Zika virus: what do we know about the viral structure, mechanisms of transmission, and neurological outcomes?

Abstract

The Zika virus epidemic that started in Brazil in 2014 has spread to >30 countries and territories in Latin America, leading to a rapid rise in the incidence of microcephalic newborns and adults with neurological complications. At the beginning of the outbreak, little was known about Zika virus morphology, genome structure, modes of transmission, and its potential to cause neurological malformations and disorders. With the advancement of basic science, discoveries of the mechanisms of strain variability, viral transfer to the fetus, and neurovirulence were published. These will certainly lead to the development of strategies to block vertical viral transmission, neuronal invasion, and pathogenesis in the near future. This paper reviews the current literature on Zika virus infections, with the aim of gaining a holistic insight into their etiology and pathogenesis. We discuss Zika virus history and epidemiology in Brazil, viral structure and taxonomy, old and newly identified transmission modes, and neurological consequences of infection.

Advances in research on Zika virus

“…ZIKV proteins have also been observed in chronic villi in one case of miscarriage. These evidences support the conclusion that ZIKV reach placental tissue in pregnant women [54].…”

Achados otológicos em pacientes pós-infecção pelo zika vírus: estudos de caso

“…However, it is noteworthy that in adult patients suffering from retro-cochlear pathology, a variety of clinical findings has been discussed in the literature, where it is claimed that the audiological findings vary from normal hearing thresholds to profound hearing loss, which can be of the fluctuating type, and the acoustic reflexes can be either absent or increased (11,12) . As ZIKV is now recognized as a factor that can lead to neurological complications in adults following infection, such as Guillaine-Barré syndrome, facial paralysis, myelitis, and others that are still being analyzed, the importance of studying the damage caused by ZIKV action is further emphasized (13,14) . From this perspective, a study was performed investigating the risks of ZIKV for neuronal cells during the embryonic stage, as well as in childhood and adulthood.…”

The Zika virus in the United States: A comprehensive review

“…In addition, Zika-infected individuals may be at a greater risk for development of Guillain-Barré syndrome (GBS). After the epidemics in the Pacific and Brazil, an unusually high incidence of new cases of GBS was reported for Zikainfected individuals (Arujo et al, 2016;Musso & Gubler, 2016;Silva & Souza, 2016). GBS is an acute-onset, autoimmune-mediated peripheral polyneuropathy that can result subsequent to a variety of infections or as a result of idiopathic causes.…”

“…Recent evidence, derived with animal models, has suggested that the virus is transmitted to the fetus across the placenta. Although the exact mechanism by which the virus crosses the placental membrane is uncertain, it has been hypothesized that the virus crosses from the maternal bloodstream in the chorionic villi to the placenta, where it is amplified before spreading into the fetal circulation and moving to infect neural progenitor cells (NPCs) (Miner et al, 2016;Quicke et al, 2016;Silva & Souza, 2016;Wu et al, 2016).…”

“…Congenital Zika infection of the developing fetus may result in serious neurological defects, including microcephaly, along with other developmental anomalies primarily affecting the central nervous system (Driggers et al, 2016;Hazin et al, 2016;Kleber et al, 2016;Mlakar et al, 2016;Musso & Gubler, 2016;Silva & Souza, 2016). In the US, as of July 2016, there have been at least twelve newborns with congenital birth defects due to Zika, with more cases likely to follow (CDC: Outcomes of pregnancies, 2016).…”