Rapid decline of Zika virus NS1 antigen-specific antibody responses, northeastern Brazil.

Zika virus (ZIKV) is a positive-stranded RNA virus within the Flaviviridae family. After decades of circulation in Asia, ZIKV was introduced to Brazil in 2014-2015, associated with a rise in congenital malformations. Unlike the genetically related dengue virus (DENV), ZIKV constitutes only one serotype.

Expansion of Zika virus circulation from Africa to the Americas, 1947-2018: a literature review.

Objective: to describe the temporal and geographical expansion of Zika virus (ZIKV) circulation in countries and territories, from the time it was first isolated until 2018.

Methods: This was a non-systematic literature review covering the period from 1947 to 2018 using the MEDLINE database and World Health Organization estimates.

Results: Since its isolation in 1947, ZIKV circulation spread through Africa, Asia and the Pacific before reaching the Americas in 2013, causing serious clinical manifestations; the highest seroprevalence rates were recorded in Yap (74%) and in Brazil (63%); genetic mutations, absence of immunity and high vector susceptibility may have influenced ZIKV transmissibility and help to explain the magnitude of its expansion.