Texas Has Become the Second State to Report Local Transmission of Zika

Border cities are bracing themselves. The town of Brownsville, Texas has fallen victim to its first case of local Zika transmission—in which a mosquito spreads the virus from person to person.

It’s the second state to experience to local transmission, the first being Florida earlier this year. That situation was severe enough that the C.D.C. advised pregnant women (who, if exposed to Zika, risk bearing a child with birth defects) to avoid first the neighborhood of Wynwood, Florida—and then the entire county. But so far only one case of locally-transmitted Zika has been reported in Brownsville, so the C.D.C. isn’t issuing any travel alerts quite yet, nor is it sending an emergency response team to the area. It would take confirmation of several more cases with a one-square-mile region to elicit an aggressive reaction from federal authorities.

The patient, who is an unpregnant woman, is now the 4,444th confirmed case of Zika infection in the continental United States.

An Aedes albopictus female mosquito feeds on a human blood meal. Photo by James Gathany, Centers for Disease Control and Prevention
An Aedes albopictus female feeds on human blood

Donald G. McNeil, Jr. and Manny Fernandez, reporting for The New York Times:

The Texas patient, who was not identified, told investigators that she had not traveled recently to anywhere the virus had been spreading. She had no other risk factors, such as having sex with someone who had visited an area with Zika transmission.

“We knew it was only a matter of time before we saw a Zika case spread by a mosquito in Texas,” said Dr. John Hellerstedt, the state health commissioner.

Residents of Brownsville, a city of 183,000, are concerned but not fearful, Mayor Tony Martinez said on Monday.

“I don’t think it’s something that people need to be alarmed about, but by the same token, they need to be cautious about it and report anything that needs to be reported to our health department,” Mr. Martinez said.

“On the coast, we kind of hoped that it wouldn’t happen,” he added, “but the likelihood was pretty high.”

Unusually warm weather in the past few months made this region of Texas more mosquito-friendly, which means more cases could be confirmed in the coming weeks or in early 2017. Even now, there may be many more cases that have gone undetected—the only reason this particular case surfaced was because a local doctor tested the woman for Zika infection when she fell ill.

This isn’t the first time Brownsville has dealt with an outbreak. In 2002, dengue spread through the town around the same time as a larger outbreak of the disease in the neighboring Matamoros, Mexico just across the border. Both are impoverished communities; residents tend to lack air conditioning or window screens that would help prevent mosquitos from entering homes and other buildings. Brownsville also confirmed Texas’s first case of chikungunya earlier this year.

While health officials begin to assess the public health damage, many experts are pushing for continued support of Medicaid benefits for mosquito repellant, as well as stronger mosquito control programs. In Florida, the outbreak only died down once aerial pesticides killed off the mosquitoes and halted transmission.

Scientists have always known that Zika is strange. But just how strange? Find out in NOVA’s latest original digital documentary.