The virus is spread mainly by the Aedes aegypti mosquito, which is commonly found throughout the tropical and subtropical
A number of countries have issued travel warnings, and the outbreak is expected to significantly impact the tourism industry. Several countries have taken the unusual step of advising their citizens to delay pregnancy until more is known about the virus and its impact on fetal development.
On 1 February 2016, the World Health Organization declared recently reported clusters of microcephaly and other neurological disorders a Public Health Emergency of International Concern (PHEIC).
Microcephaly shown at left
The Zika virus was first linked with newborn microcephaly during the Brazil Zika virus outbreak. In 2015, there were 2,782 cases of microcephaly compared with 147 in 2014 and 167 in 2013. Confirmation of many of the recent cases is pending, and it is difficult to estimate how many cases went unreported before the recent awareness of the risk of virus infections.
In November 2015, the Zika virus was isolated in a newborn baby from the northeastern state of
In January 2016, a baby in
In March 2016, first solid evidence was reported on how the virus affects the development of the brain. It appears to preferentially kill developing brain cells.