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.

Conocimientos, actitudes y prácticas sobre Dengue en un barrio de la ciudad de Cartagena de Indias / Knowledge, attitudes and practice regarding dengue in a neighborhood forming part of the city of Cartagena

Objetivo Identificar los conocimientos, actitudes y prácticas sobre dengue en un barrio de la ciudad de Cartagena de Indias. Métodos Estudio descriptivo transversal en 870 sujetos residentes de un barrio ubicado en la zona suroriental de la ciudad. El muestreo fue probabilístico, aleatorio en tres etapas. Se indagó sobre los conocimientos, actitudes y prácticas sobre dengue. Para el análisis de los datos se utilizó la base de datos Stata versión 11.1 para determinar las frecuencias absolutas y relativas de cada variable estudiada. Resultados Se encontró que el 93,7 % de los encuestados conocen que existe la enfermedad; el 49,7 % no sabe cuál es el agente causal de la enfermedad. Mientras que el 80,5 % de los encuestados manifiesta tener disposición para recibir clases de educación sanitaria. El 60,1 % de la población encuestada almacena agua en sus viviendas y el 73,8 % utiliza los tanques como recipientes. El 24,8 % manifiesta que evita tener agua estancada. Conclusiones Los habitantes ratifican la alta incidencia de casos de dengue en el barrio, la cual ha sido reportada por el ente de distrital de salud. Los conocimientos sobre dengue son escasos, se adoptan prácticas de riesgo que favorecen el desarrollo de la enfermedad; sin embargo, se evidencia una actitud favorable para el control. Se requiere, entonces, promover cambios de comportamiento no solo en la comunidad, sino también, en la manera como los programas de prevención y control se están llevando a cabo.

Objective Identifying attitudes, practice and knowledge regarding dengue in a neighborhood of the city of Cartagena. Methods This was a cross-sectional study of 870 people living in a neighborhood in the south-eastern part of Cartagena. Probabilistic, randomized, three-staged sampling was used; it was intended to ascertain attitudes, practice and knowledge about dengue. The Stata statistics package (version 11.1) was used for analyzing the data to determine the absolute and relative frequency for each variable studied. Results It was found that 93.7 % of those surveyed knew about the disease; although 49.7 % did not know what the causal agent of the disease was, 80.5 % of those surveyed did express an interest. In receiving health education classes. 60.1 % of the population surveyed here stored water in their homes and 73.8 % used tanks as containers. 24.8 % of those surveyed stated that they avoided having/using stagnant water. Conclusions The residents confirmed the high incidence of dengue cases reported by the district health department. Knowledge about dengue was limited; risky practices favoring the disease's development were adopted, but an attitude towards controlling this issue was evident. Changes in current behavior patterns must thus be promoted in the community and also regarding how prevention and control programs are being carried out.

Difusión masiva de reportes situacionales sobre dengue: efectos de la intervención en Guadalajara de Buga, Colombia / Mass communication of dengue surveillance data: effect of an intervention in Guadalajara de Buga, Colombia

Introducción. La retroalimentación a las comunidades de la situación de dengue en su localidad, podría ser útil para mantener la motivación para su participación en el control del dengue y disminuir los índices entomológicos de Aedes . Objetivos. Evaluar la cobertura y el alcance de una intervención basada en la difusión masiva de reportes situacionales sobre el dengue y su efecto en la presencia de criaderos intradomiciliarios de Aedes spp. en Guadalajara de Buga, Colombia. Materiales y métodos. Se llevó a cabo un estudio observacional de corte transversal en 1.426 viviendas, para establecer la presencia de criaderos intradomiciliarios y caracterizar la exposición a la intervención. El efecto de la intervención se evaluó en un estudio de casos y controles. Los casos obedecieron al total de viviendas con criaderos positivos y, entre las viviendas sin criaderos positivos ubicadas en la misma manzana del caso, se seleccionaron aleatoriamente cuatro controles por caso. Resultados. El índice de viviendas positivas fue de 2,5 %. La cobertura fue del 59,4 % y el alcance del 22,3 %. El contacto con la intervención no se asoció con la ausencia de criaderos intradomiciliarios positivos. La presencia de matas con agua o floreros se asoció con criaderos positivos (p=0,01) y el uso de anjeos se consideró como factor protector (p=0,02). Conclusiones. Aunque la cobertura de la intervención fue adecuada, no se observó que tuviera efecto sobre la ausencia de criaderos intradomiciliarios positivos. Por lo tanto, se requiere la evaluación de la intervención en términos de su fidelidad, diseño y proceso de implementación.

Introduction: Maintaining communities abreast of their local dengue situation could help to keep them motivated to participate in dengue control and to decrease Aedes entomological indexes. Objectives: To evaluate the coverage and reach of an intervention based on mass-media communication of dengue surveillance reports and its effect on the presence of intra-domiciliary breeding sites for Aedes in Guadalajara de Buga, Colombia. Materials and methods: An observational cross-sectional study was conducted in 1,426 households to identify the intra-domiciliary breeding sites and to characterize the intervention exposure. To evaluate the effect of the intervention, a case-control study was performed. All households with positive breeding sites were considered as cases. Four controls per case were randomly selected among the non-positive breeding site households located on the same block of the case. Results: The positive house index was 2.5%; coverage was 59.4% and reach was 22.3%. There was no association between the intervention and the presence of intra-domiciliary breeding sites. The presence of water plants and flower pots were associated to positive breeding sites (p=0.01) and the use of screens was associated to the absence of breeding sites (p=0.02). Conclusions: Although intervention coverage was adequate, the lack of association between the intervention and the absence of positive breeding sites requires assessing its fidelity, factors related to the design, and the implementation process.

Spatial distribution of arboviral mosquito vectors (Diptera, Culicidae) in Vale do Ribeira in the South-eastern Brazilian Atlantic Forest / Distribuição espacial de mosquitos (Diptera, Culicidae) vetores de arbovírus no Vale do Ribeira, sudeste da Mata Atlântica, Brasil

Mosquitoes are vectors of arboviruses that can cause encephalitis and hemorrhagic fevers in humans. Aedes serratus (Theobald), Aedes scapularis (Rondani) and Psorophora ferox (Von Humboldt) are potential vectors of arboviruses and are abundant in Vale do Ribeira, located in the Atlantic Forest in the southeast of the State of São Paulo, Brazil. The objective of this study was to predict the spatial distribution of these mosquitoes and estimate the risk of human exposure to mosquito bites. Results of the analyses show that humans are highly exposed to bites in the municipalities of Cananéia, Iguape and Ilha Comprida. In these localities the incidence of Rocio encephalitis was 2 percent in the 1970s. Furthermore, Ae. serratus, a recently implicated vector of yellow fever virus in the State of Rio Grande do Sul, should be a target for the entomological surveillance in the southeastern Atlantic Forest. Considering the continental dimensions of Brazil and the inherent difficulties in sampling its vast area, the habitat suitability method used in the study can be an important tool for predicting the distribution of vectors of pathogens.

Mosquitos são vetores de arbovírus que podem causar encefalites e febres hemorrágicas em humanos. Aedes serratus (Theobald), Aedes scapularis (Rondani), e Psorophora ferox (Von Humboldt) são vetores potenciais de arbovírus e são abundantes no Vale do Ribeira, Mata Atlântica, sudeste do Estado de São Paulo, Brasil. O objetivo desse estudo foi inferir a distribuição espacial desses mosquitos e estimar o risco da exposição humana às picadas de mosquitos. Os resultados das análises indicaram que os humanos estão altamente expostos às picadas nos municípios de Cananéia, Iguape e Ilha Comprida. Nessas localidades a incidência de encefalite Rocio foi 2 por cento na década de 1970. Adicionalmente, Ae. serratus, que foi recentemente implicado vetor do vírus da febre amarela no estado do Rio Grande do Sul, deveria ser alvo da vigilância entomológica no sudeste da Mata Atlântica. Considerando a extensão territorial do Brasil e as inerentes dificuldades em amostrar esse vasto território, a modelagem de habitat empregada nesse trabalho poderia ser utilizada para a vigilância de vetores de patógenos.

Conocimientos, actitudes y prácticas comunitarias en un brote de Dengue en un municipio de Colombia, 2010 / Knowledge, attitudes and community practice during an outbreak of dengue in a town in Colombia, 2010

Objetivo Entre las semanas epidemiológicas 5-6/12-13/2010, se notificaron 17 casos de dengue provenientes del municipio El-Playón (7°28'15"-N/73°12'00"-W/510msnm). El 16/04/2010 después del Comité de Vigilancia Epidemiológica, la Secretaría de Salud de Santander decidió realizar la investigación y determinar los conocimientos-actitudes-prácticas (CAP) comunitarias frente al brote para fortalecer acciones municipales de promoción-prevención-control del Aedes aegypti. Métodos Estudio descriptivo de investigación de brote: a. Búsqueda activa de casos con cuadro clínico de dengue, según definición del protocolo; b. Encuesta entomológica; y, c. Encuesta CAP a 47 personas seleccionadas con muestreo aleatorio-simple. Sistematización/análisis con Epi-Info-3.5.1®, medidas de frecuencia-tendencia central-razón de masculinidad (RM); índices de: vivienda aegypti (IVAe)-depósitos (Idp)-Breteau (IB). Resultados a) Registros Individuales de Prestadores de Servicios con diagnósticos diferenciales para dengue 67/4 774; notificados 24(75 por ciento municipio/25 por ciento departamento); mujeres 15(63 por ciento), hombres 9(38 por ciento); urbanos 20(83 por ciento), rurales 4(17 por ciento). Tasa de ataque/incidencia acumulada: inicial=0,3 por ciento(17/6 303), final=0,4 por ciento(24/6 303), RM=1:5; b) Depósitos inspeccionados 142; positividad/tipo de criadero: tanques-bajos=8,7 por ciento(4/46), llantas=8,3 por ciento(1/12), diversos=4,4 por ciento(2/45) y plantas=2,9 por ciento(1/34); IVAe=5 por ciento, Idp=6 por ciento, IB=17 por ciento; determinación taxonómica 15 por ciento(7/47); c) Encuesta-CAP, mujeres 36(77 por ciento), hombres 11(23 por ciento); conocían el dengue/signos/síntomas 44(94 por ciento); eliminó criaderos 32(68 por ciento); consultó por dengue 3(6 por ciento); opinó "todos somos responsables del control" 25(53 por ciento). Conclusiones Se evidenció una comunidad conocedora de factores de riesgo y consciente de su responsabilidad para el control del vector. Se propone promover la participación comunitaria en función del ecosistema como herramienta para controlar el mosquito y la transmisión del dengue.

Objective 17 cases of dengue were reported from the town of El Playón (7°28'15"-N/73°12'00"-W/altitude 510 masl) during epidemiological study weeks 5-6 and 12-13/2010. The Santander Department's Health Secretariat sought outbreak investigation and community knowledge-attitudes-practice (KAP) assessment on 16-4-2010 concerning a dengue fever outbreak in the town after an epidemiological surveillance committee had met; this was to strengthen local action regarding Aedes aegypti vector promotion-prevention-control. Methods This was a descriptive outbreak investigation study using an active search for cases having clinical manifestations of dengue according to protocol definitions, an entomological survey and a KAP survey of 47 people selected by simple-random-sampling. Data was systematised and analysed using Epi-INFO (3.5.1) with measures of central tendency-male ratio, in-house Aegypti (IA), water-storage (WI) and Breatau (BI) indexes. Results 4,774 clinical records were examined. There were 67 records compatible with dengue, 24 cases were notified (75 percent town-25 percent department), 15 (63 percent) being women and 9 (38 percent) men. 20 (83 percent) cases occurred in the urban area and 4 (17 percent) in rural areas. Attack rate/cumulated incidence: initial=0.3 percent (17/6 303), final=0.4 percent (24/6 303), male ratio=1.5. 47 houses and 142 water-storage items proved positive: low water-stores=8.7 percent(4/46), rubber tyres=8.3 percent(1/12), others=4.4 percent(2/45), plants=2.9 percent(1/34). IA=5 percent, WI=6 percent, BI=17 percent, taxonomy confirmed=15 percent(7/47). 47 KAP, 36 (77 percent) women, 11 (23 percent) men; knowledge on disease, symptoms and signs 44 (94 percent), eliminating larvae deposits 32(68 percent), asked about dengue 3(6 percent), informed about responsibilities related to control 25(53 percent). Conclusions: The local community knows about risk factors and is aware of its responsibility regarding vector control. Community participation should be promoted using the ecosystem as a strategy for mosquito and dengue transmission control.

Análise da distribuição espaço-temporal de dengue e da infestação larvária no município de Tupã, Estado de São Paulo / Analysis on the spatial-temporal distribution of dengue and larval infestation in the municipality of Tupã, State of São Paulo

INTRODUÇÃO: O vírus da dengue é transmitido pela picada do mosquito Aedes aegypti e, o atual programa de controle não atinge o objetivo de impedir sua transmissão. Este trabalho objetivou analisar a relação entre a distribuição espaço-temporal de casos de dengue e os indicadores larvários no município de Tupã, de janeiro de 2004 a dezembro de 2007. MÉTODOS: Foram construídos indicadores larvários por quarteirão e totalidade do município. Utilizou-se o método cross-lagged correlation para avaliar a correlação entre casos de dengue e indicadores larvários. Foi utilizado estimador kernel para análise espacial. RESULTADOS: A correlação cruzada defasada entre casos de dengue e indicadores larvários foi significativa. Os mapas do estimador Kernel da positividade de recipientes indicam uma distribuição heterogênea, ao longo do período estudado. Nos dois anos de transmissão, a epidemia ocorreu em diferentes regiões. CONCLUSÕES: Não ficou evidenciada relação espacial entre infestação larvária e ocorrência de dengue. A incorporação de técnicas de geoprocessamento e análise espacial no programa, desde que utilizados imediatamente após a realização das atividades, podem contribuir com as ações de controle, indicando os aglomerados espaciais de maior incidência.

INTRODUCTION: The dengue virus is transmitted by the bite of the mosquito Aedes aegypti and the current control program has not met the target of preventing its transmission. This study aimed to analyze the relationship between the spatial-temporal distribution of dengue cases and the larval indices in the municipality of Tupã between January 2004 and December 2007. METHODS: Larval indices were built up block by block and for the entire municipality. We used the cross-lagged correlation method to assess the correlation between dengue cases and larval indices. The kernel estimator was used for spatial analysis. RESULTS: The cross-lagged correlation between dengue cases and larval indices was significant. The kernel estimator maps of positive findings among recipients indicated heterogeneous distribution over the course of the study period. Over two years of transmission, the epidemic occurred in different regions. CONCLUSIONS: There was no evidence of a relationship between larval infestation and dengue occurrence. Incorporation of geoprocessing techniques and spatial analysis into the program, if used immediately after completion of activities, might contribute towards the control actions, thereby indicating spatial agglomerations of higher incidence.

An entomological surveillance system based on open spatial information for participative dengue control

Aedes aegypti is a very efficient disseminator of human pathogens. This condition is the result of evolutionary adaptations to frequent haematophagy, as well as to the colonization of countless types of habitats associated with environmental and cultural factors that favor the proliferation of this mosquito in urban ecosystems. Studies using sensitive methods of monitoring demonstrate that the methods of surveillance used in the Brazilian program do not show the high degrees of the infestation of cities by this vector. To increase the capacity of the health sector, new tools are needed to the practice of surveillance, which incorporate aspects of the vector, place and human population. We describe here the SMCP-Aedes - Monitoring System and Population Control of Aedes aegypti, aiming to provide an entomological surveillance framework as a basis for epidemiological surveillance of dengue. The SMCP-Aedes is uphold in the space technology information, supported by the intensive use of the web and free software to collect, store, analyze and disseminate information on the spatial-temporal distribution of the estimated density for the population of Aedes, based on data systematically collected with the use of ovitraps. Planned control interventions, intensified where and when indicated by the entomological surveillance, are agreed with the communities, relying on the permanent social mobilization.

Associadas a fatores bióticos, climáticos e culturais que favorecem a proliferação do Aedes aegypti em ecossistemas urbanos, adaptações evolutivas à hematofagia freqüente e quase exclusiva em humanos e à colonização de tipos infinitos de habitats, fazem deste mosquito um disseminador extremamente eficiente de patógenos ao homem. Estudos utilizando métodos sensíveis de monitoramento demonstram que os métodos de vigilância usados no programa brasileiro não revelam as elevadas intensidades da infestação das cidades por este vetor. Para ampliar a capacidade do setor de saúde novos instrumentos são necessários à prática da vigilância, incorporando aspectos do vetor, do lugar e das pessoas do lugar. Apresentamos aqui o SMCP-Aedes - Sistema de Monitoramento e Controle Populacional do Ae. aegypti, cuja meta é a instrumentalização da vigilância entomológica como base para a vigilância epidemiológica da dengue. Para isso ele se apóia em tecnologias da informação espacial baseadas no uso intensivo da web e de software livre para coletar, armazenar, analisar e disseminar informações relativas à distribuição espaço-temporal da densidade estimada para a população do Aedes, com base em amostras obtidas continuamente com ovitrampas. Intervenções de controle planejadas e intensificadas onde e quando indicado pela vigilância entomológica, são pactuadas com os habitantes, apoiando-se na mobilização social permanente.

Dengue in the Americas: challenges for prevention and control: [review] / Dengue en las Américas: desafíos para su prevención y control: [revisión]

Dengue is the most important vector-borne disease in the Americas and threatens the lifes of millions of people in developing countries. Imprecise morbidity and mortality statistics underestimate the magnitude of dengue as a regional health problem. As a result, it is considered a low priority by the health sector with no timely steps for effective control. Dengue is perceived as a problem of "others" (individually, collectively and institutionally), therefore responsibility for its control is passed on to others (neighbors, the community, municipality, health institutions, or other governmental agencies). With no precise risk indicators available there is little opportunity for timely diagnoses, treatment, health interventions or vector control (poor surveillance). Solutions only targeting the vector reduce the impact of interventions and there is no sustainable control. Without political commitment there are insufficient resources to face the problem. This paper discusses the challenges for prevention and control in the Americas.

El dengue es la enfermedad transmitida por vector más importante en las Américas, que amenaza la vida de millones de personas. Las cifras subestiman la magnitud del problema y el dengue no figura como prioridad para las autoridades en salud y no se identifica como problema (baja percepción de riesgo), por lo que las medidas para el control se realizan tardíamente. El dengue se considera un problema de "otros" (individuo, colectividad, institucional) y la responsabilidad del control se desvía hacia otros (vecindario, comunidad, municipio, el Ministerio de Salud, etc.). Se carece de indicadores de riesgo precisos, por lo que no hay oportunidad para acciones de diagnóstico, tratamiento, prevención y control vectorial. Con intervenciones poco efectivas no hay control sostenible y sin compromiso político no hay recursos suficientes para enfrentar este problema sanitario. Este artículo aborda los desafíos para la prevención y el control del dengue en las Américas.