CDC supporting Texas investigation of possible local Zika transmission

The Centers for Disease Control and Prevention (CDC) has been informed by Texas health officials that Zika virus infection has been diagnosed in a resident of Brownsville, Texas, without any other known risk factors, suggesting possible local transmission of Zika virus infection. This case may be the first known occurrence of local mosquito-borne Zika virus transmission in the state. CDC is closely coordinating with Texas and local officials to increase surveillance efforts and vector control activities in this area.

State and local officials in Texas proactively issued Health Alerts in October 2016 expanding the testing criteria for Zika virus disease. They are responding rapidly to the current situation with a community-wide search for additional Zika cases, as recommended in CDC’s Zika interim response plan. Residents, especially pregnant women, should take steps to protect themselves from mosquito bites. They should use an insect repellent registered by the Environmental Protection Agency (EPA) containing one of the following ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol, or 2-undecanone, wear long-sleeved shirts and long pants, use or repair screens on windows and doors, use air conditioning when available, and remove standing water inside and outside where mosquitoes can lay eggs.

"Even though it is late in the mosquito season, mosquitoes can spread Zika in some areas of the country," said CDC Director Tom Frieden, M.D., M.P.H. "Texas is doing the right thing by increasing local surveillance and trapping and testing mosquitoes in the Brownsville area."

Zika virus spreads to people primarily through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus), but can also spread during sex by a person infected with Zika to his or her partner. Most people infected with Zika won’t have symptoms, but for those who do, the illness is usually mild. However, Zika infection during pregnancy can cause a serious birth defect of the brain called microcephaly and other severe brain defects in fetuses and infants.

We continue to learn about Zika virus, and we are working hard with our state, county, and local partners to find out more about Zika virus infection in Brownsville. Here is what we do know:

• Zika is spread to people primarily through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus), both found in Brownsville.
• A pregnant woman can pass Zika virus to her fetus during pregnancy or during birth.
• Zika virus infection during pregnancy can cause microcephaly and other severe brain defects and is associated with other adverse pregnancy outcomes in fetuses and infants.
• A person who is infected with Zika virus can pass it to sex partners.
• Many people infected with Zika virus won’t have symptoms or will only have mild symptoms.
• No vaccines or treatments are currently available to treat or prevent Zika infections.

As of Nov 23, 2016, 4,444 cases of Zika have been reported to CDC in the continental United States and Hawaii; 182 of these were the result of local spread by mosquitoes. These cases include 36 believed to be the result of sexual transmission and one that was the result of a laboratory exposure. This number does not include the current case under investigation in Texas.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES