Zika virus disease

Zika (Zee-ka) virus disease is a mosquito-borne viral infection that primarily occurs in tropical and subtropical areas of the world. Most people infected with Zika virus have no signs and symptoms, while others report mild fever, rash and muscle pain. Other signs and symptoms may include headache, red eyes (conjunctivitis) and a general feeling of discomfort.

Zika virus infections during pregnancy have been linked to miscarriage and can cause microcephaly, a potentially fatal congenital brain condition. Zika virus also may cause other neurological disorders such as Guillain-Barre syndrome.

Researchers are working on a Zika virus vaccine. For now the best prevention is to prevent mosquito bites and reduce mosquito habitats.

Symptoms

The mosquito that carries Zika virus is found worldwide.

As many as four out of five people infected with Zika virus have no signs or symptoms. When symptoms do occur, they usually begin two to seven days after being bitten by an infected mosquito. Signs and symptoms of Zika virus disease most commonly include:

• mild fever
• rash
• joint or muscle pain

Other signs and symptoms may include:

• headache
• red eyes (conjunctivitis)

Most people recover fully, with symptoms resolving in about a week.

When to see a doctor

See your doctor if you think you or a family member may have Zika virus, especially if you have recently traveled to an area where there's an ongoing outbreak. The Centers for Disease Control and Prevention (CDC) has blood tests to look for Zika virus or similar diseases such as dengue or chikungunya viruses, which are spread by the same type of mosquitoes.

Causes

Zika virus is transmitted primarily through the bite of an infected Aedes species mosquito, which is found throughout the world. It was first identified in the Zika Valley in Africa in 1947, but outbreaks have since been reported in southeastern and southern Asia, the Pacific Islands and the Americas.

When a mosquito bites a person infected with a Zika virus, the virus enters the mosquito. When the infected mosquito then bites another person, the virus enters that person's bloodstream.

Spread of the virus through sexual contact and blood transfusion have been reported.

Risk factors

Factors that put you at greater risk of developing Zika virus disease include:

• Living or traveling in countries where there have been outbreaks. Being in tropical and subtropical areas increases your risk of exposure to the virus that causes Zika virus disease. Especially high-risk areas include several islands of the Pacific region, a number of countries in Central, South and North America, and islands near West Africa. Because the mosquito that carries Zika virus is found worldwide, it's likely that outbreaks will continue to spread to new regions.
  The mosquitoes that carry Zika virus are found in some parts of the United States. Although local transmission has not been reported in the U.S., cases of Zika virus infection have been reported in returning travelers. Local transmission has occurred in Puerto Rico.
• Having unprotected sex. Isolated cases of sexually transmitted Zika virus have been reported. The CDC advises abstinence from sexual activity during pregnancy or condom use during all sexual contact for men with a pregnant sex partner if the man has traveled to an area of active Zika virus transmission.

Complications

Zika virus infections during pregnancy have been linked to miscarriage and microcephaly, a potentially fatal congenital brain condition. Zika virus also may cause other neurological disorders such as Guillain-Barre syndrome.

Diagnosis

Your doctor will likely ask about your medical and travel history. Be sure to describe international trips in detail, including the countries you and your sexual partner have visited and the dates, as well as any contact you may have had with mosquitoes.

There is no commercial test available for the Zika virus. The CDC has blood tests to look for Zika virus or similar diseases such as dengue or chikungunya viruses, which are spread by the same type of mosquitoes.

A pregnant woman with no symptoms of Zika virus infection with a history of recent travel to an area with active Zika virus transmission can be offered testing two to 12 weeks after her return.

Following positive, inconclusive or negative test results, care providers may:

• Perform an ultrasound to detect microcephaly or other abnormalities of the brain
• Offer to take a sample of amniotic fluid using a hollow needle inserted into the uterus (amniocentesis) to screen for Zika virus.

Treatment

No specific antiviral treatment for Zika virus disease exists. Treatment is aimed at relieving symptoms with rest, fluids and medications — such as acetaminophen (Tylenol, others) and ibuprofen (Advil, Motrin IB, others) — to relieve joint pain and fever.

No vaccine exists to prevent Zika virus.

What you can do

Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.

• Write down key personal information. List your international travel history, with dates and countries visited and medications taken while traveling. Bring a record of your immunizations, including pre-travel vaccinations.
• Make a list of all your medications. Include any vitamins or supplements you take regularly.
• Write down questions to ask your doctor. Preparing a list of questions can help you make the most of your time with your doctor. List your questions from most important to least important in case time runs out.

For Zika virus disease, some basic questions to ask your doctor include:

• What's the most likely cause of my symptoms?
• What kinds of tests do I need?
• What treatments are available?
• How long will it be before I'm feeling better?
• Are there any long-term effects of this illness?
• Do you have any brochures or other printed material that I can take home with me? What websites do you recommend?

What to expect from your doctor

Be prepared to answer questions from your doctor, such as:

• When did your symptoms begin?
• Are you pregnant or trying to become pregnant? Do you use condoms?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• Does anything seem to make your symptoms better or worse?
• Where have you traveled in the past month?
• Were you bitten by mosquitoes while traveling?
• Have you been in contact recently with anyone who was ill?

Zika virus transmitted through blood transfusion

A blood donor screening test for Zika virus is not currently available. To reduce the risk of transmitting Zika virus through blood transfusion in areas where there are no active Zika virus outbreaks, the Food and Drug Administration recommends not donating blood for four weeks if you:

• Have a history of Zika virus infection
• Traveled or lived in an area with active Zika virus transmission
• Have symptoms that are suggestive of Zika virus infection within two weeks of travel from an area with Zika virus
• Have had sexual contact with a male partner who has been diagnosed with Zika virus infection
• Have had sexual contact with a male partner who has traveled or lived in an area with active Zika virus transmission in the past three months.