New World Screwworm Is Back in Texas: What Livestock Owners Should Know

In June 2026, USDA's Animal and Plant Health Inspection Service (APHIS) confirmed New World screwworm (NWS) in a bovine in Zavala County, Texas, with additional cases in cattle and other animals confirmed across a multi-county area of South and Central Texas since, according to APHIS and the Texas Animal Health Commission (TAHC). If you run cattle, goats, horses, or other livestock anywhere near the affected region — or you've just seen the term showing up in ag news and aren't sure what it means for your operation — here's a plain-language rundown, along with a reminder to check pricing on the wound care and fly control basics that matter a little more than usual right now.

What New World Screwworm Actually Is

NWS is the larval stage of a blowfly whose females lay eggs in open wounds on warm-blooded animals. Unlike ordinary flies that feed on dead tissue, screwworm larvae feed on living flesh, which is what makes an infestation more serious than a typical fly strike if it goes unnoticed. The U.S. eradicated the pest decades ago through a long-running sterile-insect release program, which is why this year's detections are being treated as a reintroduction and covered so heavily in agricultural press rather than a routine pest story.

Where Cases Have Been Confirmed

According to APHIS, the initial detection was in a bovine in Zavala County, Texas, and TAHC has since established an infested zone spanning more than a dozen South and Central Texas counties, with additional detections reported in New Mexico. State and federal officials have put movement controls and quarantine measures in place within that zone. If your operation is well outside the affected region, your immediate risk is much lower, but animal health officials nationwide are asking all livestock owners to stay alert given how the fly can travel and spread.

What This Means for Day-to-Day Herd Management

The practical guidance from state and federal officials is straightforward: check your animals regularly, and pay particular attention to any open wound — fresh brands, dehorning or castration sites, tick bites, or a newborn's umbilical stump — for unusual swelling, foul odor, or visible larvae. If you see anything suspicious, the right move is to contact your veterinarian or your state animal health office rather than trying to diagnose or treat it yourself. This isn't a condition to guess at based on something read online, including this article.

The Response Effort Underway

APHIS has been expanding its sterile fly release program in the affected area, a strategy that worked to eliminate the pest from the U.S. the first time around by releasing sterile male flies to outcompete wild ones and collapse the local population over time. It's a multi-year, region-wide effort rather than something resolved in a single season, so continued vigilance from producers in and near the affected zone is likely to matter for a while yet.

What You Can Reasonably Do Right Now

Short of the affected zone, there's no need to overreact — but a few ordinary biosecurity habits are worth tightening up regardless of where you're located. Minimize unnecessary open wounds when you have flexibility on timing for things like dehorning or castration during high fly-pressure months, keep basic wound care supplies on hand so a minor injury gets attention promptly instead of sitting unnoticed, and keep up routine fly control to reduce overall fly pressure around your herd. None of that is a guaranteed defense against NWS specifically, and any confirmed or suspected case still needs to go through your vet and state animal health officials — but reducing open wounds and fly exposure is sound practice either way.

If You're Restocking Wound Care or Fly Control Supplies

Because wound sprays and fly control products are exactly the items most likely to get bought in a hurry at whatever price is available if a need shows up unexpectedly, this is a reasonable moment to check pricing ahead of time rather than waiting for an emergency purchase. Fly control in particular is already a seasonal category where prices climb as demand rises, so comparing retailers now — while you're restocking calmly instead of reacting — is worth the few minutes it takes.

The Bottom Line

For most producers outside the confirmed infested zone, this is a situation to stay informed about rather than panic over: keep checking your animals, know who to call if something looks off, and follow guidance from APHIS and your state animal health office rather than secondhand information. It's also a good prompt to make sure your fly control and wound care basics are stocked at a price you've actually compared, not just whatever was on the shelf during a scramble.

Ready to compare? See our price breakdowns for cattle fly control and horse fly control.