What is Zika and how is it spread?
Zika is a virus that spreads to people primarily through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus). People can also get Zika through sex and it can be spread from a pregnant woman to her fetus. People can protect themselves from contracting Zika sexually or through mosquito bites. This FAQ explains who’s most affected and why, symptoms and treatment, and how to protect against Zika.
How is Zika transmitted?
Zika can be transmitted in the following ways:
- Mosquito Transmission: These mosquitoes typically lay eggs in and near standing water in things like buckets, bowls, animal dishes, flower pots and vases. They prefer to bite people, and live indoors and outdoors near people. Mosquitoes that spread chikungunya, dengue, and Zika are aggressive daytime biters, though they also bite at night. Mosquitoes become infected when they feed on a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites.
- From Mother to Child: A pregnant woman can pass Zika virus to her fetus during pregnancy. Zika is a cause of microcephaly and other severe fetal brain defects. Studies on a full range of other potential health problems that Zika virus infection during pregnancy may cause are underway. A pregnant woman already infected with Zika virus can pass the virus to her fetus during pregnancy or around the time of birth. To date, there are no reports of infants getting Zika virus through breastfeeding. Because of the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas where Zika virus is found.
- Sexual Transmission: Zika can be passed through sex from a person who has Zika to his or her partners. Zika can be passed through sex, even if the infected person does not have symptoms at the time.
- It can be passed from a person with Zika before their symptoms start, while they have symptoms, and after their symptoms end. The virus may also be passed by a person who carries the virus but never develops symptoms.
- Studies are underway to find out how long Zika stays in the semen and vaginal fluids of people who have Zika, and how long it can be passed to sex partners. Zika can remain in semen longer than in other body fluids, including vaginal fluids, urine and blood.
- Blood Transfusion Transmission: As of February, 1, 2016, there have not been any confirmed blood transfusion transmission cases in the United States. There have been multiple reports of blood transfusion transmission cases in Brazil. These reports are currently being investigated. During the French Polynesian outbreak, 2.8% of blood donors tested positive for Zika and in previous outbreaks in other places around the world, the virus has been found in blood donors.
Why is Zika 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-Barre syndrome in people, an uncommon sickness of the nervous system that causes weakness in the arms and legs, in areas affected by Zika.
Can Zika be prevented?
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. Here’s how:
- Wear long-sleeved shirts and long pants.
- Stay in places with air conditioning and window and door screens to keep mosquitoes outside.
- Take steps to control mosquitos inside and outside your home.
- Treat your clothing and gear with permethrin or buy pre-treated items. (Clothes sprayed with permethrin will protect you for 6 weeks. You can wash your clothes up to six times during the 6 weeks and the permethrin will still protect you. Do NOT spray permethrin on your skin.)
- Use Environmental Protection Agency (EPA)-registered insect repellents. Always follow label instructions. When used as directed, these insect repellents are proven safe and effective even for pregnant and breastfeeding women. Do NOT use insect repellents on babies younger than 2 months. Instead, use mosquito netting in carriers, strollers, or cribs to protect infants that are 2 months old or younger.
- Prevent sexual transmission of Zika by using condoms or not having sex.
If a woman who is not pregnant is bitten by a mosquito and infected with Zika virus, will her future pregnancies be at risk?
We do not know the risk to the baby if a woman is infected with Zika virus while she is pregnant. However, Zika virus infection does not pose a risk of birth defects for future pregnancies. Zika virus usually remains in the blood of an infected person for only a few days to a week. The virus will not cause infections in a baby that is conceived after the virus is cleared from the blood.
People who live in an area or have traveled to an area with Zika should talk to their healthcare provider prior to attempting pregnancy.
What should I do if I have Zika?
There are no medicines to treat Zika. Instead, individuals should treat the symptoms:
- Get plenty of rest
- Drink fluids to prevent dehydration
- Take medicines such as acetaminophen to reduce fever and pain
- Do not take aspirin or other non-steroidal anti-inflammatory drugs If you are taking medicine for another medical condition, talk to your healthcare provider before taking additional medication.
To help prevent others from getting sick, strictly follow steps to prevent mosquito bites during the first week of illness.