Zika virus is a type of virus that is primarily transmitted to people through the bite of infected Aedes species mosquitoes. The virus was first identified in the Zika Forest of Uganda in 1947, and sporadic outbreaks of the disease have occurred in various parts of the world since then. The most significant outbreak of the virus occurred in 2015-2016, primarily in Latin America and the Caribbean.

The symptoms of Zika virus infection are often mild and include fever, rash, joint pain, and red eyes. In most cases, people with Zika virus infection do not require hospitalization and recover within a week. However, the virus can cause severe birth defects, including microcephaly (a condition where the baby's head is smaller than expected) in infants whose mothers were infected during pregnancy.

There is currently no specific treatment for Zika virus infection. Treatment is focused on relieving symptoms and may include rest, fluids, and over-the-counter pain relievers. Prevention of Zika virus infection primarily involves avoiding mosquito bites, such as by using insect repellent, wearing long-sleeved clothing and pants, and staying in air-conditioned or screened areas. Travelers to areas where the Zika virus is endemic should also take precautions to avoid mosquito bites.

Pregnant women, in particular, should take extra precautions to avoid Zika virus infection, as the virus can cause severe birth defects in infants. Women who are pregnant or trying to become pregnant should avoid traveling to areas with known Zika virus transmission. If travel cannot be avoided, women should take strict precautions to avoid mosquito bites and should be monitored closely for the development of 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.

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.
• Practice safe sex. If you have a partner who lives in or has traveled to an area where there is an outbreak of the Zika virus, the CDC recommends abstaining from sex during pregnancy or using a condom during all sexual activity.

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:

• Stay in air-conditioned or well-screened housing. The mosquitoes that carry the Zika virus are most active from dawn to dusk, but they can also bite at night. Consider sleeping under a mosquito bed net, especially if you are outside.
• Wear protective clothing. When you go into mosquito-infested areas, wear a long-sleeved shirt, long pants, socks and shoes.
• Use insect repellent. You can apply permethrin to your clothing, shoes, camping gear and bed netting. You can also buy clothing made with permethrin already in it. For your skin, use a repellent that contains DEET, picaridin, or one of the other active ingredients registered with the Environmental Protection Agency and known to be effective against mosquitoes. When used as directed, these repellents are proven safe and effective, even for pregnant and breastfeeding women.
• Reduce mosquito habitat. The mosquitoes that carry the Zika virus usually live in and around houses and breed in standing water that has collected in containers such as animal dishes, flower pots and used automobile tires. At least once a week, empty any sources of standing water to help lower mosquito populations.

The Zika virus and blood donation

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.

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.