The rapid spread of Zika virus in the Americas and current outbreak of microcephaly in Brazil has raised attention to the possible deleterious effects that the virus may have on fetuses. We report a case of a 20-year-old pregnant woman who was referred to our service after a large Zika virus outbreak in the city of Salvador, Brazil with an ultrasound examination that showed intrauterine growth retardation of the fetus at the 18^th gestational week. Ultrasound examinations in the 2^nd and 3^rd trimesters demonstrated severe microcephaly, hydranencephaly, intracranial calcifications and destructive lesions of posterior fossa, in addition to hydrothorax, ascites and subcutaneous edema. An induced labor was performed at the 32^nd gestational week due to fetal demise and delivered a female fetus. ZIKV-specific real-time polymerase chain reaction amplification products were obtained from extracts of cerebral cortex, medulla oblongata and cerebrospinal and amniotic fluid, while extracts of heart, lung, liver, vitreous body of the eye and placenta did not yield detectable products. This case report provides evidence that in addition to microcephaly, there may be a link between Zika virus infection and hydrops fetalis and fetal demise. Given the recent spread of the virus, systematic investigation of spontaneous abortions and stillbirths may be warranted to evaluate the risk that ZIKV infection imparts on these outcomes. The rapid spread of Zika virus in the Americas and outbreak of microcephaly in Brazil has raised attention to the possible deleterious effects that the virus may have on fetuses. We report a case of a 20-year-old pregnant woman from Salvador, Brazil whose fetus had developed hydrops fetalis, a condition where there is abnormal accumulation of fluid in the fetus, as well as severe central nervous system defects such as microcephaly and hydranencephaly. After fetal demise, ZIKV RNA was detected in central nervous system tissues and amniotic fluid. The case report provides evidence that in addition to microcephaly, there may be a link between Zika virus infection and hydrops fetalis and fetal demise. Given the recent spread of the virus, systematic investigation of spontaneous abortions and stillbirths may be warranted to evaluate the risk that ZIKV infection imparts on these outcomes.

Zika dynamics in South America: The infection dynamics of Zika virus (ZIKV) are difficult to characterize. Many ZIKV infections are asymptomatic, and the clinical presentation of ZIKV is nonspecific. Rodriguez-Barraqueret al.took advantage of a long-term health study under way in Salvador, Brazil, the epicenter of the recent outbreak in the Americas. They used multiple serological assays, from before and after the emergence of ZIKV in October 2015, to distinguish ZIKV immune responses from those against Dengue virus (DENV). About 73% of the population was attacked by ZIKV. The presence of preexisting antibodies to DENV was associated with less risk of ZIKV infection and fewer symptoms.Science, this issue p.607

Rat-borne leptospirosis is an emerging zoonotic disease in urban slum settlements for which there are no adequate control measures. The challenge in elucidating risk factors and informing approaches for prevention is the complex and heterogeneous environment within slums, which vary at fine spatial scales and influence transmission of the bacterial agent. We performed a prospective study of 2,003 slum residents in the city of Salvador, Brazil during a four-year period (2003–2007) and used a spatiotemporal modelling approach to delineate the dynamics of leptospiral transmission. Household interviews and Geographical Information System surveys were performed annually to evaluate risk exposures and environmental transmission sources. We completed annual serosurveys to ascertain leptospiral infection based on serological evidence. Among the 1,730 (86%) individuals who completed at least one year of follow-up, the infection rate was 35.4 (95% CI, 30.7–40.6) per 1,000 annual follow-up events. Male gender, illiteracy, and age were independently associated with infection risk. Environmental risk factors included rat infestation (OR 1.46, 95% CI, 1.00–2.16), contact with mud (OR 1.57, 95% CI 1.17–2.17) and lower household elevation (OR 0.92 per 10m increase in elevation, 95% CI 0.82–1.04). The spatial distribution of infection risk was highly heterogeneous and varied across small scales. Fixed effects in the spatiotemporal model accounted for the majority of the spatial variation in risk, but there was a significant residual component that was best explained by the spatial random effect. Although infection risk varied between years, the spatial distribution of risk associated with fixed and random effects did not vary temporally. Specific “hot-spots” consistently had higher transmission risk during study years. The risk for leptospiral infection in urban slums is determined in large part by structural features, both social and environmental. Our findings indicate that topographic factors such as household elevation and inadequate drainage increase risk by promoting contact with mud and suggest that the soil-water interface serves as the environmental reservoir for spillover transmission. The use of a spatiotemporal approach allowed the identification of geographic outliers with unexplained risk patterns. This approach, in addition to guiding targeted community-based interventions and identifying new hypotheses, may have general applicability towards addressing environmentally-transmitted diseases that have emerged in complex urban slum settings. Leptospirosis is a rat-borne infectious disease that occurs worldwide, predominantly among vulnerable populations, such as urban slum communities with poor sanitation infrastructure. However, urban slums are complex local settings, where transmission of the disease varies over space and time, and the factors that influence this risk difference are unknown. An improved understanding of the environmental and social factors that modify the risk of this infection is needed in order to guide interventions to reduce the disease burden. We recruited a cohort of 2003 community residents of a high- risk urban slum in Salvador, Brazil. We followed them for a four-year period to understand yearly variation in individual and spatial risk factors for infection using spatiotemporal statistical modeling techniques. Our findings suggest that environmental factors related to topology such as household elevation and inadequate sewage drainage systems increase the risk of transmission in the slum microenvironment by promoting contact with mud contaminated with the pathogenic leptospiral bacteria, and that individual characteristics such as age and gender increase risk through behaviors that lead to increased exposures to a contaminated environment. Through this technique, we also identified local geographic areas where the risks are not well explained by these factors. This will help generate new hypotheses and identify intervention strategies for targeted prevention of leptospirosis in urban slum populations.