An infection with the Zika virus usually has no symptoms. Any symptoms that do occur are usually very mild. However, in Brazil doctors saw more babies with microcephaly (small heads) at the time of the outbreak of the Zika virus. The link between the Zika virus and microcephaly is now being studied intensively. The Zika virus cannot spread in The Netherlands. As a precaution RIVM provides travel advice for pregnant women and women who want to become pregnant for areas where the Zika virus is prevalent.