New World Screwworm Outbreak Approaching Texas Border

The U.S. Centers for Disease Control and Prevention (CDC) issued a Health Alert Network advisory (CDCHAN-00526) on January 20, 2026, warning about cases of New World screwworm (NWS) in animals in Mexico's Tamaulipas state, which borders Texas.

As of that date, no human or animal cases have been reported in the United States, but the CDC is raising awareness among travelers to Mexico and healthcare providers due to the potential for the disease to spread northward.

The current NWS outbreak in Central America and Mexico has resulted in over 1,190 human cases, seven deaths, and 24 hospitalizations in Mexico, as well as 601 active animal cases.

Specifically, the Free and Sovereign State of Tamaulipas has eight confirmed active animal cases.

Tamaulipas has about 230 miles of land along the U.S.–Mexico border with the state of Texas, adjacent to cities such as South Padre Island and McAllen.

At this time, the risk to the U.S. public remains low, says the CDC.

NWS is a parasitic fly whose larvae infest open wounds or mucous membranes in warm-blooded animals and humans. These larvae feed on living tissue and can cause fatal infections if left untreated.

The disease was eradicated from the U.S. in the 1960s using the sterile insect technique, which involves releasing sterile males to prevent reproduction. This technique was also successfully employed in Florida in 2017.

A sterile fly barrier at the Darién Gap had been effective since 2006, but a surge in Panama in 2023, driven by cattle movement, migration, and farming, led to a rapid northward spread.

The USDA's Animal and Plant Health Inspection Service is currently managing the containment efforts in Mexico and in Texas through sterile fly releases, animal movement restrictions, surveillance, and public education.

The CDC is supporting these public health initiatives to identify and treat potential human cases promptly.

Travelers to affected areas should clean and cover all wounds, avoid livestock areas and outdoor sleeping during the day, and use bed nets or stay in screened facilities.

Clinicians should suspect NWS in patients with larvae or eggs present in wounds or orifices, signs of tissue destruction, foul odor, pain, or a history of recent travel to endemic regions. Suspected cases must be reported immediately to local health departments for CDC confirmation via the DPDx lab.

Additionally, it is crucial to remove and dispose of all larvae, preserve them in 70% ethanol for identification, recheck lesions in 24 to 48 hours, and provide supportive care to infected people.

As of January 21, 2026, no specific medications or vaccines have been proven effective against NWS.

For timely updates, please visit Vax-Before-Travel.com, which will monitor this developing situation.