Like soldiers on the front line, uniformed special forces are quietly patrolling the Texas-Mexico border, diligently protecting the nation from the deadly invasion of small, single-celled organisms that left unchecked could disrupt the U.S. food supply and wreak havoc on the nation’s cattle industry.

These troops aren’t part of the U.S. military but members of a USDA Animal and Plant Health Inspection Service (USDA-APHIS) team permanently assigned to provide mounted patrols along a 400-plus mile strip of land reaching from the mouth of the Rio Grande River north to Amistad Reservoir near Del Rio, an estimated 150,000-acre area where a permanent livestock quarantine is being enforced as part of the Cattle Fever Tick Eradication Program (CFTEP). These troops are officially known as mounted patrol inspectors, but are known along the border as tick riders.

The day starts early for tick riders. Rising before the sun is up, they feed their horses and mount up to begin a day of riding the river banks in search of stray cows that may have wandered out of Mexico and across shallow crossings on the river.