Federal and state officials have confirmed that the number of New World screwworm cases in the United States has risen to 20, with all but one located in Texas.

What we know: Timeline: The current U.S. outbreak began on June 3, 2026, when the first case was reported in a 3-week-old calf in Zavala County.

Since then, the parasite has steadily surfaced in multiple counties across West and South Texas.