Zika Virus - Defense Centers for Public Health

Zika (zee-kah) virus is primarily spread from an infected person to an uninfected person through the bite of an infected Aedes species mosquito. Although most infections do not cause symptoms and do not require treatment, Zika infection may cause birth defects in pregnant women. Outbreaks of Zika have occurred in parts of Africa, Southeast Asia, and the Pacific Islands. Zika spread to the Western Hemisphere in 2015 and is estimated to have affected more than a million people in South and Central America, Mexico, and the Caribbean, including Puerto Rico and the Virgin Islands. In the United States, cases of Zika virus infection have been identified in travelers returning from areas with ongoing disease transmission. Mosquito-transmitted (“locally transmitted”) Zika virus infections have occurred in two U.S. locations. Prevent Zika virus infections by protecting yourself against mosquito bites and eliminating mosquito breeding areas.

Zika Virus


Aedes aegypti	Aedes albopictus

How do people become infected with Zika virus?

The disease is spread to people primarily through the bite of an infected Aedes species mosquito. These are the same mosquitoes that spread dengue, yellow fever, and chikungunya viruses. These mosquitoes are aggressive daytime biters. They can also bite at night, indoors, and around the outside of homes. The yellow fever mosquito (Ae. aegypti), and the Asian tiger mosquito (Ae. albopictus) have been implicated in large outbreaks of Zika virus. Zika virus can also be spread through sexual activity, possible blood transfusion, and from mother to fetus during pregnancy. Zika infection during pregnancy can cause a birth defect called “microcephaly" where the skull and brain do not fully develop. It is also linked to other problems including miscarriage, stillbirth, and other birth defects. There have also been increased reports of Guillain-Barré syndrome— an uncommon nervous system disorder— in areas affected by Zika. According to the U.S. Centers for Disease Control and Prevention (CDC), Zika virus has been found in breast milk, and there have been several reports of Zika virus infection in babies from breastfeeding. However, there have been no reported health problems in babies consuming Zika virus-infected breastmilk.

What are the signs and symptoms of Zika virus infection?

Most people infected with Zika virus won't have symptoms or will only have mild symptoms. Symptoms usually begin 2-7 days after being bitten by an infected mosquito. Common symptoms include fever, rash, joint pain and red eyes. Other symptoms include muscle pain, headache, pain behind the eyes, and vomiting. As symptoms are often mild, infection may go unrecognized or be misdiagnosed. Approximately one in five people infected with Zika virus will develop symptoms. Once a person has been infected with Zika, they may have immunity to future infections.

Is there a diagnostic test available to confirm Zika virus infection in humans?

Yes, your healthcare provider may order blood or urine tests for Zika or other viruses with similar symptoms spread by the same mosquitoes. See your healthcare provider if you have recently traveled to affected areas and have developed the symptoms described above.

Is there a treatment for Zika virus infection?

There is no vaccine or specific treatment available. Persons experiencing Zika virus symptoms should rest and drink plenty of fluids. Take medicine such as acetaminophen (TYLENOL®), to relieve fever and pain. DO NOT TAKE aspirin and other non-steroidal anti-inflammatory drugs until other diseases can be ruled out by your medical care provider.

What should I do if I think I am infected Zika virus?

Seek medical attention if you experience the symptoms described above and have traveled to an area where Zika virus occurs. Be sure to tell your healthcare provider your recent travel history. If you think you have Zika virus, avoid mosquito bites to prevent the virus from spreading to others.

What can I do to reduce my risk of becoming infected with Zika virus?

Women who are pregnant (in any trimester): Consider postponing travel to areas where Zika virus transmission is ongoing. If you must travel to one of these areas, talk to your doctor first and strictly follow steps to prevent mosquito bites during your trip. Using approved insect repellents is safe during pregnancy.
Women who are trying to become pregnant: Before you travel, talk to your doctor about your plans to become pregnant and the risk of Zika virus infection. Strictly follow steps to prevent mosquito bites during your trip, including using approved insect repellents.
Zika can be passed through sex from a person with Zika to his or her partners.
The best way to prevent diseases spread by mosquitoes is to protect yourself from mosquito bites by using the DoD Insect Repellent System. It incorporates insect repellent on the uniform, DEET, picaridin, or IR3535 repellent on exposed skin, a properly worn uniform, and sleeping inside a insecticide-treated bed net.

 Select the image for more information on the DoD Insect Repellent System.

Graphic showing the DoD Insect Repellent System