Adult Health Library

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A to Zika: All About the Mosquito-Borne Disease

Mosquitoes are vectors—or carriers—of many diseases. These include such well-known infections as malaria, yellow fever, and West Nile virus. You should also know about Zika. It can be a serious health concern, mainly for mothers-to-be and their unborn babies.

What is Zika?

Zika is a virus. It was first discovered in the Zika Forest of Uganda in 1947. For many decades, it was thought to be a rare cause of viral infection. It was found only in small areas of Africa, the Yap Islands in the Pacific, and Easter Island. But in April 2015, it was found in Brazil. For unknown reasons, it has since spread quickly to many countries in South and Central America, and to the Caribbean and Mexico.

A number of cases have also been found in the U.S. Most of these people got the virus while visiting other parts of the world where mosquitoes are spreading it. But very recently experts reported that the virus had been spread by mosquitoes in the U.S.

The Zika virus is mostly passed on by the bite of the mosquito species Aedes. Pregnant women who have it can also pass it on to their unborn child. New data suggests people may also get it through sexual contact and blood transfusion. But experts know so little about the virus that they are still learning all the ways it can be passed on.

What are the symptoms of Zika?

Most people infected with the Zika virus have no symptoms. For the 1 out of 5 people who do have symptoms, they are usually very mild. They last 5 to 7 days and then go away completely. They may include:

Fever
Rash
Headache
Joint and muscle pain
Conjunctivitis, when the eyes become red, irritated, and inflamed

But for pregnant women, Zika can be a far more serious concern. A woman can pass the virus on to her unborn child. This is true even if she has no symptoms. The virus can cause a condition called microcephaly in these infants. Babies with this serious birth defect are born with a smaller than normal head and a less developed brain. That can lead to developmental problems, learning disabilities, and neurological problems.

The Zika virus may also very rarely cause Guillain-Barré syndrome (GBS) in adults. GBS causes muscle weakness or paralysis. If the muscle weakness is severe enough or widespread enough, the person may need to use a machine to breathe (ventilator). Most people with GBS recover. But it may take months. Sometimes recovery is not complete. Researchers are looking more closely at the possible link between Zika and GBS.

How is Zika diagnosed and treated?

A blood test can detect the Zika virus. Pregnant women who live in or have traveled to areas where the virus is active should talk with their healthcare provider. Four out of 5 women with the infection will have no symptoms. So testing is now recommended for all pregnant women living or traveling in such areas. More testing may be needed to check on the health of the unborn child, or the health of a newborn whose mother has recently traveled to those areas. Experts update information weekly on who should be tested. Check the CDC website for the latest advice.

There is no medicine to cure the Zika virus. Treatment is aimed at easing symptoms. Rest and drinking plenty of fluids are helpful. Acetaminophen can help ease fever and pain.

How can you prevent the Zika virus?

Zika can be prevented in the same way as other mosquito-borne diseases. That means taking steps to protect against mosquito bites:

Wear long-sleeved shirts and pants when outdoors in areas where mosquitoes are active.
Put on insect repellent before going outdoors.
Use air conditioning or screens on doors and windows to keep mosquitoes out of your home.
Empty water from any containers so mosquitoes have fewer places to breed. Even small items like bottle caps can hold enough water for mosquitoes to multiply.
Avoid traveling to places where there is a Zika outbreak, especially if you are pregnant or plan to become pregnant.
If you have traveled to an area where Zika is found, or you have already been infected with the virus, use protection or abstain from sex.