Zika virus is shown in cross section at center left. On the outside, it includes envelope protein (red) and membrane protein (magenta) embedded in a lipid membrane (light purple). Inside, the RNA genome (yellow) is associated with capsid proteins (orange). The viruses are shown interacting with receptors on the cell surface (green) and are surrounded by blood plasma molecules at the top.
Transmission of Zika virus is primarily through the bite of an infected Aedes species mosquito. Zika is generally asymptomatic, although some infected individuals may develop symptoms such as fever, rash, joint and muscle pain and conjunctivitis. It is possible for maternal-fetal transmission to occur, which can cause microcephaly and other severe brain defects in the developing fetus.