USDA is suspending live animal imports from Mexico. The decision announced May 11 by Agriculture Secretary Brooke Rollins was made due to concerns over New World screwworm and its rapid spread. According to an agency release, the screwworms have been reported in remote farms near Oaxaca and Veracruz in southern Mexico. Those cities are roughly 700 miles from the U.S. border.
Rollins said she has been working closely with Mexico’s secretary of agriculture, Julio Berdegué, to stop the screwworm’s spread. Despite those joint efforts, Rollins said her duty requires taking all steps within her control to protect the U.S. livestock industry from a devastating pest.
“The protection of our animals and safety of our nation’s food supply is a national security issue of the utmost importance,” Rollins said in the May 11 public statement. “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.”
Berdegué responded in a May 11 social media post that Mexico didn’t agree with the measure. Still, he remained confident the U.S. and Mexico would reach an agreement sooner than later. According to him, Rollins told him the border would be closed to live cattle imports for 15 days as officials from both nations review their joint strategy against screwworm.
Small pest brings huge problems
The threat of screwworm caused U.S. officials to temporarily suspend cattle imports from Mexico in November after Mexican officials notified USDA of New World screwworm in a cow from the Mexican state of Chiapas. The import ban was lifted in February following an agreement between the two nations on how to prevent the parasite’s spread.
According to USDA, the latest suspension of imports will continue on a month-to-month basis until USDA determines that the threat has been contained.
An adult screwworm is about the size of a common housefly. The pest gets its name from the behavior of its maggots that burrow into animal wounds like a screw. The wounds can enlarge quickly as more maggots hatch and feed on the festering tissue. Left untreated, the parasites can kill a full-grown cow in a matter of weeks.
Screwworms are typically found in South America and the Caribbean. Over the past two years, the pest has spread north through Central America and into Mexico, renewing fears of a pest that U.S. officials have previously declared eradicated.
According to the USDA Animal and Plant Health Inspection Service, reports of screwworms in the southwestern U.S. go back as far as 1842. By the 1950s, the spread of screwworm was costing producers up to $150 million each year.
Around the same time, USDA had successfully developed a method of sterilizing screwworms to prevent them from reproducing
By 1966, the U.S. declared the eradication program a success after establishing a New World screwworm barrier along the U.S.-Mexico border. That barrier proved hard to maintain as pests south of the border brought more outbreaks north. According to USDA statistics, Texas alone spent more than $132 million per year to manage outbreaks of New World screwworm.
A joint U.S.-Mexico Screwworm Eradication Commission would eventually work to drive the parasites all the way to Mexico’s southern border. The work was declared a success in 1986.
In 2016, screwworm reappeared in the Florida Keys, affecting endangered key deer. The pests were successfully eradicated within a year.
What would an outbreak look like today?
A large-scale screwworm outbreak could prove devastating to the cattle industry. A 1976 screwworm epidemic in Texas impacted more than 1.4 million cattle and 332,600 sheep and goats. According to a recent USDA study, a similar outbreak today would cost Texas cattle producers $732 million a year. It would also deliver a $1.8 billion hit to the state’s economy.
The National Cattlemen’s Beef Association released a statement May 11 saying the organization agreed with the border closure decision. NCBA officials blame weak governmental participation in eradication efforts by Central American countries for allowing the insect to spread north out of Panama. NCBA also cited a lack of timely action by Mexican officials for putting not only cattle, but also livestock, wildlife, pets and even humans at risk.
While NCBA acknowledges the border closure will hurt producers and disrupt supply chains, it said the alternative would be worse.
CEO Colin Woodal said USDA’s border closure was “entirely avoidable.” According to him, U.S. government officials, NCBA and leaders from affiliated state cattle industry associations have been sounding the alarm for months. Unfortunately, he said, the Mexican government created unnecessary bureaucratic hurdles that rendered prevention efforts ineffective and allowed screwworm cases to spread unchecked beyond control points in southern Mexico.
“The Mexican government’s failure to knock down senseless obstacles has left America with no alternative but a closure of the U.S. border until the outbreak is verifiably stopped, and the flies pushed back south of Panama’s Darien Gap,” Woodal said.