BackgroundThe physiopathology of dengue hemorrhagic fever (DHF), a severe form of Dengue Fever, is poorly understood. We are unable to identify patients likely to progress to DHF for closer monitoring and early intervention during epidemics, so most cases are sent home. This study explored whether patients with selected co-morbidities are at higher risk of developing DHF.MethodsA matched case-control study was conducted in a dengue sero-positive population in two Brazilian cities. For each case of DHF, 7 sero-positive controls were selected. Cases and controls were interviewed and information collected on demographic and socio-economic status, reported co-morbidities (diabetes, hypertension, allergy) and use of medication. Conditional logistic regression was used to calculate the strength of the association between the co-morbidities and occurrence of DHF.Results170 cases of DHF and 1,175 controls were included. Significant associations were found between DHF and white ethnicity (OR = 4.70; 2.17–10.20), high income (OR = 6.84; 4.09–11.43), high education (OR = 4.67; 2.35–9.27), reported diabetes (OR = 2.75; 1.12–6.73) and reported allergy treated with steroids (OR = 2.94; 1.01–8.54). Black individuals who reported being treated for hypertension had 13 times higher risk of DHF then black individuals reporting no hypertension.ConclusionsThis is the first study to find an association between DHF and diabetes, allergy and hypertension. Given the high case fatality rate of DHF (1–5%), we believe that the evidence produced in this study, when confirmed in other studies, suggests that screening criteria might be used to identify adult patients at a greater risk of developing DHF with a recommendation that they remain under observation and monitoring in hospital.

Background Prenatal exposure to ZIKV has potential teratogenic effects with a wide spectrum of clinical presentation called congenital Zika syndrome (CZS). There are limited data on survival of children with CZS, we estimated mortality comparing live births with and without CZS. Methods A population-based cohort study using linked routinely collected data in Brazil, from January 2015 to December 2018. Kaplan-Meier and survival analyses were performed adjusted for confounding and stratified by gestational age, birth weight and small for gestational age. Results We followed 11,737,554 live births for up to 36 months. The mortality rate among live births with CZS was 52.6 (95% confidence interval [CI] 47.6-58.0) and among those without CZS it was 5.6 (5.6-5.7) per 1000 person-years. The mortality rate ratio was 11.3 (95%CI 10.2-12.4) times higher among live births with CZS than those without CZS up to the age of 36 months. For infants born before 32 weeks' gestation or with birth weight less than 1500g, the risk of death was similar regardless of CZS. Infants with CZS born at term (mortality rate with and without CZS—38.4 vs 2.7) or with birth weight greater than 2499g (mortality rate with and without CZS—32.6 vs 2.5) were 14.3 (95%CI 12.4-16.4) and 12.9 (95%CI 10.9-15.3) times more likely to die than those without CZS. The burden of congenital anomalies, diseases of the nervous system and infectious diseases, as recorded causes of deaths, were higher among the CZS group. Conclusion There is a higher mortality risk in live births with CZS than live births without CZS that persists throughout the first three years of life.

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The transmission of vector infectious diseases, which produces complex spatiotemporal patterns, is analyzed by a periodically forced two-dimensional cellular automata model. The system, which comprises three population levels, is introduced to describe complex features of the dynamics of the vector transmitted dengue epidemics, known to be very sensitive to seasonal variables. The three coupled levels represent the human, the adult and immature vector populations. The dynamics includes external seasonality forcing (rainfall intensity data), human and mosquito mobility, and vector control effects. The model parameters, even if bounded to well defined intervals obtained from reported data, can be selected to reproduce specific epidemic outbursts. In the current study, explicit results are obtained by comparison with actual data retrieved from the time-series of dengue epidemics in two cities in Brazil. The results show fluctuations that are not captured by mean-field models. It also reveals the qualitative behavior of the spatiotemporal patterns of the epidemics. In the extreme situation of absence of external periodic drive, the model predicts completely distinct long time evolution. The model is robust in the sense that it is able to reproduce the time series of dengue epidemics of different cities, provided the forcing term takes into account the local rainfall modulation. Finally, the dependence between epidemics threshold and vector control undergoes a transition from power law to stretched exponential behavior due to human mobility effect.

Background: The clinical manifestations of microcephaly/congenital Zika syndrome (microcephaly/CZS) have harmful consequences on the child’s health, increasing vulnerability to childhood morbidity and mortality. This study analyzes the case fatality rate and child–maternal characteristics of cases and deaths related to microcephaly/CZS in Brazil, 2015–2017. Methods: Population-based study developed by linkage of three information systems. We estimate frequencies of cases, deaths, case fatality rate related to microcephaly/CZS according to child and maternal characteristics and causes of death. Multivariate logistic regression models were applied. Results: The microcephaly/CZS case fatality rate was 10% (95% CI 9.2–10.7). Death related to microcephaly/CZS was associated to moderate (OR = 2.15; 95% CI 1.63–2.83), and very low birth weight (OR = 3.77; 95% CI 2.20–6.46); late preterm births (OR = 1.65; 95% CI 1.21–2.23), Apgar < 7 at 1st (OR = 5.98; 95% CI 4.46–8.02) and 5th minutes (OR = 4.13; 95% CI 2.78–6.13), among others. Conclusions: A high microcephaly/CZS case fatality rate and important factors associated with deaths related to this syndrome were observed. These results can alert health teams to these problems and increase awareness about the factors that may be associated with worse outcomes.

Background Applying the Robson classification to all births in Brazil, the objectives of our study were to estimate the rates of caesarean section delivery, assess the extent to which caesarean sections were clinically indicated, and identify variation across socioeconomic groups. Methods We conducted a population-based study using routine records of the Live Births Information System in Brazil from January 1, 2011, to December 31, 2017. We calculated the relative size of each Robson group; the caesarean section rate; and the contribution to the overall caesarean section rate. We categorised Brazilian municipalities using the Human Development Index to explore caesarean section rates further. We estimated the time trend in caesarean section rates. Results The rate of caesarean sections was higher in older and more educated women. Prelabour caesarean sections accounted for more than 54 % of all caesarean deliveries. Women with a previous caesarean section (Group 5) made up the largest group (21.7 %). Groups 6–9, for whom caesarean sections would be indicated in most cases, all had caesarean section rates above 82 %, as did Group 5. The caesarean section rates were higher in municipalities with a higher HDI. The general Brazilian caesarean section rate remained stable during the study period. Conclusions Brazil is a country with one of the world’s highest caesarean section rates. This nationwide population-based study provides the evidence needed to inform efforts to improve the provision of clinically indicated caesarean sections. Our results showed that caesarean section rates were lower among lower socioeconomic groups even when clinically indicated, suggesting sub-optimal access to surgical care.

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This study analyzed 3129 fecal samples derived from 1626 patients with sudden onset acute flaccid paralysis clinically compatible with poliomyelitis. The samples were collected in the period ranging from January 1990 to September 1993 in all regions of Brazil. Among the 1626 cases studied, 196 had isolation of poliovirus. Nevertheless, it was observed that some factors influenced the isolation rate and the intratypic characterization of these polioviruses. No cases of acute flaccid paralysis has been found to be etiologically related with wild polioviruses.