The Zika (ZEE-kuh) virus is most often spread to people through mosquito bites, primarily in tropical and subtropical areas of the world. Most people infected with the Zika virus have no signs and symptoms. Some people have mild fever, rash and muscle pain. In rare cases, the Zika virus may cause brain or nervous system complications, such as Guillain-Barre syndrome, even in people who never show symptoms of infection. Infection with the Zika virus is also called Zika, Zika fever or Zika virus disease.
Women who are infected with the Zika virus during pregnancy have an increased risk of miscarriage. Zika virus infection during pregnancy also increases the risk of serious birth defects in infants, including a potentially fatal brain condition called microcephaly.
Researchers are working on a vaccine for the Zika virus. For now, the best way to prevent infection is to avoid mosquito bites and reduce mosquito habitats.
As many as 4 out of 5 people infected with the Zika virus have no signs or symptoms. When symptoms do occur, they usually begin two to 14 days after a person is bitten by an infected mosquito. Symptoms usually last about a week, and most people recover fully.
Signs and symptoms of the Zika virus most commonly include:
Other signs and symptoms may include:
See your doctor if you think you or a family member may have the Zika virus, especially if you have recently traveled to an area where there's an ongoing outbreak. The U.S. Centers for Disease Control and Prevention (CDC) has blood tests to look for the Zika virus and other viruses spread by mosquitoes.
If you're pregnant and have recently traveled to an area where the Zika virus is common, ask your doctor whether you should be tested, even if you don't have symptoms.
The Zika virus is most often spread to a person through the bite of an infected mosquito. The mosquitoes that are known to carry the virus include two aedes species mosquitoes, which can be found throughout the world.
When a mosquito bites a person who is already infected with the Zika virus, the virus infects the mosquito. Then, when the infected mosquito bites another person, the virus enters that person's bloodstream and causes an infection.
During pregnancy, the Zika virus can also spread from a mother to the fetus.
The virus can also spread from one person to another through sexual contact. In some cases, people contract the virus through blood transfusion or organ donation.
Factors that put you at greater risk of catching the Zika virus include:
Living or traveling in countries where there have been outbreaks. Being in tropical and subtropical areas increases your risk of exposure to the Zika virus. Especially high-risk areas include several of the Pacific Islands, a number of countries in Central, South and North America, and islands near West Africa. Because the mosquitoes that carry the Zika virus are found worldwide, it's likely that outbreaks will continue to spread to new regions.
Most cases of Zika virus infection in the U.S. have been reported in travelers returning to the U.S. from other areas. But the mosquitoes that carry the Zika virus do live in some parts of the United States and its territories. Local transmission has been reported in Florida, Texas, the U.S. Virgin Islands and Puerto Rico.
Women who are infected with the Zika virus during pregnancy have an increased risk of miscarriage, preterm birth and stillbirth. Zika virus infection during pregnancy also increases the risk of serious birth defects in infants (congenital Zika syndrome), including:
In adults, infection with the Zika virus may cause brain or nervous system complications, such as Guillain-Barre syndrome, even in people who never show symptoms of infection.
There is no vaccine to protect against the Zika virus. But you can take steps to reduce your risk of exposure to the virus.
If you or your partner is pregnant or trying to get pregnant, these tips may help lower your risk of Zika virus infection:
Plan travel carefully. The CDC recommends that all pregnant women avoid traveling to areas where there is an outbreak of the Zika virus.
If you're trying to become pregnant, talk to your doctor about whether you or your partner's upcoming travel plans increase the risk of Zika virus infection. Your doctor may suggest you and your partner wait to try to conceive for two to three months after travel.
If you are living in or traveling to areas where the Zika virus is known to be, take steps to reduce your risk of mosquito bites:
In some cases, the Zika virus has spread from one person to another through blood products (blood transfusion). To reduce the risk of spread through blood transfusion, blood donation centers in the United States and its territories are required to screen all blood donations for the Zika virus. If you had Zika or if you live in the U.S. and recently traveled to an area where the Zika virus is widespread, your local blood donation center may recommend that you wait four weeks to donate blood.
Your doctor will likely ask about your medical and travel history. Be sure to describe any international trips in detail, including the countries you and your sexual partner have visited, the dates of travel, and whether you may have had contact with mosquitoes.
If your doctor suspects that you may have a Zika virus infection, he or she may recommend a blood or urine test to confirm the diagnosis. The blood or urine samples can also be used to test for other, similar mosquito-borne diseases.
If you are pregnant and don't have symptoms of Zika virus infection but you or your partner recently traveled to an area with active Zika virus transmission, ask your doctor if you need to be tested.
If you are pregnant and at risk of Zika virus infection, your doctor may also recommend one of the following procedures:
There is no specific treatment for infection with the Zika virus. To help relieve symptoms, get plenty of rest and drink plenty of fluids to prevent dehydration. The over-the-counter (OTC) medication acetaminophen (Tylenol, others) may help relieve joint pain and fever.
The symptoms of Zika virus infection are similar to other mosquito-borne illnesses, such as dengue fever. If you're feeling ill after recent travel to an area where mosquito-borne illness is common, see your doctor. Don't take ibuprofen (Advil, Motrin IB, others), naproxen sodium (Aleve) or aspirin until your doctor has ruled out dengue fever. These medications can increase the risk of serious complications from dengue fever.
You'll likely start by seeing your primary care doctor. But you might be referred to a doctor who specializes in infectious diseases or travel medicine.
Because appointments can be brief, and because there's often a lot to discuss, it's a good idea to be well prepared for your appointment. Here's some information to help you get ready, and what to expect from your doctor.
Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
For Zika virus infection, some basic questions to ask your doctor include:
Be prepared to answer questions from your doctor, such as:
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