US’s Screwworm Fix Is Still a Year Away, Risking More Spread

The US’s best weapon against a deadly cattle parasite threatening the beef industry is more than a year away from showing meaningful results, raising concerns over how far the outbreak could spread before then.

When the New World screwworm reached the US earlier this month after advancing across Mexico for more than a year, federal officials were prepared to quarantine animals and distribute treatments. But the country’s key tool for suppressing the pest — a facility that breeds sterile flies to halt reproduction of the parasite — isn’t slated to begin operating until November 2027.

A sterile fly dispersal station hangs at Chaparrosa Ranch in La Pryor, Texas, on June 11.

Photographer: Eric Vryn/Bloomberg

The screwworm is actually ...