Ag Chat from 6/10/26: The New World Screwworm update is offered
From our Livestock Agent , Bailee Sheffield

The U.S. Department of Agriculture (USDA) has confirmed the nation's first domestic case of the New World screwworm since 1966. The flesh-eating parasite was detected on June 3, 2026, in the umbilical area of a three-week-old calf in Zavala County, Texas. Federal and state authorities have immediately locked down a 12 mile quarantine zone around the Texas farm to contain the screwworm. Because the fly can travel long distances through livestock transport, vehicles, and wildlife, agricultural experts warn that out-of-state producers, including those here in North Carolina, should begin monitoring their herds immediately. State officials emphasize that this is a livestock production threat and not a food safety issue. The commercial meat supply remains completely safe.

What do they look like
Unlike standard blowflies that feed on dead tissue, the New World screwworm fly lays eggs exclusively at the edges of open wounds on live, warm-blooded animals. The fly looks similar to a standard house fly but features a distinct, shiny metallic blue-green body, prominent orange-red eyes, and three dark stripes running down its back. Within 12 to 24 hours of eggs being laid, the larvae hatch and burrow deep into the living tissue. The maggots are tapered and ringed with dark spines, giving them the appearance of a wood screw. Infested wounds typically become enlarged, deep-pocketed, and produce a foul-smelling, bloody discharge.

Steps for Local Producers
Producers should check all livestock daily, paying close attention to newborn navels, tick bites, or fresh wounds from shearing, dehorning, and castrating.

Prevention
Treat Navels: Apply iodine or an approved preventative to the navels of all newborn livestock immediately after birth.
Protect Wounds: Treat any accidental cuts, scratches, or surgical wounds promptly with protective fly sprays or wound dressings.
Control Ticks: Keep up with your external parasite control. Tick bites create the exact raw wounds that adult screwworm flies look for to lay their eggs.
Inspect New Arrivals: If you bring any new animals onto your property, isolate them and do a thorough skin inspection before letting them join the herd.

If you notice a suspicious, maggot-infested wound on your livestock or pets:
Isolate the animal immediately.
Do not clean or treat the wound right away. Cleaning or applying larvicide can destroy the physical evidence required for a definitive laboratory diagnosis.
Request or collect a sample. Contact your veterinarian or Bailee to come out & collect a sample of live larvae from the deep pocket of the wound, and rush them to the state lab for testing.

There are currently no cases in North Carolina, please keep a check on your livestock.

To report a suspect animal/collect a sample, Set up a farm visit, or any other questions contact Bailee Sheffield at 336-694-4158 ext. 5 or bailee_sheffield@ncsu.edu.