Questions about Zika Zika virus disease is caused by the Zika virus, which is spread to people primarily through the bite of an infected mosquito (
Aedes aegypti and
Aedes albopictus). The illness is usually mild with symptoms lasting up to a week, and many people do not have symptoms or will have only mild symptoms. However, Zika virus infection during pregnancy can cause a serious birth defect called microcephaly and other severe brain defects.
Prevent Mosquito Bites Use Environmental Protection Agency (EPA)-registered insect repellents with one of the active ingredients below. When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women.