Zika Virus

Overview of Zika Virus

Zika virus disease (Zika) is a mild illness caused by the transmission of the Zika virus in Aedes mosquitos. People do not usually get sick enough to go to the hospital and rarely die from Zika. Its symptoms can include fever, red eyes and joint pain. There is currently no vaccine or specific medicine for Zika, and the best prevention method is to avoid mosquito bites. Currently, Zika virus is known to exist in Africa, the Americas, Asia and the Pacific. Recent outbreaks of Zika virus have been linked with various neurological and autoimmune complications, including microcephaly, but current evidence is not sufficient to declare a causal link between these issues and the virus.

For Pregnant People or People with the Potential to Become Pregnant

Infection with Zika has been linked to birth defects, including microcephaly, a condition where infants are born with significantly smaller heads compared to babies of the same age and sex. The exact relationship is not known, but the CDC has issued a travel warning for people who are or are planning to become pregnant. People whose male sexual partners are traveling to areas with Zika are encouraged to use condoms for vaginal, anal and oral sex to reduce the risks of transmission.


Only about 1 in 5 infected people become ill. Zika virus disease has mostly mild symptoms that can last for several days to a week and commonly include: 

  • Fever
  • Skin rash
  • Joint pain
  • Conjunctivitis (red eyes)
  • Muscle pain
  • Headache

The incubation period, or the time from exposure to symptoms, is not known, but likely lasts a few days. Infected people usually do not get sick enough to go to the hospital, and death is extremely rare. The Zika virus can remain in the blood of an infected person for about a week, but persists longer in some people. Once someone has been infected, they will likely be protected from future infections. 


If you show the symptoms of Zika after recent travel to an area where Zika is found, you should see a healthcare provider. Lab testing of blood, saliva or urine can confirm the presence of Zika virus RNA in the body. 


There is currently no vaccine or specific medicine to prevent or treat Zika viral infections. To treat the symptoms:

  • Rest
  • Drink fluids to avoid dehydration
  • Take medicine like acetaminophen (Tylenol®) for fever and pain relief
  • Avoid aspirin and other non-steroidal anti-inflammatory drugs
  • If you are already taking medicine for another condition, ask your healthcare provider before taking additional medicines


Mosquito bites

  • The primary mode of transmission is from the bite of an infected mosquito in the genus Aedes, native to tropical areas. It is known to bite mostly during the daytime, and can also transmit Dengue and Chikungunya viruses.


  • Zika can be passed to sexual partners through semen. Zika is known to last longer in semen than in blood and can be transmitted before any Zika symptoms show.

Mother to child

  • A mother can transmit Zika to the fetus. In very rare cases, Zika can be passed from a recently infected mother to the child during delivery.

Other routes of transmission are being investigated. Check the CDC for up-to-date information.


The most effective way to prevent Zika is to avoid mosquito bites. For information on how to best avoid mosquitos, see the Centers for Disease Control (CDC) and World Health Organization (WHO) websites: 

Because it can be transmitted sexually, condoms are suggested for vaginal, anal and oral sex to reduce the risk of transmission.

Areas Affected

Currently, Zika outbreaks are occurring in Africa, the Americas and the Pacific. For up-to-date news on locations with Zika, see the CDC website.