Epidemiology

The role of Zika virus infections during pregnancy is being studied. Out of an abundance of caution, the Centers for Disease Control and Prevention (CDC) advise that pregnant women avoid traveling to countries with ongoing Zika virus infections. If pregnant women need to travel to a country with Zika virus, it is recommended they take the following steps to avoid mosquito bites:

• Choose an EPA-registered insect repellant and use according to the product label.  Use the repellent day and night because the mosquito species that transmit Zika virus are daytime biters that will also enter buildings and bite at night
• Use permethrin-treated clothing
• Cover exposed skin by wearing long sleeves, pants, and hats
• Sleep indoors in rooms with screened windows or air-conditioning, or use a bed net if you sleep in an room that is exposed to the outdoors

In May 2015, the World Health Organization reported the first local transmission of Zika virus in the Western Hemisphere with cases identified in Brazil. As of January 4, 2017, active transmission had been identified in 51 countries or territories in the Americas.

During the current outbreak, Zika virus infections have been confirmed in several infants with microcephaly (abnormal smallness of the head, associated with incomplete brain development) and in fetal losses in women infected during pregnancy. Exactly how Zika virus infection is associated with pregnancy outcomes is not known; additional studies are planned to learn more about the risks of Zika virus infection during pregnancy.

Zika virus infection should be considered in patients with new onset of fever, maculopapular rash, arthralgia or conjunctivitis who had recent travel to areas with ongoing Zika transmission in the two weeks before illness started. Clinical disease is usually mild.

For additional information, please visit the CDC website http://www.cdc.gov/zika/. You may also call the Health Department. If you have questions about mosquito control programs, you may also contact the Virginia Mosquito Control Association http://www.mosquito-va.org/contact.htm.

During the current outbreak, Zika virus infections have been confirmed in several infants with microcephaly (abnormal smallness of the head, associated with incomplete brain development) and in fetal losses in women infected during pregnancy. Exactly how Zika virus infection is associated with pregnancy outcomes is not known; additional studies are planned to learn more about the risks of Zika virus infection during pregnancy.

Zika virus infection should be considered in patients with new onset of fever, maculopapular rash, arthralgia or conjunctivitis who had recent travel to areas with ongoing Zika transmission in the two weeks before illness started. Clinical disease is usually mild.

Zika virus infection is a viral disease spread to people through bites of infected mosquitoes. Mosquitoes become infected by feeding on infected persons. Zika virus is transmitted primarily by Aedes aegypti (Yellow fever mosquito). Aedes albopictus (Asian tiger mosquito) can also spread the virus.

Anyone traveling to an area where Zika virus is found can become infected. Infections have been reported in travelers returning to the U.S. from affected areas. Those who do not travel to affected areas are not currently at risk of becoming infected because local spread in the continental U.S. has not been reported.

Zika virus is mainly spread in a person-to-mosquito-to-person cycle. An infected mosquito bites a person. The person infected by the mosquito will have Zika virus in their blood, especially in the first week of illness. Another mosquito bites that infected person, becomes infected and can then bite another person. People who are infected but who are not sick may still pass the virus on to mosquitoes that bite them. Zika virus can also spread from mother to baby during pregnancy or during the time of birth.

About 80% of people who are infected do not become sick. For the 20% who do become sick, the most common symptoms include fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild and the symptoms typically last several days to a week.

Symptoms usually start 3-7 days after being bitten by an infected mosquito.

During the 2015–2016 outbreak of Zika virus infection in Brazil, a large increase in the number of babies born with a congenital birth defect called microcephaly was observed. Microcephaly describes a baby or child with a smaller than normal brain and head. Studies are being done to see if the increase in reports of babies with microcephaly is because of an infection with Zika virus. Other causes are also being investigated. In other past Zika virus outbreaks, there have been reports of neurologic syndromes, such as Guillain-Barre Syndrome, in a small number of patients.

The role of Zika virus infections during pregnancy is being studied. Out of an abundance of caution, the Centers for Disease Control and Prevention (CDC) advise that pregnant women avoid traveling to countries with ongoing Zika virus infections. If pregnant women need to travel to a country with Zika virus, it is recommended they take the following steps to avoid mosquito bites:

• Choose an EPA-registered insect repellant and use according to the product label.  Use the repellent day and night because the mosquito species that transmit Zika virus are daytime biters that will also enter buildings and bite at night
• Use permethrin-treated clothing
• Cover exposed skin by wearing long sleeves, pants, and hats
• Sleep indoors in rooms screened windows or air-conditioning, o or use a bed net if you sleep in an room that is exposed to the outdoors

There is no specific treatment for Zika virus infection. Healthcare providers primarily provide supportive care to relieve symptoms. This may include rest, fluids, and use of over-the-counter medicine.

There is no vaccine to prevent Zika virus infection. Infections can be prevented by avoiding mosquito bites. This includes wearing long-sleeved shirts, long pants and socks, using insect repellent or permethrin-treated clothing (especially during the daytime when mosquitos are active), using air conditioning or window/door screens to keep mosquitos outside, and eliminating standing water from containers in yards (including bird baths, flower pots, buckets) to stop mosquito breeding.

If you have symptoms of Zika virus infection and have been to an affected area in the past two weeks, contact your healthcare provider.

For additional information, please visit the CDC website http://www.cdc.gov/zika/. You may also call the Health Department. If you have questions about mosquito control programs, you may also contact the Virginia Mosquito Control Association http://www.mosquito-va.org/contact.htm.

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