...
By Alice Gibbs
Senior Reporter
0
Share
Newsweek is a Trust Project member
See more of our trusted coverage when you search.Prefer Newsweek on Googleto see more of our trusted coverage when you search.
A growing outbreak of New World screwworm in the United States has now reached 20 confirmed cases, according to the latest federal data, raising concerns among livestock producers even as officials insist the overall risk remains low.
Cases recorded by the U.S. Department of Agriculture (USDA) show infections concentrated in Texas, with one additional case detected in neighboring New Mexico.
Where Screwworm Cases Have Been Confirmed in the US
Data published by the USDA’s Animal and Plant Health Inspection Service (APHIS) shows nearly all recent cases have been recorded in Texas, with multiple detections in Terrell and Edwards counties and additional cases in Zavala, La Salle and Medina.
Read More on News
The incidents—primarily affecting cattle, but also goats, sheep and at least one domestic dog—have been reported throughout June, suggesting a steady uptick rather than a single isolated flare-up.
Official Response
Federal officials have sought to reassure the public while mobilizing a large-scale response.
“USDA is responding aggressively to the current outbreak through a fully coordinated effort that includes trapping, animal inspections, wildlife surveillance, sterile insect releases, and extensive public outreach. Together, these tools isolate cases and break the pest’s lifecycle to help prevent further spread,” a USDA spokesperson told Newsweek.
"Rather than focusing on risk, we are underscoring that New World screwworm is treatable, and animals recover quickly with prompt care. That’s why it is essential for people to closely monitor their animals for any signs of screwworm infestation and report immediately if they notice anything suspicious."
The USDA has announced around $105 million in funding for projects aimed at improving detection, control and eradication tools. The federal response has also been visible on the ground. At a June 11 press conference in La Pryor, Texas, Agriculture Secretary Brooke Rollins oversaw the release of tens of thousands of sterile New World screwworm flies—part of a long‑established eradication strategy designed to suppress reproduction by ensuring females mate only with sterile males.
In a statement on June 16, Rollins said: “We have beaten this pest before, and by leveraging innovative solutions and advancements in technology we will beat it again in record time.”
Why Screwworm Cases Are Rising in Texas
The current cluster is unfolding against a broader regional threat.
According to USDA briefings, screwworm—eradicated from the U.S. decades ago—has been spreading northward and was detected in southern Mexico in November 2024, raising the risk to border states.
The parasite spreads when flies lay eggs in open wounds; the resulting larvae burrow into living tissue, causing severe damage if untreated. Transmission can be driven by livestock movement, wildlife carriers and gaps in surveillance.
...
Can the US Contain the Screwworm Outbreak?
The U.S. eradicated screwworm in the 1960s using sterile insect techniques—releasing sterilized flies to disrupt reproduction—a method still central to current plans.
USDA strategy documents emphasize three core pillars: restricting animal movement, strengthening surveillance systems and deploying sterile insect technology at scale.
“If a domestic detection occurs, USDA will act swiftly to implement a response. Isolating the incident, deploying resources, and initiating surveillance,” the agency said in its preparedness framework.
The response has also included movement restrictions across a large swathe of Texas. The Texas Animal Health Commission (TAHC) has established a quarantine zone covering multiple counties, including Bandera, Edwards, Kerr and Zavala, where all warm‑blooded animals cannot be moved without prior authorization.
Under the rules, animals leaving the zone must undergo inspection by animal health officials and be issued certification confirming treatment or preventative measures before transport. The agency said the restrictions are designed to limit the spread of screwworm while federal and state partners carry out surveillance, investigations and eradication efforts in affected areas.
How This Compares to Past Screwworm Outbreaks
While 20 confirmed cases mark a notable return of the parasite, the current outbreak remains small by historical standards.
Before eradication in the mid-20th century, screwworm infestations were widespread across the southern United States, affecting millions of livestock and causing major economic losses.
Today, cases are being detected early and tracked in real time, meaning authorities are attempting containment at a far earlier stage than in previous outbreaks.
...
Texas Farmers and Industry Respond
Texas farmers and industry groups have responded with a mix of vigilance, concern and cautious reassurance as cases rise.
Earlier this month, the Texas Farm Bureau said the detections mark “a new chapter” for the state, warning that livestock producers “must now be vigilant” in managing the pest.
Industry leaders have focused on early detection and coordination with authorities. Stephen Diebel, president of the Fort Worth-based Texas & Southwestern Cattle Raisers Association, urged ranchers to support suspected cases quickly in an interview with Texas Public Radio. “The quicker we report, the quicker we have solutions,” he said. “A really big component of this is landowner communication and communication with our agencies.”
Texas Agriculture Commissioner Sid Miller publicly has called for a more aggressive response from officials. “We have a narrow window to stop this pest before it gains a stronger foothold in the United States. Washington needs to move faster, deploy every proven tool available," he said in a statement earlier this month.
Can Screwworm Spread to Humans or Pets?
Screwworm infestations primarily affect livestock, but they can also impact pets, wildlife and, in rare cases, humans.
Health authorities note that human infections are uncommon and typically treated through manual removal of larvae, sometimes alongside antiparasitic medications. There are no widely used targeted treatments for humans.
Meanwhile, the FDA has issued emergency authorizations for antiparasitic drugs for animals, as demand increases in affected areas.
Officials continue to stress that the outbreak does not pose a risk to the U.S. food supply, but vigilance is critical—particularly in summer conditions that can support the pest’s spread.
Contact Newsweek editors on this story: Tobias Meyjes and Emma Lee-Sang.
Update 06/26/26 08:40 a.m. ET: This story was updated with additional comment from the USDA.
View 0 Comments
Submit Correction
View Editorial & AI Guidelines