New World Screwworm Found Near U.S. Border Raises Threat to Cattle Industry and Beef Prices

A dangerous outbreak of the New World Screwworm has moved closer to the United States, raising serious concerns for the livestock industry and agricultural economy. According to the U.S. Department of Agriculture (USDA), the flesh-eating parasitic fly was recently detected in a six-month-old sheep in Mexico’s Coahuila state, approximately 31 miles (50 kilometers) from the U.S. border.

The discovery marks the closest confirmed case of the New World Screwworm during the current outbreak and increases fears that the pest could eventually spread into the United States. Cattle producers and agricultural officials have been monitoring the situation for more than a year as the parasite steadily advances northward through Mexico.

The New World Screwworm poses a major threat to livestock because female flies lay hundreds of eggs in open wounds on warm-blooded animals. Once the eggs hatch, the larvae burrow into living tissue and feed on flesh, causing severe injuries that can become fatal if left untreated. The parasite can infect cattle, sheep, wildlife, pets, and other animals.

Experts warn that an outbreak in the United States could significantly impact the beef industry, which is already facing challenges from historically low cattle inventories. The U.S. cattle herd has fallen to its lowest level in more than seven decades, contributing to record-high beef prices. A screwworm infestation could further reduce cattle supplies by affecting calf survival rates and livestock health.

USDA estimates suggest that a major outbreak could cause as much as $1.8 billion in economic losses in Texas alone, the nation’s leading cattle-producing state. To prevent the pest from spreading north, the United States has restricted cattle imports from Mexico for more than a year.

Federal authorities have invested millions of dollars in sterile fly production programs, a proven method for controlling and eliminating screwworm populations. However, several new production facilities are still under development and have not yet begun full operations. Agricultural officials continue working with Mexican authorities to contain the outbreak and prevent the parasite from reaching U.S. livestock operations.