Zika outbreaks are currently happening in many countries. The mosquitoes that can become infected with and spread Zika live in many parts of the world, including parts of the United States.

The mosquitoes that carry Zika are aggressive daytime biters, but they can also bite at night. A mosquito becomes infected when it bites a person already infected with Zika. That mosquito can then spread the virus by biting more people. Zika virus can also spread:

• During sex with a man infected with Zika
• From a pregnant woman to her fetus during pregnancy or around the time of birth
• Through blood transfusion (this is likely but not confirmed)

Many people infected with Zika won’t have symptoms or will only have mild symptoms. The most common symptoms are fever, rash, joint pain or red eyes. Other common symptoms include muscle pain and headache. Symptoms can last for several days to a week. People usually don’t get sick enough to go to the hospital, and they very rarely die of Zika. Once a person has been infected with Zika, they are likely to be protected from future infection.

Why Zika is Risky for Some People

Zika infection during pregnancy can cause fetuses to have a birth defect of the brain called microcephaly. Other problems have been detected among fetuses and infants infected with Zika virus before birth, such as defects of the eye, hearing deficits and impaired growth. There have also been increased reports of Guillain-Barré syndrome, an uncommon sickness of the nervous system, in areas affected by Zika.

There is no vaccine to prevent Zika. The best way to prevent diseases spread by mosquitoes is to protect yourself and your family from mosquito bites.

For more information, visit the Centers for Disease Control and Prevention website.