Índices larvais de Aedes aegypti e incidência de dengue: um estudo ecológico no Estado do Rio de Janeiro, Brasil / Aedes aegypti larval indices and dengue incidence: an ecological study in the state of Rio de Janeiro, Brazil / Índices larvales de Aedes aegypti e incidencia de dengue: un estudio ecológico en el estado de Río de Janeiro, Brasil

Resumo: A circulação simultânea da dengue, Zika e chikungunya impõe desafios importantes para o Brasil, que em decorrência das mudanças climáticas e outros fatores associados, estas arboviroses podem expor mais de 2 bilhões de pessoas no mundo, segundo a Organização Mundial da Saúde. A principal estratégia dos programas de controle do Aedes aegypti baseia-se no Levantamento de Índice Rápido para o Ae. aegypti (LIRAa), um inquérito amostral no qual o Índice de Infestação Predial (IIP) obtido é utilizado para priorizar áreas de intervenção. Neste estudo, analisou-se o desempenho do LIRAa quanto à sua sensibilidade na previsão de epidemias de dengue em municípios do Estado do Rio de Janeiro, em anos considerados epidêmicos. Foram obtidas as taxas de incidência (TI) por município nos anos de 2011, 2012, 2013, 2015 e 2016, e os IIP de outubro dos anos anteriores. Foram elaborados diagramas de dispersão, visando à análise exploratória e à visualização gráfica da relação entre as referidas variáveis, assim como análises de correlação de Spearman entre o IIP e o Índice de Breteau (IB) de cada ano, a fim de estimar a qualidade do LIRAa. A análise comparativa dos valores dos IIP e as respectivas TI no período indicou correlação significativa entre estas variáveis apenas em 2011/2012 (rs = 0,479; p < 0,01). Adicionalmente, foi observada correlação entre os IIP e IB. É urgente repensar os parâmetros estabelecidos pela metodologia LIRAa e investir em metodologias alternativas de vigilância entomoepidemiológica, que mensurem de forma confiável o risco de transmissão no território e assim delinear estratégias mais efetivas para o controle dessas arboviroses.

Abstract: The simultaneous circulation of dengue, Zika, and chikungunya poses major challenges for Brazil. Due to climate changes and other associated factors, more than two billion people in the world may be exposed to these arbovirus infections, according to the World Health Organization. The principal strategy for Aedes aegypti control programs is based on the Infestation Index Rapid Survey for Ae. aegypti (LIRAa), a sample survey in which the Building Infestation Index (BII) is used to prioritize areas for intervention. This study analyzed the performance of LIRAa in terms of its sensitivity for predicting dengue epidemics in municipalities in the state of Rio de Janeiro in epidemic years. Incidence rates per municipality for the years 2011, 2012, 2013, 2015, and 2016, plus the BII in October of the previous years. Scatterplots were created, aimed at an exploratory analysis and graphic visualizations of the relationship between the above-mentioned variables, as well as analyses of the Spearman correlation between the BII and the Breteau Index for each year, aimed at estimating the quality of the LIRAa. Comparative analysis of the values for the BII and the respective incidence rates in the period only indicated significant correlation between these variables in 2011/2012 (rs = 0.479; p < 0.01). There was also a correlation between BII and Breteau Index. It is urgent to rethink the parameters established by the LIRAa methodology and invest in alternative methodologies in entomological and epidemiological surveillance that reliably measure transmission risk in the territory and thus design more effective strategies to control these arbovirus infections.

Resumen: La circulación simultánea del dengue, Zika y chikungunya impone desafíos importantes para Brasil, que, a consecuencia del cambio climático y otros factores asociados, pueden estar expuestas a estas arbovirosis más de 2 billones de personas en el mundo, según la Organización Mundial de la Salud. La principal estrategia de los programas de control del Aedes aegypti se basa en el Levantamento de Índice Rápido para el Ae. aegypti (LIRAa), una encuesta de muestreo en la que el Índice de Infestación de Edificios (IIP) obtenido es utilizado para priorizar áreas de intervención. En este estudio se analizó el desempeño del LIRAa, en cuanto a su sensibilidad en la previsión de epidemias de dengue en municipios del estado de Río de Janeiro, durante años considerados epidémicos. Se obtuvieron tasas de incidencia (TI) por municipio de los años de 2011, 2012, 2013, 2015 y 2016, y los IIP de octubre de años anteriores. Se elaboraron diagramas de dispersión, visando el análisis exploratorio y visualización gráfica de la relación entre las referidas variables, así como análisis de correlación de Spearman entre el IIP y el Índice de Breteau (IB) de cada año, con el objetivo estimar la calidad del LIRAa. El análisis comparativo de los valores de los IIP y las respectivas TI en el período indicó correlación significativa entre esas variables solamente en 2011/2012 (rs = 0,479; p < 0,01). Asimismo, se observó correlación entre los IIP e IB. Es urgente repensar los parámetros establecidos por la metodología LIRAa, e invertir en metodologías alternativas de vigilancia entomoepidemiológica, que midan de forma confiable el riesgo de transmisión en el territorio y así delinear estrategias más efectivas para el control de esas arbovirosis.

Prostaglandin A1 triggers Mayaro virus inhibition and heat shock protein 70 expression in an epithelial cell model

Abstract INTRODUCTION: The Mayaro virus (MAYV), which is an arbovirus closely related to the Chikungunya virus, causes a dengue-like acute illness that is endemic to Central and South America. We investigated the anti-MAYV activity of prostaglandin A1 (PGA1), a hormone which exhibits antiviral activity against both ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) viruses. Further, we examined the effects of inducting the stress protein HSP70 following PGA1 treatment. METHODS: Hep-2 cells infected with MAYV were treated with PGA1 (0.1-6μg/ml) 12h before infection and for different periods post-infection. Inhibition of viral replication inhibition was analyzed via viral titer determination, whereas the effect of PGA1 on viral morphogenesis was examined via transmission electron microscopy (TEM). Autoradiography (with 35S methionine labeling) and western blotting were used to assess the effect of PGA1 treatment on viral and cellular protein synthesis, and on HSP70 induction, respectively. RESULTS: PGA1 strongly reduced viral replication in Hep-2 cells, particularly when added during the early stages of viral replication. Although PGA1 treatment inhibited viral replication by 95% at 24 hours post-infection (hpi), viral structural protein synthesis was inhibited only by 15%. TEM analysis suggested that PGA1 inhibited replication before viral morphogenesis. Western blot and densitometry analyses showed that PGA1 treatment increased HSP70 protein levels, although this was not detectable via autoradiography. CONCLUSIONS: PGA1 inhibits MAYV replication in Hep-2 cells at early stages of viral replication, prior to production of viral structural proteins, possibly via HSP70 induction.