Zika virus is a virus that is transmitted by mosquitoes. Most people infected with Zika virus have no signs or symptoms, while others may report mild fever, rash and muscle pain. Other signs and symptoms may include headache, red eyes (conjunctivitis) and a general feeling of discomfort. Signs and symptoms of Zika virus usually begin two to seven days after being bitten by an infected mosquito.
Zika virus may cause microcephaly, a potentially fatal congenital brain condition, in newborn infants if the mother contracts the virus during her pregnancy. Zika virus also may cause other neurological disorders such as Guillain-Barre syndrome.
No vaccine exists to prevent Zika virus, and there's no effective antiviral treatment. Treatment is aimed at relieving symptoms with rest, fluids and medications — such as acetaminophen (Tylenol, others) and ibuprofen (Advil, Motrin IB, others) — to relieve joint pain and fever.
Where is it found?
Zika virus was first identified in the Zika Valley in Africa in 1947. Outbreaks have since been reported in southeastern and southern Asia, the Pacific Islands and the Americas. More than 650 cases have been reported in Brazil since May 2015.
Zika virus is transmitted primarily through the bite of an infected Aedes species mosquito, which is found throughout the world. For this reason, it's likely that outbreaks will continue to spread to new countries. Spread of the virus through sexual contact and blood transfusion have been reported.
Puerto Rico reported its first Zika virus case in December 2015. No locally transmitted cases have been reported elsewhere in the United States, but cases of Zika virus have been reported in returning travelers.
How concerned should I be?
The Centers for Disease Control and Prevention (CDC) recommends all pregnant women avoid traveling to areas where there is an outbreak of Zika virus. The virus may cause severe complications in newborn infants if the mother becomes infected with Zika virus during her pregnancy.
If you're traveling to an area with known outbreaks of Zika virus, take precautions. Preventive measures are focused on protection from infected mosquitoes. Use insect repellent containing DEET or picaridin, wear long sleeves and pants treated with permethrin, and stay indoors or in screened-in places when possible.
Most people recover fully, with symptoms resolving in about a week.
When should I see a doctor?
See your doctor if you think you or a family member may have Zika virus, especially if you have recently traveled to an area where there's an ongoing outbreak. The CDC has blood tests to look for Zika virus or similar diseases such as dengue or chikungunya viruses, which are spread by the same type of mosquitoes.
Feb. 09, 2016
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- Ventura CV, et al. Zika virus in Brazil and macular atrophy in a child with microcephaly. The Lancet. 2016;387:228.
- Melo O, et al. Zika virus intrauterine infection causes fetal brain abnormality and microcephaly: Tip of the iceberg? Ultrasound in Obstetrics & Gynecology. 2016;47:6.
- Longo DL, et al., eds. Arthropod-borne and rodent-borne virus infections. In: Harrison's Principles of Internal Medicine. 19th ed. New York, N.Y.: McGraw-Hill Education; 2015. http://accessmedicine.com. Accessed Jan. 15, 2016.
- Zika virus. Centers for Disease Control and Prevention. http://www.cdc.gov/zika/. Accessed Jan. 15, 2016.
- Zika virus infection and Zika fever: Frequently asked questions. Pan American Health Organization. http://www.paho.org/hq/index.php?option=com_content&view=article&id=9183&Itemid=41463&lang=en. Accessed Jan. 15, 2016.
- Tosh PK (expert opinion). Mayo Clinic, Rochester, Minn. Jan. 15, 2016.