A case was confirmed in a calf in La Pryor, Texas, a town about 30 miles (48 km) northeast of the US-Mexico border - a blow to US cattle ranchers.

If confirmed, it would be the fly's first breach of the US-Mexico border.

The U.S. Department of Agriculture has confirmed that the New World screwworm fly has arrived in south Texas.

The flesh-eating larvae has threatened the nation's cattle industry