McALLEN, Texas (Border Report) — The first case of New World screwworm has been reported in the northern Mexican border state of Tamaulipas.
Texas Agriculture Secretary Sid Miller on Wednesday said a six-day-old calf tested positive for the deadly fly larvae on Saturday in Tamaulipas, just 197 miles south of the South Texas border.
“The continued detections of New World screwworm near the Texas border are grim reminders of the serious threat this pest poses to our state,” Miller said.
Mexican officials with the National Service of Agro-Alimentary Health, Safety, and Quality (SENASICA) confirmed the detection of the deadly pest, Miller said.
The Mexican agency is tasked with overseeing agriculture and food industries throughout the country.
Mexico has implemented strict quarantining procedures if screwworm infections are found.
And the United States is not allowing any cattle to be imported from Mexico in order to prevent the spread across the border.
In October, a cow in Sabinas Hidalgo, in the northern Mexican state of Nuevo Leon, was discovered with screwworm just 70 miles from the South Texas border. However, no further cases were noted, and officials say it has not spread across the border into the United States.
The Texas cattle industry says if screwworms cross the border, it could devastate livestock and cost the industry $2.1 billion in damages.
“In coordination with Mexico, its northward spread has been halted, and this recent case promises to be a one-off, for now. But to fully eradicate this threat, the bottom line remains unchanged: we need sterile flies,” Miller said in a statement.
Planes loaded with one million sterilized screwworm adult male flies are being flown to southern Mexico and Panama from Moore Air Base in the South Texas town of Edinburg after Agriculture Secretary Brooke Rollins visited the air base earlier this year.
The base is being renovated to produce up to three million sterile flies per week to be sent to Mexico and Central America, but that is not expected to be ready until 2026.
The U.S. Department of Agriculture operates a real-time website for updates on the screwworm located here.
New World screwworm larvae can burrow into the flesh of animals, livestock, pets, birds and even people. They can kill animals in two weeks by causing infections and feeding on wounds with their screw-like teeth.
The pests were eradicated from the United States in 1966 using sterile flies. However the flies re-emerged in Panama during the COVID pandemic when the number of on-site inspectors decreased. Since then, they have steadily made a northward trek toward the U.S. border.
Adult screwworm flies are the size of a common housefly, or slightly larger, with orange eyes, a metallic blue or green body and three dark stripes along their back.
Infected animals show these signs:
- Irritated behavior
- Head shaking
- Smell of decay
- Presence of fly larvae maggots in wounds
Preventative drugs have been approved as effective treatments for dogs and cats in the United States, should the flies cross the border into the interior.
Sandra Sanchez can be reached at SSanchez@BorderReport.com.