Colossal Biosciences Aims to Wipe Out Screwworms Using Gene‑Drive Technology

When you think of the biggest threats to cattle and sheep, you probably picture predators or disease. Few people, however, picture a tiny, maggot‑like parasite that burrows under the skin, eats away flesh and can kill an animal in just a few days. That’s the New World screwworm, a fly whose larvae have plagued livestock across the Americas for over a century.

Enter Colossal Biosciences, the biotech startup best known for its audacious talk of de‑extincting the woolly mammoth. This time the company is setting its sights on something far more immediate: eradicating the screwworm. Their weapon of choice? A gene‑drive system that spreads a sterilizing gene through wild populations, effectively turning the pest into its own worst enemy.

It sounds like science‑fiction, but the idea builds on decades of research. Gene drives have already been tested in mosquitoes to curb malaria. In the case of the screwworm, scientists plan to edit the insects so that males produce offspring that are all males—and sterile. Over successive generations, the population would crash, leaving farms free from the parasitic menace.

The plan isn’t just laboratory talk. Colossal has teamed up with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, which has a long‑standing eradication program for screwworms in North America. Together they hope to field‑test the engineered flies in a limited area, monitor impacts, and, if all goes well, scale up.

Farmers stand to gain enormously. Screwworm infestations cost the U.S. cattle industry hundreds of millions of dollars each year in lost animals, treatment, and preventive measures. A successful eradication would mean fewer emergency veterinary procedures, less reliance on insecticides, and a healthier herd overall.

Of course, there are concerns. Critics point to the ecological risks of releasing a self‑propagating gene drive into the wild. What if the engineered trait spreads beyond the target region? Could it affect related species? Colossal and its partners say they’re proceeding with “rigorous containment and monitoring” protocols, and that the drive is designed to be self‑limiting after a few generations.

For now, the project remains in the experimental phase, but the excitement among agricultural circles is palpable. If the gene‑drive screwworm can be tamed, it would be one of the first major victories of synthetic biology applied directly to a real‑world pest problem.

Whether this bold venture succeeds or falters, it underscores a growing trend: biotech firms venturing beyond the lab to tackle age‑old agricultural challenges. In the not‑too‑distant future, the phrase “genetic pest control” might become as familiar to farmers as “vaccination” is to doctors.