The Epidemiology

Abstract

ZKV was first described in Uganda in 1947. It was isolated from the blood of a Rhesus monkey from the Zika Forest, during a yellow fever study and afterwards in 1948, it was also isolated from multiple Aedes africanus from the same forest. Human illness was first described in 1954, in the context of yellow fever outbreak in Nigeria. Since then, very few cases had been described in literature until 2007, when a ZIKV outbreak in Yap Island (Federated States of Micronesia) affected an estimated number of 5000 patients among the population older than 3 years. In the following years, until 2012, sporadic cases were described in some countries in Africa and Asia. In 2013, a new outbreak in Pacific Islands was estimated to affect over 30,000 people and implied an increasing number of neurological complications like Guillain–Barré syndrome (GBS). Also, in 2014 the first confirmation of the potential ZKV sexual transmission (ZIKV was isolated in a semen sample) and the first vertical transmission cases were described. In March 2015, the first ZIKV cases in America during an outbreak of exanthematous illness in Brazil (Bahia) were confirmed. During which ZIKV cases have been reported in other American and Caribbean countries and territories, with a continuous geographical expansion. At the same time, an increasing number of microcephaly and other central nervous system syndromes in newborns and GBS cases in most of these countries have been reported. On 1 February 2016, World Health Organization (WHO) declared Public Health Emergency of International Concern (PHEIC), the potential link with ZIKV infection and the microcephaly and other neurologic syndromes cases. So far, 25 countries from Americas, Africa and Asia had notified confirmed autochthonous ZIKV cases and additional seven countries have reported ongoing outbreaks of ZIKV infection.