December 14, 2016, 16:15 ET (4:15 PM ET)

CDCHAN-00399

On November 28, 2016, the Texas Department of State Health Services (TDSHS) reported the first case of locally

acquired mosquito-borne Zika virus infection in the city of Brownsville, Cameron County, Texas. On December 9,

2016, four additional cases in people living in proximity to the first case were reported. TDSHS continues to

investigate Zika virus transmission in Brownsville.

Currently only five cases are known to have been locally acquired in the Brownsville area, and there is not yet any

evidence of widespread, sustained local transmission. However, temperatures in the region are still conducive to

mosquito-borne transmission, and therefore the risk of continued local transmission of Zika virus cannot be ruled

out. CDC, TDSHS, and local authorities continue to investigate the cases in Brownsville and will share up-to-date

information and recommendations as the situation develops. The active, ongoing surveillance and response

underway in Texas will provide more information over time that may allow for more precise and focused

assessment of risk. The exact level and location of risk of Zika virus infection in Brownsville is unknown; pregnant

women in the area are at some risk for Zika virus infection.

For these reasons, CDC is designating the city of Brownsville as a Zika cautionary (yellow) area for testing and

travel guidance, as recommended in the CDC Interim Zika Response Plan (https://www.cdc.gov/zika/pdfs/zikadraft-

interim-conus-plan.pdf ). Based on the earliest time of symptom onset for cases of locally acquired Zika virus

infection in Brownsville and a maximum 2-week incubation period for Zika virus, this guidance applies to pregnant

women, women of reproductive age, and their sexual partners who live in or traveled to Brownsville on or after

October 29, 2016. Because many people with Zika virus infection will not have symptoms or will have only mild

symptoms, additional people may be infected.

Brownsville is located in Cameron County, Texas, which shares a border with Mexico

(https://www.cdc.gov/zika/intheus/texas-update.html). Many people travel regularly across the United States-

Mexico border to temporarily live, work, attend school, socialize, and seek medical care. Areas of active Zika virus

transmission have also been reported in Mexico near the United States-Mexico border, and CDC issued a Travel

Notice for Mexico (https://wwwnc.cdc.gov/travel/notices/alert/zika-virus-mexico) on December 10, 2015,

recommending that pregnant women should not travel to any area of Mexico below 6,500 feet.

This is an ongoing investigation, and TDSHS, Cameron County Health Department, Brownsville Health

Department, and CDC are working together to rapidly learn more about the extent of Zika virus transmission in

Brownsville. CDC will update these recommendations as more information becomes available.

CDC HAN 399 CDC Guidance for Travel and Zika Testing Brownsville Cameron Co Texas 12 14 2016.pdf