Zika virus : the causal agent of a new congenital syndrome

Abstract

Zika virus, a flavivirus transmitted by Aedes mosquitoes, was first identified in 1947 in a sentinel rhesus monkey in the Zika forest area of Uganda, and later on in humans in Nigeria. Despite having been discovered almost 70 years ago, only about a dozen human infections were reported before 2007 and were mainly confined to the African continent. The Zika virus came to global attention when it caused an explosive outbreak in the island of Yap in Micronesia in 2007 followed by a major outbreak in French Polynesia in 2013. The virus continued to spread and entered the Western hemisphere where a major outbreak was reported in May 2015 in Brazil. For many years Zika virus was considered self-limiting causing a mild disease and with no long-term consequences. However, since the end of 2015, there has been reported an increase in the incidence of Guillain-Barré syndrome (GBS) and foetal neurological complications including microcephaly, raising serious worldwide public health concerns. Believed to be only transmitted by mosquitoes, now there have been proposed other non-vector-borne transmission routes including sexual transmission, vertical transmission and blood transfusion transmission. Recently many efforts have been invested in clarifying such worrisome relationship and in developing ZIKV models either in vitro or in vivo. Here, we broadly review what is currently known about this emerging virus and focused on its consequences for brain development.