A flesh-eating parasite has returned to Texas cattle for the first time in 60 years. Officials confirmed the discovery in a single calf near the US-Mexico border.
First US Case in 60 Years Detected in Texas
The New World screwworm poses a direct threat to livestock health. While the initial case remains isolated, the larvae feed on living tissue. This biological breach ends decades of stability for domestic producers. Experts are now monitoring the risk to wider herds and public health as the parasite re-emerges in the country.
A single calf near the US-Mexico border has tested positive for a flesh-eating parasite. The first confirmed case[3] of the New World screwworm appeared in Texas cattle recently. This discovery marks the first time the fly has been detected in Texas cattle since its large-scale eradication from the United States.
For over half a century, the United States remained free of this specific threat. The parasite, known scientifically as Cochliomyia hominivorax[5], re-emerged in the country after more than 50 years. This return ends a long period of stability for domestic livestock producers.
A parasite from the south
The fly is not a new arrival to the Western Hemisphere. It is native to South America[5]. While the species has been documented since 1858, its presence in the U.S. had been largely managed through decades of intensive control efforts.
This recent detection brings back a biological threat that many had assumed was gone for good. The larvae of the fly feed on the living tissue of animals. While the current detection is isolated, the return of such a specialized parasite changes the landscape for border-region ranching.
No other US cases are confirmed
Federal and state officials have not found the parasite elsewhere in the United States. The initial detection remains isolated to that single calf near the border. No other parts of the country have reported similar infestations since the Texas case surfaced.
Agriculture Secretary Brooke Rollins addressed the situation as a priority for monitoring. She noted that authorities are working to prevent a wider spread. The focus remains on the border region to stop the fly from moving inland.
The threat is growing south
The parasite is currently resurging in Latin America[6]. This trend makes the border a high-risk zone for new arrivals. As the fly populations grow in neighboring countries, the chance of another jump into Texas increases.
Border dynamics play a major role in how the fly travels. Trade and migration[3] have frequently driven similar infestations along the US-Mexico border over the last decade. Moving livestock and people across the line can accidentally carry the flies or their larvae into new territory.
Monitoring these movement patterns is the primary defense. If the fly hitches a ride on cattle shipments, the eradication success of the last 60 years could vanish. For ranchers, the risk is not just a single lost calf, but a permanent change in how they must manage their herds.
The threat to herds and humans
Screwworm larvae pose a direct threat to livestock production. The larvae feed on the living tissue of their hosts. This process can cause severe damage to animals. For ranchers, the cost of managing such an infestation could be high.
While the impact on animals is clear, the food supply remains safe. The fly's larvae do not infest food products[2]. You do not need to worry about meat or dairy being contaminated by the parasite. The risk stays with the living animal.
Human health is also at stake, though the danger is different. Infestations in people are rare. However, the parasite can cause severe illness if it is left untreated. It remains a flesh-eating threat to any living host.
History shows how these parasites can devastate local wildlife. In Florida, similar infestations have previously impacted the Key deer population. This serves as a reminder of the parasite's potential for destruction.
The risk to the food supply remains low because the larvae do not infest food products. For ranchers, the primary concern is the potential for a permanent change in herd management. The focus remains on the border region to stop the fly from moving inland.
