Commissioner Sounds Urgent Alarm: Additional Screwworm Case Detected Just 215 Miles from Texas Border

Commissioner Sounds Urgent Alarm: Screwworm Detected Near Texas Border

A Threat to Livestock and Livelihoods

Texas Agriculture Commissioner Sid Miller has issued a dire warning following the confirmation of a New World screwworm (NWS) case in a seven-year-old bovine in González, Tamaulipas, Mexico, a mere 215 miles from the Texas border. This detection, with no reported history of animal movement outside of Tamaulipas, marks the third active case in the state and raises concerns about the parasite potentially spreading independently, without commercial animal transport. The situation demands immediate attention and heightened vigilance from livestock producers in Texas and across the nation.

The New World screwworm, Cochliomyia hominivorax, is a parasitic fly whose larvae can infest warm-blooded animals, including livestock, pets, wildlife, and even humans. Unlike common maggots that feed on dead tissue, screwworm larvae consume living tissue, causing a condition known as myiasis. This infestation leads to severe tissue damage, pain, weight loss, reduced production, and, if left untreated, can be fatal.

The Economic Impact of Screwworm

The potential economic consequences of a screwworm outbreak are staggering. Prior to its eradication from the U.S. in 1966, screwworm infestations caused significant economic losses to the livestock industry. The USDA estimates that the U.S. livestock industry saves approximately $900 million a year as a result of screwworm eradication. A 1976 outbreak in Texas, for example, would cost livestock producers an estimated $732 million, with an overall economic impact of $1.8 billion in 2024 terms. These costs include animal deaths, reduced productivity, veterinary treatment, and increased labor.

Understanding the Screwworm Threat

How Screwworms Infest

The female screwworm fly lays its eggs on open wounds or sores of warm-blooded animals. These wounds can be caused by:

  • Tick bites
  • Castration or dehorning
  • Branding
  • Shearing
  • Sore mouth in sheep
  • Navels of newborn mammals
  • Mucous membranes of bodily orifices (nostrils, eyes, mouth, ears, vulva, anus, prepuce, and urethral fossa)

Once the eggs hatch, the larvae burrow into the living tissue, feeding aggressively and causing extensive damage. The odor of screwworm feeding on live flesh is distinct and often a first sign of detection.

Signs of Screwworm Infestation

Livestock and pet owners should be vigilant and monitor their animals for the following signs of screwworm infestation:

  • Foul-smelling wounds
  • Visible maggots in the wound
  • Wounds that worsen over time
  • Bloody discharge from the wound
  • Irritated behavior around the wound (biting, licking, head shaking)
  • Decreased appetite
  • Lower milk production
  • Lethargy or isolation from the herd

Prevention and Control Measures

Early Detection and Reporting

Early detection and rapid reporting are crucial to preventing the spread of screwworm. Commissioner Miller urges ranchers along the Texas border to “Inspect your animals daily. Check every open wound. If anything looks suspicious, report it right away. Better a false alarm than a delayed response—early detection and rapid reporting are our strongest defenses against this devastating pest.”

If you suspect a screwworm infestation:

  1. Contact Authorities:
    • Texas Animal Health Commission (TAHC) for livestock and pets: 800-550-8242
    • Texas Parks and Wildlife Department (TPWD) for wildlife: 512-389-4505
  2. Notify your private veterinarian.
  3. Isolate the affected animal to prevent further spread.
  4. Collect samples of larvae, if possible, and preserve them in 70% alcohol for identification.
  5. Follow the instructions of your veterinarian or animal health professional on next steps.

Preventative Measures

  • Keep open wounds clean and covered.
  • Avoid management practices that create wounds (castration, dehorning, branding, ear tagging) during peak fly season.
  • Control other wound-causing parasites such as ticks.
  • Treat the umbilical cords of newborn animals immediately with an approved insecticide.
  • Monitor livestock regularly for any signs of infestation.

Treatment Options

  • Wound Care: Clean wounds thoroughly and apply disinfectant.
  • Topical Treatments: Permethrin sprays and ear tags can kill and repel flies.
  • Systemic Treatments: Consult with your veterinarian about appropriate systemic treatments.
  • FDA Approved Treatments: The FDA has conditionally approved Dectomax-CA1, a doramectin injection, for treating screwworm infestations and preventing reinfestation for 21 days in cattle.

Sterile Insect Technique (SIT)

The sterile insect technique (SIT) is a proven method for eradicating screwworm. This technique involves releasing sterile male flies into an area with an established screwworm population. The sterile males mate with wild females, who then lay nonviable eggs. Since female screwworm flies only mate once in their lifetime, the population decreases without the addition of new larvae and dies off naturally over a few lifecycles.

The USDA is investing heavily in SIT, including an $8.5 million sterile fly dispersal facility in Mission, Texas, capable of producing up to 300 million sterile flies per week.

The Role of Legal Action

While preventative measures and eradication programs are essential, legal avenues may also be available to livestock producers who suffer economic losses due to screwworm infestations. If negligence or failure to implement proper control measures contributes to an outbreak, producers may have grounds to pursue legal action to recover damages.

Staying Informed and Vigilant

The threat of screwworm re-emergence in the United States is a serious concern. By staying informed, implementing preventative measures, and acting quickly to report suspected cases, livestock producers can protect their animals, their livelihoods, and the nation’s food supply.

Resources:

Call to Action:

Protect your livestock and your livelihood. Stay vigilant, monitor your animals, and report any suspicious signs to the appropriate authorities. Together, we can prevent the devastating impact of screwworm on the Texas livestock industry.