The Texas Department of State Health Services has ramped up efforts to protect people from Zika virus and is urging people to follow mosquito precautions.

Aedes aegypti/CDC
Aedes aegypti/CDC

“Mosquito season is approaching, and the number of travel-related cases continues to inch up for Texas. It’s only a matter of time before Zika virus is locally transmitted here by mosquitoes,” said Dr. John Hellerstedt, DSHS commissioner.

While there is no evidence of local transmission by Texas mosquitoes now, state health officials have quickly implemented Zika virus prevention plans in anticipation of increased mosquito activity and the potential for local mosquito transmission. Zika virus is spread to people primarily through the bite of an infected Aedes aegypti mosquito. Aedes aegypti mosquitoes can be found in Texas, particularly urban areas in the south and southeast portions of the state, but can live anywhere humans are present.

Texas has confirmed 18 cases of Zika virus disease. Seventeen of those are related to travel abroad to areas with active Zika transmission. One case, from Dallas County, was likely the result of sexual contact with someone who acquired the Zika infection while traveling abroad.

State Action

Texas is now testing for Zika virus at its public health lab in Austin. Current state lab capacity is up to 135 human specimens per week, and capacity across the state is increasing as local labs add testing capability in anticipation of a possible surge in demand. This testing, called polymerase chain reaction or “PCR” testing, is used to detect Zika virus in human specimens collected less than seven days after illness onset. The PCR test is considered confirmatory for the presence of Zika virus. Specific testing guidance is available at

Texas is also adding the more complex serologic testing for Zika virus. The benefit of serologic testing is that it can detect Zika infection in people who may not have had symptoms, and the test can be conducted up to 12 weeks after a person is infected. A positive serologic test result requires confirmatory testing to definitively pinpoint Zika because it can cross-react with other viruses, such as dengue.

Texas is working with local officials in the Rio Grande Valley area to monitor mosquito activity and conducted spot trapping in the area in February, which yielded no Aedes aegypti mosquitoes. The Rio Grande Valley is considered to be a potential area of increased risk of Zika virus transmission. DSHS is urging communities to consider expanding their surveillance in coordination with local mosquito control efforts.

The agency’s Birth Defects Epidemiology and Surveillance Branch is analyzing historical microcephaly data to better understand patterns, trends and causes of microcephaly in Texas. Microcephaly is a birth defect that may be linked to Zika virus infection in other parts of the world. Texas also is implementing the “rapid ascertainment” of microcephaly, which means the condition will be closely monitored going forward for Zika virus and other causes.

The Governor’s 31-member Task Force on Infectious Disease Preparedness and Response, directed by Dr. Hellerstedt, will meet in Austin March 9 to discuss infectious disease prevention, and Zika will be part of that discussion.