The U.S. paused cattle imports from Mexico as the flesh-eating insect that has ravaged livestock in South America moves north.

New World screwworm poses a significant threat to livestock: The pest can enter an animal through an open wound and feed on their living flesh, which can lead to death.

The U.S. successfully eradicated the pests in the 1960s using sterile flies. At the time, the larvae were costing producers an estimated $50 million to $100 million in losses a year.

However, detections in Mexico throughout the 1970s caused flareups in the southwestern U.S. The outbreaks prompted the two countries to team up and successfully eradicate the fly in Mexico in 1986, according to a USDA reference guide.

Over the last two years, New World screwworm has moved north from a biological barrier the U.S. helped establish in Panama. The fly has been found in Costa Rica, Nicaragua, Honduras and Guatemala.

Increased livestock movement and land use changes from deforestation have allowed the fly to escape traditional containment areas, according to the North American Invasive Species Management Association. Rising temperatures linked to climate change have also led to more favorable conditions for the flies to spread.

U.S. Ranchers have been asked to remain on high alert for the fly, which has orange eyes and three dark stripes across its back. Infestations can be difficult to detect early in animals, according to the NAISMA, with symptoms like enlarged wounds, discomfort and visible larvae appearing after significant damage has already occurred.

“The current outbreaks in Central America demonstrate the need for USDA to increase its investment in NWS eradication and prevention,” Jenny Lester Moffitt, USDA Under Secretary for Marketing and Regulatory Programs, said in a statement. “If NWS were to spread to the United States, it would result in significant economic losses and threats to animal health and welfare.”

Source - https://www.agriculturedive.com