Schistosomiasis Mansoni in the Amazon Region:Malacological Surveys of Intermediate Hosts for the Identification of Disease Transmission Areas in Belem,Para,Brazil

In Brazil,schistosomiasis occurrence is related to the presence of the etiological agent Schistosoma mansoni.The presence of mollusks for Biomphalaria genus is a necessary condition for development of the parasite cycle.In Parástate,the species B.schrammi,B.kuhniana,B.straminea and B.glabrata have already been identified,with reports of the last two occurring in Belém.The aim of this study was to determine the spatial distribution of Biomphalaria species in Belém,Pará,Brazil,identifying risk areas for schistosomiasis transmission.Biannual malacological surveys were carried out between September 2013 and October 2017 in 35 neighborhoods of Belém.The collection points were georeferenced using a Global Positioning System(GPS)receiver and the Kernel Density Estimation(KDE)was used to the spatial analysis.The mollusks,after measurement,were exposed to light to verify the presence of S.mansoni cercariae.Subsequently,mollusks were sacrificed and fixed for dissection and morphological identification of species.The surveys resulted in a total of 10,803 mollusks collected,of which 9,367(86.70%)specimens were examined.Among the analyzed mollusks,5,820(62.14%)were identified as B.glabrata and 3,547(37.86%)as B.straminea.The presence of the parasite was observed in 208(2.22%)specimens,all B.glabrata.Positive mollusks were found in six neighborhoods:Guamá(51 mollusks/24.5%),Sacramenta(47 mollusks/22.6%),Telégrafo(47 mollusks/22.6%),Terra Firme(36 mollusks/17.3%),Condor(20 mollusks/9.6%)and Barreiro(7 mollusks/3.4%).This study confirms that B.glabrata species actively participates as intermediate host in the disease maintenance in Belém.The KDE allowed to analyze the spatial distribution of collection sites and consequently to determine possible risk areas of schistosomiasis transmission in Belem.The development of maps identifying sites with schistosomiasis positive snails may support efforts of this municipality by directing activities related to endemic disease control.

Microcephaly prevalence after the 2015 to 2016 Zika outbreak in Tangará da Serra, Brazil: a population-based study

Objective::Prenatal infection with the Zika virus (ZIKV) can lead to congenital Zika syndrome (CZS), characterized by microcephaly and brain injury. However, there are questions regarding the prevalence of microcephaly/CZS after the ZIKV outbreak in defined geographic areas. This study aimed to identify adverse outcomes in live births of fetuses exposed in utero to the ZIKV, compared to unexposed births, as well as maternal sociodemographic, delivery, and birth characteristics.Methods::Here, we conducted a cross-sectional observational study to investigate the characteristics of all live births in the city of Tangará da Serra, Mato Grosso, Brazil, in 2016, after the outbreak of ZIKV infection in late 2015. All live births of children to women residing in the municipality of Tangará da Serra between January 1 and December 31, 2016, were evaluated, and head circumference was measured at birth and after 24 hours. Children born with microcephaly or a maternal history of confirmed or suspected prenatal ZIKV infection were evaluated by a multidisciplinary team. The outcomes of the exposed and non-exposed children were compared. Prevalence ratios and their respective 95% confidence intervals were calculated for sociodemographic, delivery, and live birth characteristics.Results::Of 1,441 live births, 106 (7.3%) were from mothers with confirmed or highly probable exposure to ZIKV. The prevalence of severe congenital microcephaly (41.7/10,000) in Tangará da Serra in 2016 was ten-fold higher than that in Latin America before 2015.Conclusion::This study may serve as a model to investigate possible outbreaks of infections in a defined geographical space in the future.