Epidemiological monitoring of the last outbreak of yellow fever in Brazil - An outlook from Portugal.

BACKGROUND: Yellow Fever (YF) is a high fatality rate disease (30-50%) caused by Flavivirus, present in some African and South American countries. In order to determine the magnitude and epidemiological distribution of YF cases, vaccination coverage and most affected regions in Brazil, a descriptive epidemiological study monitoring the last outbreak was undertaken in Portugal. METHOD: The Brazilian database "Portal da Saude" was used to collect data on cases of YF. We used Microsoft Excel on a weekly basis to update the suspected, confirmed and mortality cases as well as the case fatality rate and epizootics in non-human primates. RESULTS: Case Fatality Rate was 33.6%. A total and 82% of confirmed cases were males. The outbreak predominantly affected two south-eastern states, Minas Gerais and Espírito Santo, both with a very low vaccination coverage. CONCLUSIONS: The last outbreak of YF was by far the largest observed over the last few decades! Until the emergence of this outbreak, Espírito Santo, Bahia and Rio de Janeiro were states of low risk for YF and the vaccine not previously recommended. The World Health Organization's "Global Strategy to Eliminate Yellow Fever Epidemic" (EYE) should be on the way, to prevent YF outbreaks in Brazil and other countries in Africa and South America.

A study protocol to evaluate the relationship between outdoor air pollution and pregnancy outcomes.

BACKGROUND: The present study protocol is designed to assess the relationship between outdoor air pollution and low birth weight and preterm births outcomes performing a semi-ecological analysis. Semi-ecological design studies are widely used to assess effects of air pollution in humans. In this type of analysis, health outcomes and covariates are measured in individuals and exposure assignments are usually based on air quality monitor stations. Therefore, estimating individual exposures are one of the major challenges when investigating these relationships with a semi-ecologic design. METHODS/DESIGN: Semi-ecologic study consisting of a retrospective cohort study with ecologic assignment of exposure is applied. Health outcomes and covariates are collected at Primary Health Care Center. Data from pregnant registry, clinical record and specific questionnaire administered orally to the mothers of children born in period 2007-2010 in Portuguese Alentejo Litoral region, are collected by the research team. Outdoor air pollution data are collected with a lichen diversity biomonitoring program, and individual pregnancy exposures are assessed with spatial geostatistical simulation, which provides the basis for uncertainty analysis of individual exposures. Awareness of outdoor air pollution uncertainty will improve validity of individual exposures assignments for further statistical analysis with multivariate regression models. DISCUSSION: Exposure misclassification is an issue of concern in semi-ecological design. In this study, personal exposures are assigned to each pregnant using geocoded addresses data. A stochastic simulation method is applied to lichen diversity values index measured at biomonitoring survey locations, in order to assess spatial uncertainty of lichen diversity value index at each geocoded address. These methods assume a model for spatial autocorrelation of exposure and provide a distribution of exposures in each study location. We believe that variability of simulated exposure values at geocoded addresses will improve knowledge on variability of exposures, improving therefore validity of individual exposures to input in posterior statistical analysis.