintos (Ascaris lumbricoides 25,1%; ancilostomídeos 15,3%, Trichuris trichiura 12,2%). A proporção de geo-helmintíases para o conjunto na zona rural foi 45,7%; na urbana, 32,2%. Baixa renda familiar (OR = 1,75; 1,38-2,23), baixa escolaridade materna (OR = 1,69; 1,39-2,06), presença de lixo próximo ao domicílio (OR = 1,50; 1,22-1,84) e maior número de pessoas no domicílio (OR = 1,41; 1,17-1,71) mostraram-se associadas a tais infecções. Conclui-se que a ocorrência destas parasitoses está relacionada às condições sócio-econômicas e evidencia a importância de intervenções públicas direcionadas à melhoria das condições de vida para sua prevenção. Stool surveys were conducted to estimate the prevalence and identify risk factors for geohelminth infections among children in ten Brazilian municipalities with low human development indices (HDI). Socioeconomic and environmental data were obtained from the children's parents or guardians, and stool samples were examined. The proportion of geohelminth infections according to target variables was calculated. Risk factors were evaluated using multilevel logistic regression. Of the 2,523 children, 36.5% were infected with one or more geohelminths (Ascaris lumbricoides, 25.1%; hookworm, 15.3%; Trichuris trichiura, 12.2%). Overall prevalence of geohelminth infections was 45.7% in rural areas and 32.2% in urban areas. Low family income (OR = 1.75; 1.38-2.23), low maternal schooling (OR = 1.69; 1.39-2.06), presence of garbage near the home (OR = 1.50; 1.22-1.84), and number of individuals in the household (OR = 1.41; 1.17-1.71) were associated with infection. In conclusion, geohelminth infections were closely related to socioeconomic conditions, thus emphasizing the importance of targeted public interventions to improve living conditions as part of sustainable prevention.

Stool surveys were conducted to estimate the prevalence and identify risk factors for geohelminth infections among children in ten Brazilian municipalities with low human development indices (HDI). Socioeconomic and environmental data were obtained from the children's parents or guardians, and stool samples were examined. The proportion of geohelminth infections according to target variables was calculated. Risk factors were evaluated using multilevel logistic regression. Of the 2,523 children, 36.5% were infected with one or more geohelminths (Ascaris lumbricoides, 25.1%; hookworm, 15.3%; Trichuris trichiura, 12.2%). Overall prevalence of geohelminth infections was 45.7% in rural areas and 32.2% in urban areas. Low family income (OR = 1.75; 1.38-2.23), low maternal schooling (OR = 1.69; 1.39-2.06), presence of garbage near the home (OR = 1.50; 1.22-1.84), and number of individuals in the household (OR = 1.41; 1.17-1.71) were associated with infection. In conclusion, geohelminth infections were closely related to socioeconomic conditions, thus emphasizing the importance of targeted public interventions to improve living conditions as part of sustainable prevention.

O municipio de Itubera foi selecionado por compor area endemica de Leishmaniose Tegumentar Americana (LTA) no Baixo Sul da Bahia. O presente trabalho tem como objetivo discutir os aspectos ecoepidemiologicos da LTA neste municipio. Para a analise do perfil epidemiologico foi consultada a base de dados do Sistema de Informacao de Agravos de Notificacao. O Inquerito Entomologico foi realizado entre 17.10 e 13.11 de 2010, como preconizado pelo Ministerio da Saude. Foram capturados 11.383 exemplares, sendo identificadas 19 especies. Acreditamos que o predominio das especies sinantropicas Nyssomyia whitmani e Nyssomyia intermedia decorre da interferencia do homem no ambiente rural de Itubera. Sugerimos que essas sejam as principais vetoras da LTA a populacao local, considerando ainda a alta antropofilia e a ocorrencia em todos os pontos de coleta. Destacamos a elevada transmissao silvestre desta enfermidade, devido a exposicao diaria dos trabalhadores rurais ao vetor no interior da mata. A transmissao domiciliar deve ser considerada devido ao grande numero de flebotomineos nas casas; a existencia de doentes de todas as faixas etarias; e a proximidade fisica das habitacoes em relacao a mata. A avaliacao de fatores ambientais propicios ao estabelecimento da LTA e crucial na implantacao das medidas de controle efetivas.

Triatoma infestans foi considerado, por anos, o principal vetor da doenca de Chagas no Brasil. A reducao dos indices de infestacao predial associados a especie conferiu ao pais, em 2006, certificacao de eliminacao da transmissao da doenca por esse vetor. Porem, focos residuais foram encontrados no municipio de Novo Horizonte (BA), Brasil, a partir do ano de 2010. Diante desse panorama, foi desenvolvido um estudo com objetivo de descrever os focos residuais de T. infestans no municipio de Novo Horizonte, area de caatinga da Bahia. As pesquisas foram realizadas na localidade de Fazenda Queimadas 6a, zona rural do municipio, nos anos de 2011 a 2013. Os triatomineos coletados foram identificados, triados e dissecados para diagnostico molecular da infeccao natural pelo Trypanosoma cruzi e avaliacao de suas fontes alimentares. Durante o estudo, foram coletados 502 exemplares, distribuidos em dois focos residuais: em 2011 com 71 individuos no intra e peridomicilio; e, em 2013, com 431, apenas no peridomicilio. Desse total, 143 exemplares foram selecionados para analises moleculares: todos os coletados em 2011 e 16,7% dos coletados em 2013. O Indice de Infeccao Natural pelo T. cruzi foi de 4,2%. O DNA de ave foi detectado em 60% dos triatomineos analisados, 1 infectado por T. cruzi. Ja o DNA humano ocorreu em 3% das amostras, com nenhum triatomineo infectado. A convivencia de seres humanos e animais domesticos com colonias de T. infestans suscita a possibilidade de recolonizacao dessa especie na Bahia, aumentando a chance de transmissao vetorial da doenca de Chagas.

A escassez de informacoes dos fatores envolvidos na interacao vetor-parasitahospedeiro nas areas endemicas de leishmanioses na Bahia dificulta substancialmente a aplicacao de medidas de controle desse agravo. O diagnostico molecular da infeccao natural dos vetores das leishmanioses surge como uma alternativa para analisar os flebotomineos provenientes das atividades da Rede Estadual de Vigilância Entomologica da Bahia. Para tanto, e de fundamental importância padronizar as condicoes para a deteccao do DNA dos flebotomineos no processo de extracao. O presente trabalho objetivou padronizar as condicoes para a extracao automatizada do DNA de flebotomineos no Laboratorio Central de Saude Publica da Bahia (LACEN-BA). O material recebido pelo Nucleo de Entomologia do LACEN-BA foi triado e 100 exemplares de flebotomineos machos foram previamente acondicionados em alcool a 70%. Os exemplares foram separados em amostras com pools de 10 flebotomineos. Cada amostra foi macerada em 80μL de tampao de lise para realizacao da extracao automatizada de DNA no EasyMAG®. Foram realizados PCRs com primers capazes de detectar genes especificos de flebotomineos que regulam sua cacofonia. A deteccao dos produtos da PCR foi feita por meio de eletroforese em gel de agarose (1%), com produto de amplificacao dos alvos testados de 220pb. A eletroforese permitiu a observacao do DNA amplificado de gene cacofonia de flebotomineos, evidenciando o sucesso da tecnica de extracao automatizada do DNA dos vetores das leishmanioses no LACEN-BA. Este trabalho contribuira nos estudos epidemiologicos futuros acerca da identificacao dos parasitas envolvidos nos ciclos epidemiologicos das leishmanioses no estado.