Zika Virus Fact Sheet

  • Zika virus is mainly transmitted to humans by the bite of infected Aedes mosquito species, specifically Aedes aegypti and Aedes albopictus.

  • Mosquitoes become infected when they feed on a person already infected with the virus. Infected mosquitoes can then spread the disease to other
    people through bites.

  • Zika virus was first identified in Uganda in 1947 in rhesus monkeys. For many years only sporadic human cases were detected in Africa and Southern
    Asia. In 2007, the first documented outbreak of Zika virus disease occurred in the Pacific. Since 2013, cases and outbreaks of the disease have
    been reported from the Western Pacific, the Americas and Africa.

  • With the recent outbreaks, the number of Zika cases among travelers visiting or returning to the United States will likely increase.

  • These imported cases could result in local spread of the virus in some areas of the United States.


  • Zika virus is primarily transmitted to humans through bites from Aedes mosquitoes, which often live around buildings in urban areas and are usually
    active during daylight hours (peak biting activity occurs in early mornings and late afternoons).

  • Some evidence suggests Zika virus can also be transmitted between humans through blood transfusion, perinatal transmission, and sexual
    transmission. However, these modes are rare and more investigation is needed.


  • About one in five people infected with Zika virus become ill (i.e., develop Zika).

  • The most common symptoms of Zika are fever, rash, joint pain, or conjunctivitis (red eyes). Other common symptoms include muscle pain and headache.
    The incubation period (the time from exposure to symptoms) for Zika virus disease is not known, but is likely to be a few days to a week.

  • The illness is usually mild with symptoms lasting for several days to a week.

  • Zika virus usually remains in the system of an infected person for a few days but it can be found longer in some people.

  • Severe disease requiring hospitalization is uncommon.

  • Deaths are rare.


  • The symptoms of Zika are similar to those of dengue and chikungunya, diseases spread by the same mosquitoes that transmit Zika virus.

  • See your healthcare provider if you develop the symptoms described above and have visited areas where there was active Zika virus transmission.

  • If you have recently traveled, tell your healthcare provider when and where you traveled.

  • Your healthcare provider may order blood tests to look for Zika or other similar viruses like dengue or chikungunya.

  • For more information on travel and Zika virus vist the CDC’s Travelers’ Health website (http://wwwnc.cdc.gov/travel/page/zika-travel-information)


  • No vaccine or medications are available to prevent or treat Zika infections.

  • CDC recommends the following to treat the symptoms:

    • Get plenty of rest.

    • Drink fluids to prevent dehydration.

    • Take medicine such as acetaminophen to relieve fever and pain.

    • Do not take aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen and naproxen. Aspirin and NSAIDs should be avoided
      until dengue can be ruled out to reduce the risk of hemorrhage (bleeding). If you are taking medicine for another medical condition, talk to
      your healthcare provider before taking additional medication.

  • If you have Zika, prevent mosquito bites for the first week of your illness.

    • During the first week of infection, Zika virus can be found in the blood and be passed from an infected person if bitten by a mosquito that can
      transmit the virus.

    • An infected mosquito can then spread the virus to other people.

Pregnancy and Zika virus

  • Zika virus has been linked to a recent increase in the incidence of microcephaly in South America.

  • Microcephaly is a birth defect where a baby’s head is smaller than expected. This is due to abnormal brain development in the womb or during


  • Preventing mosquito bites is the primary way to avoid becoming infected.

  • Use an effective insect repellent containing DEET, Picaridin or Oil of Lemon Eucalyptus.

  • Pregnant women and women who are breast feeding can and should use insect repellent. Always follow label instructions.

  • If weather permits wear long sleeves and pants.

  • Use air conditioning or window/door screens to keep mosquitoes outside.

  • Drain all standing water from around your yard especially in flower pots, bird baths, tires, buckets and other small containers.