Missouri moved Friday, June 27, to update the requirements for animals crossing into the state — a direct response to the spread of New World Screwworm, a flesh-eating parasitic fly that can kill livestock and, in rare cases, infect other warm-blooded animals.
The revised rules affect animals entering Missouri, though the specific documentation or inspection requirements attached to the update weren’t immediately detailed in state communications. New World Screwworm — Cochliomyia hominivorax — lays eggs in open wounds; the larvae then burrow into living tissue. An infestation can kill an otherwise healthy animal within days if untreated.
The parasite was eradicated from the United States decades ago but has been creeping back toward the southern border through Central America and Mexico, putting livestock-heavy states on alert. Missouri runs one of the larger cattle industries in the Midwest — a fact that makes any screwworm incursion a serious economic concern, not just a veterinary one.
Missouri isn’t alone. Several other states have adjusted animal-movement rules this year as federal agriculture authorities watch the parasite’s northward spread. The Missouri Department of Agriculture oversees animal import certificates and inspection protocols, though the department hadn’t posted updated regulatory language to its public website as of Friday evening.
Producers hauling animals across state lines — or receiving out-of-state shipments — should contact the department directly for the current requirements. The full scope of the rule changes, including which species are covered and what documentation is now required at the border, had not been publicly released by late Friday.
