The U.S. suspends Mexico cattle imports after New World screwworm (NWS) was identified in an infected cow at a livestock inspection checkpoint close to the border of Guatemala, in the state of Chiapas. The U.S. was notified by Mexico government officials on Nov. 22, 2024.
The USDA Animal and Plant Health Inspection Service (APHIS) put a temporary pause on live cattle imports until information on the size and scope of the NWS infestation is identified, and precautions are put into place to prevent it from entering into the states.
“Given the northward movement of NWS, APHIS has in recent months stepped up its efforts in Central America to partner with impacted countries to push this pest out of newly affected areas,” said Dr. Rosemary Sifford, chief veterinary officer of the U.S., in a USDA APHIS news release. “With this latest find in Mexico, we will further intensify this work to protect American agriculture and reestablish the barrier in Central America.”
The news release adds, “Given the severity of the threat from NWS, APHIS is restricting the importation of animal commodities originating from or transiting Mexico effective immediately and pending further information from Mexican veterinary authorities on the size and scope of the infestation.”
Already high feeder cattle futures jumped the days following, as the U.S. has relied on livestock from Mexico to compensate for the low cattle numbers from multiple years of herd number declines here in the U.S. A long-term closure of the border could have severe effects on U.S. beef production and prices in the following months.
The screwworm gets its name because it burrows into wounds like a screw. NWS are fly larvae that infest living tissue of warm-blooded animals and humans, causing infection. They most often enter an animal through an open wound and feed on the animal’s living flesh.
The last outbreak of NWS appeared in Florida in 2016 and was the first outbreak in the U.S. in decades.
“APHIS is working with partners in Mexico and Central America to stop the spread of NWS into the United States and asking all producers along the southern border to watch their livestock and pets for signs of NWS and immediately report potential cases. Screwworm infestations are difficult to detect at first. Check your pets and livestock for draining or enlarging wounds and signs of discomfort. Also look for screwworm larvae or eggs. Screwworm eggs are creamy and white and are deposited on or near the edges of superficial wounds. If you suspect your animal is infected with screwworm, contact your veterinarian.”
