Zika virus infection and microcephaly: Evidence regarding geospatial associations

Abstract

BackgroundAlthough the Zika virus (ZIKV) epidemic ceased to be a public health emergency by the end of 2016, studies to improve knowledge about this emerging disease are still needed, especially those investigating a causal relationship between ZIKV in pregnant women and microcephaly in neonates. However, there are still many challenges in describing the relationship between ZIKV and microcephaly. The few studies focusing on the epidemiological profile of ZIKV and its changes over time are largely limited to systematic reviews of case reports and dispersal mapping of ZIKV spread over time without quantitative methods to analyze patterns and their covariates. Since Brazil has been at the epicenter of the ZIKV epidemic, this study examines the geospatial association between ZIKV and microcephaly in Brazil.MethodsOur study is categorized as a retrospective, ecological study based on secondary databases. Data were obtained from January to December 2016, from the following data sources: Brazilian System for Epidemiological Surveillance, Disease Notification System, System for Specialized Management Support, and Brazilian Institute of Geography and Statistics. Data were aggregated by municipality. Incidence rates were estimated per 100,000 inhabitants. Analyses consisted of mapping the aggregated incidence rates of ZIKV and microcephaly, followed by a Getis-Ord-Gi spatial cluster analysis and a Bivariate Local Moran’s I analysis.ResultsThe incidence of ZIKV cases is changing the virus’s spatial pattern, shifting from Brazil’s Northeast region to the Midwest and North regions. The number of municipalities in clusters of microcephaly incidence is also shifting from the Northeast region to the Midwest and North, after a time lag is considered. Our findings suggest an increase in microcephaly incidence in the Midwest and North regions, associated with high levels of ZIKV infection months before.ConclusionThe greatest burden of microcephaly shifted from the Northeast to other Brazilian regions at the beginning of 2016. Brazil’s Midwest region experienced an increase in microcephaly incidence associated with ZIKV incidence. This finding highlights an association between an increase in ZIKV infection with a rise in microcephaly cases after approximately three months.

Spatiotemporal Analysis of the Population Risk of Congenital Microcephaly in Pernambuco State, Brazil

“…Previous spatial and temporal analyses of microcephaly and congenital Zika syndrome, have considered all of Brazil, Pernambuco, or Recife [9][10][11][12][13][14]. The contribution of the current analysis is to describe the patterns of microcephaly in Pernambuco in 2015 and 2016 at a fine scale in terms of both space (municipality) and time (month).…”

Perfil epidemiológico e clínico de casos de microcefalia

“…Los países con clima tropical tienen una posición destacada en la transmisión de arbovirosis. Además de la extensión territorial de Brasil para permitir las diferencias climáticas regionales, todavía existen desigualdades en la distribución de la red de saneamiento básico e hídrico que implican un mayor riesgo de enfermedad a través de patologías transmitidas por Aedes aegypti (24) .…”

“…En estudios que agruparon niños con o sin alteraciones radiológicas, se encontró el 41% de las anomalías, donde se subrayaron calcificaciones, ventriculomegalia y lisencefalia (24) . Las pruebas de laboratorio para ZIKV y TCC realizadas en 79 casos demostraron que 21 (27%) presentaban anomalías cerebrales significativas en la tomografía (25) .…”

Implicações da exposição ao zika vírus durante a gestação para o desenvolvimento da função visual

“…Supõe-se que o vírus tenha sido introduzido no país durante o ano de 2014, quando houve aumento de turistas viajando a partir da Polinésia Francesa para participar de eventos esportivos (Salvador & Fujita, 2016). Como um dos vetores responsáveis pela transmissão do vírus (A. Aegypti) é endêmico no país e existe em população abundante, principalmente no período de chuvas (entre novembro e março) (Vissoci et al, 2018), o ZIKV se alastrou pelo país em alta velocidade. Entre o início de 2015 e o final de 2016, já haviam sido registrados aproximadamente 300.000 casos suspeitos de ZIKV no país (Oliveira et al, 2017) No início de março de 2016, o vírus havia se espalhado do país para, pelo menos, outros 33 países da América do Sul e Central (Hennessey, 2016;Petersen, Jamieson, Powers, & Honein, 2016).…”

“…Uma técnica alternativa, o potencial visual evocado de varredura (PVEv) (Norcia & Tyler, 1985) -que se baseia na estimação da atividade do córtex visual quando padrões similares são apresentados a uma frequência temporal fixa -estima limiares menores que os estimados via técnica de olhar preferencial (provavelmente devido a fatores atencionais e motivacionais inerentes ao exame psicofísico), entretanto o padrão de desenvolvimento da acuidade observado é o mesmo nas duas técnicas (Norcia & Tyler, 1985 (Teller, Dobson, & Mayer, 2005;Teller et al, 1986). (Oliveira et al, 2017;Vissoci et al, 2018).…”