Flesh-Eating Screwworm Found Near US Border, How Dangerous Could in Be?

A devastating parasitic fly capable of killing livestock by feeding on living tissue has been detected in northern Mexico just 31 miles (50 km) from the US border, heightening concerns among American cattle producers and agricultural authorities. According to the US Department of Agriculture (USDA), the latest case of New World Screwworm was found in a six-month-old sheep in Mexico's Coahuila state, marking the closest confirmed detection to the United States during the current outbreak.

The discovery comes as US officials and livestock industry groups continue efforts to prevent the pest from crossing into the country. Experts warn that an outbreak in the United States could significantly disrupt cattle production, worsen already high beef prices and inflict billions of dollars in economic losses. American Doctor Among New Cases in Congo's Rare Ebola Outbreak.

Flesh-Eating Screwworm Found Near US Border

USDA data shows the infected sheep was identified in Coahuila, a Mexican state bordering Texas. The case represents the nearest confirmed detection of New World Screwworm to the United States since the parasite began spreading northward through Mexico.

The finding has intensified concerns among ranchers and cattle producers who have feared for more than a year that the pest could eventually enter the US livestock population despite ongoing containment efforts by both countries. The USDA and Mexico's Agriculture Ministry did not immediately respond to requests for comment following the latest detection. What Is Squirrel Fibromatosis? Everything To Know About Viral Skin Disease Behind 'Zombie Squirrels' in US.

Why the Parasite Is So Dangerous

New World Screwworm is considered one of the most destructive livestock pests due to the way it infects animals.

Female screwworm flies lay hundreds of eggs in open wounds on warm-blooded animals. Once the eggs hatch, the larvae burrow into living flesh using sharp, hooked mouthparts. As they feed, the wound expands and deepens, causing severe tissue damage. If infestations are left untreated, the parasite can ultimately kill its host. The fly can infect cattle, sheep, goats, wildlife, pets and other warm-blooded animals.

Potential Impact on US Beef Supply

Agricultural experts have warned that the arrival of New World Screwworm in the United States could place additional strain on an already tight cattle market.

The U.S. cattle herd is currently at its lowest level in 75 years, while beef prices have reached record highs. Any outbreak that affects livestock health or restricts cattle movements could further reduce supply and contribute to higher consumer prices.

Experts caution that more calves could be kept out of the U.S. cattle supply if the parasite spreads, creating additional pressure on beef production and processing operations.

The financial implications of a potential outbreak are substantial. According to a USDA estimate, a New World Screwworm outbreak could cause approximately USD 1.8 billion in economic damage to Texas alone. Texas is the largest cattle-producing state in the United States and plays a critical role in the country's beef industry.

Losses could stem from livestock deaths, veterinary treatment costs, movement restrictions, trade disruptions and reduced agricultural productivity.

In an effort to keep the parasite south of the border, Washington has blocked cattle imports from Mexico for more than a year. At the same time, USDA has invested millions of dollars in programs aimed at controlling the pest. One of the most effective methods involves breeding and releasing sterile male flies into affected regions. When sterile flies mate with wild females, reproduction declines and populations can eventually collapse.

Officials have invested in facilities designed to produce sterile flies on a large scale, though those facilities have not yet become operational.

The latest detection underscores the continuing challenge of containing New World Screwworm as it advances through northern Mexico. Agricultural authorities are closely monitoring the situation, with the livestock industry watching for any signs that the parasite could move closer to or cross the US border.

For now, containment efforts remain focused on preventing the pest from reaching American livestock, where experts say the consequences for the cattle industry and broader economy could be significant.

(The above story first appeared on LatestLY on May 30, 2026 09:04 AM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).