USDA Halts Live Animal Imports Amid New World Screwworm Outbreak
The New World screwworm, a parasitic fly responsible for severe infestations in livestock and even humans, has re-emerged as a significant concern following an outbreak reported in Mexico. In response, the U.S. Department of Agriculture (USDA) has immediately suspended imports of live cattle, bison, and horses from the southern border.
Background on the New World Screwworm
This harmful fly lays larvae that burrow into the flesh of its hosts, causing intense pain and potentially leading to fatal outcomes. The New World screwworm was successfully eradicated from the United States in 1966 after an exhaustive 30-year effort, which involved the release of hundreds of millions of sterile flies to disrupt reproduction among the wild population.
Current Developments in Mexico
Recent reports indicate that the screwworm has been detected on remote farms in Mexico, with sightings extending as far as Oaxaca and Veracruz, approximately 700 miles from the U.S. border. These discoveries prompted immediate action from the USDA.
USDA Response and Border Suspension
USDA Secretary Brooke Rollins emphasized the urgency of the situation, stating, “Due to the threat of New World Screwworm, I am announcing the suspension of live cattle, horse, and bison imports through U.S. southern border ports of entry effective immediately. The last time this devastating pest invaded America, it took 30 years for our cattle industry to recover. This cannot happen again.”
Inspection and Trade Resumption
The first reported case of infestation in Mexico reached U.S. authorities in November 2024, leading to a ban on live animal trade. However, after the implementation of comprehensive inspection and treatment protocols by the USDA’s Animal and Plant Health Inspection Service (APHIS) and Mexican officials, limited trade resumed in February 2025.
Control Measures in Place
To combat the threat, APHIS is deploying sterile flies in key locations across southern Mexico and parts of Central America. This strategy aims to prevent the screwworm’s population from growing and spreading further.
Statement from the USDA
In a recent news release, Secretary Rollins reiterated the importance of protecting animal health and ensuring the safety of the food supply, stating, “The protection of our animals and the 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 halt on imports is not intended as a political measure against Mexico but is fundamentally about safeguarding food and animal safety in the United States.