http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004530 http://journals.plos.org/plosntds/article?id=10.1371/journal... "Historically, adult

http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004530 http://journals.plos.org/plosntds/article?id=10.1371/journal... "Historically, adult human infection with Zika virus has presented with mild, non-life threatening symptoms in 20% of infected patients, with 80% being clinically asymptomatic during initial infection."