Maine has moved to restrict the import of animals into the state, citing the threat of New World Screwworm — a parasitic fly whose larvae bore into the living tissue of warm-blooded animals and can be fatal if untreated.
The restrictions took effect as of June 30, 2026. Details on which species are covered, what documentation importers must provide, and how long the rules will stay in place had not been fully disclosed as of that date.
New World Screwworm (Cochliomyia hominivorax) was eradicated from the United States decades ago but has been spreading northward through Central America and Mexico in recent years, raising alarm among livestock producers and state agriculture officials across the country. The fly lays eggs in open wounds; the hatching larvae feed on live flesh, widening the wound and, if untreated, killing the host animal within days.
Maine isn’t alone in watching the spread closely. Federal agriculture authorities have warned that any reintroduction into domestic livestock populations could carry serious consequences for the cattle and deer industries — both of which have a presence in Maine’s rural counties.
Import restrictions are among the first tools states reach for when a pest is moving but hasn’t yet arrived. The logic is straightforward: if infested animals cross the border before anyone knows they’re carrying the pest, the infestation can take hold before detection.
Whether Maine’s rules apply to pets and companion animals in addition to livestock wasn’t immediately clear. The full scope of the order — including which border crossings or points of entry face added inspection — hadn’t been publicly detailed by the end of June.
