Cattle are detained in the pens of the Chihuahua Regional Livestock Union, at the Jeronimo-Santa Teresa border crossing in Ciudad Juarez, Mexico. Christian Torres/Anadolu via Getty Images

The United States will suspend imports of live cattle through ports along the southern border with Mexico for at least two weeks to review the joint strategy in the fight against the screwworm, the U.S. Department of Agriculture said on Sunday.

Secretary Brooke Rollins said in a statement that the screwworm, which is parasite that could be fatal, was recently detected in remote farms as far north as Oaxaca and Veracruz, about 700 miles away from the U.S. border.

"The protection of our animals and safety of our nation's food supply is a national security issue of the utmost importance," she said in a 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."

Mexico's Agriculture Secretary Julio Berdegué said on social media that he had spoken with Rollins, who had informed of the decision.

"We don't agree with this measure, but we're confident we'll reach an agreement sooner rather than later," Berdegué said.

What is a screwworm?
The screwworm is a larva of the Cochliomyia hominivorax fly that can invade the tissues of any warm-blooded animal, including humans. The parasite enters animals' skin, causing severe damage and lesions that can be fatal.

Mexico's Health Ministry issued an epidemiological alert this month after the first human case of screwworm myiasis was confirmed on April 17 in a 77-year-old woman living in the southern state of Chiapas. Also this year, the Texas Parks and Wildlife Department issued a warning in January about animals that may been impacted by the dangerous "maneater" parasites.

The U.S. restricted Mexican cattle shipments in late November following the detection of the pest but lifted the ban in February after protocols were put in place to evaluate the animals prior to entry into the country.

But there has been an "unacceptable northward advancement" of the screwworm, the U.S. Department of Agriculture said in a statement Sunday.

"Additional action must be taken to slow the northern progression of this deadly parasitic fly," the statement added.

Over the last two years, screwworm has spread north throughout Panama and into Costa Rica, Nicaragua, Honduras, Guatemala, El Salvador, Belize, and now Mexico, the department said.

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