The burden of arboviruses in the Americas is high and may result in long-term sequelae with infants disabled by Zika virus infection (ZIKV) and arthritis caused by infection with Chikungunya virus (CHIKV). We aimed to identify environmental drivers of arbovirus epidemics to predict where the next epidemics will occur and prioritize municipalities for vector control and eventual vaccination. We screened sera and urine samples (n = 10,459) from residents of 48 municipalities in the state of Rio de Janeiro for CHIKV, dengue virus (DENV), and ZIKV by molecular PCR diagnostics. Further, we assessed the spatial pattern of arbovirus incidence at the municipal and neighborhood scales and the timing of epidemics and major rainfall events. Lab-confirmed cases included 1,717 infections with ZIKV (43.8%) and 2,170 with CHIKV (55.4%) and only 29 (<1%) with DENV. ZIKV incidence was greater in neighborhoods with little access to municipal water infrastructure (r = -0.47, p = 1.2x10-8). CHIKV incidence was weakly correlated with urbanization (r = 0.2, p = 0.02). Rains began in October 2015 and were followed one month later by the largest wave of ZIKV epidemic. ZIKV cases markedly declined in February 2016, which coincided with the start of a CHIKV outbreak. Rainfall predicted ZIKV and CHIKV with a lead time of 3 weeks each time. The association between rainfall and epidemics reflects vector ecology as the larval stages of Aedes aegypti require pools of water to develop. The temporal dynamics of ZIKV and CHIKV may be explained by the shorter incubation period of the viruses in the mosquito vector; 2 days for CHIKV versus 10 days for ZIKV.

BackgroundThis study aims to describe the role of mobility in malaria transmission by discussing recent changes in population movements in the Brazilian Amazon and developing a flow map of disease transmission in this region.Methodology/Principal findingsThis study presents a descriptive analysis using an ecological approach on regional and local scales. The study location was the municipality of Porto Velho, which is the capital of Rondônia state, Brazil. Our dataset was obtained from the official health database, the population census and an environmental database. During 2000–2007 and 2007–2010, the Porto Velho municipality had an annual population growth of 1.42% and 5.07%, respectively. This population growth can be attributed to migration, which was driven by the construction of the Madeira River hydroelectric complex. From 2010 to 2012, 63,899 malaria-positive slides were reported for residents of Porto Velho municipality; 92% of the identified samples were autochthonous, and 8% were allochthonous. The flow map of patients' movements between residential areas and areas of suspected infection showed two patterns of malaria transmission: 1) commuting between residential areas and the Jirau hydropower dam reservoir, and 2) movements between urban areas and farms and resorts in rural areas. It was also observed that areas with greater occurrences of malaria were characterized by a low rate of deforestation.ConclusionsThe Porto Velho municipality exhibits high malaria endemicity and plays an important role in disseminating the parasite to other municipalities in the Amazon and even to non-endemic areas of the country. Migration remains an important factor for the occurrence of malaria. However, due to recent changes in human occupation of the Brazilian Amazon, characterized by intense expansion of transportation networks, commuting has also become an important factor in malaria transmission. The magnitude of this change necessitates a new model to explain malaria transmission in the Brazilian Amazon.

RESUMO: Introdução: A ocorrência da tuberculose tem sido relacionada à organização espacial e à melhoria das condições de vida da população. Contudo, essa relação não é de forma direta, e o adoecimento por tuberculose envolve processos de diferentes níveis de organização. Método: Estudo ecológico que analisa a relação entre condições de vida e tuberculose no município de Niterói, Brasil. Foram criados dois indicadores, socioambiental e programático, por meio de análise fatorial e analisados por regressão no período de 2008 a 2012. Foram construídos mapas temáticos com os dados referentes à taxa de incidência e aos indicadores, para verificar o padrão da distribuição da taxa de incidência e desses indicadores no município. Resultados: Os resultados apontaram associação direta e significativa entre os dois indicadores com a taxa de incidência de tuberculose. O aumento em uma unidade no indicador programático esteve associado com um aumento na taxa de incidência em 7%. Já o indicador socioambiental associou-se com uma taxa de tuberculose 27% mais elevada. Discussão: Os resultados do presente trabalho foram consistentes ao constatar relação direta entre tuberculose e condições de vida no município de Niterói. Conclusão: Podemos concluir que a dinâmica da transmissão da tuberculose no município de Niterói pode ser explicada pela ocorrência da doença em áreas de periferia social consolidada e pela vulnerabilidade social de grupos específicos.