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

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

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

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

Las epidemias en La Pampa (Argentina), en perspectiva histórica* / The epidemics in La Pampa (Argentina), from a historical perspective

Resumen Este artículo describe el inicio de las preocupaciones sanitarias vinculadas a las epidemias ocurridas durante el siglo XX en La Pampa, provincia argentina. Las epidemias, como las de la viruela, fueron un estímulo para estas políticas que frecuentemente tuvieron origen en Buenos Aires, la capital del país. El contagio de muchas epidemias dependía de carencias de infraestructura: agua, desagüe y desecho adecuado de basuras, de la ausencia de un número suficiente de trabajadores de salud, de la presencia de vectores transmisores de enfermedades como los mosquitos y, en última instancia, de la pobreza. La experiencia histórica descrita en este texto resalta la importancia de analizar el impacto del SARS-CoV-2 más allá de las grandes ciudades.

Abstract This article describes the emergence of health concerns relating to the epidemics that occurred during the twentieth century in La Pampa, a province in Argentina. Epidemics such as smallpox drove such policies, which frequently originated in Buenos Aires, the country's capital. The spread of many epidemics was due to shortages: water, sewage and adequate refuse disposal, an insufficient number of health care workers, the presence of disease transmission vectors such as mosquitos, and, ultimately, poverty. The historical experience described in this text highlights the importance of analyzing the impact of SARS-CoV-2 beyond the big cities.

Definition of persistent areas with increased dengue risk by detecting clusters in populations with differing mobility and immunity in Rio de Janeiro, Brazil / Definição de áreas persistentes com risco aumentado de dengue através da detecção de clusters em populações com diferentes padrões de mobilidade e imunidade no Rio de Janeiro, Brasil / Definición de áreas persistentes con riesgo elevado de dengue, mediante la detección de clústeres en poblaciones con diferente movilidad e inmunidad, en Río de Janeiro, Brasil

Dengue is a re-emerging arbovirus infection of major epidemiological importance. The detection of dengue clusters is an important epidemiological surveillance strategy, contributing to better allocation of control measures and prioritizing areas that are subject to increased risk of transmission. Studies involving human populations with low mobility are scarce, and the current study thus aims to investigate the presence of persistent dengue clusters in the city of Rio de Janeiro, Brazil, in populations with different mobility and immunity. Epidemiological data on dengue were obtained from the Brazilian Ministry of Health. Areas of increased risk were defined by the space-time scan statistical method and analysis of persistence with use of map algebra. For both study populations, the clusters that were identified did not show spatial concordance, except in years when both presented the same immunological profile. Their persistent clusters were located mostly in the West Zone of city. The clusters of the two study populations only displayed spatial concordance in years with similar immune profiles, which confirms the confounding role of immunity and supports the use of populations with high percentages of susceptible individuals when designing territory-based dengue studies. The space-time similarity between the areas of persistent risk in both populations suggests that the West Zone, a region with disorderly urban growth and low mean income, shows the highest risk of dengue transmission. The definition of persistent dengue clusters contributes to the improvement of dengue control strategies and territorial planning.

A dengue é uma arbovirose reemergente de grande importância epidemiológica. A detecção de clusters de dengue representa uma importante estratégia de vigilância epidemiológica, que contribui para melhor alocação de medidas de controle no território e priorização de áreas sujeitas a risco aumentado de transmissão. São raros os estudos que envolvem populações humanas com mobilidade baixa; portanto, este estudo tem como objetivo investigar a presença de clusters persistentes de dengue no Município do Rio de Janeiro, Brasil, entre populações com diferentes padrões de mobilidade e imunidade. Os dados epidemiológicos sobre dengue foram obtidos do Ministério da Saúde. As áreas de risco aumentado foram definidas pelo método estatístico de varredura espaço-tempo, e a análise de persistência usou a álgebra cartográfica. Para as duas populações do estudo, os clusters identificados não mostraram concordância espacial, exceto nos anos em que ambas apresentaram o mesmo perfil imunológico. Para ambas as populações, os clusters persistentes estavam localizados principalmente na Zona Oeste da cidade. Os clusters nas duas populações do estudo mostraram concordância especial apenas nos anos em que ambas apresentavam perfis imunológicos semelhantes, o que confirma o papel de confounding da imunidade e sustenta o uso de populações com percentuais altos de indivíduos suscetíveis no desenho de estudos sobre dengue com base territorial. A semelhança espaço-temporal entre as áreas de risco persistente em ambas as populações sugere que a Zona Oeste, uma região com crescimento urbano desordenado e média de renda baixa, apresenta o maior risco de transmissão de dengue. A definição de clusters de dengue persistentes contribui para o aprimoramento das estratégias de controle da dengue e de planejamento territorial.

El dengue es una infección por arbovirus reemergente de mucha importancia epidemiológica. La detección de clústeres de dengue es una importante estrategia de vigilancia epidemiológica, que contribuye a mejorar la asignación de medidas de control en el territorio, priorizando áreas que están sujetas a un riesgo de transmisión más elevado. Los estudios que implican poblaciones humanas con baja movilidad son escasos y, por tanto, el presente estudio tiene como fin investigar la presencia de clústeres persistentes de dengue en la ciudad de Río de Janeiro, Brasil, en poblaciones con diferente movilidad e inmunidad. Los datos epidemiológicos sobre dengue se obtuvieron del Ministerio de Salud brasileño. Las áreas de riesgo elevado se definieron mediante un método de análisis espacio-tiempo estadístico, además, el análisis de persistencia utilizó álgebra de mapas. Para las dos poblaciones en estudio, los clústeres que fueron identificados no mostraron concordancia espacial, excepto durante los años en que ambos presentaron el mismo perfil inmunológico. Para ambas poblaciones, los clústeres persistentes se localizaron en su mayoría en la zona oeste de la ciudad. Los clústeres de las dos poblaciones en estudio solo mostraron concordancia espacial durante los años en que ambas contaban con perfiles inmunes similares, lo que confirma el rol confusor de la inmunidad y respalda el uso de poblaciones con altos porcentajes de individuos susceptibles, cuando se diseñan estudios sobre el dengue basados en territorios. La similitud espacio-tiempo entre áreas de riesgo persistente en ambas poblaciones sugiere que la zona oeste, la región con un crecimiento urbano desordenado y una media de ingresos bajos, muestra el riesgo más alto de transmisión de dengue. La definición de los clústeres dengue persistente contribuye a la mejora de las estrategias para el control del dengue y su planificación territorial.

Investigação da influência de fatores ambientais na presença, densidade e distribuição espacial de culicídeos vetores, na zona oeste da capital, São Paulo / Investigation of the influence of environmental factors on the presence, density and spatial distribution of culicids vectors, in the western zone of the capital, São Paulo

Introdução: Várias espécies de culicídeos são vetores de patógenos que causam graves doenças em humanos e outros animais. Objetivos: Investigar a presença e distribuição espacial de insetos vetores na Cidade Universitária, zona Oeste - São Paulo e os fatores ambientais associados a sua ocorrência. Metodologia: A área de estudo foi a Cidade Universitária Armando de Salles Oliveira (CUASO), que foi dividido em quatro partes. As coletas com ovitrampas e adultraps foram realizadas de dezembro de 2013 a novembro de 2014, mensalmente foram sorteados dez pontos de coleta por área, em cada área foram instaladas dez ovitrampas e dez adultraps. As coletas com aspirador ocorreram de janeiro a dezembro de 2014 e mensalmente foram sorteados dois pontos por área para realização das aspirações, totalizando oito pontos de coletas por mês, resultando em 120 minutos/mensal. Todo material coletado foi levado ao Laboratório de Entomologia em Saúde Pública da Faculdade de Saúde Pública da USP para análise. Resultados: De maneira geral as variáveis ambientais influenciaram na presença dos culicídeos coletados. O índice de densidade de ovos sofreu influência significativa da temperatura, enquanto que a pluviosidade afetou mais significativamente a presença do adulto. Em relação à aspiração Culex quinquefasciatus foi a espécie predominante em todas as coletas, seguida de Aedes albopictus e Aedes aegypti. Porém apenas Aedes albopictus e Aedes aegypti apresentaram correlação significativa com as variáveis climáticas. Conclusão: a presença de culicídeos vetores na Cidade universitária foi expressiva praticamente o ano inteiro, tornando esse local um meio propício para propagação de várias arboviroses, necessitando um monitoramento constante da presença desses vetores

Introduction: Several species of culicidae are vectors of pathogens that cause serious diseases in humans and other animals. Objectives: To investigate the presence and spatial distribution of vector insects in Cidade Universitária, Oeste - São Paulo and the environmental factors associated with its ocurrence. Methodology: The study area was the University City Armando de Salles Oliveira (CUASO), which was divided into four parts. The collections with ovitraps and adultraps were carried out from December 2013 to November 2014, monthly there were drawn ten collection points per area, in each area were installed ten ovitraps and ten adultraps. The collections with eletric aspirators (12V battery) occurred from January to December 2014 and monthly there were drawn two points per area to make the aspirations, totaling eight collection points per month, resulting in 120 minutes / month. All collected material was taken to the Laboratory of Entomology in Public Health of the Faculty of Public Health of USP for analysis. Results: In general the environmental variables influenced the presence of culicids collected. The egg density index was significantly influenced by temperature, while rainfall affected the adult presence more significantly. Regarding aspiration Culex quinquefasciatus was the predominant species in all collections, followed by Aedes albopictus and Aedes aegypti. However, only Aedes albopictus and Aedes aegypti showed a significant correlation with climatic variables. Conclusion: the presence of culicids insects in the University City was expressive practically all year round, making this place a propitious medium for the propagation of several arboviruses, necessitating a constant monitoring of the presence of these vectors

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

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

Time trends and changes in the distribution of malaria cases in the Brazilian Amazon Region, 2004-2013

Recent efforts to reduce malaria incidence have had some successes. Nevertheless, malaria persists as a significant public health problem in the Brazilian Amazon. The objective of this study was to describe changes in malaria case characteristics and to identify trends in malaria incidence in the Brazilian Amazon. This study used data from the Malaria Epidemiological Surveillance and Case Notification Information System from 2004 to 2013. The annual parasite incidence (API) was calculated and joinpoint regression was used to assess the trends in API over time. There was a sharp increase in API in the state of Acre, followed by two periods of decrease. Pará also presented inconsistent decreases over the study period. Amapá, Amazonas, Rondônia, and Roraima showed statistically significant decreases over the period. The sharpest decrease occurred in Rondônia, with a reduction of 21.7% in the average annual percent change (AAPC) (AAPC: -21.7%; 95% confidence interval: -25.4%, -17.8%; p < 0.05). This panorama of malaria incidence highlights the importance of integrating evidence-based malaria surveillance and control. Malaria is highly preventable, and eliminating its transmission should be a goal in coming decades.

Mapping the global geographic potential of Zika virus spread

The Americas are presently experiencing the most serious known outbreak of Zika virus (ZIKV). Here, we present a novel set of analyses using environmental characteristics, vector mosquito distributions, and socioeconomic risk factors to develop the first map to detail global ZIKV transmission risk in multiple dimensions based on ecological niche models. Our model predictions were tested against independent evaluation data sets, and all models had predictive ability significantly better than random expectations. The study addresses urgent knowledge gaps regarding (1) the potential geographic scope of the current ZIKV epidemic, (2) the global potential for spread of ZIKV, and (3) drivers of ZIKV transmission. Our analysis of potential drivers of ZIKV distributions globally identified areas vulnerable in terms of some drivers, but not for others. The results of these analyses can guide regional education and preparedness efforts, such that medical personnel will be better prepared for diagnosis of potential ZIKV cases as they appear.

A geografia social do zika no Brasil / The social geography of zika in Brazil

A crise do vírus do zika, como todas as doenças, é um indicador da desigualdade que persiste no Brasil mesmo após décadas de democracia. O zika ilustra disparidade não apenas em termos de classe e com a variedade de questões que se conectam com classe, como gênero e raça. Questões éticas relacionadas ao vírus do zika também têm impactos diferenciais em termos de escolhas reprodutivas, no uso de produtos químicos para a pulverização e no desenvolvimento de mosquitos geneticamente modificados. Ao utilizarem um conjunto multidisciplinar de métodos baseados em história, antropologia e ecoepidemiologia, os autores mostram como a crise atual do zika é parte do histórico de saúde no Brasil com as relações muitas vezes tensas entre atores estatais e população em geral

The Zika virus crisis, like of all diseases, is an indicator of the inequality that persists in Brazil, even after decades of democracy. Zika illustrates disparity not only in terms of class, and a variety of other issues linked to class, but also of gender and race. Ethical issues related to the Zika virus also have different impacts in terms of reproductive choices, the use of chemicals for spraying, and the development of genetically-modified mosquitoes. By using a multi-disciplinary set of methods based on history, anthropology, and eco-epidemiology, the authors show how the current Zika crisis is part of the long history of health in Brazil, with often-tense relations between agents of the State and the population at-large

Percepção do risco de transmissão de zoonoses em um Centro de Referência / Perception risk of transmission of zoonoses in a Reference Center / Percepción del riesgo de transmisión de zoonosis en un Centro de Referencia

Questões relacionadas às condições sociais, econômicas, culturais e ambientais têm contribuído para a expansão da leishmaniose e esporotricose. Pretendeu-se identificar a percepção de risco de transmissão dessas doenças e os fatores que influenciam no processo de adoecimento. Foram entrevistados 27 pacientes(sete com leishmaniose e vinte com esporotricose). A maioria não identificou algum tipo de risco específico de transmissão e nomeou como fator principal a contaminação ambiental Ações de promoção de saúde devem estar integradas com outras abordagens que levem em conta a participação dos indivíduos, particularidades sociais, culturais, geográficas e políticas...

Issues related to social, economic, cultural and environmental conditions have contributed to the expansionof leishmaniasis and sporotrichosis. We attempted to identify the perception of risk of transmissionof these diseases and the factors that influence the disease process. Twenty-seven patients (seven withleishmaniasis and 20 with sporotrichosis) were interviewed. The majority has not identified any specifictype of risk of transmission and attributed as the main factor to environmental contamination. Actions ofhealth promotion should be integrated with other approaches that take into account the participation ofindividuals, social, cultural, geographical and political features...

Preguntas relacionadas a las condiciones sociales, económicas, culturales y ambientales han contribuidoa la propagación de la leishmaniasis y la Esporotricosis. Su objetivo es identificar la percepción deriesgo de transmisión de estas enfermedades y los factores que influyen en el proceso de la enfermedad.Entrevistamos a 27 pacientes (siete con la leishmaniasis y 20 con esporotricosis). La mayoría no identificaningún tipo específico de riesgo para la transmisión y atribuye como el principal factor a la contaminaciónambiental. Acciones de promoción de la salud deben ser integradas con otros enfoques que tomen en cuentala participación de los individuos, las particularidades sociales, culturales, geográficas y políticas...

Estudio entomológico de vectores transmisores de la infección por Trypanosoma cruzi en la población rural del estado Sucre, Venezuela / Entomological study of Trypanosoma cruzi vectors in the rural communities of Sucre state, Venezuela

Introducción. Debido a los cambios ambientales y a la intervención del hombre en los espacios silvestres, se ha cambiado el nicho ecológico de los vectores reduvídeos. Objetivo. En el presente estudio se evaluó la situación actual de los índices entomológicos de los triatominos responsables de la transmisión de Trypanosoma cruzi en el estado Sucre. Materiales y métodos. Se llevó a cabo un estudio prospectivo transversal en 96 centros poblados y 576 viviendas de los 15 municipios del estado Sucre, Venezuela, entre agosto y noviembre de 2008. Los vectores se identificaron con base en sus características morfológicas. La identificación de Trypanosoma spp. en las heces de los triatominos se hizo mediante el examen directo por microscopía. Las láminas positivas se tiñeron con Giemsa y los parásitos se identificaron por sus características morfológicas. Resultados. Los índices entomológicos con los valores más elevados fueron la dispersión en centros poblados rurales del estado Sucre (16,67 %) y la colonización de las viviendas (33,33 %). Las especies de triatominos capturados fueron Rhodnius prolixus , Rhodnius pictipes , Rhodnius robustus , Triatoma maculata y Panstrongylus geniculatus , siendo T . maculata el principal vector en el domicilio. Conclusiones. A pesar del bajo índice de infección natural en vectores (1,72 %), la existencia de especies con éxito reproductivo en el domicilio y el peridomicilio puede garantizar el mantenimiento de la cadena epidemiológica, tanto de la enfermedad como del parásito.

Introduction: The ecological niche of Reduvidae vectors has been modified due to environmental changes and human encroachment into the rural areas. Objective: This study evaluates the current entomological indices of triatomines responsible for Trypanosoma cruzi infection in Sucre State, Venezuela. Materials and methods: A cross-sectional and prospective study was conducted in 95 towns and 577 dwellings in the 15 municipalities of the state of Sucre, Venezuela, from August to November, 2008. Triatomine bugs were identified on the basis of morphological characteristics, and their feces examined for T. cruzi infection through direct microscopy. Positive slides were stained with Giemsa and parasites were identified by morphologic characterization. Results: The entomological indices expressing the highest values were dispersion (16.67%) and household colonization (33.33%). The triatomine species captured were: Rhodnius prolixus , Rhodnius main intradomiciliaryvector. Conclusions: Despite the low index of vector infection (1.72%), the existence of species with domiciliary and peridomiciliary reproductive success ensures the persistence of the epidemiological chain both for the disease and the parasite.

Productividad de Aedes aegypti (L.) (Diptera: Culicidae) en viviendas y espacios públicos en una ciudad end éndemica para dengue en Colombia / Estimation of Aedes aegypti (L.) (Diptera: Culicidae) productivity in households and public spaces in a dengue endemic city in Colombia

Introducción. Aedes aegypti es el vector del dengue en Colombia y su presencia se puede estimar mediante el conteo de pupas. Objetivo. Determinar la productividad de Ae. aegypti en viviendas y espacios públicos de Girardot (Colombia), en época de lluvias y de sequía. Materiales y métodos. Se evaluó la productividad de pupas de Ae. aegypti en 20 conglomerados seleccionados aleatoriamente en Girardot, cada uno compuesto de 100 viviendas y sus espacios públicos. Se hizo una inspección en época de lluvias (febrero a mayo de 2011) y, otra, en época de sequía (agosto a septiembre de 2011). Se estimaron los índices de pupas en viviendas y en recipientes, así como el índice de Breteau, y los índices por persona y por hectárea. Resultados. En época de lluvias, las viviendas aportaron el 94 % de las pupas (n=7.098) y, los espacios públicos, el 6 % (n=482), y en época de sequía, el 98 % (n=9.138) y el 2 % (n=223), respectivamente. Las albercas y tanques bajos (>20 litros) aportaron más del 87 % de las pupas en viviendas; los tarros, llantas y sumideros en espacios públicos fueron más productivos (=20 litros). No se encontraron diferencias significativas en el índice de pupas por persona (lluvias=1,0; sequía=1,3), ni por hectárea (lluvias=0,96, sequía=0,45) (p>0,05). Los espacios públicos con más pupas en época de lluvias, fueron las zonas verdes y los lotes abandonados, y en época de sequía, los colegios y las calles. Conclusiones. La productividad de pupas de Ae. aegypti en las albercas y tanques bajos de las viviendas fue elevada tanto en la época de sequía como en la de lluvias, en tanto que los espacios públicos contribuyeron con más sitios de cría durante la época de lluvias. Las estrategias de control vectorial focalizadas en las pupas, permitirían un uso más racional y eficaz de los recursos.

Introduction: Aedes aegypti is a vector for the dengue virus in Colombia. Its productivity can be estimated using pupal counts. Objective: To determine Ae. aegypti productivity in households and public spaces in Girardot (Colombia) during both wet and dry seasons. Materials and methods: The amount of Ae. aegypti pupae was evaluated in 20 randomly selected clusters in Girardot, each consisting of 100 households and public spaces. Inspections were performed during the rainy (February-May, 2011), and dry (August-September, 2011) seasons. House, container, Breteau, person and hectare pupae indices were estimated. Results: During the rainy season households contributed 94% to the total number of pupae (n=7,098) while only 6% (n=482) were found in public spaces. In the dry season, 98% (n=9,138) of pupae were found in households and 2% (n=223), in public spaces. Low water-storage tanks and tanks for washing purposes provided >87% of pupae in households, whereas jars, tires and sinks contained most pupae in public spaces. High pupal densities were observed in public spaces during the rainy season and in streets and schools in the dry season. There were no significant differences in the index per person (rainy season=1.0; dry season=1.3) or per hectare (rainy season=0.96, dry season=0.45) between seasons. Conclusions: High Ae. aegypti pupal densities were found inside households in low water-storage tanks and tanks for washing purposes during both the dry and rainy seasons. Public spaces provided more aquatic habitats during the rainy season. Vector control strategies targeting these containers could allow a more rational use of resources and increase efficiency.

São Paulo urban heat islands have a higher incidence of dengue than other urban areas

Urban heat islands are characterized by high land surface temperature, low humidity, and poor vegetation, and considered to favor the transmission of the mosquito-borne dengue fever that is transmitted by the Aedes aegypti mosquito. We analyzed the recorded dengue incidence in Sao Paulo city, Brazil, in 2010-2011, in terms of multiple environmental and socioeconomic variables. Geographical information systems, thermal remote sensing images, and census data were used to classify city areas according to land surface temper- ature, vegetation cover, population density, socioeconomic status, and housing standards. Of the 7415 dengue cases, a majority (93.1%) mapped to areas with land surface temperature >28 ◦ C. The dengue incidence rate (cases per 100,000 inhabitants) was low (3.2 cases) in high vegetation cover areas, but high (72.3 cases) in low vegetation cover areas where the land surface temperature was 29 ± 2 ◦ C. Interestingly, a multiple cluster analysis phenogram showed more dengue cases clustered in areas of land surface temperature >32 ◦ C, than in areas characterized as low socioeconomic zones, high population density areas, or slum-like areas. In laboratory experiments, A. aegypti mosquito larval development, blood feeding, and oviposition associated positively with temperatures of 28-32 ◦ C, indicating these temperatures to be favorable for dengue transmission. Thus, among all the variables studied, dengue incidence was most affected by the temperature.

Capacidade vetorial de Lutzomyia (Lutzomyia) cruzi (Diptera: Psychodidae) para Leishmania (Leishmania) infantum / Vectorial capacity of Lutzomyia (Lutzomyia) cruzi (Diptera: Psychodidae) for Leishmania (Leishmania) infantum

Em algumas regiões, como nos municípios de Corumbá e Ladário, no Estado de Mato Grosso do Sul, existem evidências ecológicas e epidemiológicas de que Lutzomyia (Lutzomyia) cruzi (Mangabeira, 1938) seja a principal responsável pela transmissão do protozoário Leishmania (Leishmania) infantum Nicolle, 1908 (ou subespécie de L. (L.) infantum chagasi Cunha & Chagas, 1937 segundo alguns autores), agente etiológico da leishmaniose visceral (LV). A ausência de Lutzomyia (Lutzomyia) longipalpis (Lutz & Neiva, 1912), principal vetor do parasito, reforçam esta hipótese. Este estudo teve por objetivo avaliar os parâmetros e estimar a capacidade vetorial de Lu. cruzi para L. (L.) infantum e Leishmania (Leishmania) amazonensis Lainson & Shaw, 1972. Para este último, apenas foram avaliados os parâmetros, sem a estimativa numérica da capacidade vetorial. A avaliação da capacidade vetorial foi realizada a partir de experimentos laboratoriais (infecção experimental) e de campo (atratividade aos flebotomíneos). Por intermédio da infecção experimental de Lu. cruzi pelo parasito, foi possível estimar a expectativa de sobrevida diária de fêmeas infectadas (estimativa vertical e laboratorial), avaliar o período de incubação extrínseco do parasita e obter duração do ciclo gonotrófico. Para a avaliação da competência vetorial do inseto, foram realizadas tentativas de transmissão experimental e natural de Leishmania, a partir de fêmeas provenientes de colônia cujos indivíduos foram alimentados durante o xenodiagnóstico e de fêmeas selvagens capturadas em campo, respectivamente. A distribuição sazonal de Lu. cruzi foi avaliada por meio da instalação semanal de armadilhas luminosas no peridomicílio de cinco residências na área urbana do Município de Corumbá. Variáveis meteorológicas obtidas junto ao Centro de Monitoramento do Tempo, do Clima e dos Recursos Hídricos de Mato Grosso do Sul, índices radiométricos calculado a partir de imagens de resolução espacial (GeoEye) e o percentual de cobertural vegetal foram utilizados neste estudo. Os resultados obtidos permitiram estimar a capacidade vetorial de Lu. cruzi para L. (L.) infantum, que foi de 0,24, ou seja, espera-se que a população de fêmeas da área produzam 0,24 novas infecções viii por dia de exposição de uma infecção. A competência vetorial de Lu. cruzi para L. (L.) infantum e L. (L.) amazonensis, via picada, foi demonstrada por meio de transmissão natural e experimental dos parasitos, respectivamente. Também foi identificada a infecção natural de Lu. cruzi por L. (L.) amazonensis. Com relação à distribuição mensal, embora não tenha sido observada a presença de associação entre essas espécies e as variáveis ambientais de vegetação e clima, foi possível observar picos elevados populacionais na estação chuvosa e picos menores na estação seca. O padrão da distribuição sazonal das espécies de flebotomíneos demonstrado neste estudo foi determinado basicamente pelos espécimes de Lu. cruzi capturados, uma vez que eles representam 93,94 por cento . A variação mensal demonstrou que a espécie Lu. cruzi tem grande plasticidade, tendo sido observada em todos os meses de coleta.

In some regions such as in the municipalities of Corumbá and Ladário in Mato Grosso do Sul state, there are ecological and epidemiological evidence that Lutzomyia (Lutzomyia) cruzi (Mangabeira, 1938) is the vector of Leishmania (Leishmania) infantum Nicolle, 1908 (or subspecies of L. (L.) infantum chagasi Cunha & Chagas, 1937 according to some authors), the etiologic agent of visceral leishmaniasis (VL). The absence of Lutzomyia (Lutzomyia) longipalpis (Lutz & Neiva, 1912), the main vector of the parasite, supports this hypothesis. This study aimed to evaluate the parameters and estimate the vectorial capacity of Lu. cruzi for L. (L.) infantum and Leishmania (Leishmania) amazonensis Lainson & Shaw, 1972. For the latter, only parameters was evaluated without numerical estimation of the vectorial capacity. The evaluation of the vectorial capacity was carried out from laboratory experiments (experimental infection) and field (attractiveness to sandflies). Through experimental infection by the parasite, it was possible to estimate the expected daily survival of infected females (vertical and laboratory estimate), evaluate the extrinsic incubation period of the parasite and get the length of gonotrophic cycle. To evaluate the insect vector competence, attempts have been made of experimental and natural transmission of Leishmania from females from colony whose subjects were fed for xenodiagnosis and wild females captured in the field, respectively. Monthly and seasonal distribution of Lu. cruzi was evaluated by weekly installation of light traps in the peridomicile of five residences in the urban area of the Municipality of Corumbá. Meteorological variables obtained from the Weather Monitoring Center, Climate and Water of Mato Grosso do Sul Resources, radiometric indices calculated from spatial resolution images (GeoEye) and the percentage of plant cobertural were used in this study. Results allowed estimating the vectorial capacity of Lu. cruzi for L. (L.) infantum, which was 0.24, i.e., it is expected that the female population in the region produce 0.24 new infections per day of exposure to an infection. Vector competence of Lu. cruzi for L. (L.) infantum and L. (L.) amazonensis by biting, was demonstrated by natural and experimental transmission of both parasites, respectively. Natural infection of Lu. cruzi by L. (L.) amazonensis was identified. Regarding the monthly x distribution, there was no significant association between of sandflies and the environmental and climate variables. It was observed high peaks population in the rainy season and lower peaks in the dry season. The pattern of seasonal distribution of species of sand flies demonstrated in this study was determined primarily by Lu. cruzi specimens, since this species represent 93.94 per cent of the total captured. The monthly change showed that Lu. cruzi species has great plasticity and has been observed in all months of collection.

The peri-urban interface and house infestation with Triatoma infestans in the Argentine Chaco: an underreported process?

Peri-urban infestations with triatomine bugs, their sources and their dynamics have rarely been investigated. Here, we corroborated the reported occurrence of Triatoma infestans in a peri-urban area and in neighbouring rural houses in Pampa del Indio, in the Argentine Chaco, and identified its putative sources using spatial analysis and demographic questionnaires. Peri-urban householders reported that 10% of their premises had triatomines, whereas T. infestans was collected by timed manual searches or community-based surveillance in only nine (3%) houses. Trypanosoma cruzi-infected T. infestans and Triatoma sordida were collected indoors only in peri-urban houses and were infected with TcV and TcI, respectively. The triatomines fed on chickens, cats and humans. Peri-urban infestations were most frequent in a squatter settlement and particularly within the recently built mud houses of rural immigrants, with large-sized households, more dogs and cats and more crowding. Several of the observed infestations were most likely associated with passive bug transport from other sources and with active bug dispersal from neighbouring foci. Thus, the households in the squatter settlement were at a greater risk of bug invasion and colonisation. In sum, the incipient process of domestic colonisation and transmission, along with persistent rural-to-urban migratory flows and unplanned urbanisation, indicate the need for active vector surveillance and control actions at the peri-urban interface of the Gran Chaco.