Zika virus in the Americas: Early epidemiological and genetic findings

Abstract

Zika virus genomes from Brazil The Zika virus outbreak is a major cause for concern in Brazil, where it has been linked with increased reports of otherwise rare birth defects and neuropathology. In a phylogenetic analysis, Faria et al. infer a single introduction of Zika to the Americas and estimated the introduction date to be about May to December 2013—some 12 months earlier than the virus was reported. This timing correlates with major events in the Brazilian cultural calendar associated with increased traveler numbers from areas where Zika virus has been circulating. A correlation was also observed between incidences of microcephaly and week 17 of pregnancy. Science , this issue p. 345

Molecular mapping of Zika spread

“…In this way, they could reconstruct Zika's spread by following a trail of mutations -accumulated by virus strains that the authors sampled at different times and places -back to the outbreak's most recent common ancestor. These trees confirm previous evidence 6 that northeastern Brazil is the outbreak's hub.…”

“…The Zika strain that founded the American outbreak was evidently introduced from the Pacific islands 6 , but the current studies cannot prove that transmission to Brazil was direct. Indeed, Faria et al note that some of the deepest branches and earliest samples on the American Zika tree are from the Caribbean.…”

“…PFK1 and PKM2 each exist in both dimeric and tetrameric forms, with the tetrameric forms being more active 5,6 . Tests to investigate the effect of phosphorylation of these enzymes gave results consistent with a model in which phosphorylation inhibits the activities of PFK1 and PKM2 by reducing the formation of tetramers in favour of the less-active dimers.…”

Congenital Zika syndrome phenotype in a child born in Brazil in December 2011

“…According to the phylogenetic and molecular results of Faria et al2 in 2016, the estimated introduction of Zika to Americas occurred between May and December 2013, more than 1 year before the virus was first reported 2…”

“…Multiple cases were reported in Thailand between March 2012 and July 2014. Single cases were confirmed in the Philippines and in travelers who visited Indonesia in 2012 2. Between 2013 and 2014, ZIKV was responsible for a large epidemic in French Polynesia with a geographic expansion of the Asian lineage 1.…”