Nearly four months after Florida became the first state in the nation to report a locally acquired Zika infection, the Centers for Disease Control and Prevention announced this week that its epidemiologists are working with Texas health officials on what they suspect is that state's first local case.
CDC officials said Zika has been diagnosed in a resident of Brownsville — which borders Mexico at the state’s southernmost tip — without any other known risk factors for contracting the disease, such as sexual transmission or travel to an area where the virus is widespread.
If confirmed, the case would be the first known occurrence of mosquito-borne Zika infection in Texas. And the state would join Florida as the two states in the nation with active local transmission of the virus. Florida reported its first case in late July in a one-square-mile area of Miami’s Wynwood neighborhood, followed by cases in Miami Beach and the Little River neighborhood.
In response to the suspected case in Brownsville, Texas health officials stepped up surveillance and spraying to control mosquitoes, the CDC reported, and they are testing for Zika to determine if there have been additional infections in the area.
“Even though it is late in the mosquito season, mosquitoes can spread Zika in some areas of the country,” said CDC Director Tom Frieden. “Texas is doing the right thing by increasing local surveillance and trapping and testing mosquitoes in the Brownsville area.”
In Florida, state health officials report that mosquitoes continue to spread Zika in two areas: a 1.5 square mile area of South Beach between 8th and 28th Streets from the ocean to the bay; and a one-square-mile area of Miami’s Little River neighborhood.
The Wynwood area no longer has active cases. And on Nov. 22, Gov. Rick Scott lifted part of Miami Beach’s Zika zone covering most of Middle Beach after the health department reported that 45 days had passed without a new local case.
Zika spreads to people primarily through the bite of an infected Aedes species of mosquito — most frequently Aedes aegypti, but also sometimes the Aedes albopictus. Both species are found in Brownsville.
Zika can also spread during sex between an infected person and his or her partner. And though most people infected with Zika won’t have symptoms — which can include fever, muscle pain, rash and red eyes — the virus poses the greatest risk to pregnant women because it can cause a severe birth defect of the brain called microcephaly and other neurological complications in fetuses and infants.
There is no vaccine or therapy to treat or prevent Zika.
As of Monday, the Florida Department of Health reported 1,206 Zika infections statewide, with 953 travel-related cases and 238 locally acquired cases. An additional 15 cases are labeled “undetermined” because the state could not identify the source of exposure due to the person traveling to several areas where the virus is spreading, including most of South Beach and a section of Miami’s Little River neighborhood.
According to the CDC, a total of 4,444 cases of Zika have been reported in the continental United States and Hawaii as of Nov. 23, including 182 infections spread locally by mosquitoes and 36 believed to be the result of sexual transmission.