Zika Virus Disease

Zika virus disease is caused by the Zika virus. Presentation is usually asymptomatic, but patients may present with mild non-specific flu-like symptoms such as fever, rash, joint pain, and conjunctivitis. For this reason, most patients might not realize they have been infected. However, infection in a pregnant woman can cause transplacental transmission to the fetus, resulting in serious birth defects such as microcephaly.

Disease Transmission

Transmission to people is primarily through the bite of an infected Aedes species mosquito (especially Aedes aegypti and Aedes albopictus), but transmission can also be sexual, transplacental, or via blood transfusion.

(L) Aedes aegypti and (R) Aedes albopictus

Disease Distribution

The recent outbreak of Zika started in May 2015, and has been largely confined to South American countries. As at September 7, 2016, there were 2,964 confirmed cases of Zika in the U.S. (161 cases in Texas). Florida is currently the only state with locally transmitted cases (43 of the state’s total 571 cases were acquired locally).

Disease Prevention

There is no vaccine for Zika virus disease. Prevention can be achieved by avoiding mosquito bites. Individuals in areas with Zika and other mosquito-borne diseases are advised to wear long sleeves and long pants, use insect repellant, sleep under mosquito nets, screen doors and windows, and apply insecticide and clear likely breeding grounds. Pregnant women and their sex partners (male or female) who live in or have traveled to an area with Zika should use condoms consistently and correctly when having vaginal, anal, or oral sex or avoid sex during the pregnancy. Likewise, men and women who are not pregnant and want to reduce the risk for disease transmission should use condoms consistently and correctly or abstain from sex if either partner lives in or has traveled to an area with Zika.

Disease Vector

Zika is primarily transmitted by infected Aedes species mosquito. Although person to person transmission of Zika in the U.S. is currently confined to Florida, the vector is widely distributed in the southern U.S. These mosquitoes live indoors and outdoors near people. They are aggressive daytime biters, but they can also bite at night. They typically lay eggs in and near standing water, such as buckets, tires, Styrofoam containers, bird baths, pet water bowls, clogged gutters, trash, and flower pots.

CDC estimated range of Aedes species

More Information

For the most up-to-date information about Zika, please visit the Centers for Disease Control and Prevention’s website at cdc.gov/zika/about/needtoknow.