Fast Facts: Zika Virus

  • The most common way the Zika virus is spread is by mosquitos called aedes aegypti and aedes albopictus. These mosquitoes are found throughout the United States and are more common (including in winter months) in the warmer and wetter states.
    • These mosquitoes tend to bite during the day and indoors
    • The mosquitos are the same as the type that spread dengue fever and chikungunya
  • Symptoms begin 3-7 days after a bite by infected mosquito; last for several days to a week
    • Only about 1 out of 4-5 infected people will have symptoms
    • Usually a mild illness with fever, maculopapular rash, joint pain and conjunctivitis. Also may have muscle pain, headache, pain behind eyes and vomiting
  • Treatment is for symptoms; there is no cure
  • Zika virus has now been confirmed by the CDC as being the cause of adverse brain development. This includes:
    • Microcephaly
    • Lissencephaly/polymicrogyria (smoothing of the brain’s normal folds)
    • Cerebral calcifications (deposits of calcium in certain areas of the brain)
    • Hydrocephalus (enlarged ventricles in the brain)
    • Eye and perhaps ear (hearing) anomalies
    • Joints that do not move properly (called contractures) and/or cerebral palsy
    • Currently no other known structural malformations
  • Although there are reports of Zika virus found in breast milk, there have been no reports of transmission through breastfeeding. Right now, women are encouraged to keep breastfeeding.
  • Passing Zika through sex (sexual transmission)
    • Zika virus can pass between sexual partners during unprotected vaginal, anal, or oral sex or through the use of sex toys
    • Zika virus can stay in semen longer than in blood, but we don’t know exactly how long Zika stays in semen or how long it can be passed to sex partners

All pregnant women with sex partners who live in or have traveled to an area with Zika should use condoms during sex or abstain from sex for the rest of their pregnancy.