Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) mainly spread through the bite of infected mosquitoes.  Although less common, some people have been infected through sexual contact with an infected partner, in utero from mothers infected during pregnancy, and from transfusion of infected blood products.

Most people are infected by the yellow fever mosquito, Aedes aegypti, which is found in the tropics and southern United States.  This mosquito is not known to be established in Ohio.  The Asian tiger mosquito, Aedes albopictus, is a related mosquito that is found in Ohio and may potentially transmit Zika virus, although it has not been implicated in the transmission of human cases in the United States.

The best way to prevent Zika virus infection is to prevent mosquito bites when traveling to areas with a risk of Zika.

Because of the risk of serious birth defects, pregnant women should not travel to areas with a risk of Zika.  People who do travel to areas with a risk of Zika should take precautions to reduce the risks of sexually transmitting the virus to their partners.

What are the signs and symptoms of Zika virus disease?

Approximately 80% of people who are infected with Zika virus will not show any symptoms at all, but there is no way to know in advance if you will develop an illness or not.  Those who do develop symptoms usually do so between three and 14 days after they are bitten by the infected mosquito.

About 20% of people who become infected will have mild symptoms that can last for a few days to a week and include:

• Fever.
• Rash.
• Headache.
• Joint pain.
• Conjunctivitis (red eyes).
• Muscle pain.

Infants born to women infected during pregnancy may develop serious birth defects and a unique pattern of defects termed congenital Zika syndrome.  The birth defects can include:

• Microcephaly.
• Seizures.
• Vision impairment.
• Hearing impairment.
• Decreased brain tissue with brain damage.
• Damage to the back of the eye (i.e., scarring, pigment changes).
• Joints with limited range of motion, such as clubfoot.
• Too much muscle tone restricting body movement soon after birth.

Although very rare, some people infected with Zika virus may develop Guillain-Barre syndrome (GBS).  This is an uncommon disorder of the nervous system following infection in which a person's own immune system damages the nerve cells, causing muscle weakness and sometimes paralysis.

For more information, see the Centers for Disease Control and Prevention (CDC)'s website for Zika virus disease symptoms.

How is Zika virus infection diagnosed?

Zika virus infection can only be diagnosed by a healthcare provider.  A blood, urine, or cerebrospinal fluid sample may be collected for laboratory testing.  Please visit the CDC's website for information on diagnosis and testing.

What is the treatment for Zika virus disease?

There is no specific treatment for Zika virus infection, and care is based on symptoms.

Who is at risk in Ohio?

Anyone who travels to an area with a risk of Zika is at risk for infection.  The primary mosquito that transmits Zika virus, the yellow fever mosquito, is often found in tropical urban areas in and near homes.

All Ohioans reported with Zika virus infection since the virus was first identified in the Western hemisphere acquired their infections while traveling in areas with a risk of Zika.  One case was identified in a sexual contact whose partner had traveled to an area with a risk of Zika.  No cases have been identified in Ohio in infants infected in utero or people who received a transfusion of infected blood products.

* Other countries include: Aruba, Bonaire, British Virgin Islands, Curaçao, Grenada, Guadeloupe, Jamaica, and St. Martin.

What time of year are Ohioans at risk for contracting Zika virus disease?

The primary mosquito that transmits Zika virus, the yellow fever mosquito, is widely found throughout the tropics and southern United States.  Because of the warm temperatures year-round, the risk of infection is present in these areas year-round.

Most of the cases reported in Ohio were during the summer of 2016 when the virus was rapidly spreading throughout Central and South America and the Caribbean.

Zika Virus by Week of Illness Onset, Ohio, 2016-2017

Source: Ohio Department of Health

What are the trends over time?

Ohio has tracked human cases of Zika virus infection since 2016 when it was first introduced into the Western hemisphere.  However, no cases have been reported in Ohioans since 2017.

How can I reduce my risk of Zika virus infection?

Steps to prevent Zika virus infection include avoiding mosquitoes and mosquito bites, planning ahead when traveling to areas with a risk for Zika virus infection, and stopping mosquitoes from breeding in and around your home.

Pregnant women should not travel to areas with a risk of Zika.  People who do travel to areas with a risk of Zika should take precautions to reduce the risk of sexually transmitting the virus to their partners and should avoid mosquito exposures for three weeks after returning from their trip to avoid infecting mosquitoes in Ohio.

What are the roles of other animals in Zika virus transmission?

Mosquitoes, particularly Aedes aegypti and possibly Aedes albopictus, become infected with Zika virus through taking blood meals from infected humans.