Probability of dengue transmission and propagation in a non-endemic temperate area: conceptual model and decision risk levels for early alert, prevention and control.

BACKGROUND: Dengue viruses have spread rapidly across tropical regions of the world in recent decades. Today, dengue transmission is observed in the Americas, Southeast Asia, Western Pacific, Africa and in non-endemic areas of the USA and Europe. Dengue is responsible for 16% of travel-related febrile illnesses. Although most prevalent in tropical areas, risk maps indicate that subtropical regions are suitable for transmission. Dengue-control programs in these regions should focus on minimizing virus importation, community engagement, improved vector surveillance and control. RESULTS: We developed a conceptual model for the probability of local introduction and propagation of dengue, comprising disease vulnerability and receptivity, in a temperate area, considering risk factors and social media indicators. Using a rich data set from a temperate area in the south of Brazil (where there is active surveillance of mosquitoes, viruses and human cases), we used a conceptual model as a framework to build two probabilistic models to estimate the probability of initiation and propagation of local dengue transmission. The final models estimated with good accuracy the probabilities of local transmission and propagation, with three and four weeks in advance, respectively. Vulnerability indicators (number of imported cases and dengue virus circulation in mosquitoes) and a receptivity indicator (vector abundance) could be optimally integrated with tweets and temperature data to estimate probability of early local dengue transmission. CONCLUSIONS: We demonstrated how vulnerability and receptivity indicators can be integrated into probabilistic models to estimate initiation and propagation of dengue transmission. The models successfully estimate disease risk in different scenarios and periods of the year. We propose a decision model with three different risk levels to assist in the planning of prevention and control measures in temperate regions at risk of dengue introduction.

Meteorological variables and mosquito monitoring are good predictors for infestation trends of Aedes aegypti, the vector of dengue, chikungunya and Zika.

BACKGROUND: Aedes aegypti is an important vector for arboviroses and widely distributed throughout the world. Climatic factors can influence vector population dynamics and, consequently, disease transmission. The aim of this study was to characterize the temporal dynamics of an Ae. aegypti population and dengue cases and to investigate the relationship between meteorological variables and mosquito infestation. METHODS: We monitored and analyzed the adult female Ae. aegypti population, the dengue-fever vector, in Porto Alegre, a subtropical city in Brazil using the MI-Dengue system (intelligent dengue monitoring). This system uses sticky traps to monitor weekly infestation indices. We fitted generalized additive models (GAM) with climate variables including precipitation, temperature and humidity, and a GAM that additionally included mosquito abundance in the previous week as an explanatory variable. Logistic regression was used to evaluate the effect of adult mosquito infestation on the probability of dengue occurrence. RESULTS: Adult mosquito abundance was strongly seasonal, with low infestation indices during the winters and high infestation during the summers. Weekly minimum temperatures above 18 °C were strongly associated with increased mosquito abundance, whereas humidity above 75% had a negative effect on abundance. The GAM model that included adult mosquito infestation in the previous week adjusted and predicted the observed data much better than the model which included only meteorological predictor variables. Dengue was also seasonal and 98% of all cases occurred at times of high adult Ae. aegypti infestation. The probability of dengue occurrence increased by 25%, when the mean number of adult mosquitos caught by monitoring traps increased by 0.1 mosquitoes per week. CONCLUSIONS: The results suggest that continuous monitoring of dengue vector population allows for more reliable predictions of infestation indices. The adult mosquito infestation index was a good predictor of dengue occurrence. Weekly adult dengue vector monitoring is a helpful dengue control strategy in subtropical Brazilian cities.

Eticidade do uso de placebo em pesquisa clínica: proposta de algoritmos decisórios / Ethics of the use of placebos in clinical research: a proposal for decision-making algorithms

O uso de placebo em pesquisa clínica tem sido motivo de debate nos últimos anos, sobretudo após a Associação Médica Mundial publicar, em 2002, nota de esclarecimento do parágrafo 29 da Declaração de Helsinki. O Brasil tem se destacado por sua posição firme e contrária ao uso flexível de placebo. Tanto o Conselho Federal de Medicina quanto o Conselho Nacional de Saúde editaram resoluções que normatizam seu uso no Brasil, de forma a não admiti-lo em caso da existência de um método terapêutico melhor. O presente artigo reforça essa posição e tem por objetivo descrever as diversas aplicações de placebo em pesquisa clínica, bem como trazer à luz a complexa decisão sobre a eticidade de seu uso. Além disso, os autores propõem uma reflexão acerca da utilização de placebo no âmbito da pesquisa, por meio de algoritmos decisórios baseados nas normativas éticas brasileiras...

The use of placebos in clinical research has been a matter of considerable debate in recent years, notably when the World Medical Association published, in 2002, a note of clarification for paragraph 29 of the Helsinki Declaration. Brazil is known for its strong opposition to the flexible use of placebos. Both the Federal Council of Medicine and the National Health Council have published resolutions regulating the use of placebos in Brazil, preventing their use if there is a more effective therapeutic method already in place. The present study reinforces that position and aims to describe the various uses of placebos in clinical research, as well as examining the complex decisions relating to the ethics of their use. Additionally, the authors propose a reflection on the use of placebos through decision-making algorithms based on Brazilian ethical standards...

El uso del placebo en la investigación clínica ha sido un tema de debate en los últimos años, sobre todo después de que la Asociación Médica Mundial publicara, en 2002, una nota aclaratoria del párrafo 29 de la Declaración de Helsinki. Brasil se ha destacado por su firme posición en contra de la utilización flexible del placebo. Tanto el Consejo Federal de Medicina como el Consejo Nacional de Salud editaron resoluciones que regulan el uso del placebo en Brasil, no admitiéndose su uso cuando existe un mejor método terapéutico. El presente artículo refuerza esa posición y tiene como objetivo describir diferentes usos del placebo en la investigación clínica, así como contribuir en la discusión sobre la ética de su uso. Además, los autores proponen una reflexión sobre el uso del placebo en la investigación a través de algoritmos para la toma de decisiones, los cuales se basan en las normativas éticas de Brasil...

Rotavírus e bactérias associados a enterite aguda em crianças de Porto Alegre: comentários sobre prevalência, estacionalidade e faixa etária / Rotavirus and bacteria associated with acute enteritis in children of Porto Alegre: comments about prevalence, stationality and age

Analisa-se o material fecal de 388 crianças com idade entre 0-60 meses, através de enzima imunoensaio (EIE), microscopia eletrônica direta (MED) e coprocultura para detecçäo de agentes diarreiogênicos associados a enterite aguda (EA). O material foi coletado do Hospital Santa Casa de Misericórdia, em Porto Alegre. Foi encontrado rotavírus em 41,8% dos casos. A sua maior freqüência ocorreu no mês de janeiro (78,1%). As bactérias diarreiogênicas E. coli, Shigella e Salmonella foram detectadas em 43,0% dos 388 casos analisados. A maior freqüência de bactérias ocorreu no mês de dezembro (66,7%). Näo foi possível a caracterizaçäo estacional bacteriana, quando comparadas, entre sí, suas freqüencias mensais. A infecçäo mista foi registrada em 18,8% dos casos. A faixa etária mais atingida pela EA foi a de 0-12 meses (89,9%). Neste grupo, as crianças com 4-6 meses mostraram as maiores freqüências rotaviral (43,8%) e bacteriana (47,3%)

Pesquisa exploratoria sobre a presença de rotavirus associado a gastroenterite aguda em crianças de Manaus (Amazonas) / Research about presence of rotavirus associated with acute gastroenteritis from childrens in Manaus (Amazon)

Material fecal de crianças na idade de zero ate 5 anos. diagnosticadas com GEA em um hospital de Manaus, foi estudado atraves de microscopia eletronica (ME) e enzima-imunoensaio (EIE). As amostras foram coletadas antes de qualquer tratamento medico no hospital. Dos 29 casos estudados, 12 mostraram positividade para rotavirus (41,4%). Dos 29 casos, 48,3% foram tratados com reidarataçao isolada, 31,0% com antibioticoterapia e 20,7% com quimioterapia. Dos 12 casos positivos, 3 foram tratados com antibioticos e 3 com quimioterapicos. A maior frequencia de rotavirus ocorreu em crianças com idade entre zero e 12 meses. Nesta faixa etaria, o maior numero de casos de GEA e rotavirus foi detectado entre o setimo e o decimo segundo mes