What is the Zika virus?
The Zika virus is an infectious disease that primarily spreads through the bites of infected mosquitoes. For most people, the infection doesn’t cause severe symptoms. However, if a person is infected while pregnant, it can increase the risk of certain birth defects in a developing fetus.
How common is the Zika virus?
Outbreaks of the Zika virus happen around the world, mostly in places with warm, tropical climates where mosquitoes thrive. In 2015 and 2016, Florida, Texas, Puerto Rico and the U.S. Virgin Islands experienced outbreaks. Even then, most sites had fewer than 50 cases.
As of September 2020, there were 13 Zika virus infections in U.S. territories — all of them presumably acquired through mosquitoes. There was only one case in the United States, and that person got sick while traveling outside the country. If you’re traveling abroad, check the Centers for Disease Control and Prevention (CDC) travel information page for the latest on Zika virus outbreaks.
How does the Zika virus spread?
You’re most likely to get the Zika virus from the bite of an Aedes aegypti mosquito. These mosquitoes thrive in tropical climates. The mosquito picks up the virus when it bites someone who is infected with Zika. You can get the virus if the infected mosquito bites you.
The Zika virus also spreads from:
- Pregnant person to the fetus.
- Sex with an infected person.
- Blood transfusion (extremely rare, with zero incidents in the U.S.).
Can you get the Zika virus more than once?
People who have the Zika virus appear to develop immunity. You’re unlikely to have another Zika infection even if you’re exposed to the virus again.
Who might get the Zika virus?
Anyone who hasn’t had the Zika virus and travels to or lives in an area where the virus is present can get it.
Symptoms and Causes
What causes a Zika virus infection?
Zika is a virus — specifically a flavivirus. Arthropods (bugs with an outside shell), such as mosquitoes and ticks, carry flaviviruses. Other flaviviruses include dengue fever and yellow fever.
What are the symptoms of a Zika virus infection?
Many people infected with the Zika virus have mild symptoms or no symptoms at all. Signs of Zika can appear three to 14 days after infection and last for up to one week. You may experience:
Diagnosis and Tests
How is a Zika virus infection diagnosed?
If you show signs of an infection or have traveled to a place with an active Zika virus outbreak, your healthcare provider can order a blood or urine test to check for the virus. Testing should take place as soon as possible, while you have symptoms.
Management and Treatment
How does the Zika virus affect pregnancy?
Pregnant people who get the Zika virus can pass the infection to the fetus. The virus increases the risk of microcephaly, a birth defect that affects brain development. Babies born with this birth defect have smaller-sized brains and heads. The CDC recommends that pregnant people not travel to areas with known Zika virus outbreaks.
The Zika virus also increases the risk of:
- Low birth weight (newborns who weigh less than 5 pounds, 8 ounces).
- Miscarriage (early pregnancy loss).
- Premature labor (childbirth before the 37th week of pregnancy).
- Stillbirth (delivering a fetus that died in the uterus after the 20th week of pregnancy).
What are the complications of the Zika virus?
Most people experience mild symptoms. Rarely, an infected person develops Guillain-Barré syndrome. This condition causes the immune system to attack the nervous system. Symptoms, such as muscle weakness and paralysis, typically go away over time.
How is a Zika virus infection managed or treated?
There isn’t a vaccine or specific medication for the Zika virus. You can take these steps to ease symptoms:
- Drink lots of fluids.
- Get plenty of rest.
- Take over-the-counter pain medicines (acetaminophen) for fever and pain. Don’t take aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) unless tests confirm you don’t have dengue fever. These medicines can increase bleeding risk in people with dengue fever.
How can I protect myself from mosquitoes that carry the Zika virus?
These steps can protect you and your family from mosquito bites:
- Apply insect repellant that’s registered with the Environmental Protection Agency (EPA).
- Get rid of standing water in buckets or puddles around your home.
- Stay indoors at dusk and dawn, when mosquitoes are most active.
- Treat clothing and shoes with permethrin, an insecticide.
- Wear long sleeves and pants outside.
What else can I do to protect myself against the Zika virus?
If you or your sexual partner travel to an area with known Zika risk, you should use condoms for at least three months after traveling to prevent pregnancy and infection. A person infected with the Zika virus can pass the infection to a partner through oral, vaginal or anal sex. You can give the virus to someone before symptoms appear, while you have symptoms or months later. Men are infectious longer than women. The virus remains in a man’s semen for months.
Outlook / Prognosis
What is the prognosis (outlook) for people who have the Zika virus?
Most people who get the Zika virus experience a mild illness, if they have any signs at all. The biggest health risk is for pregnant people. The fetus may develop a birth defect that affects brain development.
Because the virus also spreads through sexual intercourse, you should practice safe sex for several months after being in an area with an active Zika outbreak or while recovering from a Zika infection.
When should I call the doctor?
You should call your healthcare provider if you experience:
- Difficulty breathing.
- High fever.
- Muscle weakness or paralysis.
- Vision problems.
What questions should I ask my doctor?
If you have concerns about the Zika virus, you may want to ask your healthcare provider:
- What is the best way to treat my symptoms?
- How can I prevent spreading the infection to others?
- How long am I contagious?
- How can I protect myself and loved ones from mosquitoes that carry the Zika virus?
- Am I at risk for other problems?
- Should I look out for signs of complications?
A note from Cleveland Clinic
Zika virus infections are rare in the U.S., but outbreaks occasionally happen. If you’re traveling to an area where the virus is prevalent, you should take steps to prevent mosquito bites. You’ll also need to use condoms to avoid spreading the infection to sexual partners when you return. Contact your healthcare provider if you’ve been in a Zika-prone area and develop symptoms. Most people don’t experience serious problems. But pregnant people are at risk for miscarriage, and the fetus may develop birth defects.
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