Associação entre infecção pelo vírus Zika e a ocorrência de doenças do sistema nervoso no estado da Bahia: um estudo epidemiológico ecológico.

Abstract

Zika virus represents an important public health problem, particularly in tropical regions such as Bahia, Brazil, due to its association with congenital complications and neurological manifestations, including encephalitis, myelitis, and peripheral neuropathies. Considering the high viral circulation in the state and the limited epidemiological studies addressing its relationship with nervous system diseases, this study aimed to analyze the association between Zika virus infection notifications and hospitalizations due to nervous system diseases in Bahia from 2016 to 2025. This is an ecological, observational, retrospective, and quantitative epidemiological study using secondary data from the Notifiable Diseases Information System (SINAN) and the Hospital Information System of the Brazilian Unified Health System (SIH/SUS), both available through DATASUS. Notifications of Zika virus infection and hospitalizations due to nervous system diseases (ICD-10 G00–G99) were analyzed according to their temporal and spatial distribution across municipalities in Bahia. Zika notifications were highly concentrated in 2016, representing the main epidemic peak of the historical series, followed by a marked decline in subsequent years. In contrast, hospitalizations due to nervous system diseases showed an increasing trend over time, reaching the highest values in 2025. Although no direct temporal association was observed between the variables at the state level, spatial overlap was identified between municipalities with higher Zika notification rates and those with higher hospitalization rates, particularly Salvador, Feira de Santana, Vitória da Conquista, Itabuna, and Ilhéus. This pattern suggests an ecological association influenced by demographic, healthcare, and structural factors such as population density, urbanization, healthcare network organization, and diagnostic capacity. The findings highlight the need for further studies using individual-level data, laboratory confirmation, and specific neurological diagnoses to clarify a possible causal relationship between Zika virus infection and neurological outcomes.