The New World screwworm is a parasitic fly whose larvae infest living tissue in warm-blooded animals, causing painful wounds, serious infections, and potentially death if not treated, Bloomberg reports.
After being largely eliminated from the United States for decades, it has recently begun spreading northward from Mexico into parts of the southern U.S., with detections now appearing beyond the original containment zone in Texas.
This expansion is raising concern because it suggests that previous control barriers are being challenged. In response, agricultural and animal health authorities are increasing surveillance of livestock, enforcing movement restrictions and quarantines in affected areas, and stepping up efforts to control the fly population through sterile insect release programs, which involve breeding and releasing sterilized male flies to reduce reproduction rates.
The situation is especially significant for the cattle industry, which could face higher veterinary costs, livestock losses and potential disruptions to trade if the parasite continues to spread.
While the outbreak is still being actively managed, the widening range is seen as a warning sign that containment is becoming more difficult.
