The United States (US) has suspended the import of live cattle from Mexico over a rapid spread of New World Screwworm (NWS).
US Secretary of Agriculture Brooke L. Rollins announced the suspension, saying it would also include live horses and bison and was effective immediately.
When NWS fly larvae (maggots) burrow into the flesh of a living animal, they cause serious, often deadly damage to the animal. NWS can infest livestock, pets, wildlife, occasionally birds, and in rare cases, people.
“The US has ordered the suspension of livestock imports through ports of entry along our southern border after the continued spread of the New World Screwworm in Mexico. Secretary Berdegué and I have worked closely on the NWS response; however, it is my duty to take all steps within my control to protect the livestock industry in the US from this devastating pest,” Secretary Rollins said.
“The protection of our animals and safety of our nation’s food supply is a national security issue of the utmost importance. Once we see increased surveillance and eradication efforts, and the positive results of those actions, we remain committed to opening the border for livestock trade. This is not about politics or punishment of Mexico, rather it is about food and animal safety.”
The suspension - impacting live animal commodities originating from, or transiting Mexico - will continue on a month-by-month basis, until a significant window of containment is achieved.
The first case of NWS in Mexico was reported to the US in November 2024, when USDA shut down the border for live animal trade.
In February USDA resumed imports after APHIS and Mexico agreed to and implemented a comprehensive pre-clearance inspection and treatment protocol to ensure safe movement and steps to mitigate the threat of NWS.
The United States and Mexico continue efforts to interdict and eradicate NWS in Mexico - including strategically releasing sterile flies, focusing on Southern Mexico and other areas throughout Central America. However, despite these efforts and the economic impact on both countries due to this action, there has been unacceptable northward advancement of NWS and additional action was deemed necessary to be taken to slow the northern progression of the deadly parasitic fly.
The US previously and successfully led the eradication of NWS in the US and Mexico, however this cost billions of dollars and took decades.
It's not known if the presence of NWS in the US could limit possibilities for that country to export beef to Australia, a key discussion point in the recent 10% tariff placed on Australian imports.