Transmissão vetorial e sexual do vírus Zika e os efeitos clínicos e de desenvolvimento em crianças nascidas durante a epidemia em Salvador, Brasil.

Abstract

Background: In 2015, the first confirmed case of Zika virus infection in the continental territory of the Americas was reported, specifically in Northeast Brazil. However, the factors contributing to the high infection rate and its heterogeneous geographic distribution are still unclear. Additionally, Zika virus differs from other arboviruses due to the possibility of congenital and sexual transmission, making it crucial to evaluate exposed children for the development of preventive measures that limit the impact on child development. Objective: To evaluate Zika virus transmission and risk factors in vulnerable urban communities and its clinical and developmental effects in children born during the 2015-2016 epidemic in Salvador, Brazil. Methods: Two cohorts were evaluated in the city of Salvador, Brazil. The first, conducted in the community of Pau da Lima, aimed to evaluate Zika virus transmission and participants were followed through semi-annual follow-ups before and after the 2015 outbreak. In the second cohort, conducted at the Roberto Santos General Hospital (HGRS), infant developmental outcomes including anthropometric growth, neurodevelopment, and neurological, ophthalmological, and auditory clinical outcomes were evaluated at 2 and 3 years after birth. Exposure to Zika virus was determined using the IgG3 immunological assay for ZIKV in the Pau da Lima cohort and the Plaque Reduction Neutralization Test (PRNT) with maternal blood samples collected at birth and during follow-up in the HGRS hospital cohort. Results: The results of this study were described in four articles. 1) In the Pau da Lima cohort, it was identified that individuals with informal jobs and food insecurity had a higher chance of ZIKV seropositivity, while those with high socioeconomic status had a lower chance. 2) In the same cohort, it was identified that men who engaged in casual sexual relationships were more likely to test positive for ZIKV, and women with less than 6 years of formal education had twice the chance of a positive result. 3) In the HGRS cohort, the focus was on the neurodevelopment of children without microcephaly, finding that children exposed to ZIKV had a higher risk of overall neurodevelopmental impairment. 4) In the same cohort, the neurodevelopment of children with microcephaly was characterized, with severe developmental delays observed in children with SCZ. Additionally, higher 4 scores on the neurological evaluation were associated with better cognitive and motor scores on the Bayley-III, and larger head circumference at follow-up was associated with better cognitive and motor scores. Conclusion: In summary, these studies provide information on social and behavioral factors associated with ZIKV transmission in vulnerable communities, as well as the role of intrauterine exposure and its impact on the neurodevelopment of children with and without microcephaly. Consequently, it is crucial to highlight the need for measures beyond those focused on vector control and to take into account social and behavioral factors to minimize the impact of the disease. Additionally, it is important to conduct long-term evaluations of children exposed to ZIKV to allow for early and effective interventions.