New World Screwworm Reaches Texas from Mexico Border

USDA Confirms First Texas Case in Zavala County Calf

The United States Department of Agriculture confirmed on June 3 and 4 that a three-week-old calf in Zavala County, Texas, carried New World screwworm larvae in its umbilical area. This marks the first time the flesh-eating parasite has crossed from Mexico into the United States during the current northward spread.

Families who raise livestock along the border now face new worries. In rural colonias near the Rio Grande, many small ranchers depend on a few head of cattle for their livelihood. A single infestation can threaten an entire season’s work.

Outbreak Moves North Through Coahuila Just Miles from the Border

Five days before the Texas confirmation, USDA officials identified the parasite in a young sheep in Coahuila, Mexico, only 31 miles from the international boundary. The pest has been tracking northward from Central America through Mexico for more than a year.

Campesinos in northern Mexican states remember the last major outbreaks. Many still speak of the coordinated efforts that finally eradicated the screwworm from Mexico in 1991. Today those same communities watch the situation closely as larvae appear closer to their own herds.

More Than 350 Human Cases Reported Across Mexico

Mexico’s Health Ministry has documented over 350 human infestations nationwide. Chiapas remains the hardest-hit state with 131 cases. This week authorities also confirmed the first human case in Nuevo León, while Mexico City recorded its initial case on May 27, 2026.

Both Mexico City and Nuevo León will host World Cup matches in 2026. Local health workers in these cities are already preparing extra outreach in markets and neighborhoods where families gather daily.

Three Import Suspensions in 18 Months Disrupt Cross-Border Trade

The United States has suspended cattle imports from Mexico three times in the past 18 months because of the advancing parasite. Each pause affects ejido members and small producers who sell calves across the border to support their families.

In states such as Coahuila and Chihuahua, ranchers who once moved animals freely now wait for clearer signals before planning sales. The uncertainty touches everyone from feed suppliers to truck drivers who move goods through the region.

USDA Official Expresses Confidence in Past Success

USDA official Dudley Hoskins stated, “The United States has defeated this pest before, and we will do it again.” His words echo the successful programs that eliminated the screwworm from the United States in the 1960s and Mexico in 1991.

Still, the agency estimates potential economic losses of $1.8 billion for Texas alone if the infestation spreads further. Those figures matter to Mexican producers whose animals cross the same supply chains.

Practical Steps Recommended by Mexico’s Health Ministry

The Health Ministry advises protective clothing and the use of authorized repellents when working with livestock or spending time outdoors. Community health centers in affected states are distributing simple guides in both Spanish and indigenous languages.

In Chiapas villages and Nuevo León colonias, teachers and local leaders are sharing these tips at tianguis and community meetings so families can act quickly if they notice unusual wounds on animals or people.

World Cup Host Cities Prepare for Millions of Visitors

With the first human case now confirmed in Mexico City and another in Nuevo León, health authorities in both World Cup host cities are reviewing hospital readiness. Millions of visitors are expected, and officials want clear information available at airports, stadiums, and popular tourist sites.

Ordinary residents in these cities hope the extra attention will also bring resources to neighborhoods that have already been dealing with the parasite for months.

Tags: New World screwworm, Texas border, Mexico health, Coahuila livestock, Chiapas cases, World Cup 2026, cattle trade, USDA response, rural communities

By Rosa Martinez, Staff Writer