Reuters correspondent Cassandra Garrison heads to the Texas-Mexico border to see firsthand how smugglers are sneaking horses across undetected — and why that's raising fears over the spread of New World screwworm ▻ ↧ ↧ Horse smuggling exposes cracks in US defenses against screwworm Horse smuggling across the Texas-Mexico border may expose a gap in U.S. defenses against New World screwworm, a costly threat to livestock. Horse smuggling exposes cracks in US defenses against screwworm Horse smuggling across the Texas-Mexico border may expose a gap in U.S. defenses against New World screwworm, a costly threat to livestock.