THURSDAY, Dec. 15, 2016 (HealthDay News) -- Pregnant women should avoid traveling to a south Texas town that sits on the state's border with Mexico, because five cases of local Zika infection have been reported there, U.S. health officials advised Wednesday.
The town of Brownsville is still experiencing temperatures that are warm enough for mosquitoes to continue to breed, according to the U.S. Centers for Disease Control and Prevention. Zika is transmitted primarily via the bite of the Aedes aegypti mosquito, although it can also be spread through sexual contact.
"We're recommending pregnant women not travel to Brownsville, and if they do travel to that area, to ensure that they avoid mosquito bites and they avoid the risk of sexual transmission," the CDC's Dr. Denise Jamieson said in an agency news release. "And that when they return from the area, that they undergo testing for Zika virus infection."
None of the Brownsville cases involve pregnant women, officials added.
While most adults who are infected with the Zika virus experience mild symptoms, infection during pregnancy can have catastrophic consequences for infants. Thousands of babies have been born in Brazil and Colombia with microcephaly, a birth defect that results in an abnormally small head and an underdeveloped brain.
In the United States, CDC officials have tallied 32 cases of Zika-linked birth defects in babies. Most of those cases resulted from infections picked up in Zika-prone countries in Latin America and the Caribbean
Meanwhile, the CDC urges caution and vigilance.
"We are working closely with Texas to gather and analyze new information every day. With the new information that there has been local spread of Zika for at least several weeks, we conclude that pregnant women should avoid the Brownsville area -- and make every effort to prevent mosquito bites if they live or work there," said Dr. Tom Frieden, director of the CDC. "Together with Texas officials, we are working to protect pregnant women from the potentially devastating effects of this virus."
Florida is the only other U.S. state that has reported local cases of Zika infection. But that state was recently declared Zika-free after 45 days passed without any new infections in the last active zone, located in South Miami Beach.
As of Dec. 7, a total of 1,172 Zika infections in the continental United States have involved pregnant women, according to CDC estimates.
On Wednesday, new research from CDC scientists estimated that 6 percent of infected pregnant women will have babies who are born with Zika-linked birth defects, with the first and second trimesters being the most vulnerable period for maternal infection. Their findings were reported in the Journal of the American Medical Association.
The CDC urges residents -- especially pregnant women -- to take steps to protect themselves from mosquito bites. They should use an insect repellent registered by the Environmental Protection Agency containing one of the following ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol, or 2-undecanone. They should also 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.
The CDC also says:
- Zika is spread to people primarily through the bite of infected Aedes species mosquitoes, which are found in Brownsville.
- A pregnant woman can pass Zika virus to her fetus during pregnancy or birth.
- A person infected with Zika virus can pass it on to sex partners.
- No vaccines or treatments are currently available to treat or prevent Zika infections.
The World Health Organization has more on Zika.
This Q & A will tell you what you need to know about Zika.
To see the CDC list of sites where Zika virus is active and may pose a threat to pregnant women, click here.